U.S. Department of Health and Human Services
U.S. Department of Housing and Urban Development
Suggested citation: Centers for Disease Control and Prevention and U.S. Department of Housing and Urban
Development. Healthy housing reference manual. Atlanta: US Department of Health and Human Services; 2006.
Use of trade names is for identification only and does not imply endorsement by the Centers for Disease Control and
Prevention, the Public Health Service, the U.S. Department of Health and Human Services, or the U.S. Department
of Housing and Urban Development.
Cover: Large photo by Teresa M. Sims; small photo by Don W. Johnson.
Updates to this manual will appear in the downloadable version available at
www.cdc.gov/healthyplaces/healthyhomes.htm.
Additional copies of this manual can be obtained by
downloading (HTML or PDF) from www.cdc.gov/healthyplaces/healthyhomes.htm
or
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Note that quantities of hard copies and CD-ROMs are limited.
Contents
List of Figures . . .
. . .7
List of Tables . . .
. . .11
Preface
.13
Acknowledgments . . .
. .15
Abbreviations and Acronyms
. . .17
Definitions
.19
Standards and Organizations
. . .23
Executive Summary . . .
.27
Chapter 1—Housing History and Purpose
Introduction . . .
.1-1
Preurban Housing . . .
. . .1-1
Ephemeral Dwellings . . .
. . .1-1
Episodic Dwellings
.1-1
Periodic Dwellings . . .
. .1-1
Seasonal Dwellings
.1-2
Semipermanent Dwellings . . .
. .1-2
Permanent Dwellings . . .
. . .1-2
Urbanization . . .
.1-2
Trends in Housing . . .
. . .1-3
References . . .
. . .1-7
Additional Sources of Information . . .
. . .1-7
Chapter 2—Basic Principles of Healthy Housing
Introduction . . .
.2-1
Fundamental Physiologic Needs . . .
. .2-1
Fundamental Psychologic Needs
.2-3
Protection Against Disease . . .
. . .2-3
Protection Against Injury . . .
.2-5
Protection Against Fire
. .2-6
Fire Extinguishers
. .2-9
Protection Against Toxic Gases . . .
. . .2-9
References . . .
. . .2-9
Additional Sources of Information . . .
. . .2-11
Chapter 3—Housing Regulations
Introduction . . .
.3-1
History . . .
. .3-1
Zoning, Housing Codes, and Building Codes . . .
.3-2
Zoning and Zoning Ordinances . . .
.3-3
Exceptions to the Zoning Code
.3-5
Housing Codes . . .
.3-6
Building Codes . . .
.3-12
References . . .
. . .3-12
Additional Sources of Information . . .
. . .3-13
Healthy Housing Reference Manual
1
Chapter 4—Disease Vectors and Pests
Introduction . . .
.4-1
Disease Vectors and Pests . . .
.4-1
Rodents
. . .4-1
Cockroaches
. . .4-4
Fleas . . .
. . .4-6
Flies
. . .4-7
Termites
. . .4-8
Fire Ants . . .
. . .4-13
Mosquitoes . . .
.4-15
References . . .
. . .4-17
Chapter 5—Indoor Air Pollutants and Toxic Materials
Introduction . . .
.5-1
Indoor Air Pollution
.5-1
Biologic Pollutants . . .
. .5-1
Chemical Pollutants
. . .5-6
Toxic Materials
. .5-13
Asbestos
. . .5-13
Lead . . .
. . .5-15
Arsenic
.5-19
References . . .
. . .5-20
Chapter 6—Housing Structure
Introduction . . .
.6-1
New Housing Terminology
.6-1
Old Housing Terminology . . .
. .6-6
Foundation . . .
. .6-8
Vapor Barriers . . .
. . .6-10
Crawl Space Barriers
. . .6-10
Vapor Barriers for Concrete Slab Homes
. . .6-10
Wall and Ceiling Vapors
. . .6-10
House Framing . . .
. .6-10
Foundation Sills
. . .6-10
Flooring Systems . . .
. . .6-10
Studs
. .6-11
Interior Walls
. .6-11
Stairways . . .
. . .6-12
Windows
. .6-12
Doors . . .
. .6-13
Roof Framing . . .
. . .6-15
Rafters
.6-15
Collar Beam
. . .6-15
Purlin . . .
. .6-15
Ridge Board
. . .6-15
Hip
. . .6-15
Roof Sheathing . . .
.6-15
Dormer
. . .6-15
2
Contents
Roofs
. . .6-15
Asphalt Shingle . . .
.6-15
EPDM . . .
.6-15
Asphalt Built-up Roofs
.6-16
Coal Tar Pitch Built-up Roofs
. .6-16
Slate Roofs
.6-16
Tile Roofs . . .
. .6-16
Copper Roofs . . .
. .6-16
Galvanized Iron Roofs . . .
. .6-16
Wood Shingle Roofs
. . .6-16
Roof Flashing
. .6-16
Gutters and Leaders . . .
.6-16
Exterior Walls and Trim . . .
. .6-16
Putting It All Together . . .
. . .6-17
References . . .
. . .6-21
Additional Sources of Information . . .
. . .6-22
Chapter 7—Environmental Barriers
Introduction . . .
.7-1
Roof
. . .7-2
Insulation . . .
. . .7-3
Siding . . .
. . .7-3
Fiber Cement . . .
. .7-4
Brick
. .7-4
Stucco
.7-4
Vinyl
. .7-5
Asbestos
. . .7-5
Metal . . .
. .7-5
References
. .7-6
Chapter 8—Rural Water Supplies and Water-quality Issues
Introduction . . .
.8-1
Water Sources . . .
. . .8-1
Source Location
.8-2
Well Construction . . .
. . .8-3
Sanitary Design and Construction
. .8-4
Pump Selection . . .
.8-4
Dug and Drilled Wells . . .
. . .8-4
Springs
.8-6
Cisterns
. . .8-6
Disinfection of Water Supplies . . .
. . .8-7
Chlorine Carrier Solutions . . .
. .8-9
Routine Water Chlorination (Simple) . . .
. . .8-9
Well Water Shock Chlorination . . .
.8-9
Backflow, Back-siphonage, and Other Water Quality Problems
. . .8-9
Backflow . . .
. . .8-9
Back-siphonage . . .
.8-10
Other Water Quality Problems . . .
. .8-10
Healthy Housing Reference Manual
3
Protecting the Groundwater Supply . . .
. .8-10
References . . .
. . .8-11
Additional Sources of Information . . .
. . .8-12
Chapter 9—Plumbing
Introduction . . .
.9-1
Elements of a Plumbing System . . .
. .9-1
Water Service
. .9-1
Hot and Cold Water Main Lines . . .
. . .9-3
Water Heaters . . .
. .9-7
Drainage System . . .
. . .9-8
Corrosion Control . . .
. . .9-13
Water Conservation . . .
. .9-13
Putting It All Together . . .
. . .9-14
References . . .
. . .9-15
Additional Sources of Information . . .
. . .9-16
Chapter 10—On-site Wastewater Treatment
Introduction
. . .10-1
Treatment of Human Waste . . .
.10-1
On-site Wastewater Treatment Systems . . .
. .10-3
Septic Tank Systems
. .10-3
Alternative Septic Tank Systems . . .
. . .10-6
Maintaining the On-site Wastewater Treatment Systems
.10-8
Symptoms of Septic System Problems . . .
. .10-9
Septic Tank Inspection . . .
.10-9
References . . .
. .10-11
Additional Sources of Information
. .10-12
Chapter 11—Electricity
Introduction
. . .11-1
Flow of Electric Current
. . .11-2
Electric Service Entrance
. . .11-3
Service Drop . . .
. .11-3
Underground Service . . .
. .11-4
Electric Meter
.11-4
Grounding
.11-4
Two- or Three-wire Electric Services . . .
.11-6
Residential Wiring Adequacy . . .
. . .11-6
Wire Sizes and Types . . .
. . .11-7
Reducing Risk . . .
.11-7
Wire Sizes . . .
.11-7
Wire Types
. . .11-8
Types of Cable
.11-8
Flexible Cords . . .
. .11-9
The Problem . . .
. .11-9
The Standards . . .
.11-9
4
Contents
Safety Suggestions
.11-9
Wiring
.11-10
Open Wiring
.11-10
Concealed Knob and Tube Wiring . . .
.11-10
Electric Service Panel . . .
. . .11-10
Over-Current Devices
. .11-10
Circuit Breakers (Fuseless Service Panels)
. .11-11
Ground Fault Circuit Interrupters
.11-11
Arc-fault Circuit Interrupters . . .
. .11-12
Fused Ampere Service Panel (Fuse Box)
. . .11-12
Electric Circuits . . .
.11-13
Outlet Switches and Junction Boxes . . .
. . .11-13
Grounding Outlets
. . .11-13
Polarized Plugs and Connectors
. . .11-14
Common Electrical Violations . . .
. .11-14
Excessive or Faulty Fusing
.11-15
Cords Run Through Walls or Doorways and Hanging Cords or Wires . . .
. .11-15
Temporary Wiring . . .
.11-16
Excessively Long Extension Cords
.11-16
Dead or Dummy Outlets . . .
. .11-16
Aluminum Wiring Inside the Home . . .
. . .11-16
Inspection Steps
. . .11-16
References . . .
. .11-17
Additional Sources of Information
. .11-17
Chapter 12—Heating, Air Conditioning, and Ventilating
Introduction
. . .12-1
Heating . . .
.12-4
Standard Fuels . . .
.12-4
Central Heating Units . . .
.12-7
Space Heaters
.12-12
Hydronic Systems . . .
.12-14
Direct Vent Wall Furnaces . . .
.12-15
Cooling
. . .12-15
Air Conditioning . . .
. .12-15
Circulation Fans
. .12-16
Evaporation Coolers
. .12-16
Safety
. .12-17
Chimneys . . .
.12-17
Fireplaces
.12-18
References . . .
. .12-19
Additional Sources of Information
. .12-19
Chapter 13—Energy Efficiency
Introduction
. . .13-1
Energy Systems . . .
.13-1
R-values
. . .13-1
Healthy Housing Reference Manual
5
Roofs
. .13-2
Ridge Vents . . .
. .13-3
Fan-powered Attic Ventilation
. .13-3
White Roof Surface . . .
. .13-3
Insulation
. .13-3
Wall Insulation
. .13-4
Floor Insulation . . .
. .13-4
Doors . . .
. .13-5
Hot Water Systems
. .13-7
Windows
. .13-7
Caulking and Weather-stripping . . .
. .13-7
Replacing Window Frames . . .
. .13-7
Tinted Windows . . .
. .13-8
Reducing Heat Loss and Condensation
. .13-8
Glazing . . .
. .13-8
Layering
. .13-8
Other Options
. .13-9
Solar Energy
. .13-9
Active Solar Systems
. .13-9
Passive Solar Systems . . .
. .13-10
Conducting an Energy Audit . . .
. .13-10
References . . .
. .13-11
Additional Sources of Information
. .13-11
Chapter 14—Residential Swimming Pools and Spas
Introduction
. .14-1
Child-proofing
. .14-1
Hazards
. .14-2
Public Health Issues . . .
. .14-2
Diseases
. .14-3
Injuries
. .14-3
Water Testing Equipment
. .14-3
Disinfection
. .14-4
Content Turnover Rate
. .14-4
Filters
. .14-5
High-rate Sand Filters
. .14-5
Cartridge Filters
. .14-5
Diatomaceous Earth
. .14-5
Filter Loading Rates . . .
. .14-5
Disinfectants . . .
. .14-5
Effect of pH
. .14-6
Chlorine Disinfectants . . .
. .14-6
Pool Water Hardness and Alkalinity . . .
. .14-8
Liquid Chemical Feeders . . .
. .14-9
Positive Displacement Pump
. .14-9
Erosion and Flow-through Disinfectant Feeders
. . .14-10
Spas and Hot Tubs
.14-10
References . . .
. .14-11
Additional Sources of Information
. .14-11
6
Contents
List of Figures
Chapter 1—Housing History and Purpose
Figure 1.1.
Conditions in the Tenements
.1-3
Figure 1.2.
Levittown, New York
.1-6
Chapter 2—Basic Principles of Healthy Housing
Figure 2.1.
Circa 1890 Icebox
. . .2-5
Figure 2.2.
Smoke Alarm Testing
.2-8
Chapter 3—Housing Regulations
Figure 3.1.
Example of a Floor Area
. .3-5
Figure 3.2.
Example of an Angle of Light Obstruction . . .
.3-5
Chapter 4—Disease Vectors and Pests
Figure 4.1.
Field Identification of Domestic Rodents . . .
. .4-2
Figure 4.2.
Norway Rat . . .
. .4-2
Figure 4.3.
Roof Rat
.4-2
Figure 4.4.
Signs of Rodent Infestation . . .
. . .4-3
Figure 4.5.
Rodent Prevention
. . .4-4
Figure 4.6.
Live Trap for Rats . . .
.4-4
Figure 4.7.
Kill Traps . . .
.4-4
Figure 4.8.
American, Oriental, German, and Brown-banded Cockroaches . . .
.4-5
Figure 4.9.
American Cockroaches, Various Stages and Ages
. .4-5
Figure 4.10.
Oriental Cockroaches, Various Stages and Ages
. . .4-5
Figure 4.11.
German Cockroaches, Various Stages and Ages
. . .4-5
Figure 4.12.
Brown-banded Cockroaches, Various Stages and Ages
.4-5
Figure 4.13.
Wood Cockroach, Adult Male . . .
.4-5
Figure 4.14.
Reported Human Plague Cases (1970-1997) . . .
. .4-6
Figure 4.15.
Flea Life Cycle
. . .4-6
Figure 4.16.
Housefly (Musca domestica) . . .
. . .4-7
Figure 4.17.
Life Cycle of the Fly
. .4-8
Figure 4.18.
Termite Tube Extending From Ground to Wall
. . .4-9
Figure 4.19.
Termite Mud Shelter Tube Constructed Over A Brick Foundation
.4-9
Figure 4.20.
Differences Between Ants and Termites
. . .4-9
Figure 4.21.
Life Cycle of the Subterranean Termite
. . .4-10
Figure 4.22.
Subterranean Termite Risk in the United States
. . .4-11
Figure 4.23.
Typical Points of Attack by Termites in the Home
.4-12
Figure 4.24.
Construction Techniques That Discourage Termite Attacks . . .
.4-14
Figure 4.25.
Fire Ants
.4-14
Figure 4.26.
Range Expansion of Red Imported Fire Ants (RIFA) in the United States, 1918-1998
.4-15
Figure 4.27.
Fire Ant Mound . . .
. .4-15
Chapter 5—Indoor Air Pollutants and Toxic Materials
Figure 5.1.
Mold Growth in the Home . . .
. . .5-7
Figure 5.2.
Home Carbon Monoxide Monitor
. . .5-7
Figure 5.3.
Environmental Tobacco Smoke and Children’s Exposure . . .
. . .5-8
Figure 5.4.
Wood Products Label . . .
.5-10
Figure 5.5.
EPA Map of Radon Zones
. . .5-10
Figure 5.6.
Radon Entry
.5-11
Figure 5.7.
Home Radon Detectors
. .5-12
Healthy Housing Reference Manual
7
Figure 5.9.
Radon-resistant Construction . . .
.5-12
Figure 5.10. Arsenic Label. . .
.5-19
Chapter 6—Housing Structure
Figure 6.1.
Housing Structure Terminology, Typical House Built Today
. .6-1
Figure 6.2.
Housing Structure Terminology, Typical House Built Between 1950 and 1980 . . .
.6-6
Figure 6.3.
Foundation. . .
.6-9
Figure 6.4.
Foundation Cracks
. .6-9
Figure 6.5.
Interior Stairway
.6-12
Figure 6.6.
Classifications of Windows
. .6-12
Figure 6.7.
Three-dimensional View of a Window . . .
. . .6-13
Figure 6.8.
Window Details
.6-13
Figure 6.9.
Wall Framing. . .
.6-17
Chapter 7—Environmental Barriers
Figure 7.1.
Sources of Moisture and Air Pollutants . . .
. . .7-1
Figure 7.2.
Blown Attic Insulation . . .
. . .7-3
Figure 7.3.
Depth of Attic Insulation . . .
.7-3
Figure 7.4.
Attic Insulation . . .
. .7-3
Figure 7.5.
Brick Structural Defect
. .7-4
Figure 7.6.
Corrosion in Piping Resulting From Galvanic Response
. .7-5
Chapter 8—Rural Water Supplies
Figure 8.1.
U.S. Water Supply by Source . . .
.8-1
Figure 8.2.
Cross Section of a Driven Well . . .
. . .8-3
Figure 8.3.
Well Seal . . .
. .8-4
Figure 8.4.
Converted Dug Well . . .
.8-4
Figure 8.5.
Recapped and Sealed Dug Well
. .8-5
Figure 8.6.
Drilled Well. . .
.8-5
Figure 8.7.
Typical Dug Well
. . .8-5
Figure 8.8.
Sewage in Drainage Ditch . . .
. . .8-6
Figure 8.9.
Drilled Well. . .
.8-6
Figure 8.10. Spring Box. . .
. .8-6
Chapter 9—Plumbing
Figure 9.1.
Typical Home Water System
.9-1
Figure 9.2.
House Service Installation
. . .9-2
Figure 9.3.
Gas Water Heater
. . .9-7
Figure 9.4.
Temperature-pressure Valve
. .9-8
Figure 9.5.
Branch Connections
.9-10
Figure 9.6.
P-trap. . .
. . .9-10
Figure 9.7.
Types of S-traps . . .
. .9-10
Figure 9.8.
Trap Seal: (a) Seal Intact; (b) Fixture Draining; (c) Loss of Gas Seal . . .
. . .9-10
Figure 9.9.
Loss of Trap Seal in Lavatory Sink
. . .9-11
Figure 9.10. Back-to-back Venting (Toilet). . .
.9-11
Figure 9.11. Back-to-back Venting (Sink). . .
. .9-11
Figure 9.12. Wall-hung Fixtures
. .9-12
Figure 9.13. Unit Vent Used in Bathtub Installation
. .9-12
Figure 9.14. Toilet Venting. . .
. . .9-12
Figure 9.15. Janitor’s Sink. . .
.9-13
Figure 9.16. Common Y-trap. . .
. .9-13
Figure 9.17. Hose Bib With Vacuum Breaker
.9-13
8
List of Figures
Chapter 10—On-site Wastewater Treatment
Figure 10.1. Conventional On-site Septic System . . .
.10-1
Figure 10.2. Straight Pipe Discharge. . .
. .10-2
Figure 10.3. Clear Creek Water Contaminated With Sewage. . .
. .10-2
Figure 10.4. Septic Tank System
.10-3
Figure 10.5. Septic Tank. . .
. .10-4
Figure 10.6. On-site Sewage Disposal System Site Evaluation Form
. .10-5
Figure 10.7. Cross-section of an Absorption Field
. . .10-5
Figure 10.8. Mound System Cutaway
. . .10-7
Figure 10.9. Low Pressure On-site System . . .
. . .10-7
Figure 10.10. Plant-rock Filter System . . .
.10-8
Figure 10.11. Sludge and Scum in Multicompartment Septic Tank . . .
.10-10
Chapter 11—Electricity
Figure 11.1. Utility Overview
. . .11-3
Figure 11.2. Entrance Head. . .
. .11-3
Figure 11.3. Armored Cable Service Entrance
. . .11-4
Figure 11.4. Breakers. . .
.11-4
Figure 11.5. Thin-wall Conduit
.11-4
Figure 11.6. Electric Meter. . .
. . .11-5
Figure 11.7. Typical Service Entrance
. . .11-5
Figure 11.8. Grounding Scheme . . .
.11-6
Figure 11.9. Grounding. . .
.11-6
Figure 11.10. Three-wire Service . . .
. .11-7
Figure 11.11. Two-wire Service . . .
. . .11-7
Figure 11.12. Wire Markings. . .
. .11-8
Figure 11.13. Armored Cable.
. . .11-9
Figure 11.14.
200-Amp Service Box. . .
. . .11-11
Figure 11.15. External Power Shutoff and Meter
. .11-11
Figure 11.16. Ground Fault Circuit Interruptor . . .
. . .11-12
Figure 11.17. Arc Interrupter
.11-12
Figure 11.18. Types of Fuses. .
. . .11-13
Figure 11.19. Appliance Ground and Grounded Plug
.11-14
Chapter 12—Heating, Air Conditioning, and Ventilating
Figure 12.1. Heat Pump in Cooling Mode . . .
. . .12-5
Figure 12.2. Piping Hookup for Inside Tank Installation
.12-6
Figure 12.3. Piping Hookup for Buried Outside Tank
. . .12-6
Figure 12.4. Minimum Clearance for Pipeless Hot Air and Gravity Warm Air Furnace
. . .12-7
Figure 12.5.
Minimum Clearance for Steam or Hot Water Boiler and Mechanical Warm-air Furnace .12-7
Figure 12.6. Heating Ducts Covered With Asbestos Insulation . . .
. . .12-7
Figure 12.7. Typical Underfeed Coal Stoker Installation in Small Boilers . . .
. .12-8
Figure 12.8. Cutaway View of Typical High-pressure Gun Burner . . .
.12-9
Figure 12.9. Gas-fired Boiler . . .
.12-9
Figure 12.10. Typical Gravity One-pipe Heating System
. .12-10
Figure 12.11. One-pipe Gravity Water Heating System
. . .12-11
Figure 12.12. Two-pipe Gravity Water Heating System
. . .12-11
Figure 12.13. Warm-air Convection Furnace . . .
. .12-11
Figure 12.14. Cross-sectional View of Building Showing Forced-warm-air Heating System
.12-12
Figure 12.15. Perforated-sleeve Burner . . .
.12-13
Figure 12.16. Condition of Burner Flame With Different Rates of Fuel Flow
. .12-13
Figure 12.17. Wall and Ceiling Clearance Reduction . . .
. .12-14
Healthy Housing Reference Manual
9
Figure 12.18. Draft in Relation to Height of Chimney . . .
.12-14
Figure 12.19. Location and Operation of Typical Backdraft Diverter
. .12-15
Figure 12.20. Split-system Air Conditioner
. . .12-16
Figure 12.21. External Air-conditioning Condenser Unit . . .
. .12-16
Figure 12.22. Chimney Plan . . .
. .12-17
Figure 12.23. Fireplace Construction . . .
. .12-18
Chapter 13—Energy Efficiency
Figure 13.1. Roof Components . . .
. .13-3
Figure 13.2. Potential Effects of Radiant Barriers
.13-4
Figure 13.3. Common Floor Insulation Flaws
. . .13-5
Figure 13.4. Insulation Cavity Fill . . .
. . .13-6
Figure 13.5. Solar Panels . . .
.13-9
Chapter 14—Residential Swimming Pools and Spas
Figure 14.1. Pool Cover
.14-2
Figure 14.2. Typical Home Pool Equipment System . . .
. .14-5
10
List of Figures
List of Tables
Chapter 8—Rural Water Supplies and Water-quality Issues
Table 8.1.
Recommended Minimum Distance Between Well and Pollution Sources . . .
. .8-2
Table 8.2.
Types of Wells for Accessing Groundwater, Well Depths, and Diameters
. .8-3
Table 8.3.
Disinfection Methods
. . .8-7
Table 8.4.
Chlorination Guide for Specific Water Conditions
. . .8-8
Table 8.5.
Preparing a 200-ppm Chlorine Solution . . .
. .8-9
Table 8.6.
Analyzing and Correcting Water Quality Problems . . .
. . .8-11
Chapter 9—Plumbing
Table 9.1.
Fixture Unit Values
. .9-9
Table 9.2.
Sanitary House Drain Sizes
. .9-9
Table 9.3.
Minimum Fixture Service Pipe Diameters
. . .9-12
Chapter 10—On-site Wastewater Treatment
Table 10.1.
Mound System Advantages and Disadvantages
. .10-6
Table 10.2.
Low-pressure Pipe Systems Advantages and Disadvantages . . .
. . .10-7
Table 10.3.
Plant Rock Filter System Advantages and Disadvantages
.10-8
Table 10.4.
Septic Tank System Troubleshooting . . .
.10-10
Chapter 13—Energy Efficiency
Table 13.1.
Cost-effective Insulation R-values for Existing Homes . . .
. . .13-2
Table 13.2.
R-values of Roof Components . . .
. .13-3
Table 13.3.
Floor Insulation . . .
.13-5
Chapter 14—Residential Swimming Pools and Spas
Table 14.1.
Pool Water Quality Problem Solving
. . .14-7
Table 14.2.
pH Effect on Chlorine Disinfection . . .
.14-8
Table 14.3.
Chlorine Use in Swimming Pools . . .
. . .14-8
Table 14.4.
Swimming Pool Operating Parameters
. .14-9
Table 14.5.
Spa and Hot Tub Operating Parameters
.14-11
Healthy Housing Reference Manual
11
12
List of Tables
Preface
ousing quality is key to the public’s health. Translating that simple axiom into action is the topic of this book.
In the 30 years since the first edition was published, the nation’s understanding of how specific housing con-
H
ditions are related to disease and injury has matured and deepened. This new edition will enable public health
and housing professionals to grasp our shared responsibility to ensure that our housing stock is safe, decent, afford-
able, and healthy for our citizens, especially those who are particularly vulnerable and who spend more time in the
home, such as children and the elderly.
The Centers for Disease Control and Prevention and the U.S. Department of Housing and Urban Development
(HUD) have worked together with many others to discover the ways to eliminate substandard housing conditions that
harm health. For example, the advances in combating water borne diseases was possible, in part, through standardiza-
tion of indoor plumbing and sewage, and the institution of federal, state and local regulations and codes. Childhood
lead poisoning has been dramatically reduced, in part, through the elimination of residential lead-based paint hazards.
Other advances have been made to protect people from carbon monoxide poisoning, falls, safety hazards, electrocu-
tion, and many other risks.
However, more must be done to control existing conditions and to understand emerging threats that remain poorly
understood. For example, nearly 18 million Americans live with the health threat of contaminated drinking water
supplies, especially in rural areas where on-site wastewater systems are prevalent. Despite progress, thousands of chil-
dren still face the threat of lead poisoning from residential lead paint hazards. The increase in asthma in recent
decades and its relationship to housing conditions such as excess moisture, mold, settled dust allergens and ventilation
remains the subject of intense research. The impact of energy conservation measures on the home environment is still
unfolding. Simple affordable construction techniques and materials that minimize moisture problems and indoor air
pollution, improve ventilation, and promote durability and efficiency continue to be uncovered.
A properly constructed and maintained home is nearly timeless in its usefulness. A home is often the biggest single
investment people make. This manual will help to ensure that the investment is a sound one that promotes healthy
and safe living.
Home rehabilitation has increased significantly in the last few years and HUD has prepared a nine-part series, The
Rehab Guide, that can assist both residents and contractors in the rehabilitation process. For additional information,
go to http://www.huduser.org/publications/destech/rehabgui.html.
Healthy Housing Reference Manual
13
14
Preface
Acknowledgments
e acknowledge the suggestions, assistance, and review of numerous individuals and organizations that went
into the original and current versions of this manual. The revisions to this manual were made by a team of
W
environmental health, housing, and public health professionals led by Professor Joe Beck, Dr. Darryl
Barnett, Dr. Gary Brown, Dr. Carolyn Harvey, Professor Worley Johnson, Dr. Steve Konkel, and Professor Charles
Treser.
Individuals from the following organizations were involved in the various drafts of this manual:
• Department of Housing and Urban Development (HUD), Office of Healthy Homes and Lead Hazard
Control;
• U.S. Department of Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC),
National Center for Environmental Health (NCEH);
• National Healthy Homes Training Center and Network;
• National Association of Housing and Redevelopment Officials;
• Department of Building, Housing and Zoning (Allentown, Pennsylvania);
• Code Enforcement Associates (East Orange, New Jersey);
• Eastern Kentucky University (Richmond, Kentucky);
• University of Washington; Seattle (Washington); and
• Battelle Memorial Institute (Columbus, Ohio).
Specifically, our gratitude goes to the following reviewers:
• Dr. David Jacobs, Martin Nee, and Dr. Peter Ashley, HUD;
• Pat Bohan, East Central University;
• James Larue, The House Mender Inc.;
• Ellen Tohn, ERT Associates;
• Dr. Stephen Margolis, Emory University; and
• Joseph Ponessa and Rebecca Morley, Healthy Homes Training Center.
A special thank-you for assistance from Carolyn Case-Compton, Habitat for Humanity, 123 East Main Street,
Morehead, Kentucky. Pictures of a home under construction are courtesy of Habitat for Humanity and John King,
home builder and instructor, Rowan County Technical College, Morehead, Kentucky; and Don W. Johnson, building
photographer of Habitat for Humanity.
In addition, a special thank you to CAPT Craig Shepherd and CAPT Michael Herring, Commissioned Corps, U.S.
Public Health Service, CDC/NCEH/Environmental Health Services Branch for their research and review during the
editing of this manual. Special thanks to Pamela S. Wigington and Joey L. Johnson for their hard work preparing this
manual for publication and to Teresa M. Sims for Web publication.
Healthy Housing Reference Manual
15
16
Acknowledgments
Abbreviations and Acronyms
ABS
acrylonitrile-butadiene-styrene
ADA
Americans with Disabilities Act
AGA
American Gas Association
ALA
American Lung Association
ANSI
American National Standards Institute
APHA
American Public Health Association
ASME
American Society of Mechanical Engineers
ASSE
American Society of Structural Engineers
ASTM
American Society for Testing Materials
ATSDR
Agency for Toxic Substances and Disease Registry
AWG
American Wire Gauge
AWWA
American Waters Works Association
BTU
British thermal unit
CDC
Centers for Disease Control and Prevention
CFR
Code of Federal Regulations
CGA
Canadian Gas Association
CO
carbon monoxide
CPR
cardiopulmonary resuscitation
CPSC
Consumer Product Safety Commission
CSIA
Chimney Safety Institute of America
DDT
dichlorodiphenyltrichlorethane
DE
diatomaceous earth
DPD
N,N-diethyl-p-phenylene diamine
DWV
drain, waste, and vent
EIFS
exterior insulation and finish system
EPA
U.S. Environmental Protection Agency
EPDM
ethylene propylene dieneterpolymer
ETS
environmental tobacco smoke
FHA
Federal Housing Administration
FM
Factory Mutual
GFCI
ground fault circuit interrupter
HEPA
high-efficiency particulate air
HHS
Health and Human Services, U.S. Department of
HSC
Home Safety Council
HUD
Housing and Urban Development, U.S. Department of
HVAC
heating, ventilating and air conditioning
IAPMO
International Association of Plumbing and Mechanical Officials
ICC
International Code Council
IPM
integrated pest management
ISO
International Standard Organization
kg
kilogram
LPP
low-pressure pipe
MPMH
Military Pest Management Handbook
MSS
Mechanical Standardization Society of the Valve and Fitting Industry
NCEH
National Center for Environmental Health
NCI
National Cancer Institute
NIA
National Institute on Aging
NSF
National Science Foundation
NTU
nephelometric turbidity unit
Healthy Housing Reference Manual
17
ODTS
organic dust toxic syndrome
OSHA
Occupational Safety and Health Administration
PEX
cross-formulated polyethylene
POTW
publicly owned treatment works
ppm
parts per million
psi
pound per square inch
PVC
polyvinyl chloride
PW
potable water
RIFA
red imported fire ant
SDWA
Safe Drinking Water Act
SEER
seasonal energy efficiency ratio
T&P
temperature-pressure
TSP
trisodium phosphate
UF
urea-formaldehyde
UL
Underwriters Laboratories
USCB
U.S. Census Bureau
USDA
U.S. Department of Agriculture
USFA
U.S. Fire Administration
USGS
U.S. Geological Survey
USHA
United States Housing Authority
VA
Veteran’s Administration
VOC
volatile organic compound
XRF
X-ray fluorescence
18
Abbreviations and Acronyms
Definitions
Accessory building or structure: a detached building or structure in a secondary or subordinate capacity from the
main or principal building or structure on the same premises.
Appropriate authority/Authority having jurisdiction (AHJ): a person within the governmental structure of the
corporate unit who is charged with the administration of the appropriate code.
Ashes: the residue from burning combustible materials.
Attic: any story or floor of a building situated wholly or partly within the roof, and so designed, arranged, or built to
be used for business, storage, or habitation.
Basement: the lowest story of a building, below the main floor and wholly or partially lower than the surface of the ground.
Building: a fixed construction with walls, foundation, and roof, such as a house, factory, or garage.
Bulk container: any metal garbage, rubbish, or refuse container having a capacity of 2 cubic yards or greater and which is
equipped with fittings for hydraulic or mechanical emptying, unloading, or removal.
Central heating system: a single system supplying heat to one or more dwelling unit(s) or more than one rooming unit.
Chimney: a vertical masonry shaft of reinforced concrete, or other approved noncombustible, heat-resisting material
enclosing one or more flues, for the purpose of removing products of combustion from solid, liquid, or gaseous fuel.
Dilapidated: in a state of disrepair or ruin and no longer adequate for the purpose or use for which it was originally intended.
Dormitory: a building or a group of rooms in a building used for institutional living and sleeping purposes by four or
more persons.
Dwelling: any enclosed space wholly or partly used or intended to be used for living, sleeping, cooking, and eating.
(Temporary housing, as hereinafter defined, shall not be classified as a dwelling.) Industrialized housing and modular
construction that conform to nationally accepted industry standards and are used or intended for use for living,
sleeping, cooking, and eating purposes shall be classified as dwellings.
Dwelling unit: a room or group of rooms located within a dwelling forming a single habitable unit with facilities used
or intended to be used by a single family for living, sleeping, cooking, and eating.
Egress: arrangements and openings to assure a safe means of exit from buildings.
Extermination: the control and elimination of insects, rodents, or other pests by eliminating their harborage places;
by removing or making inaccessible materials that may serve as their food; by poisoning, spraying, fumigating,
trapping, or any other recognized and legal pest elimination methods approved by the local or state authority having
such administrative authority. Extermination is one of the components of integrated pest management.
Fair market value: a price at which both buyers and sellers will do business.
Family: one or more individuals living together and sharing common living, sleeping, cooking, and eating facilities
(See also Household).
Healthy Housing Reference Manual
19
Flush toilet: a toilet bowl that can be flushed with water supplied under pressure and that is equipped with a water-
sealed trap above the floor level.
Garbage: animal and vegetable waste resulting from handling, preparation, cooking, serving, and nonconsumption of food.
Grade: the finished ground level adjacent to a required window.
Guest: an individual who shares a dwelling unit in a nonpermanent status for not more than 30 days.
Habitable room: a room or enclosed floor space used or intended to be used for living, sleeping, cooking or eating
purposes, excluding bathrooms, laundries, furnace rooms, pantries, kitchenettes and utility rooms of less than
50 square feet of floor space, foyers, or communicating corridors, stairways, closets, storage spaces, workshops, and hobby
and recreation areas.
Health officer: the legally designated health authority of the jurisdiction or that person’s authorized representative.
Heated water: water heated to a temperature of not less than 120°F-130°F (49°C-54°C) at the outlet.
Heating device: all furnaces, unit heaters, domestic incinerators, cooking and heating stoves and ranges, and other similar devices.
Household: one or more individuals living together in a single dwelling unit and sharing common living, sleeping,
cooking, and eating facilities (see also Family).
Infestation: the presence within or around a dwelling of any insects, rodents, or other pests.
Integrated pest management: a coordinated approach to managing roaches, rodents, mosquitoes, and other pests that
combines inspection, monitoring, treatment, and evaluation, with special emphasis on the decreased use of toxic agents.
Kitchen: any room used for the storage and preparation of foods and containing the following equipment: sink or
other device for dishwashing, stove or other device for cooking, refrigerator or other device for cold storage of food,
cabinets or shelves for storage of equipment and utensils, and counter or table for food preparation.
Kitchenette: a small kitchen or an alcove containing cooking facilities.
Lead-based paint: any paint or coating with lead content equal to or greater than 1 milligram per square centimeter,
or 0.5% by weight.
Multiple dwelling: any dwelling containing more than two dwelling units.
Occupant: any individual, over 1 year of age, living, sleeping, cooking, or eating in or having possession of a dwelling
unit or a rooming unit; except that in dwelling units a guest shall not be considered an occupant.
Operator: any person who has charge, care, control or management of a building, or part thereof, in which dwelling
units or rooming units are let.
Ordinary summer conditions: a temperature 10°F (-12°C) below the highest recorded temperature in the locality for
the prior 10-year period.
Ordinary winter conditions: mean a temperature 15°F (-9.4°C) above the lowest recorded temperature in the locality
for the prior 10-year period.
20
Definitions
Owner: any person who alone, jointly, or severally with others (a) shall have legal title to any premises, dwelling, or
dwelling unit, with or without accompanying actual possession thereof, or (b) shall have charge, care or control of any
premises, dwelling, or dwelling unit, as owner or agent of the owner, or as executor, administrator, trustee, or guardian
of the estate of the owner.
Permissible occupancy: the maximum number of individuals permitted to reside in a dwelling unit, rooming unit, or dormitory.
Person: any individual, firm, corporation, association, partnership, cooperative, or government agency.
Plumbing: all of the following supplied facilities and equipment: gas pipes, gas burning equipment, water pipes,
garbage disposal units, waste pipes, toilets, sinks, installed dishwashers, bathtubs, shower baths, installed clothes
washing machines, catch basins, drains, vents, and similarly supplied fixtures, and the installation thereof, together with all
connections to water, sewer, or gas lines.
Privacy: the existence of conditions which will permit an individual or individuals to carry out an activity commenced
without interruption or interference, either by sight or sound by unwanted individuals.
Rat harborage: any conditions or place where rats can live, nest or seek shelter.
Ratproofing: a form of construction that will prevent the entry or exit of rats to or from a given space or building, or
from gaining access to food, water, or harborage. It consists of the closing and keeping closed of every opening in
foundations, basements, cellars, exterior and interior walls, ground or first floors, roofs, sidewalk gratings, sidewalk
openings, and other places that may be reached and entered by rats by climbing, burrowing, or other methods, by the
use of materials impervious to rat gnawing and other methods approved by the appropriate authority.
Refuse: leftover and discarded organic and nonorganic solids (except body wastes), including garbage, rubbish, ashes, and dead animals.
Refuse container: a watertight container that is constructed of metal, or other durable material impervious to rodents,
that is capable of being serviced without creating unsanitary conditions, or such other containers as have been
approved by the appropriate authority (see also Appropriate Authority). Openings into the container, such as covers and
doors, shall be tight fitting.
Rooming house: any dwelling other than a hotel or motel or that part of any dwelling containing one or more
rooming units, or one or more dormitory rooms, and in which persons either individually or as families are housed with or
without meals being provided.
Rooming unit: any room or group of rooms forming a single habitable unit used or intended to be used for living
and sleeping, but not for cooking purposes.
Rubbish: nonputrescible solid wastes (excluding ashes) consisting of either: (a) combustible wastes such as paper,
cardboard, plastic containers, yard clippings and wood; or (b) noncombustible wastes such as cans, glass, and crockery.
Safety: the condition of being reasonably free from danger and hazards that may cause accidents or disease.
Space heater: a self-contained heating appliance of either the convection type or the radiant type and intended
primarily to heat only a limited space or area such as one room or two adjoining rooms.
Supplied: paid for, furnished by, provided by, or under the control of the owner, operator or agent.
System: the dynamic interrelationship of components designed to enact a vision.
Healthy Housing Reference Manual
21
Systems theory: The concept proposed to promote the dynamic interrelationship of activities designed to accomplish
a unified system.
Temporary housing: any tent, trailer, mobile home, or other structure used for human shelter that is designed to be
transportable and which is not attached to the ground, to another structure, or to any utility system on the same premises for
more than 30 consecutive days.
Toxic substance: any chemical product applied on the surface of or incorporated into any structural or decorative
material, or any other chemical, biologic, or physical agent in the home environment or its immediate surroundings,
which constitutes a potential hazard to human health at acute or chronic exposure levels.
Variance: a difference between that which is required or specified and that which is permitted.
22
Definitions
Standards and Organizations
In addition to the standards and organizations listed in this section, the U.S. Justice Department enforces the
requirements of the Americans with Disabilities Act (ADA) (http://www.ada.gov) and assures that products fully
comply with the provisions of the act to ensure equal access for physically challenged users.
ABPA
The American Backflow Prevention Association, http://abpa.org
Develops cross-connections; ABPA is an organization whose members have a common interest in
protecting drinking water from contamination.
ACI
American Concrete Institute, http://www.concrete.org/general/home.asp
Has produced more than 400 technical documents, reports, guides, specifications, and codes for the best use of
concrete. ACI conducts more than 125 educational seminars each year and has 13 certification programs
for concrete practitioners, as well as a scholarship program to promote careers in the industry.
AGA
American Gas Association, http://www.aga.org
Develops standards, tests, and qualifies products used in gas lines and gas appliance installations.
AGC
Associated General Contractors of America, http://www.agc.org
Is dedicated to improving the construction industry by educating the industry to employ the finest skills,
promoting use of the latest technology and advocating building the best quality projects for owners—
public and private.
AMSA
Association of Metropolitan Sewerage Agencies, http://www.amsa-cleanwater.org
Represents the interests of the country’s wastewater treatment agencies.
ANSI
American National Standards Institute, http://www.ansi.org
Coordinates work among U.S. standards writing groups. Works in conjunction with other groups such as
ISO, ASME, and ASTM.
ARI
Air-Conditioning and Refrigeration Institute, http://www.ari.org
Provides information about the 21st Century Research (21-CR) initiative, a private-public sector research
collaboration of the heating, ventilation, air-conditioning, and refrigeration industry, with a focus on
energy conservation, indoor environmental quality, and environmental protection.
ASCE
American Society of Civil Engineers, http://www.asce.org
Provides essential value to its members, careers, partners, and the public by developing leadership,
advancing technology, advocating lifelong learning, and promoting the profession.
ASHI
The American Society of Home Inspectors, http://www.ashi.org
Is a source of information about the home inspection profession.
ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers, http://www.ashrae.org
Writes standards and guidelines that include uniform methods of testing for rating purposes, describe
recommended practices in designing and installing equipment and provide other information to guide the
industry. ASHRAE has more than 80 active standards and guideline project committees, addressing such
broad areas as indoor air quality, thermal comfort, energy conservation in buildings, reducing refrigerant
emissions, and the designation and safety classification of refrigerants.
Healthy Housing Reference Manual
23
ASME
The American Society of Mechanical Engineers, http://www.asme.org
Develops standards for materials and testing as well as finished products.
ASSE
American Society of Sanitary Engineering, http://www.asse.org
Develops standards and qualifies products for plumbing and sanitary installations.
ASTM
American Society for Testing and Materials, http://www.astm.org
Is one of the largest voluntary standards development organizations in the world-a trusted source for
technical standards for materials, products, systems, and services.
AWWA
American Water Works Association, http://www.awwa.org
Promotes public health through improvement of the quality of water and develops standards for valves, fittings, and other
equipment.
CGA
Canadian Gas Association, http://www.cga.ca
Develops standards, tests, and qualifies products used in gas lines and gas appliance installations.
CPSC
U.S Consumer Product Safety Commission, http://www.cpsc.gov
Protects the public from unreasonable risks for serious injury or death from more than 15,000 types of
consumer products. CPSC is committed to protecting consumers and families from products that pose a
fire, electrical, chemical, or mechanical hazard or can injure children.
CRBT
Center for Resourceful Building Technology, http://www.crbt.org
Contains the online Guide to Resource-Efficient Building Elements, which provides information about
environmentally efficient construction materials, including foundations, wall systems, panels, insulation,
siding, roofing, doors, windows, interior finishing, and floor coverings.
EPA
U.S. Environmental Protection Agency, http://www.epa.gov
Protects human health and the environment.
FM
Factory Mutual, http://fmglobal.com
Develops standards and qualifies products for use by the general public and develops standards for materials,
products, systems, and services.
HFHI
Habitat for Humanity International, http://www.habitat.org
Is a nonprofit, ecumenical Christian housing ministry. HFHI seeks to eliminate poverty housing and
homelessness from the world, and to make decent shelter a matter of conscience and action.
HUD
U.S. Department of Housing and Urban Development, http://www.hud.gov
As part of the HUD efforts toward eliminating childhood lead poisoning, the Office of Healthy Homes
and Lead Hazard Control is sharing local lead ordinances and regulations that have proven effective in
helping communities deal with lead-based paint hazards. Also, the design and construction of
manufactured housing are regulated by the federal government and must comply with HUD’s
Manufactured Home Construction and Safety Standards. Modular and panelized construction must
comply with model or local building codes.
IAPMO
International Association of Plumbing and Mechanical Officials, http://www.iapmo.org
Developed and maintains the Uniform Plumbing Code and the Uniform Mechanical Code.
24
Standards and Organizations
ICBO
The Uniform Building Code (UBC)/International Conference of Building Officials,
http://www.iccsafe.org
Is the most widely adopted model building code in the world and is a proven document meeting the
needs of government units charged with enforcement of building regulation. Published triennially, the
UBC provides complete regulations covering all major aspects of building design and construction relating
to fire and life safety and structural safety. The requirements reflect the latest technologic advances available
in the building and fire- and life-safety industry.
ICC
International Code Council, http://www.iccsafe.org
Produces the most widely adopted and enforced building safety codes in the United States (I-Codes).
International Residential Code (IRC) 2003 has been adopted by many states, jurisdictions, and localities.
IRC also references several industry standards such as ACI 318, ASCE 7, ASTM, and ANSI standards that
cover specific load, load combinations, design methods, and material specifications.
ISO
International Standard Organization, http://www.iso.org
Provides internationally recognized certification for manufacturers that comply with high standards of
quality control, developed standards ISO-9000 through ISO-9004, and qualifies and lists products suitable for
use in plumbing installations.
MSS
Manufacturers Standardization Society of the Valve and Fittings Industry, Inc., http://www.mss-hq.com
Develops technical codes and standards for the valve and fitting industry.
NACHI
The National Association of Certified Home Inspectors, http://www.nachi.org/index.htm
Is the world’s largest, most elite nonprofit inspection association.
NAHB
National Association of Home Builders, http://www.nahb.org
Is a trade association representing more than 220,000 residential home building and remodeling industry
members. NAHB is affiliated with more than 800 state and local home builders associations around the
country. NAHB urges codes and standards development and application that protects public health and
safety without cost impacts that decrease affordability and consequently prevent people from moving into
new, healthier, safer homes.
NEC
National Electrical Code, http://www.nfpa.org
Protects public safety by establishing requirements for electrical wiring and equipment in virtually all
buildings.
NESC
National Environmental Services Center, http://www.nesc.wvu.edu/nesc/nesc_about.htm
Is a repository for water, wastewater, solid waste, and environmental training research.
NFPA
National Fire Protection Association, http://www.nfpa.org/index.asp
Develops, publishes, and disseminates more than 300 consensus codes and standards intended to
minimize the possibility and effects of fire and other risks.
NOWRA
National Onsite Wastewater Recycling Association, http://www.nowra.org
Provides leadership and promotes the onsite wastewater treatment and recycling industry through
education, training, communication, and quality tools to support excellence in performance.
NSF
National Sanitation Foundation, http://www.nsf.org
Develops standards for equipment, products and services; a nonprofit organization now known as NSF
International.
Healthy Housing Reference Manual
25
UL
Underwriters Laboratory, http://www.ul.com
Has developed more than 800 Standards for Safety. Millions of products and their components are tested
to UL’s rigorous safety standards.
WEF
Water Environment Federation, http://www.wef.org
Is a not-for-profit technical and educational organization with members from varied disciplines who work
toward the WEF vision of preservation and enhancement of the global water environment. The WEF
network includes water quality professionals from 76 member associations in 30 countries.
26
Standards and Organizations
Executive Summary
he original Basic Housing Inspection manual was published in 1976 by the Center for Disease Control (now
known as the Centers for Disease Control and Prevention). Its Foreword stated:
T
“The growing numbers of new families and the increasing population in the United States have
created a pressing demand for additional housing that is conducive to healthful living. These
demands are increased by the continuing loss of existing housing through deterioration resulting
from age and poor maintenance. Large numbers of communities in the past few years have adopted
housing codes and initiated code enforcement programs to prevent further deterioration of existing
housing units. This growth in housing activities has caused a serious problem for communities in
obtaining qualified personnel to provide the array of housing service needed, such as information,
counseling, technical advice, inspections, and enforcement. As a result many agencies throughout the
country are conducting comprehensive housing inspection training courses. This publication has
been designed to be an integral part of these training sessions.”
The original Basic Housing Inspection manual has been successfully used for several decades by public health and
housing personnel across the United States. Although much has changed in the field of housing construction and
maintenance, and health and safety issues have expanded, the manual continues to have value, especially as it relates to
older housing.
Many housing deficiencies impact on health and safety. For example, lead-based paint and dust may contribute to
lead poisoning in children; water leakage and mold may contribute to asthma episodes; improper use and storage of
pesticides may result in unintentional poisoning; and lack of working smoke, ionization, and carbon monoxide alarms may
cause serious injury and death.
Government agencies have been very responsive to “healthy homes” issues. The U.S. Department of Housing and
Urban Development (HUD) created an office with an exclusive focus on healthy homes. In 2003, CDC joined HUD
in the effort to improve housing conditions through the training of environmental health practitioners, public health
nurses, housing specialists, and others who have interest and responsibility for creating healthy homes.
The revised Basic Housing Inspection manual, renamed the Healthy Housing Reference Manual, responds to the
enormous changes that have occurred in housing construction methods and materials and to new knowledge related
to the impact of housing on health and safety. New chapters have been added, making the manual more
comprehensive. For example, an entire chapter is devoted to rural water supplies and on-site wastewater treatment. A
new chapter was added that discusses issues related to residential swimming pools and spas. At over 230 pages, the
comprehensive revised manual is designed primarily as a reference document for public health and housing
professionals who work in government and industry.
The Healthy Housing Reference Manual contains 14 chapters, each with a specific focus. All chapters contain annotated
references and a listing of sources for additional topic information. A summary of the content of each chapter follows:
Chapter One, Housing History and Purpose, describes the history of dwellings and urbanization and housing
trends during the last century.
Chapter Two, Basic Principles of Healthy Housing, describes the basic principles of healthy housing and
safety—physiologic needs, psychologic needs, protection against injury and disease—and lays the groundwork
for following chapters.
Healthy Housing Reference Manual
27
Chapter Three, Housing Regulations, reviews the history of housing regulations, followed by a discussion of
zoning, housing, and building codes.
Chapter Four, Disease Vectors and Pests, provides a detailed analysis of disease vectors that have an impact on
residences. It includes information on the management of mice, rats, cockroaches, fleas, flies, termites, and fire ants.
Chapter Five, Indoor Air Pollution and Toxic Materials, provides information on indoor air pollution, both
biologic and chemical, and to toxic materials in the home, including methods for controlling these hazards. The
impact of cockroaches, dust mites, pets, and mold are discussed. Also included is information about the impact
of carbon monoxide, ozone, tobacco smoke, volatile organic compounds, radon, and pesticides.
Chapter Six, Housing Structure, contains information about “older” housing construction and new construction
materials and methods. The chapter also introduces new terminologies and includes information about
foundations, vapor barriers, house framing, roof framing, exterior walls, and roofs.
Chapter Seven, Environmental Barriers, provides information on roofing, insulation, and siding materials.
Chapter Eight, Rural Water Supplies and Water-quality Issues, covers issues related to the drilling and proper
maintenance of wells. Research information is provided that indicates that many wells are not properly sealed,
allowing for the leakage of contaminated water into wells during hurricanes and periods of significant flooding.
Chapter Nine, Plumbing, provides information on plumbing standards and how they can be accessed, followed
by a review of the elements of a residential water delivery system, the types of available hot-water heaters,
drainage systems, and methods for water conservation. It also includes a visual synthesis of water system
components during new residential construction.
Chapter Ten, On-site Wastewater Treatment, complements chapter seven by providing information on proper
on-site methods for the treatment of human waste.
Chapter Eleven, Electricity, expands on information contained in the original manual covering such topics as
breaker systems and polarized plugs and connectors. It also provides a format for the inspection of residential
electrical systems.
Chapter Twelve, Heating, Air Conditioning, and Ventilation, provides information about types of residential
fuels and heating systems, including solar heating and minor sources of heating (e.g., coal-fired, oil-fired, gas-
fired, and electrical space heaters). Chimney and fireplace safety and the variety of cooling systems are also
discussed.
Chapter Thirteen, Energy Efficiency, discusses energy efficiency, including R-values and their interpretation, roof
ventilation, wall and floor insulation, and door and window energy efficiency systems. It also discusses active and
passive solar systems and provides a methodology for conducting a residential energy audit.
Chapter Fourteen, Residential Swimming Pools and Spas, provides information about child safety, pool and spa
hazards, and diseases. It also provides information on methods for testing and ensuring a safe water system and
on methods for spa and pool disinfection. Further, it covers concerns related to unregulated individual
residential pools and spas.
28
Executive Summary
The quality of housing plays a decisive role in the health status of its occupants. Substandard housing conditions have
been linked to adverse health effects such as childhood lead poisoning, asthma and other respiratory conditions, and
unintentional injuries. This new and revised Healthy Housing Reference Manual is an important reference for anyone
with responsibility and interest in creating and maintaining healthy housing.
The housing design and construction industry has made great progress in recent years through the development of
new innovative techniques, materials technologies, and products. The HUD Rehab Guide series was developed to
inform the design and construction industry about state-of-the-art materials and innovative practices in housing
rehabilitation. The series focuses on building technologies, materials, components, and techniques rather than on
projects such as adding a new room. The nine volumes each cover a distinct element of housing rehabilitation and
feature breakthrough materials, labor-saving tools, and cost-cutting practices. The nine volumes address foundations;
exterior walls; roofs; windows and doors; partitions, ceilings, floors, and stairs; kitchen and baths; electrical/
electronics; heating, air conditioning, and ventilation; plumbing; and site work.
Additional information about the series can be found at http://www.huduser.org/publications/destech/rehabgui.html
and http://www.pathnet.org/sp.asp?id=997. This series is an excellent adjunct to the Healthy Housing Reference Manual.
Healthy Housing Reference Manual
29
30
Executive Summary
Chapter 1: Housing History and Purpose
“Safe, affordable housing is a basic necessity for every family.
code inspectors, housing inspectors, environmental health
Without a decent place to live, people cannot be productive
officers, injury control specialists, and epidemiologists all
members of society, children cannot learn and families
are indispensable to achieving the goal of the best
cannot thrive.”
housing in the world for U.S. citizens. This goal is the
basis for the collaboration of the U.S. Department of
Tracy Kaufman, Research Associate
Housing and Urban Development (HUD) and the
National Low Income Housing Coalition/
Centers for Disease and Control and Prevention (CDC).
Low Income Housing Information Service
http://www.habitat.org/how/poverty.html; 2003
Preurban Housing
Early dwelling designs were probably the result of cultural,
Introduction
socioeconomic, and physical forces intrinsic to the
The term “shelter,” which is often used to define housing,
environment of their inhabitants. The housing similarities
has a strong connection to the ultimate purpose of
among civilizations separated by vast distances may have
housing throughout the world. The mental image of a
been a result of a shared heritage, common influences,
shelter is of a safe, secure place that provides both privacy
or chance.
and protection from the elements and the temperature
extremes of the outside world.
Caves were accepted as dwellings, perhaps because they
were ready made and required little or no construction.
This vision of shelter, however, is complex. The
However, in areas with no caves, simple shelters were
earthquake in Bam, Iran, before dawn on December 26,
constructed and adapted to the availability of resources
2003, killed in excess of 30,000 people, most of whom
and the needs of the population. Classification systems
were sleeping in their homes. Although the homes were
have been developed to demonstrate how dwelling types
made of the most simple construction materials, many
evolved in preurban indigenous settings [1].
were well over a thousand years old. Living in a home
where generation after generation had been raised should
Ephemeral Dwellings
provide an enormous sense of security. Nevertheless, the
Ephemeral dwellings, also known as transient dwellings,
world press has repeatedly implied that the construction
were typical of nomadic peoples. The African bushmen
of these homes destined this disaster. The homes in Iran
and Australia’s aborigines are examples of societies whose
were constructed of sun-dried mud-brick and mud.
existence depends on an economy of hunting and food
gathering in its simple form. Habitation of an ephemeral
We should think of our homes as a legacy to future
dwelling is generally a matter of days.
generations and consider the negative environmental
effects of building them to serve only one or two
Episodic Dwellings
generations before razing or reconstructing them. Homes
Episodic housing is exemplified by the Inuit igloo, the
should be built for sustainability and for ease in future
tents of the Tungus of eastern Siberia, and the very
modification. We need to learn the lessons of the
similar tents of the Lapps of northern Europe. These
earthquake in Iran, as well as the 2003 heat wave in
groups are more sophisticated than those living in
France that killed in excess of 15,000 people because of
ephemeral dwellings, tend to be more skilled in hunting
the lack of climate control systems in their homes. We
or fishing, inhabit a dwelling for a period of weeks, and
must use our experience, history, and knowledge of both
have a greater effect on the environment. These groups
engineering and human health needs to construct
also construct communal housing and often practice
housing that meets the need for privacy, comfort,
slash-and-burn cultivation, which is the least productive
recreation, and health maintenance.
use of cropland and has a greater environmental impact
than the hunting and gathering of ephemeral dwellers.
Health, home construction, and home maintenance are
inseparable because of their overlapping goals. Many
Periodic Dwellings
highly trained individuals must work together to achieve
Periodic dwellings are also defined as regular temporary
quality, safe, and healthy housing. Contractors, builders,
dwellings used by nomadic tribal societies living in a
Healthy Housing Reference Manual
1-1
pastoral economy. This type of housing is reflected in the
Urbanization
yurt used by the Mongolian and Kirgizian groups and the
Permanent dwellings went beyond simply providing
Bedouins of North Africa and western Asia. These groups’
shelter and protection and moved to the consideration of
dwellings essentially demonstrate the next step in the
comfort. These structures began to find their way into what is
evolution of housing, which is linked to societal
now known as the urban setting. The earliest available
development. Pastoral nomads are distinguished from
evidence suggests that towns came into existence around
people living in episodic dwellings by their homogenous
4000 BC. Thus began the social and public health problems
cultures and the beginnings of political organization.
that would increase as the population of cities increased
Their environmental impact increases with their increased
in number and in sophistication. In preurban housing,
dependence on agriculture rather than livestock.
the sparse concentration of people allowed for movement
away from human pollution or allowed the dilution of
Seasonal Dwellings
pollution at its location. The movement of populations
Schoenauer [1] describes seasonal dwellings as reflective of
into urban settings placed individuals in close proximity,
societies that are tribal in nature, seminomadic, and based
without the benefit of previous linkages and without the
on agricultural pursuits that are both pastoral and
ability to relocate away from pollution or other people.
marginal. Housing used by seminomads for several
months or for a season can be considered semisedentary
Urbanization was relatively slow to begin, but once
and reflective of the advancement of the concept of
started, it accelerated rapidly. In the 1800s, only about
property, which is lacking in the preceding societies. This
3% of the population of the world could be found in
concept of property is primarily of communal property, as
urban settings in excess of 5,000 people. This was soon to
opposed to individual or personal property. This type of
change. The year 1900 saw the percentage increase to
housing is found in diverse environmental conditions and is
13.6% and subsequently to 29.8% in 1950. The world’s
demonstrated in North America by the hogans and armadas
urban population has grown since that time. By 1975,
of the Navajo Indians. Similar housing can be found in
more than one in three of the world’s population lived in
Tanzania (Barabaig) and in Kenya and Tanzania (Masai).
an urban setting, with almost one out of every two living
in urban areas by 1997. Industrialized countries currently
Semipermanent Dwellings
find approximately 75% of their population in an urban
According to Schoenauer [1], sedentary folk societies or
setting. The United Nations projects that in 2015 the
hoe peasants practicing subsistence agriculture by
world’s urban population will rise to approximately 55%
cultivating staple crops use semipermanent dwellings.
and that in industrialized nations it will rise to just over 80%.
These groups tend to live in their dwellings various amounts
of time, usually years, as defined by their crop yields. When
In the Western world, one of the primary forces driving
land needs to lie fallow, they move to more fertile areas.
urbanization was the Industrial Revolution. The basic
Groups in the Americas that used semipermanent
source of energy in the earliest phase of the Industrial
dwellings included the Mayans with their oval houses and
Revolution was water provided by flowing rivers. Therefore,
the Hopi, Zuni, and Acoma Indians in the southwestern
towns and cities grew next to the great waterways. Factory
United States with their pueblos.
buildings were of wood and stone and matched the houses
in which the workers lived, both in construction and in
Permanent Dwellings
location. Workers’ homes were little different in the urban
The homes of sedentary agricultural societies, whose
setting than the agricultural homes from whence they
political and social organizations are defined as nations
came. However, living close to the workplace was a
and who possess surplus agricultural products, exemplify
definite advantage for the worker of the time. When the
this type of dwelling. Surplus agricultural products
power source for factories changed from water to coal,
allowed the division of labor and the introduction of
steam became the driver and the construction materials
other pursuits aside from food production; however,
became brick and cast iron, which later evolved into
agriculture is still the primary occupation for a significant
steel. Increasing populations in cities and towns increased
portion of the population. Although they occurred at
social problems in overcrowded slums. The lack of
different points in time, examples of early sedentary
inexpensive, rapid public transportation forced many
agricultural housing can be found in English cottages,
workers to live close to their work. These factory areas
such as the Suffolk, Cornwall, and Kent cottages [1].
were not the pastoral areas with which many were
familiar, but were bleak with smoke and other pollutants.
The inhabitants of rural areas migrated to ever-expanding
1-2
Housing History and Purpose
cities looking for work. Between 1861 and 1911 the
population of England grew by 80%. The cities and
towns of England were woefully unprepared to cope with
the resulting environmental problems, such as the lack of
potable water and insufficient sewerage.
In this atmosphere, cholera was rampant; and death rates
resembled those of Third World countries today. Children
had a one in six chance of dying before the age of 1 year.
Because of urban housing problems, social reformers such
as Edwin Chadwick began to appear. Chadwick’s Report
on an Enquiry into the Sanitary Condition of the Labouring
Population of Great Britain and on the Means of its
Improvement [2] sought many reforms, some of which
concerned building ventilation and open spaces around
the buildings. However, Chadwick’s primary contention
was that the health of the working classes could be improved
by proper street cleaning, drainage, sewage, ventilation,
and water supplies. In the United States, Shattuck et al.
[3] wrote the Report of the Sanitary Commission of
Massachusetts, which was printed in 1850. In the report,
50 recommendations were made. Among those related to
housing and building issues were recommendations for
protecting school children by ventilation and sanitation of
school buildings, emphasizing town planning and controlling
Figure 1.1. Conditions in the Tenements
overcrowded tenements and cellar dwellings. Figure 1.1
demonstrates the conditions common in the tenements.
1830s as a housing unit of two to five stories, with each
story containing apartments of two to four rooms. It was
In 1845, Dr. John H. Griscom, the City Inspector of
originally built for the upper group of the working class.
New York, published The Sanitary Condition of the
The tenement house emerged in the 1830s when
Laboring Population of New York [4]. His document
landlords converted warehouses into inexpensive housing
expressed once again the argument for housing reform
designed to accommodate Irish and black workers.
and sanitation. Griscom is credited with being the first to
Additionally, existing large homes were subdivided and
use the phrase “how the other half lives.” During this
new structures were added, creating rear houses and, in
time, the poor were not only subjected to the physical
the process, eliminating the traditional gardens and yards
problems of poor housing, but also were victimized by
behind them. These rear houses, although new, were
corrupt landlords and builders.
no healthier than the front house, often housing up to
10 families. When this strategy became inadequate to
Trends in Housing
satisfy demand, the epoch period of the tenements began.
The term “tenement house” was first used in America and
dates from the mid-nineteenth century. It was often
Although unpopular, the tenement house grew in
intertwined with the term “slum.” Wright [5] notes that
numbers, and, by 1850 in New York and Boston, each
in English, tenement meant “an abode for a person or for
tenement housed an average of 65 people. During the
the soul, when someone else owned the property.” Slum,
1850s, the railroad house or railroad tenement was
on the other hand, initially was used at the beginning of
introduced. This structure was a solid, rectangular block
the 19th century as a slang term for a room. By the
with a narrow alley in the back. The structure was
middle of the century, slum had evolved into a term for a
typically 90 feet long and had 12 to 16 rooms, each about
back dwelling occupied by the lowest members of society.
6 feet by 6 feet and holding around four people. The
Von Hoffman [6] states that this term had, by the end of
facility allowed no direct light or air into rooms except
the century, begun to be used interchangeably with
those facing the street or alley. Further complicating this
tenement. The author noted that in the larger cities of
structure was the lack of privacy for the tenants. A lack of
the United States, the apartment house emerged in the
hallways eliminated any semblance of privacy. Open sewers,
a single privy in the back of the building, and uncollected
Healthy Housing Reference Manual
1-3
garbage resulted in an objectionable and unhygienic place to
bungalow was introduced into the United States in 1880
live. Additionally, the wood construction common at the
with the construction of a home in Cape Cod. The bungalow,
time, coupled with coal and wood heating, made fire an
derived for use in tropical climates, was especially popular
ever-present danger. As a result of a series of tenement
in California.
fires in 1860 in New York, such terms as death-trap and
fire-trap were coined to describe the poorly constructed
Company towns were another trend in housing in the
living facilities [6].
19th century. George Pullman, who built railway cars in the
1880s, and John H. Patterson, of the National Cash
The two last decades of the 19th century saw the
Register Company, developed notable company towns.
introduction and development of dumbbell tenements, a
Wright [5] notes that in 1917 the U.S. Bureau of Labor
front and rear tenement connected by a long hall. These
Standards estimated that at least 1,000 industrial firms were
tenements were typically five stories, with a basement and
providing housing for their employees. The provision of
no elevator (elevators were not required for any building
housing was not necessarily altruistic. The motivation
of less than six stories). Dumbbell tenements, like other
for providing housing varied from company to company.
tenements, resulted in unaesthetic and unhealthy places to
Such motivations included the use of housing as a
live. Garbage was often thrown down the airshafts, natural
recruitment incentive for skilled workers, a method of
light was confined to the first floor hallway, and the public
linking the individual to the company, and a belief that a
hallways only contained one or two toilets and a sink.
better home life would make the employees happier and
This apparent lack of sanitary facilities was compounded
more productive in their jobs. Some companies, such as
by the fact that many families took in boarders to help with
Firestone and Goodyear, went beyond the company town
expenses. In fact, 44,000 families rented space to boarders
and allowed their employees to obtain loans for homes
in New York in 1890, with this increasing to 164,000
from company-established banks. A prime motivator of
families in 1910. In the early 1890s, New York had a
company town planning was sanitation, because
population of more than 1 million, of which 70% were
maintaining the worker’s health could potentially lead to
residents of multifamily dwellings. Of this group, 80%
fewer workdays lost due to illness. Thus, in the
lived in tenements consisting mostly of dumbbell tenements.
development of the town, significant consideration was
given to sanitary issues such as window screens, sewage
The passage of the New York Tenement House Act of
treatment, drainage, and water supplies.
1901 spelled the end of the dumbbells and acceptance of
a new tenement type developed in the 1890s—the park
Before World War I there was a shortage of adequate
or central court tenement, which was distinguished by a
dwellings. Even after World War I, insufficient funding, a
park or open space in the middle of a group of buildings.
shortage of skilled labor, and a dearth of building materials
This design was implemented to reduce the activity on
compounded the problem. However, the design of homes
the front street and to enhance the opportunity for fresh
after the war was driven in part by health considerations,
air and recreation in the courtyard. The design often
such as providing good ventilation, sun orientation and
included roof playgrounds, kindergartens, communal
exposure, potable pressurized water, and at least one
laundries, and stairways on the courtyard side.
private toilet. Schoenauer [1] notes that, during the
postwar years, the improved mobility of the public led to
Although the tenements did not go away, reform groups
an increase in the growth of suburban areas, exemplified
supported ideas such as suburban cottages to be
by the detached and sumptuous communities outside
developed for the working class. These cottages were two-
New York, such as Oyster Bay. In the meantime, the
story brick and timber, with a porch and a gabled roof.
conditions of working populations consisting of many
According to Wright [5], a Brooklyn project called
immigrants began to improve with the improving
Homewood consisted of 53 acres of homes in a planned
economy of the 1920s. The garden apartment became
neighborhood from which multifamily dwellings, saloons,
popular. These units were well lighted and ventilated and
and factories were banned.
had a courtyard, which was open to all and well maintained.
Although there were many large homes for the well-to-do,
Immediately after World War I and during the 1920s, city
single homes for the not-so-wealthy were not abundant.
population growth was outpaced by population growth in
The first small house designed for the individual of
the suburbs by a factor of two. The focus at the time was
modest means was the bungalow. According to
on the single-family suburban dwelling. The 1920s were a
Schoenauer [1], bungalows originated in India. The
time of growth, but the decade following the Great
1-4
Housing History and Purpose
History of the Department of Housing and Urban Development
1934
Housing Act establishes Federal Housing Administration to insure mortgages and make loans to
low-income families; Fannie Mae created.
1937
Housing Act establishes public housing.
1944
Serviceman’s Readjustment Act creates Veteran Administration mortgages; trend toward
suburbia begins.
Late 1950s
Urban renewal begins; slum clearance developed to promote construction of affordable housing.
1965
Department of Housing and Urban Development created.
1968
Model Cities program launched; fair housing launched through the Civil Rights Act.
1971
Lead-Based Paint Poisoning Prevention Act passed.
1974
Section 8 rental subsidy program begins; Community Development Block Grant program begins.
1977
Urban Development Action Grants begin.
1986
Low-income housing tax credit created.
1987
McKinney Homeless Assistance Act passed; creation of low-income housing tax credit.
1991-1994
Public housing inspection for lead paint.
1992
Residential Lead Hazard Reduction Act passed (Title X of the 1992 Housing and Community
Development Act).
1993
Hope VI program begins to redevelop old public housing.
1996
Lead-based paint disclosure becomes law.
1999
HUD and CDC launch the Healthy Homes Initiative.
2000
HUD publishes new lead paint regulations for federally funded assisted housing; President’s Task
Force releases federal interagency plan to eliminate childhood lead paint poisoning by 2010.
2001
EPA publishes final standards for lead in paint, dust, and soil in housing.
Depression, beginning in 1929, was one of deflation,
and loan associations, and others to make loans for
cessation of building, loss of mortgage financing, and the
building homes, small business establishments, and farm
plunge into unemployment of large numbers of building
buildings. If the Federal Housing Administration
trade workers. Additionally, 1.5 million home loans were
approved the plans, it would insure the loan. In 1937,
foreclosed during this period. In 1936, the housing market
Congress passed another National Housing Act that
began to make a comeback; however, the 1930s would
enabled the Federal Housing Administration to take
come to be known as the beginning of public housing,
control of slum clearance. It made 60-year loans at low
with increased public involvement in housing
interest to local governments to help them build
construction, as demonstrated by the many laws passed
apartment blocks. Rents in these homes were fixed and
during the era [5]. The National Housing Act was
were only available to low-income families. By 1941, the
passed by Congress in 1934 and set up the Federal Housing
agency had assisted in the construction of more than
Administration. This agency encouraged banks, building
120,000 family units.
Healthy Housing Reference Manual
1-5
During World War II, the focus of home building was on
Builders also began promoting one-floor minihomes and
housing for workers who were involved in the war effort.
no-frills homes of approximately 900 to 1,200 square feet.
Homes were being built through federal agencies such as
Manufactured housing began to increase in popularity,
the newly formed Federal Housing Administration, formed
with mobile home manufacturers becoming some of the
in 1934 and transferred to HUD in 1965. According to
most profitable corporations in the United States in the
the U.S. Census Bureau (USCB) [7], in the years since
early 1970s. In the 1940 census, manufactured housing
World War II, the types of homes Americans live in have
were lumped into the “other” category with boats and tourist
changed dramatically. In 1940, most homes were considered
cabins: by the 1990 census, manufactured housing made up
attached houses (row houses, townhouses, and duplexes).
7% of the total housing inventory. Many communities
Small apartment houses with two to four apartments had
ban manufactured housing from residential
their zenith in the 1950s. In the 1960 census, two-thirds
neighborhoods.
of the housing inventory was made up of one-family detached
houses, which declined to less than 60% in the 1990 census.
According to Hart et al. [9], nearly 30% of all home sales
nationwide are of manufactured housing, and more than
The postwar years saw the expansion of suburban housing
90% of those homes are never moved once they are
led by William J. Levitt’s Levittown, on Long Island,
anchored. According to a 2001 industry report, the
which had a strong influence on postwar building and
demand for prefabricated housing is expected to increase
initiated the subdivisions and tract houses of the
in excess of 3% annually to $20 billion in 2005, with
following decades (Figure 1.2). The 1950s and 1960s saw
most units being manufactured homes. The largest
continued suburban development, with the growing ease of
market is expected to continue in the southern part of the
transportation marked by the expansion of the interstate
United States, with the most rapid growth occurring in
highway system. As the cost of housing began to increase
the western part of the country. As of 2000, five
as a result of increased demand, a grassroots movement to
manufactured-home producers, representing 35% of the
provide adequate housing for the poor began to emerge.
market, dominated the industry. This industry, over the
According to Wright [5], in the 1970s only about 25% of the
past 20 to 25 years, has been affected by two pieces of
population could afford a $35,000 home. According to
federal legislation. The first, the Mobile Home
Gaillard [8], Koinonia Partners, a religious organization
Construction and Safety Standards Act, adopted by HUD
founded in 1942 by Clarence Jordan near Albany,
in 1974, was passed to aid consumers through regulation
Georgia, was the seed for Habitat for Humanity. Habitat
and enforcement of HUD design and construction
for Humanity, founded in 1976 by Millard Fuller, is
standards for manufactured homes. The second, the 1980
known for its international efforts and has constructed
Housing Act, required the federal government to change
more than 150,000 houses in 80 countries; 50,000 of these
the term “mobile home” to “manufactured housing” in all
houses are in the United States. The homes are energy-
federal laws and literature. One of the prime reasons for
efficient and environmentally friendly to conserve resources
this change was that these homes were in reality no longer
and reduce long-term costs to the homeowners.
mobile in the true sense.
The energy crisis in the United States between 1973 and
1974 had a major effect on the way Americans lived,
drove, and built their homes. The high cost of both
heating and cooling homes required action, and some of
the action taken was ill advised or failed to consider
healthy housin concerns. Sealing homes and using untried
insulation materials and other energy conservation actions
often resulted in major and sometimes dangerous
buildups of indoor air pollutants. These buildups of
toxins occurred both in homes and offices. Sealing
buildings for energy efficiency and using off-gassing
building materials containing urea-formaldehyde, vinyl,
and other new plastic surfaces, new glues, and even
wallpapers created toxic environments. These newly sealed
environments were not refreshed with makeup air and
Figure 1.2. Levittown, New York
resulted in the accumulation of both chemical and
1-6
Housing History and Purpose
biologic pollutants and moisture leading to mold growth,
Hale EE. Workingmen’s homes, essays and stories, on the
representing new threats to both short-term and long-
homes of men who work in large towns. Boston: James
term health. The results of these actions are still being
R. Osgood and Company; 1874.
dealt with today.
History of plumbing in America. Plumbing and
References
Mechanical Magazine. 1987 Jul. Available from URL:
1.
Schoenauer N. 6,000 years of housing. New York/
http://www.plumbingsupply.com/pmamerica.html.
London: W.W. Norton & Company, Inc.; 2000.
Housing Act of 1949, The US Committee on
2.
Chadwick E. Report on an enquiry into the
Agriculture Glossary.
sanitary condition of the labouring population of
Great Britain and on the means of its
Lang RE, Sohmer RR. Editors’ introduction, legacy of
improvements. London: Clowes and Sons; 1842.
the Housing Act of 1949: the past, present, and future of
federal housing and urban policy. Housing Policy Debate
3.
Shattuck L, Banks N Jr, Abbot J. Report of the
2000; 11(2) 291-8. Available from URL:
Sanitary Commission of Massachusetts, 1850.
http://www.fanniemaefoundation.org/ programs/hpd/v11i2-
Boston: Dutton and Wentworth; 1850. Available
edintro.shtml.
from URL: http://www.deltaomega.org/shattuck.pdf.
Mason JB. History of housing in the US. 1930-1980.
4.
Griscom JH. The sanitary condition of the
Houston, TX: Gulf Publishing Company; 1982.
labouring population of New York. New York:
Harper; 1845.
Passic F. Urban renewal. Morning Star [Albion,
Michigan]. 1997 Feb 13; 6. Available from URL:
5.
Wright G. Building the dream—a social history
http://www.albionmich.com/ history/
of housing in America. Cambridge, MA/London:
histor_notebook/940213.shtml.
The MIT Press; 1998.
Red-lining [definition of], 535A.1 Definitions, Iowa
6.
Von Hoffman A. The origins of American
Code 2001: Section 535A.1. Des Moines, IA: The Iowa
housing reform. Cambridge, MA: Joint Center
Legislature. Available from URL:
for Housing Studies—Harvard University; August
http://www.legis.state.ia.us/IACODE/
1998. p. W98-2.
2001/535A/1.html.
7.
US Census Bureau. Historical census of housing
Rental Housing On Line. Federal housing acts. Port
tables—units in structure; 2002. Washington, DC:
Huron, MI: Rental Housing On Line; no date. Available
US Census Bureau; 2002. Available from URL:
from URL: http://www.rhol.org/rental/fedact.htm.
http://www.census.gov/hhes/www/housing/census/
historic/units.html.
Rental Housing On Line. Government’s role in low
income housing. Port Huron, MI: Rental Housing
8.
Gaillard F. If I were a carpenter, twenty years of
On Line; no date. Available from URL:
Habitat for Humanity. Winston-Salem, NC:
http://www.rhol.org/rental/housing.htm.
John E. Blair; 1996.
Texas Low Income Housing Information Service. The
9.
Hart JF, Rhodes MJ, Morgan JT, Lindberg MB.
past: special interests, race, and local control; Housing
The unknown world of the mobile home.
Act of 1949: bipartisan support for public housing.
Baltimore, MD: Johns Hopkins University
Austin, TX: Texas Low Income Housing Information
Press; 2002.
Service; no date. Available from URL:
http://www.texashousing.org/txlihis/ phdebate/past12.html.
Additional Sources of Information
Dolkart A. The 1901 Tenement House Act: chapter 6,
US Department of Housing and Urban Development.
cleaning up the toilets. New York: Lower East Side
Fair housing laws and presidential Executive Orders.
Tenement Museum; no date. Available from URL:
Washington, DC: US Department of Housing and
http://www.tenement.org/ features_dolkart7.html.
Healthy Housing Reference Manual
1-7
Urban Development; no date. Available from URL:
http://www.hud.gov/ offices/ fheo/ FHLaws/index.cfm.
US Department of Housing and Urban Development.
Homes and communities. Washington, DC: US
Department of Housing and Urban Development; no
date. Available from URL: http://www.hud.gov.
Warth G. Research project looking at red-lining. North
County [California] Times 2002 May 5. Available from
URL: http://www.nctimes.com/ articles/2002/05/
05/export8963.txt.
1-8
Housing History and Purpose
Chapter 2: Basic Principles of Healthy Housing
The connection between health and dwelling is one of the
6. direct sunlight,
most important that exists.”
7. adequate artificial illumination and avoidance of glare,
Florence Nightingale
8. protection from excessive noise, and
Introduction
It seems obvious that health is related to where people
9. adequate space for exercise and for children to play.
live. People spend 50% or more of every day inside their
homes. Consequently, it makes sense that the housing
The first three physiologic needs reflect the requirement
environment constitutes one of the major influences on
for adequate protection from the elements. The lack of
health and well-being. Many of the basic principles of the
adequate heating and cooling systems in homes can
link between housing and health were elucidated more
contribute to respiratory illnesses or even lead to death
than 60 years ago by the American Public Health
from extreme temperatures. According to the National
Association (APHA) Committee on the Hygiene of
Weather Service, 98 people died from extreme
Housing. After World War II, political scientists,
temperatures in 1996; 62 of these were due to extreme
sociologists, and others became interested in the relation
cold. Hypothermia occurs when the body temperature
between housing and health, mostly as an outgrowth of a
drops below 96°F (46°C). It can occur in any person
concern over poor housing conditions resulting from the
exposed to severe cold without enough protection. Older
massive influx into American cities of veterans looking
people are particularly susceptible because they may not
for jobs. Now, at the beginning of the 21st century, there is
notice the cold as easily and can develop hypothermia
a growing awareness that health is linked not only to the
even after exposure to mild cold. Susceptibility to the
physical structure of a housing unit, but also to the
cold can be exacerbated by certain medications, medical
neighborhood and community in which the house is located.
conditions, or the consumption of alcohol. Hyperthermia is
the name given to a variety of heat-related illnesses. The two
According to Ehlers and Steel [1], in 1938, a Committee
most common forms of hyperthermia are heat
on the Hygiene of Housing, appointed by APHA,
exhaustion and heat stroke. Of the two, heat stroke is
created the Basic Principles of Healthful Housing, which
especially dangerous and requires immediate medical attention.
provided guidance regarding the fundamental needs of
humans as they relate to housing. These fundamental
According to the National Institute on Aging (NIA) [2],
needs include physiologic and psychologic needs,
lifestyle factors can increase the risk for hyperthermia:
protection against disease, protection against injury,
protection against fire and electrical shock, and
Unbearably hot living quarters. This would include
protection against toxic and explosive gases.
people who live in homes without fans or air
conditioners. To help avert the problem, residents should
Fundamental Physiologic Needs
open windows at night; create cross-ventilation by opening
Housing should provide for the following physiologic needs:
windows on two sides of the building; cover windows
when they are exposed to direct sunlight and keep curtains,
1. protection from the elements,
shades, or blinds drawn during the hottest part of the day.
2. a thermal environment that will avoid undue heat loss,
Lack of transportation. People without fans or air conditioners
often are unable to go to shopping malls, movie theaters, and
3. a thermal environment that will permit adequate
libraries to cool off because of illness or the lack of
heat loss from the body,
transportation.
4. an atmosphere of reasonable chemical purity,
Inadequate or inoperable windows. Society has become
so reliant on climate control systems that when they fail,
5. adequate daylight illumination and avoidance
windows cannot be opened. As was the case in the 2003
of undue daylight glare,
heat wave in France, many homes worldwide do not even
have fans for cooling.
Healthy Housing Reference Manual
2-1
Overdressing. Older people, because they may not feel
formed a Noise Abatement Commission that was charged
the heat, may not dress appropriately in hot weather.
with evaluating noise issues and suggesting solutions. At
that time, it was concluded that loud noise affected health
Visiting overcrowded places. Trips should be scheduled
and productivity. In 1930, this same commission
during nonrush-hour times and participation in special events
determined that constant exposure to loud noises could
should be carefully planned to avoid disease transmission.
affect worker efficiency and long-term hearing levels. In
1974, the U.S. Environmental Protection Agency (EPA)
Not checking weather conditions. Older people,
produced a document titled Information on Levels of
particularly those at special risk, should stay indoors on
Environmental Noise Requisite to Protect Public Health and
especially hot and humid days, particularly when an air
Welfare With an Adequate Margin of Safety [5]. This
pollution alert is in effect.
document identified maximum levels of 55 decibels outdoors
and 45 decibels indoors to prevent interference with
USCB [3] reported that about 75% of homes in the
activities and 70 decibels for all areas to prevent hearing
United States used either utility gas or electricity for
loss. In 1990, the United Kingdom implemented The
heating purposes, with utility gas accounting for about
Household Appliances (Noise Emission) Regulations [6]
50%. This, of course, varies with the region of the
to help control indoor noise from modern appliances.
country, depending on the availability of hydroelectric
Noise has physiologic impacts aside from the potential to
power. This compares with the 1940 census, which found
reduce hearing ability. According to the American Speech-
that three-quarters of all households heated with coal or
Language-Hearing Association [7], these effects include
wood. Electric heat was so rare that it was not even an
elevated blood pressure; negative cardiovascular effects;
option on the census form of 1940. Today, coal has
increased breathing rates, digestion, and stomach
virtually disappeared as a household fuel. Wood all but
disturbances; ulcers; negative effects on developing
disappeared as a heating fuel in 1970, but made a modest
fetuses; difficulty sleeping after the noise stops; plus the
comeback at 4% nationally by 1990. This move over time
intensification of the effects of drugs, alcohol, aging, and
to more flexible fuels allows a majority of today’s homes
carbon monoxide. In addition, noise can reduce attention
to maintain healthy temperatures, although many houses
to tasks and impede speech communication. Finally, noise
still lack adequate insulation.
can hamper performance of daily tasks, increase fatigue,
and cause irritability.
The fifth through the seventh physiologic concerns
address adequate illumination, both natural and artificial.
Household noise can be controlled in various ways.
Research has revealed a strong relationship between light
Approaching the problem during initial construction is
and human physiology. The effects of light on both the
the simplest, but has not become popular. For example, in
human eye and human skin are notable. According to
early 2003, only about 30% of homebuilders offered
Zilber [4], one of the physiologic responses of the skin to
sound-attenuating blankets for interior walls. A sound-
sunlight is the production of vitamin D. Light allows us
attenuating blanket is a lining of noise abatement
to see. It also affects body rhythms and psychologic
products (the thickness depends on the material being used).
health. Average individuals are affected daily by both
Spray-in-place soft foam insulation can also be used as a
natural and artificial lighting levels in their homes.
sound dampener, as can special walking mats for floors.
Adequate lighting is important in allowing people to see
Actions that can help reduce household noise include
unsanitary conditions and to prevent injury, thus
installing new, quieter appliances and isolating washing
contributing to a healthier and safer environment.
machines to reduce noise and water passing through pipes.
Improper indoor lighting can also contribute to eyestrain
from inadequate illumination, glare, and flicker.
The ninth and final physiologic need is for adequate
space for exercise and play. Before industrialization in the
Avoiding excessive noise (eighth physiologic concern) is
United States and England, a preponderance of the
important in the 21st century. However, the concept of
population lived and worked in more rural areas with
noise pollution is not new. Two thousand years ago, Julius
very adequate areas for exercise and play. As
Caesar banned chariots from traveling the streets of Rome
industrialization impacted demographics, more people
late at night. In the 19th century, numerous towns and
were in cities without ample space for play and exercise.
cities prohibited ringing church bells. In the early 20th
In the 19th century, society responded with the
century, London prohibited church bells from ringing
development of playgrounds and public parks. Healthful
between 9:00 PM and 9:00 AM. In 1929, New York City
housing should include the provision of safe play and
2-2
Basic Principles of Healthy Housing
exercise areas. Many American neighborhoods are severely
Protection Against Disease
deficient, with no area for children to safely play. New
Eight ways to protect against contaminants include the
residential areas often do not have sidewalks or street
following:
lighting, nor are essential services available by foot
because of highway and road configurations.
1. provide a safe and sanitary water supply;
Fundamental Psychologic Needs
2. protect the water supply system against pollution;
Seven fundamental psychologic needs for healthy housing
include the following:
3. provide toilet facilities that minimize the danger
of transmitting disease;
1. adequate privacy for the individual,
4. protect against sewage contamination of the interior
2. opportunities for normal family life,
surfaces of the dwelling;
3. opportunities for normal community life,
5. avoid unsanitary conditions near the dwelling;
4. facilities that make possible the performance of
6. exclude vermin from the dwelling, which may
household tasks without undue physical and
play a part in transmitting disease;
mental fatigue,
7. provide facilities for keeping milk and food
5. facilities for maintenance of cleanliness of the
fresh; and
dwelling and of the person,
8. allow sufficient space in sleeping rooms to
6. possibilities for aesthetic satisfaction in the home
minimize the danger of contact infection.
and its surroundings, and
According to the U.S. EPA [8], there are approximately
7. concordance with prevailing social standards of
160,000 public or community drinking water systems in the
the local community.
United States. The current estimate is that 42 million
Americans (mostly in rural America) get their water from
Privacy is a necessity to most people, to some degree and
private wells or other small, unregulated water systems.
during some periods. The increase in house size and the
The presence of adequate water, sewer, and plumbing
diminishing family size have, in many instances, increased
facilities is central to the prevention, reduction, and possible
the availability of privacy. Ideally, everyone would have
elimination of water-related diseases. According to the
their own rooms, or, if that were not possible, would
Population Information Program [9], water-related diseases
share a bedroom with only one person of the same sex,
can be organized into four categories:
excepting married couples and small children. Psychiatrists
consider it important for children older than 2 years to
• waterborne diseases, including those caused by
have bedrooms separate from their parents. In addition,
both fecal-oral organisms and those caused by toxic
bedrooms and bathrooms should be accessible directly
substances;
from halls or living rooms and not through other bedrooms.
In addition to the psychologic value of privacy, repeated
• water-based diseases;
studies have shown that lack of space and quiet due to
crowding can lead to poor school performance in children.
• water-related vector diseases; and
Coupled with a natural desire for privacy is the social
• water-scarce diseases.
desire for normal family and community life. A wholesome
atmosphere requires adequate living room space and
Numerous studies link improvements in sanitation and the
adequate space for withdrawal elsewhere during periods of
provision of potable water with significant reductions in
entertainment. This accessibility expands beyond the walls
morbidity and mortality from water-related diseases.
of the home and includes easy communication with centers
Clean water and sanitation facilities have proven to
of culture and business, such as schools, churches,
reduce infant and child mortality by as much as 55%
entertainment, shopping, libraries, and medical services.
in Third World countries according to studies from the
Healthy Housing Reference Manual
2-3
1980s. Waterborne diseases are often referred to as “dirty-
Of the 13 million housing units at the time without flush
water” diseases and are the result of contamination from
toilets, 11.8 million (90.7%) had an outside toilet or
chemical, human, and animal wastes. Specific diseases
privy, another 1 million (7.6%) had no toilet or privy,
in this group include cholera, typhoid, shigella, polio,
and the remainder had a nonflush toilet in the structure.
meningitis, and hepatitis A and E. Water-based diseases
are caused by aquatic organisms that spend part of their
In contrast to these figures, the 2000 census data demonstrate
life cycle in the water and another part as parasites of
the great progress that has been made in providing sanitary
animals. Although rare in the United States, these
sewer facilities. Nationally, 74.8% of homes are served by
diseases include dracunculiasis, paragonimiasis,
a public sewer, with 24.1% served by a septic tank or cesspool,
clonorchiasis, and schistosomiasis. The reduction in these
and the remaining 1.1% using other means.
diseases in many countries has not only led to decreased rates
of illness and death, but has also increased productivity
Vermin, such as rodents, have long been linked to
through a reduction in days lost from work.
property destruction and disease. Integrated pest
management, along with proper housing construction, has
Water-related diseases are linked to vectors that breed and
played a significant role in reducing vermin around the
live in or near polluted and unpolluted water. These vectors are
modern home. Proper food storage, rat-proofing
primarily mosquitoes that infect people with the disease
construction, and ensuring good sanitation outside the
agents for malaria, yellow fever, dengue fever, and
home have served to eliminate or reduce rodent problems
filariasis. While the control of vectorborne diseases is a
in the 21st century home.
complex matter, in the United States, most of the control
focus has been on controlling habitat and breeding areas
Facilities to properly store milk and food have not only been
for the vectors and reducing and controlling human cases
instrumental in reducing the incidence of some foodborne
of the disease that can serve as hosts for the vector.
diseases, but have also significantly changed the diet in
Vectorborne diseases have recently become a more of a
developed countries. Refrigeration can be traced to the
concern to the United States with the importation of the
ancient Chinese, Hebrews, Greeks, and Romans. In the
West Nile virus. The transmission of West Nile virus
last 150 years, great strides have been made in using
occurs when a mosquito vector takes a blood meal from a bird
refrigeration to preserve and cool food. Vapor compression
or incidental hosts, such as a dog, cat, horse, or other
using air and, subsequently, ammonia as a coolant was
vertebrate. The human cases of West Nile virus in
first developed in the 1850s. In the early 1800s, natural
2003 numbered 9,862, with 264 deaths. Finally,
ice was extracted for use as a coolant and preserver of
water-scarce diseases are diseases that flourish where
food. By the late 1870s, there were 35 commercial ice
sanitation is poor due to a scarcity of fresh water. Diseases
plants in the United States and, by 1909, there were 2,000.
included in this category are diphtheria, leprosy, whooping
However, as early as the 1890s, sources of natural ice
cough, tetanus, tuberculosis, and trachoma. These
began to be a problem as a result of pollution and sewage
diseases are often transmitted when the supply of fresh
dumped into bodies of water. Thus, the use of natural ice as
water is inadequate for hand washing and basic hygiene.
a refrigerant began to present a health problem. Mechanical
These conditions are still rampant in much of the world,
manufacture of ice provided a temporary solution, which
but are essentially absent from the United States due to
eventually resulted in providing mechanical refrigeration.
the extensive availability of potable drinking water.
Refrigeration was first used by the brewing and meat-packing
In 2000, USCB [10] reported that 1.4% of U.S. homes
industries; but most households had iceboxes (Figure 2.1),
lacked plumbing facilities. This differs greatly from the
which made the ice wagon a popular icon of the late
1940 census, when nearly one-half of U.S. homes lacked
1800s and early 1900s. In 1915, the first refrigerator, the
complete plumbing. The proportion has continually
Guardian, was introduced. This unit was the predecessor of
dropped, falling to about one-third in 1950 and then to
the Frigidaire. The refrigerator became as necessary to the
one-sixth in 1960. Complete plumbing facilities are
household as a stove or sewing machine. By 1937, nearly
defined as hot and cold piped water, a bathtub or shower,
6 million refrigerators were manufactured in the United
and a flush toilet. The containment of household sewage
States. By 1950, in excess of 80% of American farms and
is instrumental in protecting the public from waterborne
more than 90% of urban homes had a refrigerator.
and vectorborne diseases. The 1940 census revealed that
more than a third of U.S. homes had no flush toilet, with
Adequate living and sleeping space are also important in
70% of the homes in some states without a flush toilet.
protecting against contagion. It is an issue not only of
2-4
Basic Principles of Healthy Housing
to the International Code Council one- and two-family
dwelling code, the purpose of building codes is to provide
minimum standards for the protection of life, limb,
property, environment, and for the safety and welfare of
the consumer, general public, and the owners and
occupants of residential buildings regulated by this
code [12].
However, as with all types of codes, the development of
innovative processes and products must be allowed to take
a place in improving construction technology. Thus,
according to the International Code Council one- and
two-family dwelling code, building codes are not
intended to limit the appropriate use of materials,
appliances, equipment, or methods by design or
construction that are not specifically prescribed by the
code if the building official determines that the proposed
alternate materials, appliances, equipment or methods of
design or construction are at least equivalent of that
prescribed in this code. While the details of what a code
should include are beyond the scope of this section,
additional information can be found at
Figure 2.1. Circa 1890 Icebox
Source: Robert R. McCormick Museum, Wheaton, Illinois
http://www.iccsafe.org/, the Web site of the International
Code Council (ICC). ICC is an organization formed by
privacy but of adequate room to reduce the potential for the
the consolidation of the Building Officials and Code
transmission of contagion. Much improvement has been
Administrators International, Southern Building Code
made in the adequacy of living space for the U.S. family
Congress International, Inc., and the International
over the last 30 years. According to USCB [11], the
Conference of Building Officials [12].
average size of new single homes has increased from a
1970 average of 1,500 square feet to a 2000 average of
According to the Home Safety Council (HSC) [13], the
2,266 square feet. USCB [11] says that slightly less than
leading causes of home injury deaths in 1998 were falls
5% of U.S. homes were considered crowded in 1990; that
and poisonings, which accounted for 6,756 and
is, they had more than one person per room. However,
5,758 deaths, respectively. As expected, the rates and
this is an increase since the 1980 census, when the figure
national estimates of the number of fall deaths were
was 4.5%. This is the only time there has been an
highest among those older than 64 years, and stairs or steps
increase since the first housing census was initiated in
were associated with 17% of fall deaths. Overall, falls were
1940, when one in five homes was crowded. During the
the leading cause of nonfatal, unintentional injuries
1940 census, most crowded homes were found in
occurring at home and accounted for 5.6 million injuries.
southern states, primarily in the rural south. Crowding
Similar to the mortality statistics, consumer products most
has become common in a few large urban areas, with
often associated with emergency department visits included
more than one-fourth of all crowded units located in four
stairs and steps, accounting for 854,631 visits, and floors,
metropolitan areas: Houston, Los Angeles, Miami, and
accounting for 556,800 visits. A national survey by HSC
New York. The rate for California has not changed
found that one-third of all households with stairs did not
significantly between 1940 (13%) and 1990 (12%).
have banisters or handrails on at least one set of stairs.
Excessive crowding in homes has the potential to increase
Related to this, homes with older persons were more
not only communicable disease transmission, but also the
likely to have banisters or handrails than were those where
stress level of occupants because modern urban
young children live or visit. The survey also revealed that
individuals spend considerably more time indoors than
48% of households have windows on the second floor or
did their 1940s counterparts.
above, but only 25% have window locks or bars to
prevent children from falling out. Bathtub mats or
Protection Against Injury
nonskid strips to reduce bathtub falls were used in 63%
A major provision for safe housing construction is
of American households. However, in senior households
developing and implementing building codes. According
Healthy Housing Reference Manual
2-5
(age 70 years and older), 79% used mats or nonskid strips.
using a metal mesh screen with fireplaces and
Nineteen percent of the total number of homes surveyed
leaving glass doors open while burning a fire;
had grab bars to supplement the mats and strips. Significantly,
only 39% of the group most susceptible to falls (people aged
installing stovepipe thermometers to monitor flue
70 years and older) used both nonskid surfaces and grab bars.
temperatures;
Protection Against Fire
leaving air inlets on wood stoves open and never
An important component of safe housing is to control
restricting air supply to the fireplaces, thus
conditions that promote the initiation and spread of fire.
helping to reduce creosote buildup;
Between 1992 and 2001, an average of 4,266 Americans
died annually in fires and nearly 25,000 were injured.
using fire-resistant materials on walls around
This fact and the following information from the United
wood stoves;
States Fire Administration (USFA) [14] demonstrate the
impact that fire safety and the lack of it have in the United
never using flammable liquids to start a fire;
States. The United States has one of the highest fire death
rates in the industrialized world, with 13.4 deaths per
using only seasoned hardwood rather than soft,
million people. At least 80% of all fire deaths occur in
moist wood, which accelerates creosote buildup;
residences. Residential fires account for 23% of all fires
and 76% of structure fires. In one- and two-family
building small fires that burn completely and
dwellings, fires start in the kitchen 25.5% of the time and
produce less smoke;
originate in the bedroom 13.7% of the time. Apartment
fires most often start in the kitchen, but at almost twice
never burning trash, debris, or pasteboard in a
the rate (48.5%), with bedrooms again being the second
fireplace;
most common place at 13.4%.
placing logs in the rear of the fireplace on an adequate
These USFA statistics also disclose that cooking is the
supporting grate;
leading cause of home fires, usually a result of unattended
cooking and human error rather than mechanical failure
never leaving a fire in the fireplace unattended;
of the cooking units. The leading cause of fire deaths in
homes is careless smoking, which can be significantly
keeping the roof clear of leaves, pine needles,
deterred by smoke alarms and smolder-resistant bedding
and other debris;
and upholstered furniture. Heating system fires tend to be
a larger problem in single-family homes than in
covering the chimney with a mesh screen spark
apartments because the heating systems in family homes
arrester;and
frequently are not professionally maintained.
removing branches hanging above the chimney,
A number of conditions in the household can contribute
flues, or vents.
to the creation or spread of fire. The USFA data indicate
that more than one-third of rural Americans use fireplaces,
USFA [14] also notes that manufactured homes can be
wood stoves, and other fuel-fired appliances as primary sources
susceptible to fires. More than one-fifth of residential fires
of heat. These same systems account for 36% of rural
in these facilities are related to the use of supplemental
residential fires. Many of these fires are the result of
room heaters, such as wood- and coal-burning stoves,
creosote buildup in chimneys and stovepipes. These fires
kerosene heaters, gas space-heaters, and electrical heaters.
could be avoided by
Most fires related to supplemental heating equipment result
from improper installation, maintenance, or use of the
• inspecting and cleaning by a certified chimney
appliance. USFA recommendations to reduce the chance
specialist;
of fire with these types of appliances include the following:
• clearing the area around the hearth of debris,
• placing wood stoves on noncombustible surfaces
decorations, and flammable materials;
or a code-specified or listed floor surface;
2-6
Basic Principles of Healthy Housing
• placing noncombustible materials around the
alarm is then triggered by the drop in current between the
opening and hearth of fireplaces;
plates [16].
• placing space heaters on firm, out-of-the-way
Photoelectric devices function in one of two ways. First, smoke
surfaces to reduce tipping over and subsequent
blocks a light beam, reducing the light reaching the photocell,
spillage of fuel and providing at least 3 feet of air
which sets off the alarm. In the second and more
space between the heating device and walls, chairs,
common type of photoelectric unit, smoke particles
firewood, and curtains;
scatter the light onto a photocell, initiating an alarm. Both
detector types are effective smoke sensors and both must
• placing vents and chimneys to allow 18 inches of air
pass the same test to be certified as Underwriters Laboratories
space between single-wall connector pipes and
(UL) smoke detectors. Ionization detectors respond more
combustibles and 2 inches between insulated
quickly to flaming fires with smaller combustion particles,
chimneys and combustibles; and
while photoelectric detectors respond more quickly to
smoldering fires. Detectors can be damaged by steam or high
• using only the fuel designated by the
temperatures. Photoelectric detectors are more expensive
manufacturer for the appliance.
than ionization detectors and are more sensitive to minute
smoke particles. However, ionization detectors have a
The ability to escape from a building when fire has been
degree of built-in security not inherent to photoelectric
discovered or detected is of extreme importance. In the
detectors. When the battery starts to fail in an ionization
modern home, three key elements can contribute to a safe
detector, the ion current falls and the alarm sounds,
exit from a home during the threat of fire. The first of
warning that it is time to change the battery before the
these is a working smoke alarm system. The average
detector becomes ineffective. Backup batteries may be used
homeowner in the 1960s had never heard of a smoke
for photoelectric detectors that are operated using the
alarm, but by the mid-1980s, laws in 38 states and in
home’s electrical system.
thousands of municipalities required smoke alarms in all
new and existing residences. By 1995, 93% of all single-
According to USFA [14], a properly functioning smoke
family and multifamily homes, apartments, nursing
alarm diminishes the risk for dying in a fire by
homes, and dormitories were equipped with alarms. The
approximately 50% and is considered the single most
cost decreased from $1,000 for a professionally installed unit
important means of preventing house and apartment fire
for a three-bedroom home in the 1970s to an owner-
fatalities. Proper installation and maintenance, however,
installed $10 unit. According to the EPA [15],
are key to their usefulness. Figure 2.2 shows a typical smoke
ionization chamber and photoelectric are the two most
alarm being tested.
common smoke detectors available commercially.
Helmenstein [16] states that a smoke alarm uses one or
Following are key issues regarding installation and
both methods, and occasionally uses a heat detector, to
maintenance of smoke alarms. (Smoke alarms should be
warn of a fire. These units can be powered by a 9-volt battery,
installed on every level of the home including the
a lithium battery, or 120-volt house wiring. Ionization
basement, both inside and outside the sleeping area.)
detectors function using an ionization chamber and a minute
source of ionizing radiation. The radiation source is
• Smoke alarms should be installed on the ceiling or
americium-241 (perhaps 1/5,000th of a gram), while the
6-8 inches below the ceiling on side walls.
ionization chamber consists of two plates separated by about a
centimeter. The power source (battery or house current)
• Battery replacement is imperative to ensuring proper
applies voltage to the plates, resulting in one plate being
operation. Typically, batteries should be replaced at
charged positively while the other plate is charged negatively.
least once a year, although some units are
The americium constantly releases alpha particles that knock
manufactured with a 10-year battery. A “chirping”
electrons off the atoms in the air, ionizing the oxygen and
noise from the unit indicates the need for battery
nitrogen atoms in the chamber. The negative plate attracts
replacement. A battery-operated smoke alarm has a
the positively charged oxygen and nitrogen atoms, while the
life expectancy of 8 to 10 years.
electrons are attracted to the positive plate, generating a
small, continuous electric current. If smoke enters the
• Battery replacement is not necessary in units that
ionization chamber, the smoke particles attach to the ions
are connected to the household electrical system.
and neutralize them, so they do not reach the plate. The
Healthy Housing Reference Manual
2-7
the National Fire Protection Association (NFPA) [17],
electrical distribution equipment was the third-leading
cause of home fires and the second-leading cause of fire
deaths in the United States between 1994 and 1998.
Specifically, NFPA reported that 38,300 home electrical
fires occurred in 1998, which resulted in 284 deaths,
1,184 injuries, and approximately $670 million in direct
property damage. The same report indicated that the
leading cause of electrical distribution fires was ground
fault or short-circuit problems. A third of the home
electrical distribution fires were a result of problems with
fixed wiring, while cords and plugs were responsible for
17% of these fires and 28% of the deaths.
Additional investigation of these statistics reveals that
electrical fires are one of the leading types of home fires in
Figure 2.2. Smoke Alarm Testing
Source: Federal Emergency Management Agency
manufactured homes. USFA [14] data demonstrate that
many electrical fires in homes are associated with
• Regardless of the type, it is crucial to test every smoke
improper installation of electrical devices by do-it-
alarm monthly. Data from HSC [13] revealed that
yourselfers. Errors attributed to this amateur electrical
only 83% of individuals with fire alarms test them
work include use of improperly rated devices such as
at least once a year; while only 19% of households
switches or receptacles and loose connections leading to
with at least one smoke alarm test them quarterly.
overheating and arcing, resulting in fires. Recommendations
to reduce the risk of electrical fires and electrocution
A second element impacting escape from a building is a
include the following:
properly installed fire-suppression system. According to USFA
[14], sprinkler systems began to be used over 100 years ago in
1.
Use only the correct fuse size and do not use
New England textile mills. Currently, few homes are protected
pennies behind a fuse.
by residential sprinkler systems. However, UL-listed home
systems are available and are designed to protect homes much
2.
Install ground fault circuit interrupters (GFCI) on
faster than standard commercial or industrial sprinklers. Based
all outlets in kitchens, bathrooms, and anywhere
on approximately 1% of the total building price in new
else near water. This can also be accomplished by
construction, sprinkler systems can be installed for a
installing a GFCI in the breaker box, thus
reasonable price. These systems can be retrofitted to
protecting an entire circuit.
existing construction and are smaller than commercial
systems. In addition, homeowner insurance discounts for
3.
Never place combustible materials near light
such systems range between 5% and 15% and are
fixtures, especially halogen bulbs that get very hot.
increasing in availability.
4.
Use only the correct bulb size in a light fixture.
The final element in escaping from a residential fire is having a
fire plan. A 1999 survey conducted by USFA [14] found
5.
Use only properly rated extension cords for the
that 60% of Americans have an escape plan, with 42% of
job needed.
these individuals having practiced the plan. Surprisingly,
26% of Americans stated they had never thought about
6.
Never use extension cords as a long-term solution
practicing an escape plan, and 3% believed escape
to the need for an additional outlet. Size the
planning to be unnecessary. In addition, of the people
extension cord to the wattage to be used.
who had a smoke alarm sound an alert over the past year
before the study, only 8% believed it to be a fire and
7.
Never run extension cords inside walls or under
thought they should evacuate the building.
rugs because they generate heat that must be able
to dissipate.
Protection from electrical shocks and burns is also a vital
element in the overall safety of the home. According to
2-8
Basic Principles of Healthy Housing
Fire Extinguishers
an electrical cord and outlet with a slash through it (do not
A fire extinguisher should be listed and labeled by an
use it on an electrical fire).
independent testing laboratory such as FM (Factory
Mutual) or UL. Fire extinguishers are labeled according to
Fire extinguishers also have a number rating. For Type A
the type of fire on which they may be used. Fires involving
fires, 1 means 1¼ gallons of water; 2 means 2½ gallons of
wood or cloth, flammable liquids, electrical, or metal sources
water, 3 means 3¾ gallons of water, etc. For Type B and
react differently to extinguishers. Using the wrong type of
Type C fires, the number represents square feet. For example,
extinguisher on a fire could be dangerous and could worsen
2 equals 2 square feet, 5 equals 5 square feet, etc.
the fire. Traditionally, the labels A, B, C, and D have been
used to indicate the type of fire on which an extinguisher
Fire extinguishers can also be made to extinguish more
is to be used.
than one type of fire. For example, you might have an
extinguisher with a label that reads 2A5B. This would
Type A—Used for ordinary combustibles such as cloth,
mean this extinguisher is good for Type A fires with a
wood, rubber, and many plastics. These types of fire
2½-gallon equivalence and it is also good for Type B fires
usually leave ashes after they burn: Type A extinguishers
with a 5-square-foot equivalency. A good extinguisher to
for ashes. The Type A label is in a triangle on the
have in each residential kitchen is a 2A10BC fire extinguisher.
extinguisher.
You might also get a Type A for the living room and
bedrooms and an ABC for the basement and garage.
Type B—Used for flammable liquid fires such as oil,
gasoline, paints, lacquers, grease, and solvents. These
PASS is a simple acronym to remind you how to operate most
substances often come in barrels: Type B extinguishers for
fire extinguishers—pull, aim, squeeze, and sweep. Pull the
barrels. The Type B label is in a square on the
pin at the top of the cylinder. Some units require the
extinguisher.
releasing of a lock latch or pressing a puncture lever. Aim
the nozzle at the base of the fire. Squeeze or press the
Type C—Used for electrical fires such as in wiring, fuse boxes,
handle. Sweep the contents from side to side at the base
energized electrical equipment, and other electrical sources.
of the fire until it goes out. Shut off the extinguisher and
Electricity travels in currents; Type C extinguishers for
then watch carefully for any rekindling of the fire.
currents. The Type C label is in a circle on the
extinguisher.
Protection Against Toxic Gases
Protection against gas poisoning has been a problem since
Type D—Used for metal fires such as magnesium,
the use of fossil fuels was combined with relatively tight
titanium, and sodium. These types of fires are very dangerous
housing construction. NFPA [17] notes that National
and seldom handled by the general public; Type D means
Safety Council statistics reflect unintentional poisonings
don’t get involved. The Type D label is in a star on the
by gas or vapors, chiefly carbon monoxide (CO),
extinguisher.
numbering about 600 in 1998. One-fourth of these
involved heating or cooking equipment in the home. The
The higher the rating number on an A or B fire extinguisher,
U.S. Consumer Product Safety Commission [18] states
the more fire it can put out, but high-rated units are often
that in 2001 an estimated 130 deaths occurred as a result
the heavier models. Extinguishers need care and must be
of CO poisoning from residential sources; this decrease in
recharged after every use—a partially used unit might as
deaths is related to the increased use of CO detectors. In
well be empty. An extinguisher should be placed in the
addition, approximately 10,000 cases of CO-related injuries
kitchen and in the garage or workshop. Each extinguisher
occur each year. NFPA [17] also notes that, similar to fire
should be installed in plain view near an escape route and
deaths, unintentional CO deaths are highest for ages 4 years
away from potential fire hazards such as heating appliances.
and under and ages 75 years and older. Additional information
about home CO monitoring can be found in Chapter 5.
Recently, pictograms have come into use on fire extinguishers.
These picture the type of fire on which an extinguisher is
References
to be used. For instance, a Type A extinguisher has a
1. Ehlers VE, Steel EW. Municipal and rural
pictogram showing burning wood. A Type C extinguisher has
sanitation. Sixth edition. New York: McGraw-Hill
a pictogram showing an electrical cord and outlet. These
Book Company; 1965. p. 462-4.
pictograms are also used to show what not to use. For
example, a Type A extinguisher also show a pictogram of
Healthy Housing Reference Manual
2-9
2.
National Institute on Aging. Hyperthermia—too
11. US Census Bureau. Historical census of housing
hot for your health, fact sheet health information.
tables—crowded and severely crowded housing
Bethesda, MD: US Department of Health and
units, 2002. Washington, DC: US Census
Human Services; no date. Available from URL:
Bureau; 2003. Available from URL:
http://www.niapublications.org/engagepages/
http://www.census.gov/hhes/ www/housing/
hyperther.asp.
census/historic/crowding.html.
3.
US Census Bureau. Historical census of housing
12. International Code Council. Fact sheet. Falls
tables—house heating fuel. Washington, DC: US
Church, VA: International Code Council; no date.
Census Bureau; 2002. Available from URL:
Available from URL: http://www.iccsafe.org/news/pdf/
http://www.census.gov/hhes/www/housing/
factssheet.pdf.
census/historic/fuels.html.
13. Home Safety Council. The state of home safety in
4.
Zilber SA. Review of health effects of indoor
America—executive summary. Washington, DC:
lighting. Architronic 1993;2(3). Available from URL:
The Home Safety Council; 2002.
http://architronic.saed.kent.edu/v2n3/v2n3.06.html.
14. US Fire Administration. Welcome to the U.S. Fire
5.
US Environmental Protection Agency.
Administration (USFA) Web site. Washington,
Information on levels of environmental noise
DC: Federal Emergency Management Agency,
requisite to protect public health and welfare with
Department of Homeland Security; 2003.
an adequate margin of safety. Washington, DC: US
Available from URL: http://www.usfa.fema.gov/.
Environmental Protection Agency; 1974.
15. US Environmental Protection Agency. Smoke
6.
Public Health, England and Wales. The Household
detectors and radiation. Washington, DC: US
Appliances (Noise Emission) Regulations 1990.
Environmental Protection Agency; 2003. Available
London: Her Majesty’s Stationery Office; 1990.
from URL: http://www.epa.gov/
radiation/sources/smoke_alarm.htm.
7.
American Speech-Language-Hearing-Association.
Noise: noise is difficult to define. Rockville, MD:
16. Helmenstein AM. How do smoke detectors work?
American Speech-Language-Hearing-Association;
Photoelectric & ionization smoke detectors, what
2003. Available from URL: http://www.asha.org/
you need to know about chemistry. New York:
public/hearing/disorders/noise.htm.
About, Inc.; 2003. Available from URL:
http://chemistry.about.com/library/weekly/
8.
US Environmental Protection Agency. Factoids:
aa071401a.htm.
drinking water and ground water statistics for
2002. Washington, DC: US Environmental
17. National Fire Protection Association. NFPA fact
Protection Agency, Office of Ground Water and
sheets—electrical safety. Quincy, MA: National
Drinking Water; January 2003. Available from URL:
Fire Protection Association; 2003. Available from
http://www.epa.gov/safewater.
URL: http://www.nfpa.org/Research/
NFPAFactSheets/Electrical/electrical.asp.
9.
Hinrichsen D, Robey B, Upadhyay UD. The health
dimension. In: Solutions for a water-short world.
18. US Consumer Product Safety Commission.
Population Report, Series M, No. 14. Baltimore, MD:
Nonfire carbon monoxide deaths: 2001 annual
Johns Hopkins School of Public Health, Population
estimate. Washington, DC: US Consumer
Information Program; 1998. Available from URL:
Product Safety Commission; 2004. Available from
http://www.infoforhealth.org/pr/m14/m14chap5.shtml
URL: http://www.cpsc.gov/LIBRARY/co04.pdf.
10. US Census Bureau. Historical census of housing
tables—plumbing facilities, 2002. Washington,
DC: US Census Bureau; 2003. Available from URL:
http://www.census.gov/hhes/www/housing/census/
historic/plumbing.html.
2-10
Basic Principles of Healthy Housing
Additional Sources of Information
Barbalace RC. Environmental justice and the NIMBY
principle. Environmental Chemistry.com: Environmental,
Chemistry, and Hazardous Materials Information and
Resources. Portland, ME; no date. Available from URL:
http://environmentalchemistry.com/yogi/hazmat/articles/
nimby.html.
Bryant B. The role of SNRE in the environmental justice
movement. Ann Arbor, MI: University of Michigan; 1997.
Available from URL: http://www.umich.edu/~snre492/
history.html.
Bullard RD. Waste and racism: a stacked deck? Forum
Appl Res Public Pol spring 1993.
National Institute on Aging. Hypothermia: a cold weather
hazard, fact sheet health information. Bethesda, MD: US
Department of Health and Human Services; 2001.
Available from URL: http://www.niapublications.org/
engagepages/ hypother.asp.
National Weather Service. Natural hazard statistics; no
date. Silver Spring, MD: National Weather Service.
Available from URL: http://www.nws.noaa.gov/
om/hazstats.shtml.
US Census Bureau. New residential construction
(building permits, housing starts, and housing
completions). Washington, DC: US Census Bureau; no
date. Available from URL:
http://www.census.gov/newresconst.
Healthy Housing Reference Manual
2-11
2-12
Basic Principles of Healthy Housing
Chapter 3: Housing Regulations
“The poorest man may in his cottage bid defiance to all the
the first tenements were built. In 1867, a report by the
force of the Crown. It may be frail—its roof may shake—the
New York Metropolitan Board of Health on living
wind may blow through it—the storm may enter, the rain
conditions in tenements convinced the New York State
may enter—but the King of England cannot enter—all his
legislature to pass the Tenement Housing Act of 1867 [2].
force dares not cross the threshold of the ruined tenement!”
The principal requirements of the act included the
following:
William Pitt, March 1763
Every room occupied for sleeping, if it does not
Introduction
communicate directly with the external air, must
William Pitt, arguing before the British Parliament against
have a ventilating or transom window of at least
excise officers entering private homes to levy the Cyder
3 square feet to the neighboring room or hall.
Tax, eloquently articulated this long-held and cherished
notion of the sanctity of private property. However, a
A proper fire escape is necessary on every tenement
person’s right to privacy is not absolute. There has always
or lodging house.
been a tension between the rights of property owners to do
whatever they desire with their property and the ability of
The roof is to be kept in repair and the stairs are to
the government to regulate uses to protect the safety,
have banisters.
health, and welfare of the community. Few, however,
would argue with the right and duty of a city government
At least one toilet is required for every
to prohibit the operation of a munitions factory or a
20 occupants for all such houses, and those toilets
chemical plant in the middle of a crowded residential
must be connected to approved disposal systems.
neighborhood.
Cleansing of every lodging house is to be to the
History
satisfaction of the Board of Health, which is to have
The first known housing laws are in the Code of Laws of
access at any time.
Hammurabi [1], who was the King of Babylonia, circa
1792-1750 BC. These laws addressed the responsibility of the
All cases of infectious disease are to be reported to
home builder to construct a quality home and outlined the
the Board by the owner or his agent; buildings are
implications to the builder if injury or harm came to the
to be inspected and, if necessary, disinfected or
owner as a result of the failure to do so. During the Puritan
vacated if found to be out of repair.
period (about 1620-1690), housing laws essentially
governed the behavior of the members of the society. For
There were also regulations governing distances between
example, no one was allowed to live alone, so bachelors,
buildings, heights of rooms, and dimensions of windows.
widows, and widowers were placed with other families as
Although this act had some beneficial influences on
servants or boarders. In 1652, Boston prohibited building
overcrowding, sewage disposal, lighting, and ventilation,
privies within 12 feet of the street. Around the turn of the
perhaps its greatest contribution was in laying a foundation
18th century, some New England communities
for more stringent future legislation.
implemented local ordinances that specified the size of
houses. During the 17th century, additional public policies
Jacob A. Riis, a Danish immigrant and a police reporter on
on housing were established. Because the English tradition
New York’s Lower East Side, published a book titled How
of using wooden chimneys and thatched roofs led to fires
the Other Half Lives—Studies Among the Tenements of New
in many dwellings, several colonies passed regulations
York [3], which swayed public opinion in the direction of
prohibiting them.
housing reform and resulted in the Tenement House Act of
1901. The basic principles established in the Tenement
After the early 17th century came an era of very rapid
House Act of 1901 still underlie much of the housing
metropolitan growth along the East Coast. This growth
efforts in New York City today [4]. Since 1909, with the
was due largely to immigration from Europe and was
establishment of the Philadelphia Housing Association, that city
spurred by the Industrial Revolution. The most serious
has had almost continual inspection and improvement.
housing problems began in New York about 1840 when
Chicago enacted housing legislation as early as 1889 and
Healthy Housing Reference Manual
3-1
health legislation as early as 1881. Regulations on
The Housing Act of 1949 allowed “primarily residential”
ventilation, light, drainage, and plumbing were put into
and “blighted” urban areas to be condemned, cleared of
effect in 1896.
buildings, and sold for private development. In addition
to assisting in slum clearance, this act also provided for
Before 1892, all government involvement in housing was
additional public housing and authorized the USDA to
at a local level. In 1892, however, the federal government
provide farmers with loans to construct, improve, repair
passed a resolution authorizing investigation of slum
or replace dwellings to provide decent, safe, and sanitary
conditions in cities with 200,000 or more inhabitants.
living conditions for themselves, their tenants, lessees,
Congress appropriated only $20,000 (roughly equal to
sharecroppers, and laborers.
$390,000 in 2003) to cover the expenses of this project,
which limited the number of investigations.
Because the many housing responsibilities administered
by various agencies within the federal government proved
No significant housing legislation was passed in the
unwieldy, the Housing and Urban Development Act was
20th century until 1929 [5], when the New York State
passed in 1965. The U.S. Department of Housing and
legislature passed its Multiple Dwelling Law. Other cities
Urban Development (HUD) was created to centralize the
and states followed New York’s example and permitted
responsibilities of the Housing and Home Finance Agency
less strict requirements in their codes. This decreased
and incorporated the FHA, the Federal National
what little emphasis there was on enforcement.
Mortgage Association, the Public Housing Administration,
Conditions declined until, by the 1930s, President
Urban Development Administration, and the Community
Franklin D. Roosevelt’s shocking report to the people was
Facilities Administration.
“that one-third of the nation is ill-fed, ill-housed, and ill-
clothed.” In response to the overwhelming loss of homes
Zoning, Housing Codes, and Building Codes
during the Great Depression, Congress passed the United
Housing is inextricably linked to the land on which it is
States Housing Act of 1937, which created the United
located. Changes in the patterns of land use in the United
States Housing Authority (USHA). This act subsidized
States, shifting demographics, an awareness of the need
construction of new public housing units and required
for environmental stewardship, and competing uses for
the elimination of at least an equivalent number of units
increasingly scarce (desirable) land have all placed added
from the local housing supply that were determined to be
stress on the traditional relationship between the property
inferior. In 1942, the USHA was renamed the Federal
owner and the community. This is certainly not a new
Public Housing Administration and, in 1947, was
development.
renamed the Public Housing Administration.
In the early settlement of this country, following the precedent
The federal government not only encouraged the
set by their forefathers from Great Britain, gunpowder
construction of public housing, but took on the role of
mills and storehouses were prohibited from the heavily
financing private housing. In 1938, the Federal National
populated portions of towns, owing to the frequent fires and
Mortgage Association was created. (Fannie Mae became a
explosions. Later, zoning took the form of fire districts
private organization in 1968 [6].) Its purpose was to
and, under implied legislative powers, wooden buildings
provide a secondary market for the FHA, created in 1934,
were prohibited from certain sections of a municipality.
and Veterans Administration (VA) mortgage loans. The
Massachusetts passed one of the first zoning laws in 1692.
Servicemen’s Readjustment Act of 1944, also known as
This law authorized Boston, Salem, Charlestown, and
the GI Bill of Rights, created a VA loan program
certain other market towns in the province to restrict the
guaranteeing home mortgage loans for veterans. This
establishment of slaughterhouses and stillhouses for
legislation, in conjunction with the FHA loan program,
currying leather to certain locations in each town.
was the impetus for initiating the huge program of home
construction and subsequent suburban growth following
Few people objected to such restrictions. Still, the tension
World War II. In 1946, the Farmers Home Administration,
remained between the right to use one’s land and the
housed in the United States Department of Agriculture
community’s right to protect its citizens. In 1926, the
(USDA), was created to make loans and grants for
United States Supreme Court took up the issue in Village
constructing and repairing farm homes and assisting rural
of Euclid, Ohio, v. Ambler Realty [7]. In this decision,
self-help housing groups.
the Court noted,
3-2
Housing Regulations
“Until recent years, urban life was comparatively
many cases, the housing inspector may be able to
simple; but with great increase and concentration of
eliminate violations or properties in violation of housing
population, problems have developed which require
codes through enforcement of the zoning ordinance.
additional restrictions in respect of the use and
occupation of private lands in urban communities.”
Zoning Objectives
As stated earlier, the purpose of a zoning ordinance is to
In explaining its reasoning, the Court said,
ensure that the land uses within a community are
regulated not only for the health, safety, and welfare of the
“the law of nuisances may be consulted not for the
community, but also are in keeping with the
purpose of controlling, but for the helpful aid of its
comprehensive plan for community development. The
analogies in the process of ascertaining the scope of the
provisions in a zoning ordinance that help to achieve
police power. Thus the question of whether the
development that provides for health, safety, and welfare
power exists to forbid the erection of a building of a
are designed to do the following:
particular kind or a particular use is to be
determined, not by an abstract consideration of the
Regulate height, bulk, and area of structure. To
building or other thing considered apart, but by
provide established standards for healthful housing
considering it in connection with the circumstances
within the community, regulations dealing with
and the locality… A nuisance may be merely the
building heights, lot coverage, and floor areas must
right thing in the wrong place—like a pig in the
be established. These regulations then ensure that
parlor instead of the barnyard.”
adequate natural lighting, ventilation, privacy, and
recreational areas for children will be realized.
Zoning, housing, and building codes were adopted to improve
These are all fundamental physiologic needs
the health and safety of people living in communities.
necessary for a healthful environment. Safety from
And, to some extent, they have performed this function.
fires is enhanced by separating buildings to meet
Certainly, housing and building codes, when enforced,
yard and open-space requirements. Through
have resulted in better constructed and maintained
requiring a minimum lot area per dwelling unit,
buildings. Zoning codes have been effective in
population density controls are established.
segregating noxious and dangerous enterprises from
residential areas. However, as the U.S. population has
Avoid undue levels of noise, vibration, glare, air
grown and changed from a rural to an urban then to a
pollution, and odor. By providing land-use
suburban society, land use and building regulations
category districts, these environmental stresses upon
developed for the 19th and early 20th centuries are
the individual can be reduced.
creating new health and safety problems not envisioned in
earlier times.
Lessen street congestion by requiring off-street
parking and off-street loading.
Zoning and Zoning Ordinances
Zoning is essentially a means of ensuring that a community’s
Facilitate adequate provision of water, sewerage,
land uses are compatible with the health, safety, and
schools, parks, and playgrounds.
general welfare of the community. Experience has shown
that some types of controls are needed to provide orderly
Provide safety from flooding.
growth in relation to the community plan for development.
Just as a capital improvement program governs public
Conserve property values. Through careful
improvements such as streets, parks and other recreational
enforcement of the zoning ordinance provisions,
facilities, schools, and public buildings, so zoning governs
property values can be stabilized and conserved.
the planning program with respect to the use of public
and private property.
To understand more fully the difference between zoning
and subdivision regulations, building codes, and housing
It is very important that housing inspectors know the general
ordinances, the housing inspector must know what cannot
nature of zoning regulations because properties in
be accomplished by a zoning ordinance. Items that
violation of both the housing code and the zoning ordinance
cannot be accomplished by a zoning ordinance include
must be brought into full compliance with the zoning
the following:
ordinance before the housing code can be enforced. In
Healthy Housing Reference Manual
3-3
• Overcrowding or substandard housing. Zoning
These initiatives are often called smart growth programs.
is not retroactive and cannot correct existing
It is imperative, if this approach is taken, that both
conditions. These are corrected through
governmental officials and citizens be involved in the
enforcement of a minimum standards housing code.
planning stage. Without this involvement, the community
may end up with major problems, such as overloaded
• Materials and methods of construction. Materials
infrastructure, structures of inappropriate construction
and methods of construction are enforced through
crowded together, and fire and security issues for
building codes rather than through zoning.
residents. Increased density could strain the existing water,
sewer and waste collection systems, as well as fire and
• Cost of construction. Quality of construction,
police services, unless proper planning is implemented.
and hence construction costs, are often regulated
through deed restrictions or covenants. Zoning
In recent years, some ordinances have been partially based
does, however, stabilize property values in an area
on performance standards rather than solely on land-use
by prohibiting incompatible development, such as
intensity. For example, some types of industrial developments
heavy industry in the midst of a well-established
may be permitted in a less intense use district provided
subdivision.
that the proposed land use creates no noise, glare, smoke,
dust, vibration, or other environmental stress exceeding
• Subdivision design and layout. Design and layout
acceptable standards and provided further that adequate
of subdivisions, as well as provisions for parks and
off-street parking, screening, landscaping, and similar
streets, are controlled through subdivision
measures are taken.
regulations.
Bulk and Height Requirements. Most early zoning
Content of the Zoning Ordinance
ordinances stated that, within a particular district, the
Zoning ordinances establish districts of whatever size,
height and bulk of any structure could not exceed certain
shape, and number the municipality deems best for
dimensions and specified dimensions for front, side, and
carrying out the purposes of the zoning ordinance. Most
rear yards. Another approach was to use floor-area ratios
cities use three major districts: residential (R), commercial
for regulation. A floor-area ratio is the relation between
(C), and industrial (I). These three may then be
the floor space of the structure and the size of the lot on
subdivided into many subdistricts, depending on local
which it is located. For example, a floor-area ratio of
conditions; e.g., R-1 (single-unit dwellings), R-2
1 would permit either a two-story building covering 50%
(duplexes), R-3 (low-rise apartment buildings), and so on.
of the lot, or a one-story building covering 100% of the lot, as
These districts specify the principal and accessory uses,
demonstrated in Figure 3.1. Other zoning ordinances
exceptions, and prohibitions [8].
specify the maximum amount of the lot that can be
covered or merely require that a certain amount of open
In general, permitted land uses are based on the intensity
space must be provided for each structure, and leave the
of land use—a less intense land use being permitted in a
builder the flexibility to determine the location of the
more intense district, but not vice versa. For example, a
structure. Still other ordinances, rather than specify a
single-unit residence is a less intense land use than a multiunit
particular height for the structure, specify the angle of
dwelling (defined by HUD as more than four living
light obstruction that will assure adequate air and light to
units) and hence would be permitted in a residential
the surrounding structures, as demonstrated in Figure 3.2.
district zoned for more intense land use (e.g., R-3). A
multiunit dwelling would not, however, be permitted in
Yard Requirements. Zoning ordinances also contain
an R-1 district. While intended to promote the health,
minimum requirements for front, rear, and side yards. These
safety, and general welfare of the community, housing
requirements, in addition to stating the lot dimensions,
trends in the last half of the 20th century have led a
usually designate the amount of setback required. Most
number of public health and planning officials to
ordinances permit the erection of auxiliary buildings in
question the blind enforcement of zoning districts. These
rear yards provided that they are located at stated
individuals, citing such problems as urban sprawl, have
distances from all lot lines and provided sufficient open
stated that municipalities need to adopt a more flexible
space is maintained. If the property is a corner lot,
approach to land use regulation—one that encourages
additional requirements are established to allow visibility
creating mixed-use spaces, increasing population densities,
for motorists.
and reducing reliance on the automobile.
3-4
Housing Regulations
Figure 3.1. Example of a Floor Area
Off-street Parking. Space for off-street parking and off-
another nonconforming use. Some zoning ordinances
street loading, especially for commercial buildings, is also
further provide a period of amortization during which
contained in zoning ordinances. These requirements are
nonconforming land use must be phased out.
based on the relationship of floor space or seating capacity
to land use. For example, a furniture store would require
Variances
fewer off-street parking spaces in relation to the floor area
Zoning ordinances contain provisions for permitting
than would a movie theater.
variances and providing a method for granting these
variances, subject to certain specified provisions. A
Exceptions to the Zoning Code
variance may be granted when, owing to the specific conditions
Nonconforming Uses
or use of a particular lot, an undue hardship would be
Because zoning is not retroactive, all zoning ordinances
imposed on the owner if the exact content of the
contain a provision for nonconforming uses. If a use has
ordinance is enforced. A variance may be granted due to
already been established within a particular district before the
the shape, topography, or other characteristic of the lot.
adoption of the ordinance, it must be permitted to
For example, suppose an irregularly shaped lot is located
continue, unless it can be shown to be a public nuisance.
in a district having a side yard requirement of 20 feet on a
side and a total lot size requirement of 10,000 square feet.
Provisions are, however, put into the ordinance to aid in
Further suppose that this lot contains 10,200 square feet
eliminating nonconforming uses over time. These
(and thus meets the total size requirement); however, due
provisions generally prohibit a) an enlargement or
to the irregular shape of the lot, there would be sufficient
expansion of the nonconforming use, b) reconstruction of
space for only a 15-foot side yard. Because a hardship
the nonconforming use if more than a certain portion of
would be imposed on the owner if the exact letter of the
the building should be destroyed, c) resumption of the
law is applied, the owner of the property could apply to
use after it has been abandoned for a period of specified
the zoning adjustment board for a variance. Because the
time, and d) changing the use to a higher classification or to
total area of the lot is sufficient and a lessening of the
Figure 3.2. Example of an Angle of Light Obstruction
Healthy Housing Reference Manual
3-5
ordinance requirements would not be detrimental to the
It is critical for the housing or building inspector and the
surrounding property, nor would it interfere with neighboring
zoning inspector to work closely in municipalities where
properties, a variance would probably be granted. Note
these positions and responsibilities are separate. Experience
that a variance is granted to the owner under specific
has shown that illegally converted properties are often
conditions. Should use of the property change, the
among the most substandard encountered in the municipality
variance would be voided.
and often contain especially dangerous housing code violations.
Exceptions
In communities where the zoning code is enforced effectively,
An exception is often confused with a variance. In every
the resulting zoning compliance helps to advance, as well
city there are some necessary uses that do not correspond
as sustain, many of the minimum standards of the
to the permitted land uses within the district. The zoning
housing code such as occupancy, ventilation, light, and
code recognizes, however, that if proper safeguards are
unimpeded egress. By the same token, building or
provided, these uses would not have a detrimental effect
housing inspectors can often aid the zoning inspector by
on the district. An example would be a fire station that
helping eliminate some nonconforming uses through code
could be permitted in a residential area, provided the
enforcement.
station house is designed and the property is properly
landscaped to resemble or fit in with the characteristics of the
Housing Codes
neighborhood in which it is located.
A housing code, regardless of who promulgates it, is basically
an environmental health protection code. Housing codes
Administration
are distinguished from building codes in that they cover
Zoning inspectors are essential to the zoning process
houses, not buildings in general. For example, the housing
because they have firsthand knowledge of a case. Often,
code requires that walls support the weight of the roof,
the zoning inspector may also be the building inspector or
any floors above, and the furnishings, occupants, etc.,
housing inspector. Because the building inspector or
within a building.
housing inspector is already in the field making
inspections, it is relatively easy for that individual to
Early housing codes primarily protected only physical health;
check compliance with the zoning ordinances. Compliance
hence, they were enforced only in slum areas. In the
is determined by comparing the actual land use with that
1970s, it was realized that, if urban blight and its associated
allowed for the area and shown on the zoning map.
human suffering were to be controlled, housing codes
must consider both physical and mental health and must
Each zoning ordinance has a map detailing the permitted
be administered uniformly throughout the community.
usage for each block. Using a copy of this map, the
inspector can make a preliminary check of the land use in
In preparing or revising housing codes, local officials must
the field. If the use does not conform, the inspector must
maintain a level of standards that will not merely be
then contact the Zoning Board to see whether the property in
minimal. Standards should maintain a living environment
question was a nonconforming use at the time of the
that contributes positively to healthful individual and
passage of the ordinance and whether an exception or variance
family living. The fact that a small portion of housing
has been granted. In cities where up-to-date records are
fails to meet a desirable standard is not a legitimate reason
maintained, the inspector can check the use in the field.
for retrogressive modification or abolition of a standard.
The adoption of a housing ordinance that establishes low
When a violation is observed, and the property owners
standards for existing housing serves only to legalize and
are duly notified of the violation, they have the right to
perpetuate an unhealthy living environment. Wherever
request a hearing before the Zoning Board of Adjustment
local conditions are such that immediate enforcement of
(also called the Zoning Board of Appeals in some cities).
some standards within the code would cause undue
The board may uphold the zoning enforcement officer or
hardship for some individuals, it is better to allow some
may rule in favor of the property owner. If the action of
time for compliance than to eliminate an otherwise
the zoning officer is upheld, the property owner may, if
satisfactory standard. When immediate health or safety
desired, seek relief by appealing the decision to the courts;
hazards are not involved, it is often wise to attempt to
otherwise, the violation must be corrected to conform to
create a reasonable timetable for accomplishing necessary
the zoning code.
code modifications.
3-6
Housing Regulations
History
dwellings were needed. Commonly called housing codes,
To assist municipalities with developing legislation necessary
these ordinances establish minimum standards to make
to regulate the quality of housing, the American Public
dwellings safe, sanitary, and fit for human habitation by
Health Association (APHA) Committee on the Hygiene
governing their condition and maintenance, their
of Housing prepared and published in 1952 a proposed
supplied utilities and facilities, and their occupancy. The
housing ordinance. This provided a prototype on which
2003 International Code Council (ICC) [13,14]
such legislation might be based and has served as the
International Residential Code-One- and Two-Family
basis for countless housing codes enacted in the United
Dwellings (R101.3) states
States since that time. Some municipalities enacted it without
change. Others made revisions by omitting some portions,
“the purpose of this code is to provide minimum
modifying others, and sometimes adding new provisions [9].
requirements to safeguard the public safety, health
and general welfare, through affordability, structural
The APHA ordinance was revised in 1969 and 1971. In 1975,
strength, means of egress, facilities, stability, sanitation,
APHA and the CDC jointly undertook the job of
light and ventilation, energy conservation, safety to
rewriting and updating this model ordinance. The new
fire and property from fire and other hazards
ordinance was entitled the APHA-CDC Recommended
attributed to the built environment.”
Housing Maintenance and Occupancy Ordinance [10]. The
most recent model ordinance was published by APHA in
Critical Requirements of an Effective Housing Program
1986 as Housing and Health: APHA-CDC Recommended
A housing code is limited in its effectiveness by several
Minimum Housing Standards [11]. This new ordinance is
factors. First, if the housing code does not contain standards
one of several model ordinances available to communities
that adequately protect the health and well-being of the
when they are interested in adopting a housing code.
individuals, it cannot be effective. The best-trained
housing inspector, if not armed with an adequate housing
A community should read and consider each element
code, can accomplish little good in the battle against
within the model code to determine its applicability to
urban blight.
their community. A housing code is merely a means to an
end. The end is the eventual elimination of all substandard
A second issue in establishing an effective housing code is
conditions within the home and the neighborhood. This end
the need to establish a baseline of current housing conditions.
cannot be achieved if the community adopts an
A systems approach requires that you establish where you
inadequate housing code.
are, where you are going, and how you plan to achieve your
goals. In using a systems approach, it is essential to know
Objectives
where the program started so that the success or failure of
The Housing Act of 1949 [12] gave new impetus to
various initiatives can be established. Without this
existing local, state, and federal housing programs
information, success cannot be replicated, because you
directed toward eliminating poor housing. In passing
cannot identify the obstacles navigated nor the elements
this legislation, Congress defined a new national
of success. Many initiatives fail because program
objective by declaring that “the general welfare and
administrators are without the necessary proof of success
security of the nation and the health and living
when facing funding shortfalls and budget cuts.
standards of its people...require a decent home and a
suitable living environment for every American family.”
A third factor affecting the quality of housing codes is
This mandate generated an awareness that the quality of
budget. Without adequate funds and personnel, the
housing and residential environment has an enormous
community can expect to lose the battle against urban
influence upon the physical and mental health and the
blight. It is only through a systematic enforcement effort
social well-being of each individual and, in turn, on the
by an adequately sized staff of properly trained inspectors
economic, political, and social conditions in every
that the battle can be won.
community. Consequently, public agencies, units of
government, professional organizations and others sought
A fourth factor is the attitude of the political bodies
ways to ensure that the quality of housing and the
within the area. A properly administered housing program
residential environment did not deteriorate.
will require upgrading substandard housing throughout the
community. Frequently, this results in political pressures
It soon became apparent that ordinances regulating the
being exerted to prevent the enforcement of the code in
supplied utilities and the maintenance and occupancy of
certain areas of the city. If the housing effort is backed
Healthy Housing Reference Manual
3-7
properly by all political elements, blight can be controlled
enabling legislation of the code needed to resolve the
and eventually eliminated within the community. If, however,
problem or there are gaps in jurisdiction.
the housing program is not permitted to choke out the
spreading influence of substandard conditions, urban
Content of a Housing Code
blight will spread like a cancer, engulfing greater and
Although all comprehensive housing codes or ordinances
greater portions of the city. Similarly, an effort directed at
contain a number of common elements, the provisions of
only the most seriously blighted blocks in the city will
communities will usually vary. These variations stem from
upgrade merely those blocks, while the blight spreads
differences in local policies, preferences, and, to a lesser
elsewhere. If urban blight is to be controlled, it must be
extent, needs. They are also influenced by the standards
cut out in its entirety.
set by the related provisions of the diverse building,
electrical, and plumbing codes in use in the municipality.
A fifth element that limits housing programs is whether
they are supported fully by the other departments within
Within any housing code there are generally five features:
the city. Regardless of which city agency administers the
housing program, other city agencies must support the
1.
Definitions of terms used in the code.
activities of the housing program. In addition, great effort
should be expended to obtain the support and
2.
Administrative provisions showing who is
cooperation of the community. This can be accomplished
authorized to administer the code and the basic
through public awareness and public information
methods and procedures that must be followed in
programs, which can result in considerable support or
implementing and enforcing the sections of the
considerable resistance to the efforts of the program.
code. Administrative provisions deal with items
such as reasonable hours of inspections, whether
A sixth limitation is an inadequately or improperly
serving violation notices is required, how to notify
trained inspection staff. Inspectors should be capable of
absentee owners or resident-owners or tenants, how to
evaluating whether a serious or a minor problem exists in
process and conduct hearings, what rules to follow
matters ranging from the structural stability of a building
in processing dwellings alleged to be unfit for
to the health and sanitary aspects of the structure. If they
human habitation, and how to occupy or use
do not have the authority or expertise, they should
dwellings finally declared fit.
develop that expertise or establish effective and efficient
agreements with overlapping agencies to ensure timely
3.
Substantive provisions specifying the various types
and appropriate response.
of health, building, electrical, heating, plumbing,
maintenance, occupancy, and use conditions that
A seventh item that frequently restricts the effectiveness of
constitute violations of the housing code. These
a housing program is the fact that many housing groups
provisions can be and often are grouped into three
fail to do a complete job of evaluating housing
categories: minimum facilities and equipment for
problems. The deterioration of an area may be due to
dwelling units; adequate maintenance of dwellings
factors such as housing affordability, tax rates, or issues
and dwelling units, as well as their facilities and
related to investment cost and return. In many cases, the
equipment; and occupancy conditions of dwellings
inspection effort is restricted to merely evaluating the
and dwelling units.
conditions that exist, with little or no thought given to
why these conditions exist. If a housing effort is to be
4.
Court and penalty sections outlining the basis for
successful, as part of a systems approach, the question of
court action and thepenalty or penalties to which
why the homes deteriorated must be considered. Was
the alleged violator will be subjected if proved
it because of environmental stresses within the
guilty of violating one or more provisions of the code.
neighborhood that need to be eliminated or was it
because of apathy on the part of the occupants? In either
5.
Enabling, conflict, and unconstitutionality
case, if the causative agent is not removed, then the
clauses providing the date a new or amended code
inspector faces an annual problem of maintaining the
will take effect, prevalence of more stringent
quality of that residence. It is only by eliminating the
provision when there is a conflict of two codes,
causes of deterioration that the quality of the
severability of any part of the ordinance that
neighborhood can be maintained. Often the regulatory
might be found unconstitutional, and retention of
authority does not have adequate authority within the
all other parts in full course and effect. In any city
3-8
Housing Regulations
following the format of the APHA-CDC Recommended
deed registration there. If it does not, the advice of the
Housing Maintenance and Occupancy Ordinance
municipal law department should be sought about the next
[10] the housing officer or other supervisor in
steps to follow.
charge of housing inspections will also adopt
appropriate housing rules and regulations from
Due Process Requirements. Every notice, complaint,
time to time to clarify or further refine the
summons, or other type of legal paper concerning alleged
provisions of the ordinance. When rules and
housing code violations in a given dwelling or dwelling
regulations are used, care should be taken that the
unit must be legally served on the proper party to be valid
department is not overburdened with a number of
and to prevent harassment of innocent parties. This might
minor rules and regulations. Similarly, a housing
be the owner, agent, or tenant, as required by the code. It
ordinance that encompasses all rules and regulations
is customary to require that the notice to correct existing
might have difficulty because any amendments to
violations and any subsequent notices or letters be served by
it will require action by the political element of
certified or registered mail with return receipt requested. The
the community. Some housing groups, in
receipt serves as proof of service if the case has to be taken
attempting to obtain amendments to an
to court.
ordinance, have had the entire ordinance thrown
out by the political bodies.
Due process requirements also call for clarity and
specificity with respect to the alleged violations, both in
Administrative Provisions of a Housing Code
the violation notices and the court complaint-summons.
The administrative procedures and powers of the housing
For this reason, special care must be taken to be complete
inspection agency, its supervisors, and its staff are similar to
and accurate in listing the violations and charges. To
other provisions in that all are based on the police power of
illustrate, rather than direct the violator to repair all
the state to legislate for public health and safety. In
windows where needed, the violator should be told
addition, the administrative provisions, and to a lesser
exactly which windows and what repairs are involved.
extent, the court and penalty provisions, outline how the
police power is to be exercised in administering and
The chief limitation on the due process requirement, with
enforcing the code.
respect to service of notices, lies in cases involving
immediate threats to health and safety. In these instances,
Generally, the administrative elements deal with
the inspection agency or its representative may, without
procedures for ensuring that the constitutional doctrines of
notice or hearing, issue an order citing the existence of
reasonableness, equal protection under the law and due
the emergency and requiring that action deemed
process of law are observed. They also must guard against
necessary to meet the emergency be taken.
violation of prohibitions against unlawful search and seizure,
impairment of obligations of contract, and unlawful
In some areas housing courts on the municipal level have
delegation of authority. These factors encompass items of
advocates that assist both plaintiffs and defendants
great importance to housing inspection supervisors such
prepare for the court process or to resolve the issue to
as the inspector’s right of entry, reasonable hours of
avoid court.
inspection, proper service, and the validity of the provisions
of the housing codes they administer.
Hearings and Condemnation Power. The purpose of a
hearing is to give the alleged violator an opportunity to be
Owner of Record. It is essential to file legal actions
heard before further action is taken by the housing inspection
against the true owners of properties in violation of
agency. These hearings may be very informal, involving
housing codes. With the advent of the computer, this is
meetings between a representative of the agency and the
often much easier than in the past. Databases that provide
person ordered to take corrective action. They also may
this information are readily available from many offices of
be formal hearings at which the agency head presides and
local government such as the tax assessment office. The
at which the city and the defendant both are entitled to
method of obtaining the name and address of the legal
be represented by counsel and expert witnesses.
owner of a property in violation varies from place to
place. Ordinarily, a check of the city tax records will
Informal Hearings. A violator may have questions about a
suffice unless there is reason to believe these are not up to
violation notice or the notice may be served at a time
date. In this case, a further check of county or parish
when personal hardship or other factors prevent a violator
records will turn up the legal owner if state law requires
from meeting the terms of the notice. Therefore, many
Healthy Housing Reference Manual
3-9
housing codes provide the opportunity for a hearing at
If they fail to do so, some codes will hold the owner liable
which the violator may discuss questions or problems and
to the purchaser and the inspection agency for violations.
seek additional time or some modification of the order.
Administered in a firm but understanding manner, these
Tickets for Minor Offenses. Denver, Colorado, has used
hearings can serve as invaluable aids in relieving needless
minimal financial fines to prod minor violators and first
fears of those involved, in showing how the inspection
offenders into correcting violations without the city
program is designed to help them and in winning their
resorting to court action. There are mixed views about
voluntary compliance.
this technique because it is akin to formal police action.
Nevertheless, the action may stimulate compliance and
Formal Hearings. Formal hearings are often quasijudicial
reduce the amount of court action needed to achieve it.
hearings (even though the prevailing court rules of
evidence do not always apply) from which an appeal may
Forms and Form Letters. A fairly typical set of forms and
be taken to court. All witnesses must therefore be sworn
form letters are described below. It should be stressed that
in, and a record of the proceedings must be made. The
inspection forms to be used for legal notices must satisfy
formal hearing is used chiefly as the basis for determining
legal standards of the code, be meaningful to the owner
whether a dwelling is fit for human habitation,
and sufficiently explicit about the extent and location of
occupancy, or use. In the event it is proved unfit, the
particular defects, be adaptable to statistical compilation
building is condemned and the owner is given a
for the governing body reports, and be written in a manner
designated amount of time either to rehabilitate it
that will facilitate clerical and other administrative usage.
completely or to demolish it. Where local funds are
available, a municipality may demolish the building and
The Daily Report Form. This form gives the inspection
place a lien against the property to cover demolition costs
agency an accurate basis for reporting, evaluating, and, if
if the owner fails to obey the order within the time
necessary, improving the productivity and performance of
specified. This type of condemnation hearing is a very
its inspectors.
effective means of stimulating prompt and appropriate
corrective action when it is administered fairly and firmly.
Complaint Form. This form helps obtain full information
from the complainant and thus makes the relative
Procedures for Coping With Common Problems. Several
seriousness of the problem clear and reduces the number
states and local communities have developed innovative
of crank complaints.
ways to resolve code violation issues.
No-entry Notice. This notice advises occupants or owners
Limitation of Occupancy Notification. This technique
that an inspector was there and that they must return a
was pioneered in Wilmington, Delaware. It makes it
call to the inspector.
mandatory for property owners in the community to
obtain a legal notice from the housing inspection agency
Inspection Report Form. This is the most important form
specifying the maximum number of persons that may
in an agency. It comes in countless varieties, but if designed
occupy each of their properties. It also requires these owners
properly, it will ensure more productivity and more
to have a residence, place of business, or an agent for their
thoroughness by the inspectors, reduce the time spent in
properties within the community. The agent should be
writing reports, locate all violations correctly, and reduce
empowered to take remedial action on any of the
the time required for typing violation notices. Forms may
properties found in violation. In addition, if the property
vary widely in sophistication from a very simple form to
is sold, the new owner must obtain a new Limitation of
one whose components are identified by number for use
Occupancy Notification.
in processing the case by automation. Some forms are a
combined inspection report and notice form in triplicate so
Request for Inspections. Several states permit their
that the first page can be used as the notice of violation, the
municipalities to offer a request for inspection service. For
second as the office record, and the third as the guide for
a fee, the housing inspector will inspect a property for
reinspection. A covering form letter notifies the violator of
violations of the housing code before its sale so that the
the time allowed to correct the conditions listed in the
buyer can learn its condition in advance. Many states and
report form.
localities now require owners to notify prospective
purchasers of any outstanding notice of health risk or
Violation Notice. This is the legal notice that housing
violations they have against their property before the sale.
code violations exist and must be corrected within the
3-10
Housing Regulations
indicated amount of time. The notice may be in the form
Dwelling units should have provisions for preparing at least
of a letter that includes the alleged violations or has a
one regularly cooked meal per day. Minimum equipment
copy of these attached. It may be a standard notice form,
should include a kitchen sink in good working condition
or it may be a combined report-notice. Regardless of the
and properly connected to the water supply system
type of notice used, it should make the location and
approved by the appropriate authority. It should provide,
nature of all violations clear and specify the exact section
at all times, an adequate amount of heated and unheated
of the code that covers each one. The notice must advise
running water under pressure and should be connected to
violators of their right to a hearing. It should also indicate
a sewer system approved by the appropriate authority.
that the violator has a right to be represented by counsel
Cabinets or shelves, or both, for storing eating, drinking,
and that failure to obtain counsel will not be accepted as
and cooking utensils and food should be provided. These
grounds for postponing a hearing or court case.
surfaces should be of sound construction and made of
material that is easy to clean and that will not have a toxic
Hearing Forms. These should include a form letter
or deleterious effect on food.
notifying the violator of the date and time set for the hearing,
a standard summary sheet on which the supervisor can
In addition, a stove and refrigerator should be provided.
record the facts presented at an informal hearing, and a
Within every dwelling there should be a room that affords
hearing-decision letter for notifying all concerned of the
privacy and is equipped with a flush toilet in good working
hearing results. The latter should include the names of the
condition.
violator, inspector, law department, and any other city
official or agency that may be involved in the case.
Within the vicinity of the flush toilet, a sink should be
provided. In no case should a kitchen sink substitute as a
Reinspection Form Letters or Notices. These have the
lavatory sink. In addition, within each dwelling unit there
same characteristics as violation notices except that they
should be, within a room that affords privacy, either a bathtub
cover the follow-up orders given to the violator who has
or shower or both, in good working condition. Both the
failed to comply with the original notice within the time
lavatory sink and the bathtub or shower or both should be
specified. Some agencies may use two or three types of
equipped with an adequate amount of heated and
these form letters to accommodate different degrees of
unheated water under pressure. Each should be connected
response by the violator. Whether one or several are used,
to an approved sewer system.
standardization of these letters or notices will expedite the
processing of cases.
Within each dwelling unit two or more means of egress should
be provided to safe and open space at ground level. Provisions
Court Complaint and Summons Forms. These forms
should be incorporated within the housing code to meet the
advise alleged violators of the charges against them and
safety requirements of the state and community involved. The
summon them to appear in court at the specified time
housing code should spell out minimum standards for lighting
and place. It is essential that the housing inspection
and ventilation within each room in the structure. In addition,
agency work closely with the municipal law department
minimum thermal standards should be provided.
in preparing these forms so that each is done in exact
Although most codes merely provide the requirement of a
accord with the rules of court procedure in the relevant
given temperature at a given height above floor level, the
state and community.
community should give consideration to the use of
effective temperatures. The effective temperature is a means of
Court Action Record Form. This form provides an accurate
incorporating not only absolute temperature in degrees, but
running record of the inspection agency’s court actions and
also humidity and air movement, giving a better indication of
their results.
the comfort index of a room.
Substantive Provisions of a Housing Code
The code should provide that no person shall occupy or
A housing code is the primary tool of the housing
let for occupancy any dwelling or dwelling units that do
inspector. The code spells out what the inspector may or
not comply with stated requirements. Generally, these
may not do. An effort to improve housing conditions can be
requirements specify that the foundation, roof, exterior walls,
no better than the code allows. The substantive provisions of
doors, window space and windows of the structure be
the code specify the minimal housing conditions acceptable
sound and in good repair; that it be moisture-free,
to the community that developed them.
watertight and reasonably weather tight and that all
structural surfaces be sound and in good repair.
Healthy Housing Reference Manual
3-11
HUD defines a multifamily dwelling unit as one that contains
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7.
Paulson PB. Protecting zoning laws. Atlanta:
North Buckhead Civic Association; 2000 18 Mar.
“The ICC International Codes (I Codes) combine
Available from URL:
the strengths of the regional codes without regional
http://www.nbca.org/TAP_AJC_3-18.htm.
limitations. The ICC is a nonprofit organization
dedicated to developing a single set of comprehensive
8.
Municipal Code Corporation. Municipal building
and coordinated national codes to make compliance
codes (online library). Tallahassee, FL: Municipal
easier and more cost-effective. I Codes respond to the
Code Corporation. Available from URL:
needs of the construction industry and public safety.
http://www.municode.com/resources/
A single set of codes has strong support from
online_codes.asp.
government, code enforcement officials, fire officials,
architects, engineers, builders, developers, and
9.
American Public Health Association. Housing
building owners and managers.”
ordinance. Am J Public Health 1952
Jan;42(1):76-7.
10. US Public Health Service. APHA-CDC
recommended housing maintenance and occupancy
3-12
Housing Regulations
ordinance. Atlanta: US Department of Health and
US Department of Housing and Urban Development. Final
Human Services; 1975.
report of HUD review of model building codes.
Washington, DC: US Department of Housing and Urban
11. American Public Health Association. Housing
Development; no date. Available from URL:
and health: APHA-CDC recommended minimum
http://www.hud.gov/offices/fheo/disabilities/
housing standards. Washington, DC: American
modelcodes/chapter5.html.
Public Health Association; 1986.
12. Lang RE, Sohmer RR, editors. Legacy of the
Housing Act of 1949: The past, present, and
future of federal housing and urban policy.
Housing Policy Debate 2000;11(2): 291-7.
Available from URL:
http://www.fanniemaefoundation.org/programs/
hpd/pdf/ hpd_ 1102_edintro.pdf.
13. International Code Council. International
residential code 2003. Country Club Hills, IL:
ICC; 2003.
14. International Code Council. International
building code 2003. Country Club Hills, IL:
ICC; 2003.
Additional Sources of Information
American Planning Association. Available from URL:
http://www.planning.org/.
Arendt R. “Open Space” zoning: what it is and why it
works. Planners Commission Journal 1992. Available
from URL: http://www.plannersweb.com/articles/are015.html.
Bookmark, Inc. Available from URL: http://www.
bookmarki.com.
International Code Council. Available from URL:
http://www.iccsafe.org.
Rosenberg M. Zoning: residential, commercial, or
industrial? New York: About, Inc.; no date. Available
from URL: http://geography.about.com/library/weekly/
aa072801a.htm?iam=sherlock_abc/.
US Department of Energy, Land Use Planning. Smart
Communities Network. Washington, DC: US Department
of Energy; no date. Available from URL: http://www.
smartcommunities.ncat.org/landuse/luintro.shtml.
US Department of Housing and Urban Development.
Available from URL: http://www.hud.gov/.
Healthy Housing Reference Manual
3-13
3-14
Housing Regulations
Chapter 4: Disease Vectors and Pests
“Sometimes poor housing is a shorthand way of describing
This chapter deals with disease vectors and pests as
living conditions of poor people. The poor include the aged,
factors related to the health of households.
deprived, ethnic minority groups, the infirmed, and families
headed by unemployed women. In other words, the people
Disease Vectors and Pests
most at risk for illness often live in inferior housing.
Integrated pest management (IPM) techniques are
Therefore, it is a matter of conjecture whether many people
necessary to reduce the number of pests that threaten
live in poor housing because they are sick or are sick because
human health and property. This systems approach to
they live in poor housing.”
the problem relies on more than one technique to reduce
or eliminate pests. It can be visualized best as concentric
Carter L. Marshall, M.D.
rings of protection that reduce the need for the most
Dynamics of Health and Disease
risky and dangerous options of control and the potential
Appleton, Century Crofts 1972
for pests to evolve and develop. It typically involves using
some or all of the following steps:
Introduction
The most immediate and obvious link between housing and
• monitoring, identifying, and determining the
health involves exposure to biologic, chemical, and
level of threat from pests;
physical agents that can affect the health and safety of the
occupants of the home. Conditions such as childhood lead
• making the environment hostile to pests;
poisoning and respiratory illnesses caused by exposure to
radon, asbestos, tobacco smoke, and other pollutants are
• building the pests out by using pest-proof building
increasingly well understood and documented. However,
materials;
even 50 years ago, public health officials understood that
housing conditions were linked to a broader pattern of
• eliminating food sources, hiding areas, and
community health. For example, in 1949, the Surgeon
other pest attractants;
General released a report comparing several health status
indicators among six cities having slums. The publication
• using traps and other physical elimination devices; and
reported that:
• when necessary, selecting appropriate poisons
• the rate of deaths from communicable disease in
for identified pests.
these areas was the same as it was for the rest of
the country 50 years ago (i.e., around 1900);
The above actions are discussed in more detail in the
following section on the four basic strategies for
• most of the tuberculosis cases came from 25% of
controlling rodents.
the population of these cities; and
Most homeowners have encountered a problem with
• the infant mortality rate was five times higher
rodents, cockroaches, fleas, flies, termites, or fire ants.
than in the rest of the country, approximately
These pests destroy property or carry disease, or both,
equal to what it was 50 years ago.
and can be a problem for rich and poor alike.
Housing-related health concerns include asthma episodes
Rodents
triggered by exposure to dust mites, cockroaches, pets,
Rodents destroy property, spread disease, compete for human
and rodents. The existence of cockroaches, rats, and mice
food sources, and are aesthetically displeasing. Rodent-
mean that they can also be vectors for significant
associated diseases affecting humans include plague, murine
problems that affect health and well-being. They are
typhus, leptospirosis, rickettsialpox, and rat-bite fever. The
capable of transmitting diseases to humans. According to
three primary rodents of concern to the homeowner are the
a 1997 American Housing Survey, rats and mice infested
Norway rat (Rattus norvegicus), roof rat (Rattus rattus), and the
2.7 million of 97 million housing units. A CDC-sponsored
house mouse (Mus musculus). The term “commensal” is
survey of two major American cities documented that
applied to these rodents, meaning they live at people’s expense.
nearly 50% of the premises were infected with rats and mice.
The physical traits of each are demonstrated in Figure 4.1.
Healthy Housing Reference Manual
4-1
Figure 4.1. Field Identification of Domestic Rodents [2]
Barnett [1] notes that the house mouse is abundant
The roof rat (Figure 4.3) is a slender, graceful, and very
throughout the United States. The Norway rat
agile climber. The roof rat prefers to live aboveground:
(Figure 4.2) is found throughout the temperate regions
indoors in attics, between floors, in walls, or in enclosed
of the world, including the United States. The roof rat
spaces; and outdoors in trees and dense vine growth.
is found mainly in the South, across the entire nation to
Contrasted with the
the Pacific coast. As a group, rodents have certain
roof rat, the Norway rat
behavioral characteristics that are helpful in
is at home below the
understanding them. They are perceptive to touch,
ground, living in a
with sensitive whiskers and guard hairs on their bodies.
burrow. The house
Thus, they favor running along walls and between
mouse commonly is
objects that allow them
found living in human
constant contact with
quarters, as suggested by
vertical surfaces. They are
its name. Signs indicative
Figure 4.3. Roof Rat [4]
known to have poor
of the presence of
eyesight and are alleged to
rodents—aside from seeing live or dead rats and hearing
be colorblind.
rats—are rodent droppings, runways, and tracks
Contrastingly, they have an
(Figure 4.4). Other signs include nests, gnawings, food
extremely sharp sense of
scraps, rat hair, urine spots, and rat body odors. Note
smell and a keen sense of
that waste droppings from rodents are often confused
taste. The word rodent is
with cockroach egg packets, which are smooth,
derived from the Latin verb
segmented, and considerably smaller than a mouse dropping.
rodere, meaning “to gnaw.”
Figure 4.2. Norway Rat [3]
According to the Military Pest Management Handbook
The gnawing tendency leads to structural damage to
(MPMH) [2], rats and mice are very suspicious of any
buildings and initiates fires when insulation is chewed
new objects or food found in their surroundings. This
from electrical wires. Rodents will gnaw to gain entrance
characteristic is one reason rodents can survive in dangerous
and to obtain food.
environments. This avoidance reaction accounts for
prebaiting (baiting without poisoning) in control programs.
4-2
Disease Vectors and Pests
built or modified in a way that prevents easy access by
rodents. Tactics for rodent exclusion include building or
covering doors and windows with metal. Rats can gnaw
through wooden doors and windows in a very short time
to gain entrance. All holes in a building’s exterior should
be sealed. Rats are capable of enlarging openings in
masonry, especially if the mortar or brick is of poor
quality. All openings more than ¾-inch wide should be
closed, especially around pipes and conduits. Cracks
around doors, gratings, windows, and other such
openings should be covered if they are less than 4 feet
above the ground or accessible from ledges, pipes, or
wires (Figure 4.5).
Additional tactics include using proper materials for rat
proofing. For example, sheet metal of at least 26-gauge,
¼-inch or ½-inch hardware cloth, and cement are all
suitable rat-resistant materials. However, ½-inch
hardware cloth has little value against house mice. Tight
fittings and self-closing doors should be constructed.
Rodent runways can be behind double walls; therefore,
spaces between walls and floor-supporting beams should
be blocked with fire stops. A proper rodent-proofing
Figure 4.4. Signs of Rodent Infestation [2]
strategy must bear in mind that rats can routinely jump
2 feet vertically, dig 4 feet or more to get under a
Initially, rats or mice begin by taking only small amounts
foundation, climb rough walls or smooth pipes up to
of food. If the animal becomes ill from a sublethal dose of
3 inches in diameter, and routinely travel on electric
poison, its avoidance reaction is strengthened, and a
or telephone wires.
poisoning program becomes extremely difficult to
complete. If rodents are hungry or exposed to an environment
The first three strategies—good sanitation techniques,
where new objects and food are commonly found, such
habitat denial, and rat proofing—should be used initially
as a dump, their avoidance reaction may not be as strong;
in any rodent management program. Should they fail, the
in extreme cases of hunger, it may even be absent.
fourth strategy is a killing program, which can vary from
a family cat to the professional application of
The first of four basic strategies for controlling rodents is
rodenticides. Cats can be effective against mice, but
to eliminate food sources. To accomplish this, it is
typically are not useful against a rat infestation. Over-the-
imperative for the homeowner or occupant to do a good
counter rodenticides can be purchased and used by the
job of solid waste management. This requires proper
homeowner or occupant. These typically are in the red
storing, collecting, and disposing of refuse.
squill or warfarin groups.
The second strategy is to eliminate breeding and nesting
A more effective alternative is trapping. There are a
places. This is accomplished by removing rubbish from
variety of devices to choose from when trapping rats or
near the home, including excess lumber, firewood, and
mice. The two main groups of rat and mouse traps are
similar materials. These items should be stored above
live traps (Figure 4.6) and kill traps (Figure 4.7). Traps
ground with 18 inches of clearance below them. This
usually are placed along walls, near runways and burrows,
height does not provide a habitat for rats, which have a
and in other areas. Bait is often used to attract the
propensity for dark, moist places in which to burrow.
rodents to the trap. To be effective, traps must be
Wood should not be stored directly on the ground, and
monitored and emptied or removed quickly. If a rat
trash and similar rubbish should be eliminated.
caught in a trap is left there, other rats may avoid the traps.
A trapping strategy also may include using live traps to
The third strategy is to construct buildings and other
remove these vermin.
structures using rat-proofing methods. MPMH notes
that it is much easier to manage rodents if a structure is
Healthy Housing Reference Manual
4-3
Figure 4.7. Kill Traps for Rats [2]
Cockroaches
Cockroaches have become well adapted to living with and
near humans, and their hardiness is legendary. In light of
these facts, cockroach control may become a homeowner’s
most difficult task because of the time and special
knowledge it often involves. The cockroach is considered
an allergen source and an asthma trigger for residents.
Although little evidence exists to link the cockroach to
specific disease outbreaks, it has bee demonstrated to
carry Salmonella typhimurium, Entamoeba histolytica, and
the poliomyelitis virus. In addition, Kamble and Keith [6]
note that most cockroaches produce a repulsive odor that
can be detected in infested areas. The sight of cockroaches
can cause considerable psychologic or emotional distress
in some individuals. They do not bite, but they do have
heavy leg spines that may scratch.
According to MPMH [2], there are 55 species of
cockroaches in the United States. As a group, they tend to
prefer a moist, warm habitat because most are tropical in
Figure 4.5. Rodent Prevention [2]
origin. Although some tropical cockroaches feed only on
vegetation, cockroaches of public health interest tend to
live in structures and are customarily scavengers.
Cockroaches will eat a great variety of materials, including
cheese and bakery products, but they are especially fond
of starchy materials, sweet substances, and meat products.
Cockroaches are primarily nocturnal. Daytime sightings
may indicate potentially heavy infestations. They tend to
hide in cracks and crevices and can move freely from
room to room or adjoining housing units via wall spaces,
plumbing, and other utility installations. Entry into
homes is often accomplished through food and beverage
boxes, grocery sacks, animal food, and household goods
Figure 4.6. Live Traps for Rats [5]
carried into the home. The species of public health
4-4
Disease Vectors and Pests
interest that commonly inhabit human dwellings
(Figures 4.8-4.13) include the following: German
cockroach (Blattella germanica); American cockroach
(Periplaneta americana); Oriental cockroach (Blatta
orientalis); brown-banded cockroach (Supella longipalpa);
Australian cockroach (Periplaneta australasiae); smoky-
brown cockroach (Periplaneta fuliginosa); and brown
cockroach (Periplaneta brunnea).
Four management strategies exist for controlling
cockroaches. The first is prevention. This strategy
includes inspecting items being carried into the home
Figure 4.10. Oriental Cockroaches, Various Stages and Ages [7]
and sealing cracks and crevices in kitchens, bathrooms,
exterior doors, and windows. Structural modifications
would include weather stripping and pipe collars. The
second strategy is sanitation. This denies cockroaches food,
water, and shelter. These efforts include quickly cleaning
food particles from shelving and floors; timely washing of
dinnerware; and routine cleaning under refrigerators,
stoves, furniture, and similar areas. If pets are fed indoors,
pet food should be stored in tight containers and not left
in bowls overnight. Litter boxes should be cleaned
routinely. Access should be denied to water sources by
fixing leaking plumbing, drains, sink traps, and purging
clutter, such as papers and soiled clothing and rags. The
Figure 4.11. German Cockroaches, Various Stages and Ages [7]
third strategy is trapping. Commercially available cockroach
Figure 4.8. American, Oriental, German, and Brown- banded
Figure 4.12. Brown-banded Cockroaches, Various Stages and
Cockroaches [7]
Ages [7]
Figure 4.13. Wood Cockroach, Adult Male [7]
Figure 4.9. American Cockroaches, Various Stages and Ages [7]
Healthy Housing Reference Manual
4-5
traps can be used to capture roaches and serve as a
monitoring device. The most effective trap placement is
against vertical surfaces, primarily corners, and under
sinks, in cabinets, basements, and floor drains. The fourth
strategy is chemical control. The use of chemicals
typically indicates that the other three strategies have been
applied incorrectly. Numerous insecticides are available
and appropriate information is obtainable from EPA.
Fleas
The most important fleas as disease vectors are those that
carry murine typhus and bubonic plague. In addition,
fleas serve as intermediate hosts for some species of dog and
rodent tapeworms that occasionally infest people. They also
may act as intermediate hosts of filarial worms
(heartworms) in dogs. In the United States, the most
important disease related to fleas is the bubonic plague.
This is primarily a concern of residents in the southwestern
and western parts of the country (Figure 4.14).
Of approximately 2,000 species of flea, the most common
flea infesting both dogs and cats is the cat flea
Ctenocephalides felis. Although numerous animals, both
wild and domestic, can have flea infestations, it is from
the exposure of domestic dogs and cats that most
homeowners inherit flea infestation problems. According to
MPMH [2], fleas are wingless insects varying from 1 to
8½ millimeters (mm) long, averaging 2 to 4 mm, and
feed through a siphon or tube. They are narrow and
Figure 4.14. Reported Human Plague Cases (1970-1997) [8]
compressed laterally with backwardly directed spines,
which adapt them for moving between the hairs and
feathers of mammals and birds. They have long, powerful
legs adapted for jumping. Both sexes feed on blood, and
the female requires a blood meal before she can produce
viable eggs. Fleas tend to be host-specific, thus feeding on
only one type of host. However, they will infest other
species in the absence of the favored host. They are found
in relative abundance on animals that live in burrows and
sheltered nests, while mammals and birds with no
permanent nests or that are exposed to the elements tend
to have light infestations.
MPMH [2] notes that fleas undergo complete metamorphosis
(egg, larva, pupa, and adult). The time it takes to
complete the life cycle from egg to adult varies according
to the species, temperature, humidity, and food
availability. Under favorable conditions, some species can
complete a generation in as little as 2 or 3 weeks.
Figure 4.15 shows the life cycle of the flea.
Figure 4.15. Flea Life Cycle [2]
4-6
Disease Vectors and Pests
Flea eggs usually are laid singly or in small groups among
• Reapplication to heavily infested source points in
the feathers or hairs of the host or in a nest. They are
the home and the yard may be needed to elimi-
often laid in carpets of living quarters if the primary host
nate pre-emerged adults.
is a household pet. Eggs are smooth, spherical to oval,
light colored, and large enough to be seen with the naked
Flies
eye. An adult female flea can produce up to 2,000 eggs in
The historical attitude of Western society toward flies has
a lifetime. Flea larvae are small (2 to 5 mm), white, and
been one of aesthetic disdain. The public health view is to
wormlike with a darker head and a body that will appear
classify flies as biting or nonbiting. Biting flies include
brown if they have fed on flea feces. This stage is mobile
sand flies, horseflies, and deerflies. Nonbiting flies include
and will move away from light, thus they typically will be
houseflies, bottleflies, and screwworm flies. The latter
found in shaded areas or under furniture. In 5 to 12 days,
group is often referred to as synanthropic because of their
they complete the three larval stages; however, this may
close association with humans. In general, the presence of
take several months depending on environmental
flies is a sign of poor sanitation. The primary concern of
conditions. The larvae, after completing development,
most homeowners is nonbiting flies.
spin a cocoon of silk encrusted with granules of sand or
According to
various types of debris to form the pupal stage. The pupal
MPMH [2], the
stage can be dormant for 140 to 170 days. In some areas
housefly (Musca
of the country, fleas can survive through the winter. The
domestica) (Figure
pupae, after development, are stimulated to emerge as
4.16) is one of the
adults by movement, pressure, or heat. The pupal form of
most widely
the flea is resistant to insecticides. An initial treatment,
distributed insects,
while killing egg, larvae, and adult forms, will not kill the
occurring
pupae. Therefore, a reapplication will often be necessary.
throughout the
The adult forms are usually ready to feed about 24 hours
United States, and
Figure 4.16. Housefly [Musca domestica] [9]
after they emerge from the cocoon and will begin to feed
is usually the
within 10 seconds of landing on a host. Mating usually
predominant fly species in homes and restaurants. M.
follows the initial blood meal, and egg production is
domestica is also the most prominent human-associated
initiated 24 to 48 hours after consuming a blood meal.
(synanthropic) fly in the southern United States. Because
The adult flea lives approximately 100 days, depending
of its close association with people, its abundance, and its
on environmental conditions.
ability to transmit disease, it is considered a greater threat
to human welfare than any other species of nonbiting fly.
Following are some guidelines for controlling fleas:
Each housefly can easily carry more than 1 million bacteria
on its body. Some of the disease-causing agents transmitted
• The most important principle in a total flea control
by houseflies to humans are Shigella spp. (dysentery and
program is simultaneously treating all pets and their
diarrhea = shigellosis), Salmonella spp. (typhoid fever),
environments (indoor and outdoor).
Escherichia coli, (traveler’s diarrhea), and Vibrio cholera
(cholera). Sometimes these organisms are carried on the
• Before using insecticides, thoroughly clean the
fly’s tarsi or body hairs, and frequently they are
environment, removing as many fleas as possible,
regurgitated onto food when the fly attempts to liquefy it
regardless of the form. This would include indoor
for ingestion.
vacuuming and carpet steam cleaning. Special
attention should be paid to source points where pets
The fly life cycle is similar across the synanthropic group.
spend most of their time.
MPMH [2] notes that the egg and larval stages develop in
animal and vegetable refuse. Favorite breeding sites
• Outdoor cleanup should include mowing, yard raking,
include garbage, animal manure, spilled animal feed, and soil
and removing organic debris from flowerbeds and
contaminated with organic matter. Favorable
under bushes.
environmental conditions will result in the eggs hatching
in 24 hours or less. Normally, a female fly will produce
• Insecticide should be applied to the indoor and
500 to 600 eggs during her lifetime.
outdoor environments and to the pet.
The creamy, white larvae (maggots) are about ½-inch
long when mature and move within the breeding material
Healthy Housing Reference Manual
4-7
to maintain optimum temperature and moisture
or other protected sites, but will not reproduce during
conditions. This stage lasts an average of 4 to 7 days in
this time. Blowflies breed most commonly on decayed
warm weather. The larvae move to dry parts of the
carcasses (e.g., dead squirrels, rodents, birds) and in
breeding medium or move out of it onto the soil or
droppings of dogs or other pets during the summer; thus,
sheltered places under debris to pupate, with this stage
removal of these sources is imperative. Small animals, on
usually lasting 4 to 5 days. When the pupal stage is
occasion, may die inside walls or under the crawl space of
accomplished, the adult fly exits the puparium, dries, hardens,
a house. A week or two later, blowflies or maggots may
and flies away to feed, with mating occurring soon after
appear. The adult blowfly is also attracted to gas leaks.
emergence. Figure 4.17 demonstrates the typical fly life
cycle.
Termites
According to Gold et al. [11], subterranean termites are
The control of the housefly is hinged on good sanitation
the most destructive insect pests of wood in the United
(denying food sources and breeding sites to the fly). This
States, causing more than $2 billion in damage each year.
includes the proper disposal of food wastes by placing
Annually, this is more property damage than that caused
garbage in cans with close-fitting lids. Cans need to be
by fire and windstorms combined. In the natural world,
periodically washed and cleaned to remove food debris.
these insects are beneficial because they break down dead
The disposal of garbage in properly operated sanitary
trees and other wood materials that would otherwise
landfills is paramount to fly control.
accumulate. This biomass breakdown is recycled to the
soil as humus. MPMH [2], on the other hand, notes that
The presence of adult flies can be addressed in various
these insects can damage a building so severely it may
ways. Outside methods include limited placement of
have to be replaced. Termites consume wood and other
common mercury vapor lamps that tend to attract flies.
cellulose products, such as paper, cardboard, and
Less-attractive sodium vapor lamps should be used near
fiberboard. They will also destroy structural timbers,
the home. Self-closing doors in the home will deny
pallets, crates, furniture, and other wood products. In
entrance, as will the use of proper-fitting and well-
addition, they will damage many materials they do not
maintained screening on doors and windows.
normally eat as they search for food. The tunneling efforts
of subterranean termites can penetrate lead- and plastic-
Larger flies use homes for shelter from the cold, but do
covered electric cable and cause electrical system failure.
not reproduce inside the home. Caulking entry points
In nature, termites may live for years in tree stumps or
and using fly swatters is effective and much safer than the
lumber beneath concrete buildings before they penetrate
use of most pesticides. Insecticide “bombs” can be used in
hairline cracks in floors and walls, as well as expansion
attics and other rooms that can be isolated from the rest
joints, to search for food in areas such as interior door
of the house. However, these should be applied to areas
frames and immobile furniture. Termite management costs to
away from food, where flies rest.
homeowners are exceeded only by cockroach control costs.
The blowfly is a fairly large, metallic green, gray, blue,
Lyon [12] notes that termites are frequently mistaken by
bronze, or black fly. They may spend the winter in homes
the homeowner as ants and often are referred to
erroneously as white ants. Typical signs of termite
infestations occur in March through June and in
September and October. Swarming is an event where a
group of adult males and female reproductives leave the
nest to establish a new colony. If the emergence happens
inside a building, flying termites may constitute a
considerable nuisance. These pests can be collected with a
vacuum cleaner or otherwise disposed of without using
pesticides. Each homeowner should be aware of the
following signs of termite infestation:
• Pencil-thin mud tubes extending over the inside
and outside surfaces of foundation walls, piers,
sills, joists, and similar areas (Figures 4.18 and 4.19).
Figure 4.17. Life Cycle of the Fly [10]
4-8
Disease Vectors and Pests
• Presence of winged termites or their shed wings
hind pair is much shorter than the front. Additionally,
on windowsills and along the edges of floors.
ants typically have a narrow waist, with the abdomen
connected to the thorax by a thin petiole. Termites do
• Damaged wood hollowed out along the grain and
not have a narrow or pinched waist. Figure 4.20a and b
lined with bits of mud or soil. According to Oi
demonstrates the differences between the ant and termite.
et al. [15], termite tubes and nests are made of
Entomologists refer to winged ants and termites as alates.
mud and carton. Carton is composed of partially
chewed wood, feces, and soil packed together.
Figure 4.21 shows the life cycle of the termite. In each
Tubes maintain the high humidity required for
colony, there are three castes or forms of individuals
survival, protect termites from predators, and
known as reproductives, workers, and soldiers. According
allow termites to move from one spot to another.
to Lyon [12], the reproductives can be winged or
wingless, with the latter found in colonies to serve as
Differentiating the ant from the dark brown or black
replacements for the primary reproductives. The primary
termite reproductives can be accomplished by noting the
reproductives (alates) vary in color from pale yellow-
respective wings and body shape. MPMH [2] states that a
brown to coal black, are ½-inch to 3/8-inch in length, are
termite has four wings of about equal length and that the
flattened dorsa-ventrally, and have pale or smoke-gray to
wings are nearly twice as long as the body. By comparison, ant
brown wings. The secondary reproductives have short
wings that are only a little longer than the body and the
wing buds and are white to cream colored. The workers
are the same size as the primary reproductives and are
white to grayish-white, with a yellow-brown head, and
are wingless. In addition, the soldiers resemble workers,
Figure 4.18. Termite Tube Extending from Ground to Wall [Red
Figure 4.20a. Ant (Elbowed Antennae: Fore Wings Larger Than Hind;
Arrows] [13]
Constricted Waist) [16]
Figure 4.20b. Termite (Beaded Antennae; All Wings Equal) [16]
in that they are wingless, but soldiers have large,
rectangular, yellowish, and brown heads with large jaws.
MPMH [2] states there are five families of termites found
in the world, with four of them occurring in the United
States. The families in the United States are
Figure 4.19. Termite Mud Shelter Tube Constructed Over a Brick
Hodotermitidae (rotten-wood termites), Kalotermitidae
Foundation [14]
(dry-wood termites), Rhinotermitidae (subterranean
Healthy Housing Reference Manual
4-9
Dry-wood termites (Cryptotermes spp.) live entirely in
moderately to extremely dry wood. They require contact
with neither the soil nor any other moisture source and
may invade isolated pieces of furniture, fence posts,
utility poles, firewood, and structures. Dry-wood termite
colonies are not as large as other species in the United
States, so they can occupy small wooden articles, which
are one way these insects spread to different locations.
They are of major economic importance in southern
California, Arizona, and along the Gulf Coast. The West
Indian dry-wood termite is a problem in Puerto Rico, the
U.S. Virgin Islands, Hawaii, parts of Florida and
Louisiana, and a number of U.S. Pacific Island territories.
Dry-wood termites are slightly larger than most other
Figure 4.21. Life Cycle of the Subterranean Termite [17]
species, ranging from ½ inch to 5/8 inch long, and are
generally lighter in color.
termites) and Termitidae (desert termites). Subterranean
termites typically work in wood aboveground, but must
Damp-wood termites do not need contact with damp
have direct contact with the ground to obtain moisture.
ground like subterranean termites do, but they do require
Nonsubterranean termites colonize above the ground and
higher moisture content in wood. However, once
feed on cellulose; however, their life cycles and methods
established, these termites may extend into slightly drier wood.
of attack, and consequently methods of control, are quite
different. Nonsubterranean termites in the United States
Termites of minor importance are the tree-nesting groups.
are commonly called drywood termites.
The nests of these termites are found in trees, posts, and,
occasionally, buildings. Their aboveground nests are
In the United States, according to MPMH [2], native
connected to soil by tubes. Tree-nesting termites may be a
subterranean termites are the most important and the
problem in Puerto Rico and the U.S. Virgin Islands.
most common. These termites include the genus
Reticulitermes, occurring primarily in the continental
The risk for encountering subterranean termites in the
United States, and the genus Heterotermes, occurring in
United States is greater in the southeastern states and in
the Virgin Islands, Puerto Rico, and the deserts of California
southwestern California. In the United States, the risk for
and Arizona. The appearance, habits, and type of damage
termite infestations tends to decrease as the latitude
they cause are similar. The Formosan termite (Coptotermes
increases northward.
formosanus) is the newest species to become established in
the United States. It is a native of the Pacific Islands and
Figure 4.22 portrays the geographic risk of subterranean
spread from Hawaii and Asia to the United States during
termites in the United States. Subterranean termites are
the 1960s. It is now found along the Gulf Coast, in
found in all states except Alaska and are most abundant
California, and in South Carolina, and is expected to
in the south and southeastern United States [18].
spread to other areas as well. Formosan termites cause
greater damage than do native species because of their
According to Potter [19], homeowners can reduce the risk
more vigorous and aggressive behavior and their ability to
for termite attack by adhering to the following suggestions:
rapidly reproduce, build tubes and tunnels, and seek out
new items to infest. They have also shown more resistance
• Eliminate wood contact with the ground. Earth-
to some soil pesticides than native species. Reproductives
to-wood contact provides termites with
(swarmers) are larger than native species, reaching up to
simultaneous access to food, moisture, and shelter
5
/8-inch in length, and are yellow to brown in color.
in conjunction with direct, hidden entry into the
Swarmers have hairy-looking wings and swarm after dusk,
structure. In addition, the homeowner or
unlike native species, which swarm in the daytime.
occupant should be aware that pressure-treated
Formosan soldiers have more oval-shaped heads than do
wood is not immune to termite attack because
native species. On top of the head is an opening that
termites can enter through the cut ends and build
emits a sticky, whitish substance.
tunnels over the surfaces.
4-10
Disease Vectors and Pests
Do not allow moisture to accumulate near the
Never store firewood, lumber, or other wood debris
home’s foundation. Proper drainage, repair of
against the foundation or inside the crawl space.
plumbing, and proper grading will help to reduce
Termites are both attracted to and fed by this type
the presence of moisture, which attracts termites.
of storage. Wood stacked in contact with a
dwelling and vines, trellises, and dense plant
Reduce humidity in crawl spaces. Most building
material provide a pathway for termites to bypass
codes state that crawl space area should be vented
soil barrier treatment.
at a rate of 1 square foot per 150 square feet of
crawl space area. This rate can be reduced for
Use decorative wood chips and mulch sparingly.
crawl spaces equipped with a polyethylene or
Cellulose-containing products attract termites,
equivalent vapor barrier to one square foot per
especially materials that have moisture-holding
300 to 500 square feet of crawl space area. Vent
properties, such as mulch. The homeowner should
placement design includes positioning one vent
never allow these products to contact wood
within 3 feet of each building corner. Trimming
components of the home. The use of crushed
and controlling shrubs so that they do not
stone or pea gravel is recommended as being less
obstruct the vents is imperative. Installling a 4-
attractive to termites and helpful in diminishing
to 6-mil polyethylene sheeting over a minimum of
other pest problems.
75% of the crawl space will reduce the crawl-
space moisture. Covering the entire floor of the
Have the structure treated by a professional pest
crawl space with such material can reduce two
control treatment. The final, and most effective,
potential home problems at one time: excess
strategy to prevent infestation is to treat the soil
moisture and radon (Chapter 5). The barrier will
around and beneath the building with termiticide.
reduce the absorption of moisture from the air
The treated ground is then both a repellant and
and the release of moisture into the air in the
toxic to termites.
crawl space from the underlying soil.
Figure 4.22. Subterranean Termite Risk in the United States [18]
Healthy Housing Reference Manual
4-11
Figure 4.23 demonstrates some typical points of attack by
[20], an additional system is to strategically
subterranean termites and some faulty construction practices
place a series of baits around the house. The
that can contribute to subterranean termite infestations.
intention is for termite colonies to encounter one
or more of the baits before approaching the
Lyon [12] notes the following alternative termite control
house. Once termite activity is observed, the bait
measures:
wood is replaced with a poison. The termites
bring the poison back to the colony and the
• Nematodes. Certain species of parasitic round
colony is either eliminated or substantially
worms (nematodes) will infest and kill termites
reduced. This system is relatively new to the
and other soil insects. Varying success has been
market. Its success depends heavily on the
experienced with this method because it is
termites finding the bait before finding and
dependent on several variables, such as soil
damaging the house.
moisture and soil type.
Additional measures include construction techniques that
• Sand as a physical barrier. This would require
discourage termite attacks, as demonstrated in Figure 4.24.
preconstruction planning and would depend on
Termites often invade homes by way of the foundation,
termites being unable to manipulate the sand to
either by crawling up the exterior surface where their
create tunnels. Some research in California and
activity is usually obvious or by traveling inside hollow
Hawaii has indicated early success.
block masonry. One way to deter their activity is to block
their access points on or through the foundation. Metal
• Chemical baits. This method uses wood or
termite shields have been used for decades to deter
laminated texture-flavored cellulose impregnated
termite movement along foundation walls and piers on
with a toxicant and/or insect growth regulator.
up to the wooden structure. Metal termite shields should
The worker termite feeds on the substance and
extend 2 inches from the foundation and 2 inches down.
carries it back to the nest, reducing or eliminating
Improperly installed (i.e., not soldered/sealed properly),
the entire colony. According to HomeReports.com
damaged, or deteriorated termite shields may allow
Figure 4.23. Typical Points of Attack by Termites in the Home [2]
4-12
Disease Vectors and Pests
termites to reach parts of the wooden floor system.
The life cycle of the fire ant begins with the mating of the
Shields should be made of noncorroding metal and have
winged forms (alates) some 300 to 800 feet in the air,
no cracks or gaps along the seams. If a house is being
typically occurring in the late spring or early summer. The
built with metal termite shielding, the shielding should
male dies after the mating; and the newly mated queen
extend at least 2 inches out and 2 inches down at a 45°
finds a suitable moist site, drops her wings, and burrows
angle from the foundation wall. An alternative to using
in the soil, sealing the opening behind her. Ants undergo
termite shields on a hollow-block foundation is to fill the
complete metamorphosis and, therefore, have egg, larval,
block with concrete or put in a few courses of solid or
pupal and adult stages. The new queen will begin laying
concrete-filled brick (which is often done anyway to level
eggs within 24 hours. Once fully developed, she will
foundations). These are referred to as masonry caps. The
produce approximately 1,600 eggs per day over a
same approach can be used with support piers in the
maximum life span of 7 years. Soft, whitish, legless larvae
crawl space. Solid caps (i.e., a continuously poured
are produced from the hatching. These larvae are fed by
concrete cap) are best at stopping termites, but are not
the worker ants. Pupae resemble adults in form, but are
commonly used. Concrete-filled brick caps should deter
soft, nonpigmented, and lack mobility. There are at least
termite movement or force them through small gaps, thus
three distinct castes of ants: workers, queens, and males.
allowing them to be spotted during an inspection [21].
Typically, the males have wings, which they retain until
death. Queens, the largest of the three castes, normally
Fire Ants
have wings, but lose them after mating. The worker,
According to MPMH [2], ants are one of the most
which is also a female, is never winged, except as a rare
numerous species on earth. Ants are in the same order as
abnormality. Within this hierarchy, mature colonies
wasps and bees and, because of their geographic
contain males and females that are capable of flight and
distribution, they are universally recognized (Figure 4.25).
reproduction. These are known as reproductives, and an
Key to Figure 4.23
1.
Cracks in foundation permit hidden points of
11.
Stucco carried down over concrete foundation
entry from soil to sill.
permits hidden entrance between stucco and
foundation if bond fails.
2.
Posts through concrete in contact with
substructural soil. Watch door frames and
12.
Insufficient clearance for inspection also
intermediate supporting posts.
permits easy construction of termite shelter tubes
from soil to wood.
3.
Wood-framing members in contact with
earthfill under concrete slab.
13.
Wood framing of crawl hole forming
wood-soil contact.
4.
Form boards left in place contribute to
termite food supply.
14.
Mud sill and/or posts in contact with soil.
5.
Leaking pipes and dripping faucets sustain soil
15.
Wood siding and skirting form soil contact.
moisture. Excess irrigation has same effect.
There should be a minimum of 3 inches
clearance between skirting and soil.
6.
Shrubbery blocking air flow through vents.
16.
Porch steps in contact with soil. Also watch for
7.
Debris supports termite colony until large
ladders and other wooden materials.
population attacks superstructure.
17.
Downspouts should carry water away from
8.
Heating unit accelerates termite development
the building.
by maintaining warmth of colony on a year-
round basis.
18.
Improper maintenance of soil piled against pier
footing. Also makes careful inspection impossible.
9.
Foundation wall too low permits wood to
contact soil. Adding topsoil often builds exterior
19.
Wall girder entering recess and foundation wall.
grade up to sill level.
Should have a 1-inch free air space on both
sides and end and be protected with a moisture-
10.
Footing too low or soil thrown against it causes
impervious seal.
wood-soil contact. There should be 8 inches
of clean concrete between soil and pier block.
20.
Vents placed between joists tunnel air through
space without providing good substructural
aeration. Vents placed in foundation wall give
better air circulation.
Healthy Housing Reference Manual
4-13
Figure 4.24. Construction Techniques That Discourage Termite Attacks: Thin Metal Termite Shield Should Extend 2 Inches Beyond Foundation and 2 Inches
Down [2]
Alabama. RIFAs are now found in more than 275 million
acres in 11 southern states and Puerto Rico. The second
most important species is the black imported fire ant,
S. richteri, which was introduced into the United States
in the 1920s from Argentina or Uruguay. It is currently
limited in distribution to a small area of northern
Mississippi and Alabama. There are two native species
of fire ants: the tropical or native fire ant, S. geminata,
ranging from South Carolina to Florida and west to
Texas; and the Southern fire ant, S. xyloni, which occurs
from North Carolina south to northern Florida, along the
Gulf Coast, and west to California. The most important
extension of the RIFA range is thought to have occurred
during the 1950s housing boom as a result of the
transportation of sod and nursery plants (Figure 4.26).
Figure 4.25. Fire Ants [22]
RIFAs prefer open and sun-exposed areas. They are found
average colony may produce approximately 4,500 of these
in cultivated fields, cemeteries, parks, and yards, and even
per year. A healthy nest usually produces two nuptial
inside cars, trucks, and recreational vehicles. RIFAs are
flights of reproductives each year and a healthy, mature
attracted to electrical currents and are known to nest in
colony may contain more than 250,000 ants. Though
and around heat pumps, junction boxes, and similar
uncommon among ants, multiple queen colonies (10 to
areas. They are omnivorous; thus they will attack most
100) occur somewhat frequently in fire ants, resulting in
things, living or dead. Their economic effects are felt by
more numerous mounds per acre.
their destruction of the seeds, fruit, shoots, and seedlings
of numerous native plant species. Fire ants are known to
There are many species of fire ants in the United States.
tend pests, such as scale insects, mealy bugs, and aphids,
The most important are four species in the genus
for feeding on their sweet waste excretion (honeydew).
Solenopsis. Of these, the number one fire ant pest is the
RIFAs transport these insects to new feeding sites and
red imported fire ant (RIFA) Solenopsis invicta
protect them from predators. The positive side of RIFA
(Figure 4.25). This ant was imported inadvertently from
infestation is that the fire ant is a predator of ticks and
South America in the 1930s through the port of Mobile,
controls the ground stage of horn flies.
4-14
Disease Vectors and Pests
Figure 4.26. Range Expansion of Red Imported Fire Ants [RIFAs] in the United States, 1918-1998 [23]
The urban dweller with a RIFA infestation may find
Mosquitoes
significant damage to landscape plants, with reductions in
All mosquitoes have four stages of development—egg,
the number of wild birds and mammals. RIFAs can
larva, pupa, and adult—and spend their larval and pupal
discourage outdoor activities and be a threat to young
stages in water. The females of some mosquito species
animals or small confined pets. RIFA nests typically are
deposit eggs on moist surfaces, such as mud or fallen
not found indoors, but around homes, roadways, and
leaves, that may be near water but dry. Later, rain or high
structures, as well as under sidewalks. Shifting of soil after
tides reflood these surfaces and stimulate the eggs to
RIFAs abandon sites has resulted in collapsing structures.
hatch into larvae. The females of other species deposit
Figure 4.27 shows a fire ant mound with fire ants and a
their eggs directly on the surface of still water in such
measure of their relative size.
places as ditches, street catch basins, tire tracks, streams
that are drying up, and fields or excavations that hold
The medical complications of fire ant stings have been
water for some time. This water is often stagnant and
noted in the literature since 1957. People with disabilities,
close to the home in discarded tires, ornamental pools,
reduced feeling in their feet and legs, young children, and
those with mobility issues are at risk for sustaining
numerous stings before escaping or receiving assistance.
Fatalities have resulted from attacks on the elderly and on
infants. Control of the fire ant is primarily focused on the
mound by using attractant bait consisting
of soybean oil, corn grits, or chemical agents. The bait is
picked up by the worker ants and taken deep into the
mound to the queen. These products typically require
weeks to work.
Individual mound treatment is usually most effective in
the spring. The key is to locate and treat all mounds in
the area to be protected. If young mounds are missed, the
Figure 4.27. Fire Ant Mound
area can become reinfested in less than a year.
Source: CAPT Craig Shepherd, U.S. PHS; used with permission.
Healthy Housing Reference Manual
4-15
unused wading and swimming pools, tin cans, bird baths,
When mosquitoes are numerous and interfere with living,
plant saucers, and even gutters and flat roofs. The eggs
recreation, and work, you can use the various measures
soon hatch into larvae. In the hot summer months, larvae
described in the following paragraphs to reduce their
grow rapidly, become pupae, and emerge 1 week later as
annoyance, depending on location and conditions.
flying adult mosquitoes. A few important spring species
have only one generation per year. However, most species
How to Reduce the Mosquito Population
have many generations per year, and their rapid increase
The most efficient method of controlling mosquitoes is
in numbers becomes a problem.
by reducing the availability of water suitable for larval
and pupal growth. Large lakes, ponds, and streams that have
When adult mosquitoes emerge from the aquatic stages,
waves, contain mosquito-eating fish, and lack aquatic
they mate, and the female seeks a blood meal to obtain
vegetation around their edges do not contain mosquitoes;
the protein necessary for the development of her eggs.
mosquitoes thrive in smaller bodies of water in protected
The females of a few species may produce a first batch of
places. Examine your home and neighborhood and take the
eggs without this first blood meal. After a blood meal is
following precautions recommended by the New Jersey
digested and the eggs are laid, the female mosquito again
Agricultural Experiment Station [24]:
seeks a blood meal to produce a second batch of eggs.
Depending on her stamina and the weather, she may
• dispose of unwanted tin cans and tires;
repeat this process many times without mating again. The
male mosquito does not take a blood meal, but may feed
• clean clogged roof gutters and drain flat roofs;
on plant nectar. He lives for only a short time after
mating. Most mosquito species survive the winter, or
• turn over unused wading pools and other
overwinter, in the egg stage, awaiting the spring thaw,
containers that tend to collect rainwater;
when waters warm and the eggs hatch. A few important
species spend the winter as adult, mated females, resting
• change water in birdbaths, fountains, and troughs
in protected, cool locations, such as cellars, sewers, crawl
twice a week;
spaces, and well pits. With warm spring days, these
females seek a blood meal and begin the cycle again.
• clean and chlorinate swimming pools;
Only a few species can overwinter as larvae.
• cover containers tightly with window screen or
Mosquitoborne diseases, such as malaria and yellow fever,
plastic when storing rainwater for garden use
have plagued civilization for thousands of years. Newer threats
during drought periods;
include Lyme disease and West Nile virus. Organized mosquito
control in the United States has greatly reduced the
• flush sump-pump pits weekly; and
incidence of these diseases. However, mosquitoes can still
transmit a few diseases, including eastern equine encephalitis
• stock ornamental pools with fish.
and St. Louis encephalitis. The frequency and extent of
these diseases depend on a complex series of factors.
If mosquito breeding is extensive in areas such as woodland
Mosquito control agencies and health departments cooperate
pools or roadside ditches, the problem may be too great
in being aware of these factors and reducing the chance
for individual residents. In such cases, call the organized
for disease. It is important to recognize that young adult
mosquito control agency in your area. These agencies
female mosquitoes taking their first blood meal do not
have highly trained personnel who can deal with the
transmit diseases. It is instead the older females, who, if they
problem effectively.
have picked up a disease organism in their first blood meals,
can then transmit the disease during the second blood meal.
Several commercially available insecticides can be effective
in controlling larval and adult mosquitoes. These chemicals
The proper method to manage the mosquito problem in
are considered sufficiently safe for use by the public.
a community is through an organized integrated pest
Select a product whose label states that the material is
management system that includes all approaches that safely
effective against mosquito larvae or adults. For safe and
manage the problem. The spraying of toxic agents is but
effective use, read the label and follow the instructions for
one of many approaches.
applying the material. The label lists those insects that the
EPA agrees are effectively controlled by the product.
4-16
Disease Vectors and Pests
For use against adult mosquitoes, some liquid insecticides
3.
Indiana Department of Natural Resources.
can be mixed according to direction and sprayed lightly
Rodent pictures. Lafayette, IN: Indiana
on building foundations, hedges, low shrubbery, ground
Department of Natural Resources; no date.
covers, and grasses. Do not overapply liquid insecticides—
Available from URL: http://www.entm.purdue.edu/
excess spray drips from the sprayed surfaces to the ground,
wildlife/rat_pictures.htm.
where it is ineffective. The purpose of such sprays is to
leave a fine deposit of insecticide on surfaces where mosquitoes
4.
Arrow Services, Inc. Rats: roof rats. Plymouth,
rest. Such sprays are not effective for more than 1 or 2 days.
IN: Arrow Services, Inc.; no date. Available from
URL: http://www.arrowpestcontrol.com/
Some insecticides are available as premixed products or
pages/rod/roofpic.html.
aerosol cans. These devices spray the insecticide as very
small aerosol droplets that remain floating in the air and
5.
Cobb County Extension Service. Fact sheet on
hit the flying mosquitoes. Apply the sprays upwind, so
rodents: rats and mice. Marietta, GA: Cobb
the droplets drift through the area where mosquito
County Extension Service; 2003. Available from
control is desired. Rather than applying too much of
URL: http://www.griffin.peachnet.edu/ga/cobb/
these aerosols initially, it is more practical to apply them
Horticulture/Factsheets/peskycritters/ratsmice.htm.
briefly but periodically, thereby eliminating those
mosquitoes that recently flew into the area.
6.
Kamble ST, Keith DL. Cockroaches and their
control. Lincoln, NE: University of Nebraska
Various commercially available repellents can be
Cooperative Extension; 1995.
purchased as a cream or lotion or in pressurized cans, then
applied to the skin and clothing. Some manufacturers also
7.
University of Nebraska-Lincoln. Cockroach
offer clothing impregnated with repellents; coarse,
picture gallery. Lincoln, NE: University of
repellent-bearing particles to be scattered on the ground;
Nebraska-Lincoln; no date. Available from URL:
and candles whose wicks can be lit to release a repellent
http://pested.unl.edu/roachind.htm.
chemical. The effectiveness of all repellents varies from
location to location, from person to person, and from
8.
Centers for Disease Control and Prevention.
mosquito to mosquito. Repellents can be especially
Reported human plague cases by county: United
effective in recreation areas, where mosquito control may
States, 1970-1997. Atlanta: US Department of
not be conducted. All repellents should be used according
Health and Human Services; no date. Available
to the manufacturers’ instructions. Mosquitoes are
from URL: http://www.cdc.gov/ncidod/
attracted by perspiration, warmth, body odor, carbon
dvbid/plague/plagwest.htm.
dioxide, and light. Mosquito control agencies use some of
these attractants to help determine the relative number of
9.
Leslie M, editor. Netwatch: flys in the Web.
adult mosquitoes in an area. Several devices are sold that
Science 2004;306:1269. Available from URL:
are supposed to attract, trap, and destroy mosquitoes and
http://www.sel.barc.usda.gov/diptera/names/image
other flying insects. However, if these devices are
s/ science1104.pdf.
attractive to mosquitoes, they probably attract more
mosquitoes into the area and may, therefore, increase
10. Oderkirk A. Fly control in poultry barns: poultry
rather than decrease mosquito annoyance.
fact sheet. Truro, Nova Scotia, Canada: Nova Scotia
Department of Agriculture and Marketing; 2001.
References
1. Barnett DB. Vectors and their control. In: Morgan
11. Gold RE, Howell HN Jr, Glenn GJ. Subterranean
MT, editor. Environmental health. 3rd ed.
termites. College Station, TX: Texas Agricultural
Englewood, CO: Wadsworth Publishing Co.;
Extension Service; 1999. Available from URL:
2002. p. 137-50.
http://insects.tamu.edu/extension/bulletins/
b6080.html.
2. Armed Forces Pest Management Board. Military
pest management handbook. Washington, DC:
12. Lyon WF. Termite control: HYG-2092-03.
Armed Forces Pest Management Board; no date.
Columbus, OH: The Ohio State University
Available from URL: http://www.afpmb.org/
Extension; 2003. Available from URL:
MPMH/toc.htm.
http://ohioline.osu.edu/hyg-fact/2000/2092.html.
Healthy Housing Reference Manual
4-17
13. Austin AR. Sample photos of structural
22. Core J. Update: hot on the trail of fire ants. Agric
foundation defects and deficiences. Houston:
Res 2003; 51:20-23. Available from URL:
Diligent Home Inspections; no date.
http://ars.usda. gov/is/AR/archive/
Feb03/ants0203.htm.
14. Fumapest Group. Western subterranean termites.
Revesby, New South Wales, Australia: Fumapest
23. California Department of Food and Agriculture.
Group Pty.; no date. Available from URL:
First reported occurrence of red imported fire ant;
http://www.termite.com/termites/western-
Solenopsis invicta. Sacramento, CA: California
subterranean-termite.html.
Department of Food and Agriculture; no date.
Available from URL: www.cdfa.ca.gov/phpps/pdep/
15. Oi FM, Castner JL, Koehler PG. The Eastern
rifa/html/english/facts/rifaTIME.htm.
subterranean termite. Gainesville, FL: University
of Florida Cooperative Extension Service; 1997.
24. Sutherland DJ, Crans WJ.Mosquitoes in your life.
Available from URL: http://edis.ifas.ufl.edu/
New Jersey Agricultural Experiment Station
BODY_IN031.
Publication SA220-5M-86. New Brunswick, NJ:
New Jersey Agricultural Experiment Station,
16. Ferster B, Deyrup M, Scheffrahn RH. How to tell
Cook College, Rutgers, The State University of
the difference between ant and termite alates. Fort
New Jersey; no date. Available at URL:
Lauderdale, FL: University of Florida; no date.
http://www.rci.rutgers.edu/~insects/moslife.htm.
Available from URL: http://flrec.ifas.ufl.edu/
entomo/ants/Ant%20vs%20Termite.htm.
17. Su N-Y. Life cycle of the Formosan subterranean
termite, Coptotermes formosanus Shiraki.
Gainesville, FL: University of Florida; no date.
Available from URL: http://creatures.ifas.ufl.edu/
urban/termites/fst10.htm.
18. Suiter DR, Jones SC, Forschler BT. Biology of
subterranean termites in the Eastern United
States. Bulletin 1209. Columbus, OH: The Ohio
State University Extension; no date. Available
from URL: http://ohioline.osu.edu/b1209/.
19. Potter MF. Protecting your home against termites.
Lexington, KY: University of Kentucky
Department of Entomology; 2004. Available from
URL: http://www.uky.edu/Agriculture/
Entomology/entfacts/struct/ef605.htm.
20. HomeReports.com. Pest and termite control
companies. Atlanta: HomeReports.com; no date.
Available from URL: http://www.homereports.com/ge/
PestControl.htm.
21. North Carolina Cooperative Extension Service.
Termite prevention: approaches for new
construction. Raleigh, NC: North Carolina
Cooperative Extension Service; no date. Available
from URL: http://www.ces.ncsu.edu/
depts/ent/notes/Urban/termites/pre-con.htm.
4-18
Disease Vectors and Pests
Chapter 5: Indoor Air Pollutants and Toxic Materials
“Walking into a modern building can sometimes be
pollen. These biologic pollutants can be related to some
compared to placing your head inside a plastic bag that is
serious health effects. Some biologic pollutants, such as
filled with toxic fumes.”
measles, chickenpox, and influenza are transmitted
through the air. However, the first two are now
John Bower
preventable with vaccines. Influenza virus transmission,
Founder, Healthy House Institute
although vaccines have been developed, still remains of
concern in crowded indoor conditions and can be
Introduction
affected by ventilation levels in the home.
We all face a variety of risks to our health as we go about
our day-to-day lives. Driving in cars, flying in airplanes,
Common pollutants, such as pollen, originate from
engaging in recreational activities, and being exposed to
plants and can elicit symptoms such as sneezing, watery
environmental pollutants all pose varying degrees of risk.
eyes, coughing, shortness of breath, dizziness, lethargy,
Some risks are simply unavoidable. Some we choose to
fever, and digestive problems. Allergic reactions are the
accept because to do otherwise would restrict our ability
result of repeated exposure and immunologic
to lead our lives the way we want. Some are risks we
sensitization to particular biologic allergens.
might decide to avoid if we had the opportunity to make
informed choices. Indoor air pollution and exposure to
Although pollen allergies can be bothersome, asthmatic
hazardous substances in the home are risks we can do
responses to pollutants can be life threatening. Asthma is
something about.
a chronic disease of the airways that causes recurrent and
distressing episodes of wheezing, breathlessness, chest
In the last several years, a growing body of scientific
tightness, and coughing [2]. Asthma can be broken
evidence has indicated that the air within homes and
down into two groups based on the causes of an attack:
other buildings can be more seriously polluted than the
extrinsic (allergic) and intrinsic (nonallergic). Most
outdoor air in even the largest and most industrialized
people with asthma do not fall neatly into either type,
cities. Other research indicates that people spend
but somewhere in between, displaying characteristics of
approximately 90% of their time indoors. Thus, for
both classifications. Extrinsic asthma has a known cause,
many people, the risks to health from exposure to indoor
such as allergies to dust mites, various pollens, grass or
air pollution may be greater than risks from outdoor
weeds, or pet danders. Individuals with extrinsic asthma
pollution.
produce an excess amount of antibodies when exposed to
triggers. Intrinsic asthma has a known cause, but the
In addition, people exposed to indoor air pollutants for
connection between the cause and the symptoms is not
the longest periods are often those most susceptible to
clearly understood. There is no antibody hypersensitivity
their effects. Such groups include the young, the elderly,
in intrinsic asthma. Intrinsic asthma usually starts in
and the chronically ill, especially those suffering from
adulthood without a strong family history of asthma.
respiratory or cardiovascular disease [1].
Some of the known triggers of intrinsic asthma are
infections, such as cold and flu viruses, exercise and cold
Indoor Air Pollution
air, industrial and occupational pollutants, food additives
Numerous forms of indoor air pollution are possible in
and preservatives, drugs such as aspirin, and emotional
the modern home. Air pollutant levels in the home
stress. Asthma is more common in children than in
increase if not enough outdoor air is brought in to dilute
adults, with nearly 1 of every 13 school-age children
emissions from indoor sources and to carry indoor air
having asthma [3]. Low-income African-Americans and
pollutants out of the home. In addition, high temperature and
certain Hispanic populations suffer disproportionately,
humidity levels can increase the concentration of some
with urban inner cities having particularly severe
pollutants. Indoor pollutants can be placed into two
problems. The impact on neighborhoods, school
groups, biologic and chemical.
systems, and health care facilities from asthma is severe
because one-third of all pediatric emergency room visits
Biologic Pollutants
are due to asthma, and it is the fourth most prominent
Biologic pollutants include bacteria, molds, viruses,
cause of physician office visits. Additionally, it is the
animal dander, cat saliva, dust mites, cockroaches, and
leading cause of school absenteeism—14 million school
Healthy Housing Reference Manual
5-1
days lost each year—from chronic illness [4]. The U.S.
microhabitat for the accumulation of food and moisture
population, on the average, spends as much as 90% of its
for the mite, and also provide protection from removal by
time indoors. Consquently, allergens and irritants from
vacuuming. The house dust mite’s favorite food is human
the indoor environment may play a significant role in
dander (skin flakes), which are shed at a rate of
triggering asthma episodes. A number of indoor
approximately 0.20 ounces per week.
environmental asthma triggers are biologic pollutants.
These can include rodents (discussed in Chapter 4),
A good microscope and a trained observer are imperative
cockroaches, mites, and mold.
in detecting mites. House dust mites also can be detected
using diagnostic tests that measure the presence and
Cockroaches
infestation level of mites by combining dust samples
The droppings, body parts, and saliva of cockroaches can
collected from various places inside the home with
be asthma triggers. Cockroaches are commonly found in
indicator reagents [7]. Assuming the presence of mites,
crowded cities and in the southern United States.
the precautions listed below should be taken if people
Allergens contained in the feces and saliva of cockroaches
with asthma are present in the home:
can cause allergic reactions or trigger asthma symptoms. A
national study by Crain et al. [5] of 994 inner-city allergic
Use synthetic rather than feather and down pillows.
children from seven U.S. cities revealed that cockroaches
were reported in 58% of the homes. The Community
Use an approved allergen barrier cover to enclose
Environmental Health Resource Center reports that
the top and sides of mattresses and pillows and
cockroach debris, such as body parts and old shells,
the base of the bed.
trigger asthma attacks in individuals who are sensitized to
cockroach allergen [6]. Special attention to cleaning must
Use a damp cloth to dust the plastic mattress
be a priority after eliminating the presence of cockroaches
cover daily.
to get rid of the presence of any allergens left that can be
asthma triggers.
Change bedding and vacuum the bed base and
mattress weekly.
House Dust Mites
Another group of arthropods linked to asthma is house
Use nylon or cotton cellulose blankets rather than
dust mites. In 1921, a link was suggested between
wool blankets.
asthmatic symptoms and house dust, but it was not until
1964 that investigators suggested that a mite could be
Use hot (120°F-130°F [49°C-54°C]) water to
responsible. Further investigation linked a number of mite
wash all bedding, as well as room curtains.
species to the allergen response and revealed that humid
homes have more mites and, subsequently, more allergens.
Eliminate or reduce fabric wall hangings, curtains,
In addition, researchers established that fecal pellets
and drapes.
deposited by the mites accumulated in home fabrics and
could become airborne via domestic activities such as
Use wood, tile, linoleum, or vinyl floor covering
vacuuming and dusting, resulting in inhalation by the
rather than carpet. If carpet is present, vacuum
inhabitants of the home. House dust mites are distributed
regularly with a high-efficiency particulate air
worldwide, with a minimum of 13 species identified from
(HEPA) vacuum or a household vacuum with a
house dust. The two most common in the United States
microfiltration bag.
are the North American house dust mite
(Dermatophagoides farinae) and the European house dust
Purchase stuffed toys that are machine washable.
mite (D. pteronyssinus). According to Lyon [7], house dust
mites thrive in homes that provide a source of food and
Use fitted sheets to help reduce the accumulation
shelter and adequate humidity. Mites prefer relative
of human skin on the mattress surface.
humidity levels of 70% to 80% and temperatures of 75°F
to 80°F (24°C to 27°C). Most mites are found in
HEPA vacuums are now widely available and have also
bedrooms in bedding, where they spend up to a third of
been shown to be effective [8]. A conventional vacuum
their lives. A typical used mattress may have from
tends to be inefficient as a control measure and results in
100,000 to 10 million mites in it. In addition, carpeted
a significant increase in airborne dust concentrations, but
floors, especially long, loose pile carpet, provide a
can be used with multilayer microfiltration collection
5-2
Indoor Air Pollutants and Toxic Materials
bags. Another approach to mite control is reducing
matter and, provided with sufficient moisture, can live off
indoor humidity to below 50% and installing central
of many materials found in homes, such as wood,
air conditioning.
cellulose in the paper backing on drywall, insulation,
wallpaper, glues used to bond carpet to its backing, and
Two products are available to treat house dust mites and
everyday dust and dirt.
their allergens. These products contain the active
ingredients benzyl benzoate and tannic acid.
Certain molds can cause a variety of adverse human
health effects, including allergic reactions and immune
Pets
responses (e.g., asthma), infectious disease (e.g.,
According to the U.S. Environmental Protection Agency
histoplasmosis), and toxic effects (e.g., aflatoxin-induced
(EPA) [9], pets can be significant asthma triggers because
liver cancer from exposure to this mold-produced toxin in
of dead skin flakes, urine, feces, saliva, and hair. Proteins
food) [14]. A recent Institute of Medicine (IOM) review
in the dander, urine, or saliva of warm-blooded animals
of the scientific literature found sufficient evidence for an
can sensitize individuals and lead to allergic reactions or
association between exposure to mold or other agents in
trigger asthmatic episodes. Warm-blooded animals
damp indoor environments and the following conditions:
include dogs, cats, birds, and rodents (hamsters, guinea
upper respiratory tract symptoms, cough, wheeze,
pigs, gerbils, rats, and mice). Numerous strategies, such as
hypersensitivity pneumonitis in susceptible persons, and
the following, can diminish or eliminate animal allergens
asthma symptoms in sensitized persons [15]. A previous
in the home:
scientific review was more specific in concluding that
sufficient evidence exists to support associations between
• Eliminate animals from the home.
fungal allergen exposure and asthma exacerbation and
upper respiratory disease [13]. Finally, mold toxins can
• Thoroughly clean the home (including floors and
cause direct lung damage leading to pulmonary diseases
walls) after animal removal.
other than asthma [13].
• If pets must remain in the home, reduce pet
The topic of residential mold has received increasing
exposure in sleeping areas. Keep pets away from
public and media attention over the past decade. Many
upholstered furniture, carpeted areas, and stuffed
news stories have focused on problems associated with
toys, and keep the pets outdoors as much
“toxic mold” or “black mold,” which is often a reference
as possible.
to the toxin-producing mold, Stachybotrys chartarum. This
might give the impression that mold problems in homes
However, there is some evidence that pets introduced
are more frequent now than in past years; however, no
early into the home may prevent asthma. Several studies
good evidence supports this. Reasons for the increasing
have shown that exposure to dogs and cats in the first
attention to this issue include high-visibility lawsuits
year of life decreases a child’s chances of developing
brought by property owners against builders and
allergies [10] and that exposure to cats significantly
developers, scientific controversies regarding the degree to
decreases sensitivity to cats in adulthood [11]. Many
which specific illness outbreaks are mold-induced, and an
other studies have shown a decrease in allergies and
increase in the cost of homeowner insurance policies due
asthma among children who grew up on a farm and were
to the increasing number of mold-related claims. Modern
around many animals [12].
construction might be more vulnerable to mold problems
because tighter construction makes it more difficult for
Mold
internally generated water vapor to escape, as well as the
People are routinely exposed to more than 200 species of
widespread use of paper-backed drywall in construction
fungi indoors and outdoors [13]. These include moldlike
(paper is an excellent medium for mold growth when
fungi, as well as other fungi such as yeasts and
wet), and the widespread use of carpeting.
mushrooms. The terms “mold” and “mildew” are
nontechnical names commonly used to refer to any fungus
Allergic Health Effects. Many molds produce numerous
that is growing in the indoor environment. Mold colonies
protein or glycoprotein allergens capable of causing
may appear cottony, velvety, granular, or leathery, and
allergic reactions in people. These allergens have been
may be white, gray, black, brown, yellow, greenish, or
measured in spores as well as in other fungal fragments.
other colors. Many reproduce via the production and
An estimated 6%-10% of the general population and
dispersion of spores. They usually feed on dead organic
15%-50% of those who are genetically susceptible are
Healthy Housing Reference Manual
5-3
sensitized to mold allergens [13]. Fifty percent of the
also be caused by the production of excess moisture
937 children tested in a large multicity asthma study
within homes from humidifiers, unvented clothes dryers,
sponsored by the National Institutes of Health showed
overcrowding, etc. Finished basements are particularly
sensitivity to mold, indicating the importance of mold as
susceptible to mold problems caused by the combination
an asthma trigger among these children [16]. Molds are
of poorly controlled moisture and mold-supporting
thought to play a role in asthma in several ways. Molds
materials (e.g., carpet, paper-backed sheetrock) [15].
produce many potentially allergenic compounds, and
There is also some evidence that mold spores from damp
molds may play a role in asthma via release of irritants
or wet crawl spaces can be transported through air currents
that increase potential for sensitization or release of toxins
into the upper living quarters. Older, substandard
(mycotoxins) that affect immune response [13].
housing low income families can be particularly prone to
mold problems because of inadequate maintenance (e.g.,
Toxics and Irritants. Many molds also produce
inoperable gutters, basement and roof leaks), overcrowding,
mycotoxins that can be a health hazard on ingestion,
inadequate insulation, lack of air conditioning, and poor
dermal contact, or inhalation [14]. Although common
heating. Low interior temperatures (e.g., when one or two
outdoor molds present in ambient air, such as
rooms are left unheated) result in an increase in the
Cladosporium cladosporioides and Alternaria alternata, do
relative humidity, increasing the potential for water to
not usually produce toxins, many other different mold
condense on cold surfaces.
species do [17]. Genera-producing fungi associated with
wet buildings, such as Aspergillus versicolor, Fusarium
Mold Assessment Methods. Mold growth or the
verticillioides, Penicillium aiurantiorisen, and S. chartarum,
potential for mold growth can be detected by visual
can produce potent toxins [17]. A single mold species
inspection for active or past microbial growth, detection
may produce several different toxins, and a given
of musty odors, and inspection for water staining or
mycotoxin may be produced by more than one species of
damage. If it is not possible or practical to inspect a
fungi. Furthermore, toxin-producing fungi do not
residence, this information can be obtained using
necessarily produce mycotoxins under all growth
occupant questionnaires. Visual observation of mold
conditions, with production being dependent on the
growth, however, is limited by the fact that fungal
substrate it is metabolizing, temperature, water content,
elements such as spores are microscopic, and that their
and humidity [17]. Because species of toxin-producing
presence is often not apparent until growth is extensive
molds generally have a higher water requirement than do
and the fact that growth can occur in hidden spaces (e.g.,
common household molds, they tend to thrive only under
wall cavities, air ducts).
conditions of chronic and severe water damage [18]. For
example, Stachybotrys typically only grows under continuously
Portable, hand-held moisture meters, for the direct
wet conditions [19]. It has been suggested that very
measurement of moisture levels in materials, may also be
young children may be especially vulnerable to certain
useful in qualitative home assessments to aid in
mycotoxins [19,20]. For example, associations have been
pinpointing areas of potential biologic growth that may
reported for pulmonary hemorrhage (bleeding lung)
not otherwise be obvious during a visual inspection [14].
deaths in infants and the presence of S. chartarum [21-24].
For routine assessments in which the goal is to identify
Causes of Mold. Mold growth can be caused by any
possible mold contamination problems before
condition resulting in excess moisture. Common moisture
remediation, it is usually unnecessary to collect and
sources include rain leaks (e.g., on roofs and wall joints);
analyze air or settled dust samples for mold analysis
surface and groundwater leaks (e.g., poorly designed or
because decisions about appropriate intervention
clogged rain gutters and footing drains, basement leaks);
strategies can typically be made on the basis of a visual
plumbing leaks; and stagnant water in appliances (e.g.,
inspection [25]. Also, sampling and analysis costs can be
dehumidifiers, dishwashers, refrigerator drip pans, and
relatively high and the interpretation of results is not
condensing coils and drip pans in HVAC systems).
straightforward. Air and dust monitoring may, however,
Moisture problems can also be due to water vapor
be necessary in certain situations, including 1) if an
migration and condensation problems, including uneven
individual has been diagnosed with a disease associated
indoor temperatures, poor air circulation, soil air entry
with fungal exposure through inhalation, 2) if it is
into basements, contact of humid unconditioned air with
suspected that the ventilation systems are contaminated,
cooled interior surfaces, and poor insulation on indoor
or 3) if the presence of mold is suspected but cannot be
chilled surfaces (e.g., chilled water lines). Problems can
identified by a visual inspection or bulk sampling [26].
5-4
Indoor Air Pollutants and Toxic Materials
Generally, indoor environments contain large reservoirs of
exposure, some organizations support a precautionary
mold spores in settled dust and contaminated building
approach to limiting mold exposure [19]. For example,
materials, of which only a relatively small amount is
the American Academy of Pediatrics recommends that
airborne at a given time.
infants under 1 year of age are not exposed at all to
chronically moldy, water-damaged environments [18].
Common methods for sampling for mold growth include
bulk sampling techniques, air sampling, and collection of
Mold Mitigation. Common intervention methods for
settled dust samples. In bulk sampling, portions of
addressing mold problems include the following:
materials with visual or suspected mold growth (e.g., sections
of wallboard, pieces of duct lining, carpet segments, or
maintaining heating, ventilating, and air
return air filters) are collected and directly examined to
conditioning (HVAC) systems;
determine if mold is growing and to identify the mold
species or groups that are present. Surface sampling in
changing HVAC filters frequently, as
mold contamination investigations may also be used
recommended by manufacturer;
when a less destructive technique than bulk sampling is
desired. For example, nondestructive samples of mold may
keeping gutters and downspouts in working order
be collected using a simple swab or adhesive tape [14].
and ensuring that they drain water away from the
foundation;
Air can also be sampled for mold using pumps that pull
air across a filter medium, which traps airborne mold
routinely checking, cleaning, and drying drip pans
spores and fragments. It is generally recommended that
in air conditioners, refrigerators, and
outdoor air samples are collected concurrent with indoor
dehumidifiers;
samples for comparison purposes for measurement of
baseline ambient air conditions. Indoor contamination
increasing ventilation (e.g., using exhaust fans or
can be indicated by indoor mold distributions (both
open windows to remove humidity when cooking,
species and concentrations) that differ significantly from
showering, or using the dishwasher);
the distributions in outdoor samples [14]. Captured mold
spores can be examined under a microscope to identify
venting clothes dryers to the outside; and
the mold species/groups and determine concentrations or
they can be cultured on growth media and the resulting
maintaining an ideal relative humidity level in the
colonies counted and identified. Both techniques require
home of 40% to 60%.
considerable expertise.
locating and removing sources of moisture
Dust sampling involves the collection of settled dust
(controlling dampness and humidity and repairing
samples (e.g., floor dust) using a vacuum method in
water leakage problems);
which the dust is collected onto a porous filter medium
or into a container. The dust is then processed in the
cleaning or removing mold-contaminated
laboratory and the mold identified by culturing viable spores.
materials;
Mold Standards. No standard numeric guidelines exist
removing materials with severe mold growth; and
for assessing whether mold contamination exists in an
area. In the United States, no EPA regulations or
using high-efficiency air filters.
standards exist for airborne mold contaminants [26].
Various governmental and private organizations have,
Moisture Control. Because one of the most important
however, proposed guidance on the interpretation of
factors affecting mold growth in homes is moisture level,
fungal measures of environmental media in indoor
controlling this factor is crucial in mold abatement
environments (quantitative limits for fungal
strategies. Many simple measures can significantly control
concentrations).
moisture, for example maintaining indoor relative
humidity at no greater than 40%-60% through the use
Given evidence that young children may be especially
of dehumidifiers, fixing water leakage problems,
vulnerable to certain mycotoxins [18] and in view of the
increasing ventilation in kitchens and bathrooms by using
potential severity or diseases associated with mycotoxin
exhaust fans, venting clothes dryers to the outside,
Healthy Housing Reference Manual
5-5
reducing the number of indoor plants, using air
(available from URL: http://www.nyc.gov/html/
conditioning at times of high outdoor humidity, heating
doh/html/epi/moldrpt1.shtml).
all rooms in the winter and adding heating to outside wall
closets, sloping surrounding soil away from building
American Conference of Governmental Industrial
foundations, fixing gutters and downspouts, and using a
Hygienists (ACGIH) 1999 document,
sump pump in basements prone to flooding [27]. Vapor
Biosaerosols: Assessment and Control (can be
barriers, sump pumps, and aboveground vents can also be
ordered at URL http://www.acgih.org/home.htm).
installed in crawlspaces to prevent moisture problems [28].
American Industrial Hygiene Association (AIHA)
Removal and Cleaning of Mold-contaminated Materials.
2004 document, Assessment, Remediation, and
Nonporous (e.g., metals, glass, and hard plastics) and
Post-Remediation Verification of Mold in
semiporous (e.g., wood and concrete) materials
Buildings (can be ordered at URL www.aiha.org)
contaminated with mold and that are still structurally
sound can often be cleaned with bleach-and-water
Environmental Protection Agency guidance, Mold
solutions. However, in some cases, the material may not
Remediation in Schools and Commercial Buildings
be easily cleaned or may be so severely contaminated that
(includes many general principles also applicable
it may have to be removed. It is recommended that
to residential mold mitigation efforts; available at
porous materials (e.g., ceiling tiles, wallboards, and
URL: http://www.epa.gov/iaq/molds/
fabrics) that cannot be cleaned be removed and discarded
mold_remediation.html)
[29]. In severe cases, clean-up and repair of mold-
contaminated buildings may be conducted using methods
Environmental Protection Agency guidance, A
similar to those used for abatement of other hazardous
Brief Guide to Mold, Moisture, and Your Home
substances such as asbestos [30]. For example, in
(for homeowners and renters on how to clean up
situations of extensive colonization (large surface areas
residential mold problems and how to prevent
greater than 100 square feet or where the material is
mold growth; available at URL: http://www.epa.gov/
severely degraded), extreme precautions may be required,
iaq/molds/images/moldguide.pdf)
including full containment (complete isolation of work
area) with critical barriers (airlock and decontamination
Canada Mortgage and Housing Corporation,
room) and negative pressurization, personnel trained to
Clean-up Procedures for Mold in Houses,
handle hazardous wastes, and the use of full-face
(provides qualitative guidance for mold
respirators with HEPA filters, eye protection, and
mitigation; can be ordered at URL:
disposable full-body covering [26].
https://www.cmhc-schl.gc.ca:50104/b2c/b2c/
init.do?language=en).
Worker Protection When Conducting Mold Assessment
and Mitigation Projects. Activities such as cleaning or
Figure 5.1 shows mold growth in the home.
removal of mold-contaminated materials in homes, as well
as investigations of mold contamination extent, have the
Chemical Pollutants
potential to disturb areas of mold growth and release
Carbon Monoxide
fungal spores and fragments into the air. Recommended
Carbon monoxide (CO) is a significant combustion
measures to protect workers during mold remediation
pollutant in the United States. CO is a leading cause of
efforts depend on the severity and nature of the mold
poisoning deaths [32]. According to the National Fire
contamination being addressed, but include the use of
Protection Association (NFPA), CO-related nonfire
well fitted particulate masks or respirators that retain
deaths are often attributed to heating and cooking
particles as small as 1 micrometer or less, disposable
equipment. The leading specific types of equipment
gloves and coveralls, and protective eyewear [31].
blamed for CO-related deaths include gas-fueled space
heaters, gas-fueled furnaces, charcoal grills, gas-fueled
Following are examples of guidance documents for
ranges, portable kerosene heaters, and wood stoves.
remediation of mold contamination:
As with fire deaths, the risk for unintentional CO death is
• New York City Department of Health and Mental
highest for the very young (ages 4 years and younger) and
Hygiene. Guidelines on Assessment and
the very old (ages 75 years and older). CO is an odorless,
Remediation of Fungi in Indoor Environments
colorless gas that can cause sudden illness and death. It is
5-6
Indoor Air Pollutants and Toxic Materials
Assure that all gas heaters
possess safety devices that
shut off an improperly
vented gas heater. Heaters
made after 1982 use a
pilot light safety system
known as an oxygen
depletion sensor. When
inadequate fresh air exists,
this system shuts off the
heater before large
amounts of CO can
be produced.
Figure 5.1. Mold Growth in the Home
Use appliances that have
Figure 5.2. Home Carbon
Monoxide Monitor
electronic ignitions instead
a result of the incomplete combustion of carbon.
Source: U.S. Navy
of pilot lights. These
Headache, dizziness, weakness, nausea, vomiting, chest
appliances are typically more energy efficient and
pain, and confusion are the most frequent symptoms of
eliminate the continuous low-level pollutants
CO poisoning. According to the American Lung
from pilot lights.
Association (ALA) [33], breathing low levels of CO can
cause fatigue and increase chest pain in people with
• Use the proper fuel in kerosene appliances.
chronic heart disease. Higher levels of CO can cause
flulike symptoms in healthy people. In addition,
• Install and use an exhaust fan vented to the
extremely high levels of CO cause loss of consciousness
outdoors over gas stoves.
and death. In the home, any fuel-burning appliance that
is not adequately vented and maintained can be a
Have a trained professional annually inspect,
potential source of CO. The following steps should be
clean, and tune up central heating systems
followed to reduce CO (as well as sulfur dioxide and
(furnaces, flues, and chimneys) and repair them
oxides of nitrogen) levels:
as needed.
Never use gas-powered equipment, charcoal grills,
• Do not idle a car inside a garage.
hibachis, lanterns, or portable camping stoves in
enclosed areas or indoors.
The U.S. Consumer Product Safety Commission (CPSC)
recommends installing at least one CO alarm per household
Install a CO monitor (Figure 5.2) in appropriate
near the sleeping area. For an extra measure of safety,
areas of the home. These monitors are designed to
another alarm should be placed near the home’s heating
provide a warning before potentially life-
source. ALA recommends weighing the benefits of using
threatening levels of CO are reached.
models powered by electrical outlets versus models powered by
batteries that run out of power and need replacing.
Choose vented appliances when possible and keep
Battery-powered CO detectors provide continuous protection
gas appliances properly adjusted to decrease the
and do not require recalibration in the event of a power
combustion to CO. (Note: Vented appliances are
outage. Electric-powered systems do not provide protection
always preferable for several reasons: oxygen levels,
during a loss of power and can take up to 2 days to
carbon dioxide buildup, and humidity management).
recalibrate. A device that can be easily self-tested and reset
to ensure proper functioning should be chosen. The product
• Only buy certified and tested combustion
should meet Underwriters Laboratories Standard UL 2034.
appliances that meet current safety standards, as
certified by Underwriter’s Laboratories (UL),
Ozone
American Gas Association (AGA) Laboratories, or
Inhaling ozone can damage the lungs. Inhaling small amounts
equivalent.
of ozone can result in chest pain, coughing, shortness of
breath, and throat irritation. Ozone can also exacerbate
Healthy Housing Reference Manual
5-7
chronic respiratory diseases such as asthma. Susceptibility
in nonsmokers due to ETS. Additionally, passive smoking
to the effects of ozone varies from person to person, but
can lead to coughing, excess phlegm, and chest
even healthy people can experience respiratory difficulties
discomfort. NCI also notes that spontaneous abortion
from exposure.
(miscarriage), cervical cancer, sudden infant death
syndrome, low birth weight, nasal sinus cancer, decreased
According to the North Carolina Department of Health
lung function, exacerbation of cystic fibrosis, and negative
and Human Services [34], the major source of indoor
cognitive and behavioral effects in children have been
ozone is outdoor ozone. Indoor levels can vary from 10% of
linked to ETS [36].
the outdoor air to levels as high as 80% of the outdoor air.
The Food and Drug Administration has set a limit of
The EPA [37] states that, because of their relative body
0.05 ppm of ozone in indoor air. In recent years, there
size and respiratory rates, children are affected by ETS
have been numerous advertisements for ion generators that
more than adults are. It is estimated that an additional
destroy harmful indoor air pollutants. These devices create
7,500 to 15,000 hospitalizations resulting from increased
ozone or elemental oxygen that reacts with pollutants.
respiratory infections occur in children younger than
EPA has reviewed the evidence on ozone generators and
18 months of age due to ETS exposure. Figure 5.3 shows
states: “available scientific evidence shows that at
the ETS exposure levels in homes with children under age
concentrations that do not exceed public health standards,
7 years. The following actions are recommended in the
ozone has little potential to remove indoor air contaminants,”
home to protect children from ETS:
and “there is evidence to show that at concentrations that
do not exceed public health standards, ozone is not
• if individuals insist on smoking, increase
effective at removing many odor causing chemicals” [35].
ventilation in the smoking area by opening
windows or using exhaust fans; and
Ozone is also created by the exposure of polluted air to
sunlight or ultraviolet light emitters. This ozone produced
• refrain from smoking in the presence of children
outside of the home can infiltrate the house and react
and do not allow babysitters or others who work
with indoor surfaces, creating additional pollutants.
in the home to smoke in the home or near children.
Environmental Tobacco Smoke or Secondhand Smoke
Volatile Organic Compounds
Like CO, environmental tobacco smoke (ETS; also
In the modern home, many organic chemicals are used as
known as secondhand smoke), is a product of
ingredients in household products. Organic chemicals
combustion. The National Cancer Institute (NCI) [36],
that vaporize and become gases at normal room
states that ETS is the combination of two forms of smoke
temperature are collectively known as VOCs.
from burning tobacco products:
Examples of common items that can release VOCs
• Sidestream smoke, or smoke that is emitted
include paints, varnishes, and wax, as well as in many
between the puffs of a burning cigarette, pipe, or
cleaning, disinfecting, cosmetic, degreasing, and hobby
cigar; and
products. Levels of approximately a dozen common
VOCs can be two to five times higher inside the home, as
• Mainstream smoke, or the smoke that is exhaled
opposed to outside, whether in highly industrialized areas
by the smoker.
The physiologic effects of ETS are numerous. ETS can
trigger asthma; irritate the eyes, nose, and throat; and
cause ear infections in children, respiratory illnesses, and
lung cancer. ETS is believed to cause asthma by irritating
chronically inflamed bronchial passages. According to the
EPA [37], ETS is a Group A carcinogen; thus, it is a
known cause of cancer in humans. Laboratory analysis
has revealed that ETS contains in excess of
4,000 substances, more than 60 of which cause cancer
in humans or animals. The EPA also estimates that
Figure 5.3. Environmental Tobacco Smoke and Children’s Exposure [37]
approximately 3,000 lung cancer deaths occur each year
5-8
Indoor Air Pollutants and Toxic Materials
or rural areas. VOCs that frequently pollute indoor air
decline with time. In 1982, CPSC voted to ban UF foam
include toluene, styrene, xylenes, and trichloroethylene.
insulation. The courts overturned the ban; however, the
Some of these chemicals may be emitted from aerosol
publicity has decreased the use of this product.
products, dry-cleaned clothing, paints, varnishes, glues,
art supplies, cleaners, spot removers, floor waxes, polishes,
More recently, the most significant source of
and air fresheners. The health effects of these chemicals
formaldehyde in homes has been pressed wood products
are varied. Trichlorethylene has been linked to childhood
made using adhesives that contain UF resins [41]. The
leukemia. Exposure to toluene can put pregnant women
most significant of these is medium-density fiberboard,
at risk for having babies with neurologic problems,
which contains a higher resin-to-wood ratio than any
retarded growth, and developmental problems. Xylenes
other UF pressed wood product. This product is generally
have been linked to birth defects. Styrene is a suspected
recognized as being the highest formaldehyde-emitting
endocrine disruptor, a chemical that can block or mimic
pressed wood product. Additional pressed wood products
hormones in humans or animals. EPA data reveal that
are produced using phenol-formaldehyde resin. The latter
methylene chloride, a common component of some paint
type of resin generally emits formaldehyde at a
strippers, adhesive removers, and specialized aerosol spray
considerably slower rate than those containing UF resin.
paints, causes cancer in animals [38]. Methylene chloride
The emission rate for both resins will change over time
is also converted to CO in the body and can cause
and will be influenced by high indoor temperatures and
symptoms associated with CO exposure. Benzene, a
humidity. Since 1985, U.S. Department of Housing and
known human carcinogen, is contained in tobacco smoke,
Urban Development (HUD) regulations (24 CFR 3280.308,
stored fuels, and paint supplies. Perchloroethylene, a
3280.309, and 3280.406) have permitted only the use of
product uncommonly found in homes, but common to
plywood and particleboard that conform to specified
dry cleaners, can be a pollution source by off-gassing from
formaldehyde emission limits in the construction of
newly cleaned clothing. Environmental Media Services
prefabricated and manufactured homes [42]. This limit was
[39] also notes that xylene, ketones, and aldehydes are
to ensure that indoor formaldehyde levels are below 0.4 ppm.
used in aerosol products and air fresheners.
CPSC [40] notes that formaldehyde is a colorless, strong-
To lower levels of VOCs in the home, follow these steps:
smelling gas. At an air level above 0.1 ppm, it can cause
watery eyes; burning sensations in the eyes, nose, and
• use all household products according to directions;
throat; nausea; coughing; chest tightness; wheezing; skin
rashes; and allergic reactions. Laboratory animal studies
• provide good ventilation when using these products;
have revealed that formaldehyde can cause cancer in
animals and may cause cancer in humans. Formaldehyde
• properly dispose of partially full containers of old
is usually present at levels less than 0.03 ppm indoors and
or unneeded chemicals;
outdoors, with rural areas generally experiencing lower
concentrations than urban areas. Indoor areas that
• purchase limited quantities of products; and
contain products that release formaldehyde can have levels
greater than 0.03 ppm. CPSC also recommends the
• minimize exposure to emissions from products
following actions to avoid high levels of exposure to
containing methylene chloride, benzene, and
formaldehyde:
perchlorethylene.
• Purchase pressed wood products that are labeled
A prominent VOC found in household products and
or stamped to be in conformance with American
construction products is formaldehyde. According to
National Standards Institute criteria ANSI
CPSC [40], these products include the glue or adhesive
A208.1-1993. Use particleboard flooring marked
used in pressed wood products; preservatives in paints,
with ANSI grades PBU, D2, or D3. Medium-
coating, and cosmetics; coatings used for permanent-press
density fiberboard should be in conformance with
quality in fabrics and draperies; and the finish on paper
ANSI A208.2-1994 and hardwood plywood with
products and certain insulation materials. Formaldehyde
ANSI/HPVA HP-1-1994 (Figure 5.4).
is contained in urea-formaldehyde (UF) foam insulation
installed in the wall cavities of homes as an energy
• Purchase furniture or cabinets that contain a high
conservation measure. Levels of formaldehyde increase
percentage of panel surface and edges that are
soon after installation of this product, but these levels
laminated or coated. Unlaminated or uncoated
Healthy Housing Reference Manual
5-9
levels in the United States. Maps of the individual states
and areas that have proven high for radon are available at
http://www.epa.gov/iaq/radon/ zonemap.html. A free
video is available from the U.S. EPA: call 1-800-438-
4318 and ask for EPA 402-V-02-003 (TRT 13.10).
Radon, according to the California Geological Survey
Figure 5.4. Wood Products Label [42]
[45], is one of the intermediate radioactive elements
formed during the radioactive decay of uranium-238,
(raw) panels of pressed wood panel products will
uranium-235, or thorium-232. Radon-222 is the radon
generally emit more formaldehyde than those that
isotope of most concern to public health because of its
are laminated or coated.
longer half-life (3.8 days). The mobility of radon gas is
much greater than are uranium and radium, which are
• Use alternative products, such as wood panel
solids at room temperature. Thus, radon can leave rocks
products not made with UF glues, lumber, or metal.
and soil, move through fractures and pore spaces, and
ultimately enter a building to collect in high concentrations.
• Avoid the use of foamed-in-place insulation
When in water, radon moves less than 1 inch before it
containing formaldehyde, especially UF foam
decays, compared to 6 feet or more in dry rocks or soil.
insulation.
USGS [44] notes that radon near the surface of soil
typically escapes into the atmosphere. However,
• Wash durable-press fabrics before use.
where a house is present, soil air often flows toward the
house foundation because of
CPSC also recommends the following actions to reduce
existing levels of indoor formaldehyde:
• Ventilate the home well by opening doors and
windows and installing an exhaust fan(s).
• Seal the surfaces of formaldehyde-containing
products that are not laminated or coated with
paint, varnish, or a layer of vinyl or polyurethane-
like materials.
• Remove products that release formaldehyde in the
indoor air from the home.
Radon
According to the EPA [43], radon is a colorless, odorless
gas that occurs naturally in soil and rock and is a decay
product of uranium. The U.S. Geological Survey (USGS)
Figure 5.5. EPA Map of Radon Zones [43]
[44] notes that the typical uranium content of rock and
Zone 1: predicted average indoor radon screening level greater than
the surrounding soil is between 1 and 3 ppm. Higher
4 pCi/L [picocuries per liter]
levels of uranium are often contained in rock such as
Zone 2: predicted average indoor radon screening level between 2 and
light-colored volcanic rock, granite, dark shale, and
4 pCi/L
sedimentary rock containing phosphate. Uranium levels
Zone 3: predicted average indoor radon screening level less than 2 pCi/L
as high as 100 ppm may be present in various areas of the
United States because of these rocks. The main source of
Important: Consult the EPA Map of Radon Zones document [EPA-402-R-
93-071] before using this map. This document contains information on
high-level radon pollution in buildings is surrounding
radon potential variations within counties.
uranium-containing soil. Thus, the greater the level of
uranium nearby, the greater the chances are that buildings
EPA also recommends that this map be supplemented with any available
local data to further understand and predict the radon potential of a
in the area will have high levels of indoor radon.
specific area.
Figure 5.5 demonstrates the geographic variation in radon
5-10
Indoor Air Pollutants and Toxic Materials
• differences in air pressure between the soil and the
house, with soil pressure often being higher;
• presence of openings in the house’s foundation; and
• increases in permeability around the basement
(if present).
Houses are often constructed with loose fill under a basement
slab and between the walls and exterior ground. This fill
is more permeable than the original ground. Houses
typically draw less than 1% of their indoor air from the
soil. However, houses with low indoor air pressures,
poorly sealed foundations, and several entry points for soil
air may draw up to 20% of their indoor air from the soil.
Figure 5.6. Radon Entry [30]
USGS [44] states that radon may also enter the home
through the water systems. Surface water sources typically
the radon gas directly or the daughter products. The
contain little radon because it escapes into the air. In
simplest devices are passive, require no electricity, and
larger cities, radon is released to the air by municipal
include a charcoal canister, charcoal liquid scintillation
processing systems that aerate the water. However, in
device, alpha tract detector, and electret ion detectors [47].
areas where groundwater is the main water supply for
All of these devices, with the exception of the ion
communities, small public systems and private wells are
detector, can be purchased in hardware stores or by mail.
typically closed systems that do not allow radon to escape.
The ion detector generally is only available through
Radon then enters the indoor air from showers, clothes
laboratories. These devices are inexpensive, primarily used
washing, dishwashing, and other uses of water. Figure 5.6
for short-term testing, and require little to no training.
shows typical entry points of radon.
Active devices, however, need electrical power and include
continuous monitoring devices. They are customarily
Health risks of radon stem from its breakdown into
more expensive and require professionally trained testers
“radon daughters,” which emit high-energy alpha
for their operation. Figure 5.7 shows examples of the
particles. These progeny enter the lungs, attach
charcoal tester (a; left) and the alpha tract detector (b; right).
themselves, and may eventually lead to lung cancer. This
exposure to radon is believed to contribute to between
After testing and evaluation by a professional, it may be
15,000 and 21,000 excess lung cancer deaths in the
necessary to lower the radon levels in the structure. The
United States each year. The EPA has identified levels
Pennsylvania Department of Environmental Protection
greater than 4 picocuries per liter as levels at which
[48] states that in most cases, a system with pipes and a
remedial action should be taken. Approximately 1 in
fan is used to reduce radon. This system, known as a subslab
15 homes nationwide have radon above this level,
depressurization system, requires no major changes to the
according to the U.S. Surgeon General’s recent advisory
home. The cost typically ranges from $500 to $2,500 and
[46]. Smokers are at significantly higher risk for radon-
averages approximately $1,000, varying with geographic
related lung cancer.
region. The typical mitigation system usually has only one
pipe penetrating through the basement floor; the pipe also
Radon in the home can be measured either by the
may be installed outside the house. The Connecticut
occupant or by a professional. Because radon has no odor
Department of Public Health [49] notes that it is more
or color, special devices are used to measure its presence.
cost effective to include radon-resistant techniques while
Radon levels vary from day to day and season to season.
constructing a building than to install a reduction system
Short-term tests (2 to 90 days) are best if quick results are
in an existing home. Inclusion of radon-resistant
needed, but long-term tests (more than 3 months) yield
techniques in initial construction costs approximately
better information on average year-round exposure.
$350 to $500 [50]. Figure 5.8 shows examples of radon-
Measurement devices are routinely placed in the lowest
resistant construction techniques.
occupied level of the home. The devices either measure
Healthy Housing Reference Manual
5-11
rodents, mosquitoes, and other pests that integrates
inspection, monitoring, treatment, and evaluation, with
special emphasis on the decreased use of toxic agents.
However, all pest management options, including natural,
biologic, cultural, and chemical methods, should be
considered. Those that have the least impact on health
and the environment should be selected. Most household
pests can be controlled by eliminating the habitat for the
pest both inside and outside, building or screening them
out, eliminating food and harborage areas, and safely
using appropriate pesticides if necessary.
Figure 5.7. Home Radon Dectectors [31]
EPA [51] states that 75% of U.S. households used at least
A passive radon-resistant system has five major parts:
one pesticide indoors during the past year and that 80% of
most people’s exposure to pesticides occurs indoors.
1. A layer of gas-permeable material under the
Measurable levels of up to a dozen pesticides have been
foundation.
found in the air inside homes. Pesticides used in and
around the home include products to control insects
2. The foundation (usually 4 inches of gravel).
(insecticides), termites (termiticides), rodents (rodenticides),
fungi (fungicides), and microbes (disinfectants). These
3. Plastic sheeting over the foundation, with all
products are found in sprays, sticks, powders, crystals,
openings in the concrete foundation floor sealed
balls, and foggers.
and caulked.
Delaplane [52] notes that the ancient Romans killed
4. A gas-tight, 3- or 4-inch vent pipe running from
insect pests by burning sulfur and controlled weeds with
under the foundation through the house to the roof.
salt. In the 1600s, ants were controlled with mixtures of
honey and arsenic. U.S. farmers in the late 19th century
5. A roughed-in electrical junction box for the future
used copper actoarsenite (Paris green), calcium arsenate,
installation of a fan, if needed.
nicotine sulfate, and sulfur to control insect pests in field
These features create a physical barrier to radon entry.
crops. By World War II and afterward, numerous
The vent pipe redirects the flow of air under the
pesticides had been introduced, including DDT, BHC,
foundation, preventing radon from seeping into the house.
aldrin, dieldrin, endrin, and 2,4-D. A significant factor
with regard to these pesticides used in and around the
Pesticides
home is their impact on children. According to a 2003
Much pesticide use could be reduced if integrated pest
EPA survey, 47% of all households with children under
management (IPM) practices were used in the home.
the age of 5 years had at least one pesticide stored in an
IPM is a coordinated approach to managing roaches,
unlocked cabinet less than 4 feet off the ground. This is
within easy reach of children. Similarly, 74% of
households without children under the age of 5 also
stored pesticides in an unlocked cabinet less than 4 feet
off the ground. This issue is significant because 13% of all
pesticide poisoning incidents occur in homes other than
the child’s home. The EPA [53] notes a report by the
American Association of Poison Control Centers
indicating that approximately 79,000 children were
involved in common household pesticide poisonings or
exposures.
The health effects of pesticides vary with the product.
However, local effects from most of the products will be
on eyes, noses, and throats; more severe consequences,
such as on the central nervous system and kidneys and on
Figure 5.8. Radon-resistant Construction [50]
5-12
Indoor Air Pollutants and Toxic Materials
cancer risks, are possible. The active and inert ingredients
• do not place rodent or insect baits where small
of pesticides can be organic compounds, which can
children have access to them;
contribute to the level of organic compounds in indoor
air. More significantly, products containing cyclodiene
• use child-resistant packaging properly by closing
pesticides have been commonly associated with
the container tightly after use;
misapplication. Individuals inadvertently exposed during
this misapplication had numerous symptoms, including
• assure that other caregivers for children are aware
headaches, dizziness, muscle twitching, weakness, tingling
of the potential hazards of pesticides;
sensations, and nausea. In addition, there is concern that
these pesticides may cause long-term damage to the liver
• teach children that pesticides are poisons and
and the central nervous system, as well as an increased
should not be handled; and
cancer risk. Cyclodiene pesticides were developed for use
as insecticides in the 1940s and 1950s. The four main
• keep the local Poison Control Center telephone
cyclodiene pesticides—aldrin, dieldrin, chlordane, and
number available.
heptachlor—were used to guard soil and seed against
insect infestation and to control insect pests in crops.
Toxic Materials
Outside of agriculture they were used for ant control;
Asbestos
farm, industrial, and domestic control of fleas, flies, lice,
Asbestos, from the Greek word meaning “inextinguishable,”
and mites; locust control; termite control in buildings, fences,
refers to a group of six naturally occurring mineral fibers.
and power poles; and pest control in home gardens. No
Asbestos is a mineral fiber of which there are several
other commercial use is permitted for cyclodiene or
types: amosite, crocidiolite, tremolite, actinolite,
related products. The only exception is the use of
anthrophyllite, and chrysotile. Chrysotile asbestos, also
heptachlor by utility companies to control fire ants in
known as white asbestos, is the predominant commercial
underground cable boxes.
form of asbestos. Asbestos is strong, flexible, resistant to
heat and chemical corrosion, and insulates well. These
An EPA survey [53] revealed that bathrooms and kitchens
features led to the use of asbestos in up to 3,000 consumer
are areas in the home most likely to have improperly stored
products before government agencies began to phase it
pesticides. In the United States, EPA regulates pesticides under
out in the 1970s because of its health hazards. Asbestos
the pesticide law known as the Federal Insecticide, Fungicide,
has been used in insulation, roofing, siding, vinyl floor
and Rodenticide Act. Since 1981, this law has required
tiles, fireproofing materials, texturized paint and
most residential-use pesticides to bear a signal word such
soundproofing materials, heating appliances (such as
as “danger” or “warning” and to be contained in child-
clothes dryers and ovens), fireproof gloves, and ironing
resistant packaging. This type of packaging is designed to
boards. Asbestos continues to be used in some products,
prevent or delay access by most children under the age of
such as brake pads. Other mineral products, such as talc
5 years. EPA offers the following recommendations for
and vermiculite, can be contaminated with asbestos.
preventing accidental poisoning:
The health effects of asbestos exposure are numerous and
varied. Industrial studies of workers exposed to asbestos in
• store pesticides away from the reach of children in
factories and shipyards have revealed three primary health
a locked cabinet, garden shed, or similar location;
risk concerns from breathing high levels of asbestos fibers:
lung cancer, mesothelioma (a cancer of the lining of the
• read the product label and follow all directions
chest and the abdominal cavity), and asbestosis (a condition in
exactly, especially precautions and restrictions;
which the lungs become scarred with fibrous tissue).
The risk for all of these conditions is amplified as the
• remove children, pets, and toys from areas before
number of fibers inhaled increases. Smoking also
applying pesticides;
enhances the risk for lung cancer from inhaling asbestos
fibers by acting synergistically. The incubation period (from
• if interrupted while applying a pesticide, properly
time of exposure to appearance of symptoms) of these
close the package and assure that the container is
diseases is usually about 20 to 30 years. Individuals who
not within reach of children;
develop asbestosis have typically been exposed to high
levels of asbestos for a long time. Exposure levels to
• do not transfer pesticides to other containers that
asbestos are measured in fibers per cubic centimeter of air.
children may associate with food or drink;
Most individuals are exposed to small amounts of asbestos
Healthy Housing Reference Manual
5-13
in daily living activities; however, a preponderance of
Common products that contained asbestos in the past
them do not develop health problems. According to the
and conditions that may release fibers include the following:
Agency for Toxic Substances and Disease Registry
(ATSDR), if an individual is exposed, several factors
Steam pipes, boilers, and furnace ducts insulated
determine whether the individual will be harmed [54].
with an asbestos blanket or asbestos paper tape.
These factors include the dose (how much), the duration
These materials may release asbestos fibers if
(how long), and the fiber type (mineral form and
damaged, repaired, or removed improperly.
distribution). ATSDR also states that children may be
more adversely affected than adults [54]. Children breathe
Resilient floor tiles (vinyl asbestos, asphalt, and
differently and have different lung structures than adults;
rubber), the backing on vinyl sheet flooring, and
however, it has not been determined whether these
adhesives used for installing floor tile. Sanding
differences cause a greater amount of asbestos fibers to
tiles can release fibers, as may scraping or sanding
stay in the lungs of a child than in the lungs of an adult.
the backing of sheet flooring during removal.
In addition, children drink more fluids per kilogram of
body weight than do adults and they can be exposed
Cement sheet, millboard, and paper used as
through asbestos-contaminated drinking water. Eating
insulation around furnaces and wood-burning
asbestos-contaminated soil and dust is another source of
stoves. Repairing or removing appliances may
exposure for children. Certain children intentionally eat
release asbestos fibers, as may cutting, tearing,
soil and children’s hand-to-mouth activities mean that all
sanding, drilling, or sawing insulation.
young children eat more soil than do adults. Family
members also have been exposed to asbestos that was
Door gaskets in furnaces, wood stoves, and coal
carried home on the clothing of other family members
stoves. Worn seals can release asbestos fibers
who worked in asbestos mines or mills. Breathing asbestos
during use.
fibers may result in difficulty in breathing. Diseases
usually appear many years after the first exposure to
Soundproofing or decorative material sprayed on
asbestos and are therefore not likely to be seen in
walls and ceilings. Loose, crumbly, or water-
children. But people who have been exposed to asbestos
damaged material may release fibers, as will
at a young age may be more likely to contract diseases
sanding, drilling, or scraping the material.
than those who are first exposed later in life. In the small
number of studies that have specifically looked at asbestos
Patching and joint compounds for walls, ceilings,
exposure in children, there is no indication that younger
and textured paints. Sanding, scraping, or drilling
people might develop asbestos-related diseases more
these surfaces may release asbestos.
quickly than older people. Developing fetuses and infants
are not likely to be exposed to asbestos through the
Asbestos cement roofing, shingles, and siding.
placenta or breast milk of the mother. Results of animal
These products are not likely to release asbestos
studies do not indicate that exposure to asbestos is likely
fibers unless sawed, drilled, or cut.
to result in birth defects.
Artificial ashes and embers sold for use in gas-
A joint document issued by CPSC, EPA, and ALA, notes
fired fireplaces in addition to other older
that most products in today’s homes do not contain
household products such as fireproof gloves,
asbestos. However, asbestos can still be found in products
stove-top pads, ironing board covers, and certain
and areas of the home. These products contain asbestos
hair dryers.
that could be inhaled and are required to be labeled as
Automobile brake pads and linings, clutch facings,
such. Until the 1970s, many types of building products
and gaskets.
and insulation materials used in homes routinely
contained asbestos. A potential asbestos problem both
Homeowners who believe material in their home may be
inside and outside the home is that of vermiculite. According
asbestos should not disturb the material. Generally,
to the USGS [55], vermiculite is a claylike material that
material in good condition will not release asbestos fibers,
expands when heated to form wormlike particles. It is
and there is little danger unless the fibers are released and
used in concrete aggregate, fertilizer carriers, insulation,
inhaled into the lungs. However, if disturbed, asbestos
potting soil, and soil conditioners. This product ceased
material may release asbestos fibers, which can be inhaled
being mined in 1992, but old stocks may still be available.
into the lungs. The fibers can remain in the lungs for a
5-14
Indoor Air Pollutants and Toxic Materials
long time, increasing the risk for disease. Suspected
asbestos material is damaged extensively and cannot be
asbestos-containing material should be checked regularly
otherwise repaired. Removal is complex and must be done
for damage from abrasions, tears, or water. If possible,
only by a contractor with special training. Improper
access to the area should be limited. Asbestos-containing
removal of asbestos material may create more of a
products such as asbestos gloves, stove-top pads, and
problem than simply leaving it alone.
ironing board covers should be discarded if damaged or
worn. Permission and proper disposal methods should be
Lead
obtainable from local health, environmental, or other
Many individuals recognize lead in the form often seen in
appropriate officials. If asbestos material is more than
tire weights and fishing equipment, but few recognize its
slightly damaged, or if planned changes in the home
various forms in and around the home. The Merriam-
might disturb it, repair or removal by a professional is
Webster Dictionary [56] defines lead as “a heavy soft malleable
needed. Before remodeling, determine whether asbestos
ductile plastic but inelastic bluish white metallic element
materials are present.
found mostly in combination and used especially in pipes,
cable sheaths, batteries, solder, and shields against
Only a trained professional can confirm suspected
radioactivity.” Lead is a metal with many uses. It melts easily
asbestos materials that are part of a home’s construction. This
and quickly. It can be molded or shaped into thin sheets
individual will take samples for analysis and submit them
and can be drawn out into wire or threads. Lead also is
to an EPA-approved laboratory.
very resistant to weather conditions. Lead and lead
compounds are toxic and can present a severe hazard to
If the asbestos material is in good shape and will not be
those who are overexposed to them. Whether ingested or
disturbed, the best approach is to take no action and
inhaled, lead is readily absorbed and distributed
continue to monitor the material. If the material needs
throughout the body.
action to address potential exposure problems, there are
two approaches to correcting the problem: repair and removal.
Until 1978, lead compounds were an important component
of many paints. Lead was added to paint to promote
Repair involves sealing or covering the asbestos material.
adhesion, corrosion control, drying, and covering. White
Sealing or encapsulation involves treating the material
lead (lead carbonate), linseed oil, and inorganic pigments
with a sealant that either binds the asbestos fibers together
were the basic components for paint in the 18th and 19th
or coats the material so fibers are not released. This is an
centuries, and continued until the middle of the 20th century.
approach often used for pipe, furnace, and boiler
Lead was banned by CPSC in 1978. Lead-based paint was
insulation; however, this work should be done only by a
used extensively on exteriors and interior trim-work, window
professional who is trained to handle asbestos safely.
sills, sashes, window frames, baseboards, wainscoting,
Covering (enclosing) involves placing something over or
doors, frames, and high-gloss wall surfaces, such as those
around the material that contains asbestos to prevent release
found in kitchens and bathrooms. The only way to determine
of fibers. Exposed insulated piping may be covered with a
which building components are coated with lead paint is
protective wrap or jacket. In the repair process, the
through an inspection for lead-based paint. Almost all
approach is for the material to remain in position
painted metals were primed with red lead or painted with
undisturbed. Repair is a less expensive process than is removal.
lead-based paints. Even milk (casein) and water-based
paints (distemper and calcimines) could contain some
With any type of repair, the asbestos remains in place.
lead, usually in the form of hiding agents or pigments.
Repair may make later removal of asbestos, if necessary,
Varnishes sometimes contained lead. Lead compounds also
more difficult and costly. Repairs can be major or minor.
were used as driers in paint and window-glazing putty.
Both major and minor repairs must be done only by a
Lead is widespread in the environment. People absorb
professional trained in methods for safely handling asbestos.
lead from a variety of sources every day. Although lead
has been used in numerous consumer products, the most
Removal is usually the most expensive and, unless
important sources of lead exposure to children and others
required by state or local regulations, should be the last
today are the following:
option considered in most situations. This is because
removal poses the greatest risk for fiber release. However,
• contaminated house dust that has settled on
removal may be required when remodeling or making
horizontal surfaces,
major changes to the home that will disturb asbestos
material. In addition, removal may be called for if
• deteriorated lead-based paint,
Healthy Housing Reference Manual
5-15
• contaminated bare soil,
for children to be exposed to lead. Other sources of
exposure have included imported vinyl miniblinds,
• food (which can be contaminated by lead in the
crayons, children’s jewelry, and candy. In 2004, increases
air or in food containers, particularly lead-
in lead in water service pipes were observed in Washington,
soldered food containers),
D.C., accompanied by increases in blood lead levels in
children under the age of 6 years who were served by the
• drinking water (from corrosion of plumbing
water system [58].
systems), and
In some cases, children swallow nonfood items such as
• occupational exposure or hobbies.
paint chips. These may contain very large amounts of lead,
particularly in and around older houses that were painted
Federal controls on lead in gasoline, new paint, food
with lead-based paint. Many studies have verified the
canning, and drinking water, as well as lead from industrial air
effect of lead exposure on IQ scores in the United States.
emissions, have significantly reduced total human exposure
The effects of lead exposure have been reviewed by the
to lead. The number of children with blood lead levels above
National Academy of Sciences [59].
10 micrograms per deciliter (µg/dL), a level designated as
showing no physiologic toxicity, has declined from
Generally, the tests for blood lead levels are from drawn
1.7 million in the late 1980s to 310,000 in 1999-2002.
blood, not from a finger-stick test, which can be unreliable if
This demonstrates that the controls have been effective,
performed improperly. Units are measured in micrograms
but that many children are still at risk. CDC data show
per deciliter and reflect the 1991 guidance from the Centers
that deteriorated lead-based paint and the contaminated
of Disease Control [60]:
dust and soil it generates are the most common sources of
exposure to children today. HUD data show that the
• Children: 10 µg/dL (level of concern)—find
number of houses with lead paint declined from 64 million
source of lead;
in 1990 to 38 million in 2000 [57].
• Children: 15 µg/dL and above—environmental
Children are more vulnerable to lead poisoning than are
intervention, counseling, medical monitoring;
adults. Infants can be exposed to lead in the womb if
their mothers have lead in their bodies. Infants and
• Children: 20 µg/dL and above—medical treatment;
children can swallow and breathe lead in dirt, dust, or
sand through normal hand-to-mouth contact while they
• Adults: 25 µg/dL (level of concern)—find source
play on the floor or ground. These activities make it easier
of lead; and
Action Levels for Lead
Lead in paint. Differing methods report results in differing units. Lead is considered a potential hazard if
above the following levels, but can be a hazard at lower levels if improperly handled. Below are the current
action levels identified by HUD [62] and EPA (40 CFR Part 745):
Lab analysis of samples:
5,000 milligram per kilogram (mg/kg) or 5,000 parts per million (ppm)
0.5% lead by weight.
X-ray fluorescence:
1 milligram per square centimeter (mg/cm2)
Lead in dust:
Lead in soil:
Floors, 40 micrograms per square foot (µg/ft2)
High-contact bare play areas: 400 ppm
Window sills, 250 µg/ft2
Other yard areas: 1,200 ppm
Window troughs, 400 µg/ft2 (clearance only)
5-16
Indoor Air Pollutants and Toxic Materials
• Adults: 50 µg/dL—Occupational Safety and
available by calling 1-800-424-LEAD. Do-it-yourself test
Health Administration (OSHA) standard for
kits are commercially available; however, these kits do not
medical removal from the worksite.
tell you how much lead is present, and their reliability at
detecting low levels of lead has not been determined.
Adults are usually exposed to lead from occupational
Professional testing for lead in paint is recommended.
sources (e.g., battery construction, paint removal) or at
The recommended sampling method for dust is the
home (e.g., paint removal, home renovations).
surface wet wipe. Dust samples are collected from
In 1978, CPSC banned the use of lead-based paint in
different surfaces, such as bare floors, window sills, and
residential housing. Because houses are periodically
window wells. Each sample is collected from a measured
repainted, the most recent layer of paint will most likely
surface area using a wet wipe, which is sent to a
not contain lead, but the older layers underneath
laboratory for testing. Risk assessments can be fairly low-
probably will. Therefore, the only way to accurately
cost investigations of the location, condition, and severity
determine the amount of lead present in older paint is to
of lead hazards found in house dust, soil, water, and
have it analyzed.
deteriorating paint. Risk assessments also will address
other sources of lead from hobbies, crockery, water, and
It is important that owners of homes built before 1978 be
work environments. These services are critical when
aware that layers of older paint can contain a great deal of
owners are seeking to implement measures to reduce
lead. Guidelines on identifying and controlling lead-based
suspected lead hazards in housing and day-care centers or
paint hazards in housing have been published by HUD [61].
when extensive rehabilitation is planned.
Controlling Lead Hazards
HUD has published detailed protocols for risk
The purpose of a home risk assessment is to determine,
assessments and inspections [61].
through testing and evaluation, where hazards from lead
warrant remedial action. A certified inspector or risk
It is important from a health standpoint that future tenants,
assessor can test paint, soil, or lead dust either on-site or
painters, and construction workers know that lead-based
in a laboratory using methods such as x-ray fluorescence
paint is present, even under treated surfaces, so they can
(XRF) analyzers, chemicals, dust wipe tests, and atomic
take precautions when working in areas that will generate
absorption spectroscopy. Lists of service providers are
lead dust. Whenever mitigation work is completed, it is
Definitions Related to Lead
Deteriorated lead-based paint: Paint known to contain lead above the regulated level that shows signs of
peeling, chipping, chalking, blistering, alligatoring, or otherwise separating from its substrate.
Dust removal: The process of removing dust to avoid creating a greater problem of spreading lead particles;
usually through wet or damp collection and use of HEPA vacuums.
Hazard abatement: Long-term measures to remove the hazards of lead-based paint through replacement of
building components, enclosure, encapsulation, or paint removal.
Interim control: Short-term methods to remove lead dust, stabilize deteriorating painted surfaces, treat
friction and impact surfaces that generate lead dust, and repaint surfaces. Maintenance can ensure that
housing remains lead-safe.
Lead-based paint: Any existing paint, varnish, shellac, or other coating that is equal to or greater than
1.0 milligrams per square centimeter (mg/cm2) or greater than 0.5% by weight (5,000 ppm, 5,000
micrograms per gram [µg/g], or 5,000 milligrams per kilogram [mg/kg]). For new paint, CPSC has
established 0.06% as the maximum amount of lead allowed in new paint. Lead in paint can be measured by
x-ray fluorescence analyzers or laboratory analysis by certified personnel and approved laboratories.
Risk assessment: An on-site investigation to determine the presence and condition of lead-based paint,
including limited test samples and an evaluation of the age, condition, housekeeping practices, and uses of a
residence.
Healthy Housing Reference Manual
5-17
important to have a clearance test using the dust wipe
state laws generally support the reasonable control of lead-
method to ensure that lead-laden dust generated during
based paint hazards through a variety of treatments,
the work does not remain at levels above those established
ranging from modified maintenance to selective substrate
by the EPA and HUD. Such testing is required for
removal. The key to protecting children, workers, and the
owners of most housing that is receiving federal financial
environment is to be informed about the hazards of lead,
assistance, such as Section 8 rental housing. A building or
to control exposure to lead dust and lead in soil and lead
housing file should be maintained and updated whenever
paint chips, and to follow existing regulations.
any additional lead hazard control work is completed.
Owners are required by law to disclose information about
The following summarizes several important regulations
lead-based paint or lead-based paint hazards to buyers or
that affect lead-hazard reduction projects. Owners should
tenants before completing a sales or lease contract [62].
be aware that regulations change, and they have a
responsibility to check state and local ordinances as well.
All hazards should be controlled as identified in a
Care must be taken to ensure that any procedures used to
risk assessment.
release lead from the home protect both the residents and
workers from lead dust exposure.
Whenever extensive amounts of lead must be removed
from a property, or when methods of removing toxic
Residential Lead-Based Paint Hazard Reduction Act of
substances will affect the environment, it is extremely
1992, Title X [62]. Part of the Housing and Community
important that the owner be aware of the issues surrounding
Development Act of 1992 (Public Law 102-550) [63]. It
worker safety, environmental controls, and proper disposal.
established that HUD issue Guidelines for the Evaluation
Appropriate architectural, engineering, and environmental
and Control of Lead-Based Paint Hazards in Housing [61]
professionals should be consulted when lead hazard
to outline risk assessments, interim controls, and
projects are complex.
abatement of lead-based paint hazards in housing. Title X
calls for the reduction of lead in federally supported
Following are brief explanations of the two approaches for
housing. It outlines the federal responsibility toward its
controlling lead hazard risks. These controls are
own residential units and the need for disclosure of lead
recommended by HUD in HUD Guidelines for the
in residences, even private residences, before a sale. Title X
Evaluation and Control of Lead-Based Paint Hazards in
also required HUD to establish regulations for federally
Housing [61], and are summarized here to focus on
assisted housing (24 CFR Part 35) and EPA to establish
special considerations for historic housing:
standards for lead in paint, dust, and soil, as well as
standards for laboratory accreditation (40 CFR Part 745).
Interim Controls. Short-term solutions include thorough
EPA’s residential lead hazard standards are available at
dust removal and thorough washdown and cleanup, paint
http://www.epa.gov/lead/leadhaz.htm.
film stabilization and repainting, covering of lead-
contaminated soil, and informing tenants about lead
Interim Final Rule on Lead in Construction (29 Code of
hazards. Interim controls require ongoing maintenance
Federal Regulations [CFR] 1926.62) [64]. Issued by
and evaluation.
OSHA, these regulations address worker safety, training,
and protective measures. The regulations are based in part
Hazard Abatement. Long-term solutions are defined as
on personal-air sampling to determine the amount of lead
having an expected life of 20 years or more and involve
dust exposure to workers.
permanent removal of hazardous paint through chemicals,
heat guns, or controlled sanding or abrasive methods;
State Laws. States generally have the authority to regulate
permanent removal of deteriorated painted features
the removal and transportation of lead-based paint and
through replacement; removal or permanent covering of
the generated waste through the appropriate state
contaminated soil; and the use of enclosures (such as
environmental and public health agencies. Most
drywall) to isolate painted surfaces. The use of specialized
requirements are for mitigation in the case of a lead-
encapsulant products can be considered as permanent
poisoned child, for protection of children, or for oversight
abatement of lead.
to ensure the safe handling and disposal of lead waste.
When undertaking a lead-based paint reduction program,
Reducing and controlling lead hazards can be successfully
it is important to determine which laws are in place that
accomplished without destroying the character-defining
may affect the project.
features and finishes of historic buildings. Federal and
5-18
Indoor Air Pollutants and Toxic Materials
Local Ordinances. Check with local health departments,
prevent rot. Numerous studies show that arsenic sticks to
poison control centers, and offices of housing and
children’s hands when they play on treated wood, and it is
community development to determine whether any laws
absorbed through the skin and ingested when they put
require compliance by building owners. Determine
their hands in their mouths. Although most uses of
whether projects are considered abatements and will
arsenic wood treatments were phased out by 2004, an
require special contractors and permits.
estimated 90% of existing outdoor structures are made of
arsenic-treated wood [65].
Owner’s Responsibility. Owners are ultimately
responsible for ensuring that hazardous waste is properly
In a study conducted by the University of North Carolina
disposed of when it is generated on their own sites.
Environmental Quality Institute in Asheville, wood
Owners should check with their state government to
samples were analyzed and showed that
determine whether an abatement project requires a
certified contractor. Owners should establish that the
• Older decks and play sets (7 to 15 years old) that
contractor is responsible for the safety of the crew, to
were preserved with chromated copper arsenic
ensure that all applicable laws are followed, and that
expose people to just as much arsenic on the
transporters and disposers of hazardous waste have
wood surface as do newer structures (less than
liability insurance as a protection for the owner. The
1 year old). The amount of arsenic that testers
owner should notify the contractor that lead-based paint
wiped off a small area of wood about the size of a
may be present and that it is the contractor’s
4-year-old’s handprint typically far exceeds what
responsibility to follow appropriate work practices to
EPA allows in a glass of water under the Safe
protect workers and to complete a thorough cleanup to
Drinking Water Act standard. Figure 5.9 shows a
ensure that lead-laden dust is not present after the work is
safety warning label placed on wood products.
completed. Renovation contractors are required by EPA
to distribute an informative educational pamphlet
• Arsenic in the soil from two of every five
(Protect Your Family from Lead in Your Home) to
backyards or parks tested exceeded EPA’s
occupants before starting work that could disturb lead-
Superfund cleanup level of 20 ppm.
based paint (http://www.epa.gov/lead/
leadinfo.htm#remodeling).
Arsenic is not just poisonous in the short term, it causes
cancer in the long term. Arsenic is on EPA’s short list of
Arsenic
chemicals known to cause cancer in humans. According to the
Lead arsenate was used legally up to 1988 in most of the
National Academy of Sciences, exposure to arsenic causes
orchards in the United States. Often 50 applications or
lung, bladder, and skin cancer in humans, and is suspected as
more of this pesticide were applied each year. This toxic
a cause of kidney, prostate, and nasal passage cancer.
heavy metal compound has accumulated in the soil
around houses and under the numerous orchards in the
country, contaminating both wells and land. These
orchards are often turned into subdivisions as cities
expand and sprawl occurs. Residues from the pesticide
lead arsenate, once used heavily on apple, pear, and other
orchards, contaminate an estimated 70,000 to 120,000 acres
in the state of Washington alone, some of it in areas
where agriculture has been replaced with housing,
according to state ecology department officials and others.
Lead arsenate, which was not banned for use on food
crops until 1988, nevertheless was mostly replaced by the
pesticide dichlorodiphenyltrichloroethane (DDT) and its
derivatives in the late 1940s. DDT was banned in the
United States in 1972, but is used elsewhere in the world.
Figure 5.9. Arsenic Label
For more than 20 years, the wood industry has infused
green wood with heavy doses of arsenic to kill bugs and
Healthy Housing Reference Manual
5-19
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No. 102-550 (Oct 28, 1992).
Reston, VA: US Geological Survey; March 2001.
Available from URL:
64. Occupational Safety and Health Administration.
http://pubs.usgs.gov/fs/fs012-01/.
Lead exposure in construction: interim final rule.
Fed Reg 1993;58:26590-649.
56. Merriam-Webster, Inc. Merriam-Webster diction-
ary. Springfield, MA: Merriam-Webster, Inc.; no
65. Environmental Working Group. Nationwide con-
date. Available from URL: http://www.m-w.com/
sumer testing of backyard decks and play sets
home.htm.
shows high levels of arsenic on old wood.
Washington, DC: Environmental Working
57. Jacobs DE, Clickner RP, Zhou JY, Viet SM,
Group; 2002. Available from URL:
Marker DA, Rogers JW, et al. The prevalence of
http://www.ewg.org/reports/allhandsondeck/.
lead-based paint hazards in U.S. housing. Environ
Health Perspect 2002;100:A599-606.
58. Centers for Disease Control and Prevention.
Blood lead levels in residents of homes with ele-
vated lead in tap water—District of Columbia,
2004. MMWR 2004; 53(12):268-70. Available
from URL: http://www.cdc.gov/mmwr/preview/
mmwrhtml/mm5312a6.htm.
59. National Research Council. Measuring lead expo-
sure in infants, children and other sensitive popu-
lations. Washington, DC: National Academy
Press; 1993.
60. Centers for Disease Control. Preventing lead poi-
soning in young children. Report No. 99-2230.
Atlanta: US Department of Health and Human
Services; 1991.
61. US Department of Housing and Urban
Development. HUD technical guidelines for the
evaluation and control of lead-based paint hazards
in housing. Washington, DC: US Department of
Housing and Urban Development; 1995.
Available from URL: http://www.hud.gov/
offices/lead/guidelines/hudguidelines/index.cfm.
62. US Department of Housing and Urban
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rule (Section 1018 of the Residential Lead-Based
Paint Hazard Reduction Act of 1992).
Washington, DC: US Department of Housing
Healthy Housing Reference Manual
5-23
5-24
Indoor Air Pollutants and Toxic Materials
Chapter 6: Housing Structure
“The Palace of Fine Arts in Mexico City has sunk more
Figure 6.1 shows a typical house being built and
than 10 feet into the ground since it was built 60 years
inspected today and includes a terminology key. Both the
ago and the most noticeable effect is that the grand stone
figure and the key are available in an interactive format
stairway has disappeared and the entrance is now at
in the glossary on the U.S. Inspect Web site [1].
street level.”
Figure 6.2 shows a typical house built between 1950 and
C.B. Crawford,
1980 and also includes a terminology key. The figures
Canadian Building Digest
show the complexity and the numerous components of a
home. These components form the vocabulary that is
Introduction
necessary to discuss housing structure inspection issues.
The principal function of a house is to provide
protection from the elements. Our present society,
Key to Figure 6.1 (New Housing Terminology)
however, requires that a home provide not only shelter,
1. Ash dump (see 35)—A door or opening in the
but also privacy, safety, and reasonable protection of our
firebox that leads directly to the ash pit, through
physical and mental health. A living facility that fails to
which the ashes are swept after the fire is burned out.
offer these essentials through adequately designed and
All fireboxes are not equipped with an ash dump.
properly maintained interiors and exteriors cannot be
termed “healthful housing.”
2. Attic space—The open space within the attic area.
In this chapter, the home is considered in terms of the
3. Backfill—The material used to refill an excavation
parts that have a bearing on its soundness, state of repair,
around the outside of a foundation wall or pipe
and safety. These are some of the elements that the
trench.
housing inspector must examine when making a
thorough housing inspection.
4. Baluster—One of a series of small pillars that is
Figure 6.1. Housing Structure Terminology, Typical House Being Built Today [1]
Healthy Housing Reference Manual
6-1
attached to and runs between the stairs and the
and contains one or more flues and extends above the
handrails. The spacing between the balusters should
roofline.
be less than 4 inches to prevent small children from
getting stuck between the balusters. Balusters are
13. Chimney cap—The metal or masonry protective
considered a safety item and provide an additional
coveringat the top of the chimney that seals the
barrier.
chimney shaft from water entry between the chimney
enclosure and the flue tiles.
5.
Baseboard trim—Typically a wood trim board that is
placed against the wall around the perimeter of a
14. Chimney flues—The space or channel in a chimney
room next to the floor. The intent is to conceal the
that carries off the smoke and other combustion gases
joint between the floor and wall finish.
to the outside air. Most homes will have a terra cotta
tile flue or a metal flue.
6.
Basement window—A window opening installed in
the basement wall. Basement windows are
15. Collar beam/tie—A horizontal piece of framing
occasionally below the finish grade level and will be
lumber that provides intermediate support for
surrounded on the exterior by a window well.
opposite rafters. They are usually located in the
middle to upper third portion of the rafters. It is also
7.
Blind or shutter—A lightweight frame in the form of
known as a collar beam or collar brace.
a door located on each side of a window. They are
most commonly constructed of wood (solid or
16. Concrete slab floor—Typically approximately
louvered panels) or plastic. Originally they were
4 inches thick, the concrete slab floor provides a
designed to close and secure over the windows for
number of uses. It creates a solid level surface to walk
security and foul weather. Most shutters now are more
and work on. It provides a separation between the
likely decorative pieces that are secured to the house
grade/soil and a potentially livable area. It also
beside the windows.
provides lateral compression resistance for the
foundation walls, preventing soil pressure from
8.
Bridging—Small pieces of wood or metal strapping
outside the foundation from pushing the foundation
placed in an X-pattern between the floor joists at
walls and footings inward.
midspan to prevent the joists from twisting and
squeaking and to provide reinforcement and
17. Corner brace—Diagonal braces placed at the corners
distribution of stress.
of framed walls to stiffen them and provide extra strength.
9.
Building paper/underlayment—Building material,
18. Cornice—An overhang of a pitched roof at the eave
usually a felt paper that is used as a protective barrier
line that usually consists of a fascia board, a soffit, and
against air and moisture passage from the area
any appropriate moldings or vents.
beneath the flooring as well as providing a
movement/noise isolator in hardwood flooring.
19. Cornice molding—The individual pieces of wood
trim that are applied to the cornice area at the eaves.
10. Ceiling joist—A horizontally placed framing
members at the ceiling of the top-most living space of
20. Door casing/trim—The finish trim details around the
a house that provides a platform to which the finished
perimeter of the door on the interior finished wall.
ceiling material can be attached.
21. Door frame/jamb—The top and sides of the door to
11. Chair rail (not shown)—Decorative trim applied
include the wall framing as well as the actual door
around the perimeter of a room such as a formal
frame and trim.
dining room or kitchen/breakfast nook at the
approximate same height as the back of a chair. It is
22. Downspout—A pipe, usually of metal or vinyl, that is
sometimes used as a cap trim for wainscoting (see
connected to the gutters and is used to carry the roof-
wainscoting).
water runoff down and away from the house.
12. Chimney—A masonry or in more modern
23. Downspout gooseneck—Segmented section of
construction wood framed enclosure that surrounds
downspout that is bent at a radius to allow the
6-2
Housing Structure
downspout to be attached to the house and to follow
32. Finish flooring (not shown)—The final floor covering
the bends and curves of the eaves and ground.
inside the living space of a house. The most common
types of finishes are carpeting; hardwood flooring;
24. Downspout shoe—The bottom downspout
ceramic, composite, or laminate stone tile; parquet
gooseneck that directs the water from the downspout
panels; or vinyl sheet flooring.
to the extension or splash block at the grade.
33. Finished grade line—A predetermined line indicating the
25. Downspout strap—Strap used to secure the
proposed elevation of the ground surface around a
downspout to the side of the house.
building.
26. Drain tile—A tube or cylinder that is normally
34. Firebox—The cavity in the open face of the fireplace
installed around the exterior perimeter of the
in which the fire is maintained. The firebox leads
foundation footings that collects and directs ground
directly to the fireplace flue. The firebox is constructed of
water away from the foundation of the house. The tile
fire or refractory brick set in fireclay or reinforced
can be individual sections of clay or asphalt tubing or,
mortar in traditional masonry fireplaces. The firebox
in more recent construction, a perforated-plastic drain
may also be constructed of metal or ceramic-coated
tile that is approximately 4 inches in diameter. The
metal panels in more modern prefabricated fireplaces.
drain tile leads either towards a sump or to an exterior
The walls of the firebox are usually slanted toward the
discharge away from the house.
living space both to direct smoke up toward the flue
and to reflect heat into the room.
27. Entrance canopy—A small overhanging roof that
shelters the front entrance.
35. Fireplace cleanout door—The access door to the ash
pit beneath the fireplace. On a fireplace that is located
28. Entrance stoop—An elevated platform constructed of
inside the house, the cleanout door is usually located
wood framing or masonry at the front entry that
in the lowest accessible level of the house such as the
allows visitors to stand above or out of the elements.
basement or crawl space. On a fireplace that is located
The platform should be wide enough to allow
at the outside of the house, the cleanout door will be
someone to stand on the platform while opening an
located at the exterior of the chimney. Not all
outward swinging door such as a storm door even if
fireplaces are equipped with a cleanout door.
one is not present.
36. Fireplace hearth—The inner or outer floor of a
29. Exterior siding—The decorative exterior finish on a
fireplace, usually made of brick, tile, or stone.
house. Its primary function is to protect the shell of
the house from the elements. The choice of siding
37. Flashing (not shown)—The building component
materials varies widely to include wood, brick, metal,
used to connect and cover portions of a deck, roof, or
vinyl, concrete, stucco, and a variety of manufactured
siding material to another surface such as a wall, a
compositions such as compressed wood, compressed
chimney, a vent pipe, or anywhere that runoff is
cellulose (paper), fiber-reinforced cement, and
heavy or where two dissimilar materials meet. The
synthetic stucco.
flashing is mainly intended to prevent water entry and
is usually made of rubber, tar, asphalt, or various metals.
30. Fascia—The visible flat front board that caps the
rafter tail ends and encloses the overhang under the
38. Floor joists—The main subfloor framing members
eave that runs along the roof edge. The gutter is
that support the floor span. Joists are usually made of
usually attached at this location.
engineered wood I-beams or 2×8 or larger lumber.
31. Fascia/rake board—The visible flat front board that
39. Foundation footing—The base on which the
caps the rafter tail ends and encloses the overhang
foundation walls rests. The foundation is wider than
under the eave that runs along the roof edge and at
the foundation wall to spread out the load it is
the edge of the roofing at the gables. The gutter is
bearing and to help prevent settling.
usually attached to this board at the eaves.
40. Foundation wall—The concrete block, concrete slab
or other nonwood material that extends below or
Healthy Housing Reference Manual
6-3
partly below grade, which provides support for
49. Mantel—The ornamental or decorative facing around
exterior walls and other structural pans of the building.
a fireplace including a shelf that is attached to the
breast or backing wall above the fireplace.
41. Framing studs—A 2×4 or 2×6 vertical framing
member used to construct walls and partitions,
50. Moisture/vapor barrier—A nonporous material, such
usually spaced 12 to 24 inches apart.