United States Environmental Protection Agency
Indoor Environments Division
Office of Radiation and Indoor Air
EPA 402F-98-001, September 1998
What
You Should Know About Radon
Radon Entry
Talk to Your Builder
Understanding a Radon System
Testing: The Final Word
For
Architectural Drawings and Technical Information
For More Information
There are so many things to consider when having
a new home built - so many choices to make. How many bedrooms should you have?
Is the kitchen large enough? Do you need a basement?
You may even be concerned about environmental
issues, such as the fumes from new building materials and furnishings. But are
you concerned about radon? You should be.
What
You Should Know About Radon
Radon is a
radioactive gas that comes from the soil. Exposure to radon gas it the
second-leading cause of lung cancer (after smoking) in the United States. About
14,000 people die each year from radon-related lung cancer.
Radon is produced from the natural breakdown of
the uranium found in most rocks and soils. As it further breaks down, radon
emits atomic particles. These particles are in the air we breathe. Once inhaled,
they can be deposited in our lungs. The energy associated with these particles
can alter cell DNA, thus increasing the risk of lung cancer.
Radon usually does not present a health risk
outdoors because it is diluted in the open air. Radon can, however, build up to
dangerous levels inside a house.
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Radon
Entry
Radon can enter your new house through cracks or
openings in the foundation. The differences in air pressure between the inside
of a building and the soil around it also play an important role in radon entry.
If the air pressure of a house is greater than the soil beneath it, radon will
remain outside. However, if the air pressure of a house is lower than the
surrounding soil (which is usually the case), the house will act as a vacuum,
sucking radon gas inside.
Because radon comes from the soil, the geology of
an area can help to predict the potential for elevated indoor radon levels. The
U.S. Environmental Protection Agency (EPA) has worked with state and federal
geologists to develop maps which predict the
potential indoor radon levels for every county in the United States. Those
counties with the highest potential are designated as Zone 1; those with the
lowest comprise Zone 3.
Zone 1 areas have predicted average radon levels
at or above the EPA's 4.0 pico-Curies per liter (pCi/L) action level. (pCi/L is
a measure of the amount of radioactivity in a known quantity of air.) To
determine which radon zone your new house will be built, please contact your State
radon office. If you are building in a Zone 1 county, you should include a
radon control system in your new home. It is an inexpensive addition to the
total cost of your house and is an easy way to protect you and your family.
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Talk
to Your Builder
You and your builder can design your new house to
be radon resistant. For $350 to $500, on average, your builder can take the
following four simple steps to deter radon from entering your home.
- Install a layer of clean gravel or aggregate
beneath the slab or flooring system.
- Lay polyethylene sheeting on top of the gravel
layer.
- Include a gas-tight venting pipe from the
gravel level through the building to the roof.
- Seal and caulk the foundation thoroughly.
These construction techniques will be familiar to
your builder. There is no need to hire a special contractor or architect. Many
builders already incorporate some of these steps in the construction of their
houses to control moisture or increase energy efficiency. In fact,
radon-resistant construction techniques can be found in the 1995 version of the One-and-Two
Family Dwelling Code published by the Council of American Building
Officials.
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Understanding
a Radon System
The radon-resistant construction techniques
described in this brochure comprise a "passive" radon system. This
system overcomes the vacuum effect experienced by most houses by creating a
pressure barrier to radon entry. The system also includes a pipe to vent radon
gas safely to the outdoors.
Sometimes a passive radon system isn't enough to
prevent radon from entering a house. In this case, a fan can be installed to
pull the radon gas from the underlying soil into the vent pipe where it can be
exhausted outside the house. The addition of a fan and its associated wiring
creates and "active" radon system.
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Testing:
The Final Word
The only way to know if your new home has a radon
problem is to test. The EPA recommends that average annual indoor radon levels
do not exceed 4.0 pCi/L. If your home is built with a passive radon system, you
should test it immediately after moving in to make sure that radon levels are
below the EPA guideline. Remember: If your radon level is 4.0 pCi/L or above, a
fan can be installed easily to lower radon levels well below this guideline.
Even if you must install a fan, adding a radon
control system to a house under construction is much less expensive than
installing one after the house is built. The average cost for a radon control
system in an existing house is between $500 and $2,500. Adding radon-resistant
construction now will save you unnecessary expense and worry later.
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For
Architectural Drawings and Technical Information
Detailed model building standards, architectural
drawings of radon systems, and fact sheets on alternative radon installations
are available from EPA at no charge by phoning 1-800-55-RADON (1-800-557-2366).
A growing number of municipalities located in
areas known to have high radon potential now require or recommend that passive
radon systems be installed in all new houses. Contact your State
Radon Office to determine if you are building your new home in such an area.
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For
More Information
Many publications and
resources are available to you for free. Here are just a few suggestions:
Where To Find Free Information
- National Service Center for Environmental Publications (NSCEP)
http://www.epa.gov/ncepihom/ (to order EPA documents online)
Or call 1-800-490-9198/(513) 489-8695 (fax)
U.S. Environmental Protection Agency
National Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 45242
- EPA's Radon Hotline: 1-800-55-RADON (1-800-557-2366)
Also Available
- The Council of American Building Officials One- and Two-Family Dwelling Code Appendix F also details radon-resistant
techniques. Call (708) 799-2300.
To gain more information about building a radon-resistant house or testing an existing home, please contact the Radon
Office in your State.
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June 12, 2001
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