Building Codes for New Construction

Background

Radon is a naturally occurring, odorless, colorless radioactive gas produced by the decay of uranium-238 in soil and rock. It can be found everywhere in the United States. Radon easily moves up through soil into buildings, entering through:

• Cracks in solid floors
• Construction joints
• Cracks in walls
• Gaps in suspended floors
• Cavities inside walls
• Gaps around service pipes
• Water from private wells (1)

The National Academy of Sciences reports that radon is estimated to cause between 15,000 and 22,000 lung cancer deaths per year, second only to cigarette smoking (2). According to the Environmental Protection Agency (EPA), the average indoor radon level in the United States is 1.3 picocuries per liter of air (pCi/L). The average outdoor (ambient) radon level is 0.4 pCi/L (2). The EPA recommends that any home with a measured indoor radon level of 4.0 pCi/L or more, be alleviated to reduce radon levels.

An important step to reducing radon exposure is prevention. To reduce the amount of radon that can enter a home, new homes may be built using radon-resistant construction techniques. To assist building code officials in deciding whether radon-resistant features are applicable in new construction, the EPA and the United States Geological Survey evaluated the radon potential in every state to develop a map of radon zones. The map assigns each county to one of three zones based on radon potential:

• Zone 1: High potential (greater than 4pCi/L)
• Zone 2: Moderate potential (between and including 2 and 4 pCi/L)
• Zone 3: Low potential (less than 2pCi/L)

There are two general types of radon-control systems for homes. A passive radon control system reduces indoor concentrations of radon by blocking radon entry points and using the natural thermal upward movement in a vent pipe stack to slightly depressurize the area under the slab or crawl space to resist the entry of radon gas. It also provides access for an active radon control system. An active system is structurally similar to a passive system, but includes a fan to mechanically exhaust soil gas.

Policies

Amend local or state building codes in Zone 1 radon areas to require that new homes be built using radon-resistant construction standards.

The EPA recommends that new residential buildings in areas having a high radon potential be built with a passive radon control system, which includes features to facilitate any necessary post-construction radon reduction (4). In areas that have a low potential for indoor radon, application of radon-resistant construction techniques may not be appropriate (3).

• Effective January 1998, the Illinois cities of Geneva, Batavia, St. Charles and North Aurora incorporated radon-resistant construction provisions into their joint building codes, a step encouraged by the EPA. New Jersey has updated its Uniform Construction Code to require schools and residential buildings in Zone 1 areas to be constructed in a manner that minimizes radon gas entry, and facilitates any subsequent remediation that might prove necessary.



• In 1995, Rockville, Md., adopted and amended its one- and two-family dwelling code. This regulation requires radon mitigation in newly constructed detached and semi-detached single-family dwellings and townhouses (single family dwellings attached side to side). The requirement also includes basement and ground floor additions to existing dwellings, as well as conversions of grade-slab garages, carports, porches, etc. to living space.



• Effective November, 17, 1997, East Moline, Illinois, adopted a radon-resistance provision into its building code to control radon levels in new construction of one- and two-family dwellings and other new residential buildings three stories or less in height. East Moline is located in a Zone 1-high radon potential area. To promote the regulation, East Moline offers a Zone 1 Credit that allows for $150 to be discounted from the building permit fee.

Effectiveness Data

Radon-resistant construction standards have proven to be effective in reducing indoor radon levels when used to mitigate radon problems in existing homes and when applied in construction of new homes (3). Using available standards and techniques (both passive and active), levels below 2 pCi/L have been achieved in over 90 percent of new homes. Use of passive techniques alone produces indoor radon levels below the current EPA action level of 4 pCi/L in most new homes, even in areas of high radon potential (3).

There are also financial incentives for using radon-resistant building techniques. Employing radon-resistant techniques while building a home is more cost-effective than installing a radon-reduction system in an existing home (4). What's more, radon-resistant construction techniques improve energy efficiency, providing an average of $65 per year in energy savings for the homeowner (4).

Contacts

Marjorie Walle
Radon Program Manager
Illinois Dept. of Nuclear Safety
1035 Outer Park Drive
Springrield, IL 92704
Phone: 217-785-9958

Department of Community Affairs
P.O. Box 802
Trenton, NJ 08625-0802
Phone: 609-984-7609

Linda MacDermid, CBO
Chief of Inspection Services
City of Rockville
111 Maryland Avenue
Rockville, MD 20850
Phone: 301-309-3250
E-mail: lmacdermid@ci.rockville.md.us

References

1. Radon-Resistant Construction and Building Codes. International Code Council, Inc, Falls Church, VA, May 1999.
   
   
2. Biological Effects of Ionizing Radon (BEIR) VI Report. National Academy of Sciences, February 1998.
   
   
3. Model Standards and Techniques for Control of Radon in New Residential Buildings. U.S. Environmental Protection Agency, March 1994.
   
   
4. Radon-Resistant New Construction. Sources of Information on Indoor Air Quality. U.S. Environmental Protection Agency, August 1999. Web site: http://www.epa.gov/iaq.
   
   

Acknowledgements

Philip Jalbert, Environmental Protection/Real Estate Specialist, U.S. Environmental Protection Agency, Washington, D.C.