Acceptable Level of Radon

This is Part 5 of a 5-part educational series for #NationalRadonActionMonth.

There is no “acceptable level” of radon. However, the EPA has established 4 picocuries per liter of air (pCi/L) as the United States “Action Level” at which a plan should be made to correct elevated radon levels.

If needed, radon mitigation contractors will work to reduce radon levels to as low as reasonably achievable. Reducing levels to zero is likely impossible, as radon exists even in outdoor air at a level of about 0.4pCi/L.

According to the EPA, while the techniques may vary for different school foundations and building site requirements, five basic features should be included to prevent radon from entering buildings:

1. Pre-install electrical junction boxes on the roof for use with a vent fan if, after testing for radon, an active radon mitigation system is necessary.
2. A four-inch layer of gravel below the foundation of a building will allow naturally occurring soil gases, which includes radon, to move freely underneath the building.
3. Placed atop the layer of gravel, a vapor retarder can help soil gases from entering a building as well as keep the concrete foundation from clogging the gravel layer when the slab is poured.
4. Vent pipes running from the gravel layer beneath the foundation through the building’s condition space and roof can safely vent radon and other soil gases outside above the building. If necessary, a radon fan can be installed to help depressurize the space below the slab.
5. Seal all openings, cracks, and crevices in the concrete foundation floor (including the slab perimeter crack) and walls with polyurethane caulk to prevent radon and other soil gases from entering.

EAIS can help

While there is no “acceptable level” of radon, the EPA has established 4 picocuries per liter of air (pCi/L) as the United States “Action Level” at which a plan should be made to correct elevated radon levels. Since 2015 EAIS has engaged Iowa school districts with its School Radon Training & Support System to train and coach district staff through the process of testing their buildings for radon. For more information about EAIS radon work, click here.