Originally published November 19, 2025 - Margaret Henderson
On October 27, 2025, during the Indoor Environments Radon and Vapor Intrusion Symposium, Kim Steves (CRCPD) and Jane Malone (Indoor Environments Association - IEA) presented an update on the results of the 2025 International Code Council (ICC) building code hearings. The presentation included an overview of the strategy CRCPD is leading with support from IEA and EPA to support the adoption of the radon-resistant building codes (identified as Appendix BE “Radon Control Methods” of the International Residential Code).
CRCPD and IEA attended ICC hearings in April and October of 2025 to support proposals for improvements to the radon-resistant new construction techniques required by Appendix BE. These four proposals were:
1. To allow compliance with the ANSI/AARST RRNC standard as an alternative method for radon-resistant new construction techniques. The standard ANSI/AARST RRNC is “Rough-in of Radon Control components in New Construction of 1 & 2 family dwellings and townhouses.”
2. To remove the EPA Radon Zone map and Zone 1 county list from the Appendix.
3. To require installation of a minimum of 4.5 feet of perforated pipe on each side of the tee fitting below the slab or vapor barrier.
4. To require reservation of adequate cylindrical space in the attic for future potential installation of a radon fan and locate the radon vent pipe in the cylindrical space.
After testimony, feedback, revisions, and a second round of hearings, these four proposals were all approved by the Committee.
Along with ensuring that the radon-resistant new construction building code is the best version of the code that can be achieved, this code must be adopted and effectively implemented by states, tribal communities, and local jurisdictions to achieve radon risk reduction. To this end, CRCPD is working with IEA and EPA on a two-part strategy:
1. To provide support and a toolbox of resources for peer-to-peer messaging between state/tribal radon programs and building code authorities to support communications and outreach to encourage adoption of the radon building code.
2. To train the code officials and anyone who works in the field of building codes and inspection of construction to educate about and demystify radon and the radon-resistant new construction techniques.
Plans are to provide a webinar during National Radon Action Month in January to introduce the toolbox and obtain feedback from state and tribal radon partners on needed assistance. Additional webinar details will be provided at a later date.
The current version of IRC/Appendix BC (2024) can be viewed at: https://codes.iccsafe.org/content/IRC2024P2/appendix-be-radon-control-methods
United States