As an odorless, colorless gas, radon is often overlooked and underestimated, but it has potentially fatal consequences when left unmanaged. It is a radioactive gas believed to be the leading cause of lung cancer among nonsmokers, and has also recently been linked with blood cancer in women. (For more, visit www.epa.gov/radon/health-risk-radon and pressroom.cancer.org/releases?item=602_ga=1.150705269.213952884.1462371742.)
Radon is a radioactive gas that forms because of the decomposition of uranium in the earth’s crust. This process from uranium to radon takes several thousand years, but it speeds up at the later stages, continuing to break down into dangerous isotopes, such as polonium, in a matter of days. Radon and polonium emit alpha-particles that damage lung tissue and DNA.
Radon is a problem found throughout the country, especially in Colorado and northern states bordering Canada. Levels tend to fluctuate based on weather and ventilation, so variances can exist between regions, structures, or even rooms within the same building. Since radon comes up from the ground, higher amounts are often found in basements and on the first floor of buildings. While radon detection and mitigation are relatively simple, misunderstandings in the process can lead to harmful mistakes.
A common mistake when it comes to radon management is measuring only in the short-term. Radon is volatile and levels can change quickly. While measurements taken over 48 hours to a week can provide a decent indication of current radon levels, they do not necessarily predict what the level will be a month from now. Measuring during the summer, for example, will often show about half the values compared to measuring in winter. To get an accurate average radon level, a long-term test spanning several months to a year is required.
Once an accurate radon level is assessed, it is possible to determine whether or not mitigation is necessary. While the best level of radon gas is zero, the U.S. Environmental Protection Agency (EPA) recommends mitigation at 4.0 picocuries (pCi) per liter, with a long-term goal of reducing indoor radon levels to 0.4 pCi/L
(i.e. average outdoor levels). Currently, one out of five facilities has a radon level above what EPA deems actionable.
When it comes to mitigation, most systems use polyvinyl chloride (PVC) pipes, but a common radon mitigation mistake is not installing a firewall and fire-collars. According to most states’ fire codes, there must be a firewall between the PVC pipe and the building itself, as well as fire-collars at the spots where the PVC pipe enters or exits the building. In the case of a fire, this is to prevent the easily combustible PVC pipe from causing flames to spread quickly.
Even after mitigation is completed, it is important to continue monitoring radon levels. A radon fan can stop working (or be turned off), there can be a leak, or the system may simply not have been set up well. Radon detectors, similar to smoke and carbon monoxide detectors, are recommended for continuous monitoring to ensure safe levels of radon at all times.
Of course, prevention is the best cure with radon exposure. Considering ways to stop the gas from the beginning of building construction is the ideal approach to ensure safe indoor air quality (IAQ). This can be done in many ways, from creating a radon-blocking membrane in the foundation to ensuring there are zero cracks in the foundation, along with properly sealing any potential entrance-points. Additionally, setting up the ventilation system to create a mild positive pressure indoors makes it more difficult for radon to enter the building.
The opinions expressed in Failures are based on the author’s experiences and do not necessarily reflect those of The Construction Specifier or CSI.
Oyvind Birkenes is the CEO of Airthings (formerly called Corentium), a Norway-based company involved in air quality solutions. He has more than 20 years of technology experience, including key roles at Texas Instruments and Chipcon.