As promised, I spoke with Dr. Fredisdorf this morning and learned the following: District 107 tested for radon for the first time in 2006, in connection with a construction project commencing at the elementary school. That initial test discovered a couple of areas that were slight radon elevations over the EPA standard of 4 picocuries per liter (PCI/L). The district consulted a radon mitigation expert, who determined that adjustments to the schools HVAC system could ventilate the area in a fashion that would dissipate the radon and bring levels below the EPA threshold (unlike those in private homes, commercial HVAC systems are often large enough to achieve ventilation pressures that will disperse the radon to safe levels). Subsequent retesting after HVAC adjustment in 2006 brought all levels below the EPA threshold. The HVAC adjustments are what constitutes mitigation - because it worked to bring radon levels down in follow up testing - it is not a separate system like we would see in a private home. The District also retained the services of engineers to consult on the radon issue. Though testing and resting is not required, District 107 embarked upon a radon testing program roughly every two years (Dist. 106, one of the few local districts that tests for radon, stated in their community publication that they test every 5 years, which is as often the state recommends). District 107 tested for radon in 2007, 2009, 2011 and then most recently in August and September of 2014. According to Dr. Fredisdorf, none of these biannual tests were problematic, and no building radon elevations averaged above EPA levels - until the August 2014 testing in the Elementary School. The August 2014 test showed slightly elevated radon results in 6 elementary areas. The areas were retested with proper ventilation running and, in September, an initial short term follow up test showed all areas below the EPA 4.0 threshold. The District also engaged in a long term follow up test, in which units were left in various areas for a month. This long term test - (30 days?) which was the subject of concern and prompted closure and relocation, showed levels of 25 and 34 PCIL in two areas, in contradiction to the short term testing. However, the consulting expert for the District characterized these results as erratic - it appeared that, during the testing months, the HVAC fans in one tested area were turned off during the testing period, allowing the air to remain stagnant, and, in another area, an exhaust fan was turned on, which draws air from below grade and can itself elevate radon levels. These long term results were subject to retesting with the HVAC system working fully as normal, and each retest has shown that all levels of concern have dropped below 4 PCIL. As I understand it, if the HVAC system is moving the air through the building (as it typically is during school days), the tests do not show any elevations above the EPA threshold of 4.0 PCIL. Bottom line: I dont see any evidence that District 107 subjected any occupants of our buildings to any radon exposure in excess of EPA recommendations for any significant period. If anyone is aware of facts or evidence to the contrary, lets discuss it. I hope you find this information as comforting as I do.
Posted on: Thu, 23 Oct 2014 17:22:16 +0000
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