added turning one room into two rooms and the HVAC ductwork is not modified . This can result in one room having the supply air and the other having the return air . Needless to say , the one with just a return is under negative pressure and is the high radon room . Adding the ductwork to both sides so there is balance can be an easy task for the school maintenance staff .
Although there are other things to look at , I will provide one more suggestion after you are convinced that the HVAC is working properly or perhaps even as a first step . Radon levels within a building equipped with an energy management system , as is common in buildings that are not occupied 24-7 , will vary more with HVAC operation than diurnal variations as we see in residences . It is likely the testing methodology that identified the radon problem was a shortterm integrating device .
These are great indicators of potential but as a follow-up , utilize a continuous monitor to allow you to differentiate radon levels between occupied and unoccupied periods . In other words , the buildings HVAC system may already be reducing radon exposures while people are within it . I have seen radon levels above 20 at night but less than 1 during the day . That is the power of a properly operating HVAC system .
So , in closing , Active Soil Depressurization is a great technique but as radon professionals we can also be building scientists and analyze the situation and get to the root of the problem with lower costs to your client and greater immediate benefit to their employees and students . In other words : Think Outside the Pit !
If you would like more information or this topic interests you , we recommend the CE Course – C-16-108 – Addressing Radon in Daycare Facilities , Schools and Large Buildings
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