Blower door testing on homes with asbestos siding
Picking up on a comment to a post from 2014 (https://www.greenbuildingadvisor.com/article/how-worried-should-you-be-about-asbestos-in-older-homes), I wanted to ask the community about conducting blower door tests in homes with asbestos siding. While this material is clearly “rigid” in nature, it seems that the thousands of nails penetrations could easily have brought some asbestos fibers into the exterior wall cavities.
As stated in the post above (and elsewhere), most of the documented cases of asbestos-caused illnesses originate from people that worked with these materials, or lived near a mine or with a family member that worked in the industry. With that said, there’s a reason it’s banned in 50+ countries and listed as a human carcinogen. Dana Dorsett made the comment on that post saying blower door testing on homes with asbestos “is expressly illegal in Massachusetts”. I have only found documentation to support that the Mass Save program does not allow the contractor to conduct a blower door test if the asbestos material is friable. (Perhaps there is further documentation of the state’s stance on this that someone could share…)
And while asbestos siding would not be considered friable, certainly the bits and pieces of it sitting on top of the bottom plates and batt insulation in the exterior wall cavities could become airborne during either depressurization or pressurization of the home. As a contractor working in a separate utility program (that requires blower door testing unless the suspect material is friable), I always have concerns about running a BD in this scenario. The risk just doesn’t seem worth the reward.
So, am I being too cautious here or are my concerns valid?
Thanks in advance!
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