I'd like to know if BPI has banned the use of the duct blaster in the presence of asbestos ductwork. Is this the case? If there is any documentation from BPI, what/where is it?

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I don't know about BPI, but I discussed this issue (blower door and asbestos, same thing) years back with my insurance carrier and we agreed, any, that is any, asbestos and they want to see documentation from a licensed abatement company (who has insurance) stating that it is either safe as is or has been cleaned up properly and is now safe.  Since I'm not trained and licensed by the state, that is not a decision I can make.

I can't see any way BPI can state it is ok to proceed as there are many variables and again, we are not normally trained, licensed, and certified (or insured) to make that determination.

Finding asbestos in a house is an issue that I discuss in advance with the home owners so they are not blind sided by my departure.


In all seriousness - just how many do you see (tested to make sure it was) & do you really think running the tester would be worse than them running the unit normally?

With that - BPI states in EP / Heat & not sure which other ones:

Where the presence of asbestos, lead, mold and/or other known or suspected hazardous material is present, all relevant state and federal (EPA) guidelines must be followed to ensure technician and occupant safety. Blower door depressurization tests may not be performed in homes where there is a risk of asbestos becoming airborne and being drawn into the dwelling.

So no they don't ban it (and do we really need someone telling us putting our hand on a hot stove isn't smart) nor do they ban pressurizing a house

I rarely test asbestos- I just perform a visual on-site.

I do not think running the duct blaster would be worse than running the system itself. For this reason, in particularly bad cases, I have recommended not running the system at all until further investigation or an abatement is performed.

I think discussing it with the customer prior to a site visit is a great idea because different customers have different attitudes to asbestos for valid reasons.

There are customer-based, safety-related, financial and legal reasons not to run the duct blaster with asbestos, especially if it looks friable. And, as in the hot stove analogy, nothing good can come from running the duct blaster with asbestos, except for a more accurate rebate estimation. However, for this reason alone, the end does not justify the means.

Two states have concluded that blower door testing does not increase the liability wrt asbestos.  As some of you have suggested, life as usual disturbs it more than testing would. I doubt most blower door or duct testers have the time or skills to find it, so not looking is not such a bad idea because that is kinda what happens. 

Those States by the way, wanted assurance they would not be creating problems prior to instituting a blower door program. 

We find asbestos duct tape pretty commonly in our area of NW Washington State (and in some cases, fully wrapped duct runs). Our program has a policy of not conducting the blower door test when vermiculite is present in attics or friable asbestos tape is present on ductwork. Until recently, we had left it up to the auditor to evaluate whether they were comfortable completing the blower door or not, but as some of these comments have pointed out, we're not certified or insured to make this call. 

Having said all of that, I'll also give my personal opinion. When vermiculite is present, I don't test. This material is typically not disturbed and is well separated from the living space until we turn on a blower door (even pressurizing stirs it up, and fibers can remain in the air for days and days). When asbestos tape is in good condition (no tears of frayed edges) and limited only to seams in metal ductwork and boot-to-floor connections, I agree the blower door test couldn't possibly cause any more disturbance than the air handler typically does.

I would like to test in the latter scenario described above, but my opinion goes against our official policy, which means we are limited to estimating leakage in many cases. Fortunately, though, we also do a very thorough visual inspection which guides our workscopes as much as the numbers do. Without impressive numbers to show the homeowner paying for the work, they have to trust the other information we provide.

Asbestos in ductwork is often on the outside of the ducts and is commonly asbestos duct tape and mastic (the mastic may also contain asbestos), but it is on the exterior of the ducts in the attic or crawlspace or basement and not in the living area. Sure some mastic may have gotten squeezed into the cracks and seams, it is unlikely to be a source of friable asbestos - so why does everyone stop duct testing when it is on the outside?

Vermiculite should be tested for asbestos content before walking away from a job. Not all vermiculite contains asbestos.

I have run into and away from powered, blown-in asbestos insulation in attics (in a county that paved their roads with asbestos containing rock that had to be removed for all roadway surfaces after that was discovered). Scary. After informing the residents as to the nature of their insulation most didn't care and wanted their attics blown with additional insulation anyway.

Do no harm, right? Testing the material before walking doesn't harm, and who knows you might not have a problem.

As HERS Raters in California we cannot run tests if it is present per CEC protocols. It is a slippery slope here in the litigious Republic of California. I would error toward caution and if you suspect there is asbestos to not test, have suspected materials tested and recommend abatement if present. Whether or not it is in BPI HERS or other protocols is really not important. Protecting you and your clients is.


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