Combination of Test and Flush

The 3.2 Credit has the word "OR" in it implying one OR the other. I don't know if a combination has ever been accepted; however, my opinion on flush out is that it is relatively useless in accomplishing any long term benefits to indoor air quality. I am not sure how it got into LEED but we who have been in the IAQ business (e.g., industrial hygienists) for a long time have known "bake out" and "flush out" don't do a lot for IAQ. For that matter the air testing currently in LEED is fairly meaningless as well. Commisioning items that impact IAQ such as HVAC system filtration and cleanliness, outdoor air sources not near sewer vents, ease of maintenance, etc. as well as various other issues would go a lot further in accomplishing the good IAQ goal. Regardless, I would answer your question by saying you might just do the flush out (not for the point) in the admin before air testing and then do the air testing in the admin at the same time you do it in the hangar. If the admin is not too big (e.g., two or less outdoor air intake air handling units or less than 50,000 square feet), then adding a couple more sampling locations in admin shouldn't add to much to the air testing cost (e.g., no more than $700 for each additional air test set). The flush out would help remove issues such as residual cleaning chemical residues, recently applied coatings, etc. Flush out is good for short term issues that can lead to the air tests failing. Inevitably the reason air tests fail have nothing to do with the building itself. It is often something like last minute work using solvents, using cleaning chemicals (even "Green" ones) with fragrances or citrus, having occupants moving in during sampling, etc. Being that this is a hangar one thing you have to watch out for is sucking in jet fuel vapors or other airplane related solvents. The building shoiuld be positively pressurized when doing the test and the outdoor air intake should be away from pollutants sources such as the airplanes. I have had hangars fail the air testing due to this very issue.