Number of air testing samples

Qian, Based on the description of your project, I believe you are correct in concluding that you will need to take at least 2 samples for each wing and thus 8 samples in total for the entire building.

Qian and James, The requirement is "“For each portion of the building served by a separate ventilation system, the number of sampling points must not be less than 1 per 25,000 square feet or for each contiguous floor area, whichever is larger.” As I understand it, you would need to sample each floor because it says "whichever is greater". That would amount to 88 samples instead of 8. That is an excessive amount of samples, but that's how I read it.

Ian, My understanding of Qian's project is that each of the 4 wings contain 22 stories and a total of about 40,000 sf. My assumption was that, based on this info, none of the 22 floors have more than 25,000 sf of contiguous floor area and so 2 samples per wing would be the requirement. From Addenda Tables. pg. 36: (http://www.usgbc.org/resources/building-design-construction-reference-guide-addenda-2nd-edition) "Determine the number of ventilation systems serving the building. Then, determine if the individual floor plates served by each single ventilation system are larger or smaller than 25,000 square feet. If they are smaller, take at least one sample for every 25,000 square feet, or fraction thereof, served by a single ventilation system. If they are larger, take one sample per floor plate. For example, a 110,000 square foot building with ten 11,000 square foot floors, served by a single ventilation system, needs only five samples – one per 25,000 square feet (or fraction thereof) because each 11,000 foot floor plate is smaller than 25,000 square feet." I've also consulted with a industrial hygienist about this. In her view, the number and location of test samples should be determined on a case by case basis by the IAQ specialist or air testing contractor. For documentation, it's critical that a clear argument and methodological narrative, compiled by the IAQ specialist, be presented to GBCI. However, she noted that she's seen GBCI push back when the number of samples did not correspond directly to the Credit Requirements.