1) ive looked at space matrix (this is a library project)... from what i gather EVERY space has to count.. even spaces not regularly occupied (mech closet, janitor closet, etc). Is this correct?

2) building has a large two story atrium. the floor of the atrium gets air from more than one air handler unit. how would I break this down in terms of area/AHU?

3) my understanding is that there needs to be at the very minimum, one test done per air handler unit (can be more tests if a AHU supplies more than 25,000 sq ft).. Is this correct?

4) what if there is an AHU that supplies less than 25,000 sq ft - but it supplies rooms on different floors? Would a space on each floor need to be tested?

would greatly appreciate any advice. thanks....