Inlet / Outlet Sound Power
I am doing some acoustic analysis on a proposed Air Handling Unit for a school building I am working on. The unit has and Exhaust Fan and a Supply Fan. Sound power Level is given for each fan, and there are two sets of data for each fan: "inlet" and "outlet" - yielding a total of 4 sets of acoustic power data.
Here's the question, and forgive the general ignorance:
As far as the entire AHU is concerned do the Exhaust and Supply fan function at the same time, or do they alternate. Further, what is meaning of the inlet/outlet distinction.
In other words, when I am analyzing the acoustic data, should I simply analyze the values that are higher for worst case scenario, or do I presume that the four sets of data describe potentially simultaneous conditions, and I should really analyze the levels in sum.
I know this is probably very obvious to the HVAC community.