How to determine if VAV was designed with diversity?

[fxb80]

How can you know if diversity was designed into a VAV system? Will the sum of zones CFM be greater than the AHU supply CFM on the plans page CFM schedule? Or what is the standard means of determining from engineering data whether or not diversity is considered?

Just a general question, not related to a problem.

[viceman]

i have always added up the max vav box flows and compared them to the ahu design cfm

[btuhack]

Properly designed, terminal volumes will tally up to a bigger number than the ahu volume.

Terminals and the duct leading to are sized based on (zone) peak loads while the machine capacity is based on a block load calculation...adding peak and non peak zone loads during design conditions and finding time of day/year when that occurs.

A diversity of 80% is the normal in my region but doesn't necessarily apply to an old vav building thats been tweeked to comply with modern ventilation requirements.

[fxb80]

Thanks for the responses!