# Zone Air Distribution Effectiveness



## Mech (Aug 16, 2011)

2009 IMC

Automotive Repair Garage

403.3.1 Zone Outdoor Airflow

403.3.1.1 - 403.3.1.3

When providing ventilation based solely on exhaust airflow, does the Zone Air Distribution Effectiveness factor get used?  The equation for zone outdoor airflow is Voz = Vbz / Ez.  It does not directly include the exhaust airflow rate column in Table 403.3.  Or do I calculate the total exhaust airflow required base on area size and use that as the value Vbz?

Thanks in advance.


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## Dr. J (Aug 16, 2011)

Per IMC 403.1.1:

Vbz=RpPz+RaAz

Per IMC Table 403, for Repair Garage, Rp = 0, Ra = 0

Therefore and thus, Vbz = 0 and Voz = 0

Outside air is not required in a repair garage, exhaust is.  You do need to provide make-up air of course, and one way of doing that is with outside air, but that is the designer's choice.


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