chiller room exhaust fan sizing

[chadtech]

I need some help sizing a ventalation exhaust fan for a chiller/pump room. I have been told it should be sized based on amount of refrigerant in chiller? Something like 3 cfm per lb of refrigerant. Or should it be based simply on X number of air changes per hour.

[pecmsg]

There is a calculation based on total charge. Do a search on the ASHRAE site for more details.
http://www.ashrae.org/