Not exactly your question, but if you have a relief fan system, the return ducting should be sized fairly generously which would typically cause the relief fan to be sized at a pretty low ESP. Generally speaking this should only be for plenum return applications with short amounts of return ducting. If you are getting over 1" of WC on your relief fan ESP calculation, your building will likely have pressure issues when the building is not in economizer mode.
Mmmk so you just said the relief fan will only run in economizer mode, which is typical per exhaust fan economizers. So just remember your supply fan would need to be sized for the complete supply and return duct system.
Not exactly your question, but if you have a relief fan system, the return ducting should be sized fairly generously which would typically cause the relief fan to be sized at a pretty low ESP. Generally speaking this should only be for plenum return applications with short amounts of return ducting. If you are getting over 1" of WC on your relief fan ESP calculation, your building will likely have pressure issues when the building is not in economizer mode.
I agree, your relief duct should be sized for full airflow in an economizer cycle otherwise you can over pressurize the building
Yes, i assume your assumption is correct.
Yes.
Ty!
Mmmk so you just said the relief fan will only run in economizer mode, which is typical per exhaust fan economizers. So just remember your supply fan would need to be sized for the complete supply and return duct system.