Exhaust fan question

A friend of mine is finishing off his newly built 24x36 detached garage. He's looking into exhaust fans. The main part of the garage will have his work/welding area and a 10' ceiling. The other section will have two bays for vehicles, one will have a lift. He might do some spraying on that side. What do you guys think he'll need as far as CFM for a wall fan ? Any good brands ?

110 views and not one reply ?

Maybe change your location to a different state and you might get some replies . (ex-NY'r advice)

What do you mean by that ?

For general ventilation I would look for a fan that will provide a minimum of 4 to 8 air changes per hour. To determine air flow rate of fan:
(Length x width x height of building) x (# AC per hour) / 60
This will give you the flow rate (in cubic feet per minute, CFM) necessary to meet the desired air change rate.
If you are trying to perform task specific ventilation (painting, welding) you really need to address these processes with a more task specific configuration. If you want to purchase a high quality fan consider one of the following manufacturers (American Coolair, Greenheck, Loren Cook). I would recommend that you purchase a direct drive unit with no higher than a 1200 RPM motor (any higher and noise becomes a factor)...preferably a 900 rpm for best noise results.