Air Exchanges/Hour 1

[chbtech]

Can anyone tell me how many air exchanges/hour you would need to eliminate the humidity in a car wash. Is there a general rule of thumb?

I have a semi truck wash bay with the following dimensions

102' L X 30' W X 16.5' H (overhead doors on both ends)

The International Mechanical Code (IMC) states that for transit buildings exhaust requirements are 1.5CFM / sq ft. Is this going to eleminate humidity or is this more to do with CO2 and other toxic gases only? Your help is greatly appreciated.

 

[ChasBean1]

Infinity air changes per hour will reduce the humidity to the same as the outside air humidity. Honestly I wouldn't try to dehumidify the space much like I wouldn't try to dehumidify a shower. If the trucks idle through the wash and the concern is CO exposure, the occupant stay time is what, 2-4 minutes? I believe the 15 minute CO limit is 200 ppm (somebody pls correct me if I'm wrong). I didn't know if they even exhaust these places but without doing the math, the 1.5 cfm/ft2 sounds more than adequate...

 

[chbtech]

Thanks that is the calculation I used!

 

[walkes]

You would likely be trying to reduce the NOx emissions from diesel exhaust. Nitrogen Dioxide STEL 5 ppm