Joey,

 Thanks for taking the time to read and respond to all of these forum posts. My question pertains to booth pressure. We have an open booth (three walls and ceiling) built by AFC. I am wondering if you could tell me the ideal manometer reading for this type of booth is? I have just replaced the cartridge filters above the exhaust stacks and didn't notice any change which is currently around 1.5wc. I am wondering if it is time to swap out the interior booth filters which are coming up on two years old. We purge the system regularly and use a slap hammer type device at the end of each shift to lossen the powder up before final purge at shift end but it seems as though the air flow is becoming less and less. I know the manometer can tell me when the filters are ready but what is my baseline?

Regards,

Cory Mason

Cory,

  Unfortunately, that is a question I can't quite answer for you.  When you mention cartridge filters above the exhaust, I'm somewhat confused about your design.  Normally, your booth will either have cartridge filters followed by HEPA final filters, or it will be a blanket filter, pocket filters, and finally HEPA final filters.

  The difficulty in answering your question is because of several factors.  How the manometer reads is dependent on booth design, manometer design, placement of the manometer, etc.  My suggestion is to contact the booth manufacturer and have them send in a representative to show you how to interpret your manometer readings.   Sorry I couldn't be of more assistance.