Enclosed Spray Booth

Q. I manage the paint line at a company that paints automotive plastic parts. Our paint spray booth is only about two years old, but we frequently have high humidity problems in it.

Today, for example, the humidity reading in our paint room is 83 percent. Our customer’s specifications allow for no more than 65 percent humidity in the spray booth.

We are located in southern India, where the normal temperature is 30-40°C. How can we control the humidity and temperature in the spray booth? V.L.

A. The best way to control and eliminate the high humidity is to completely enclose the spray booth and use conditioned (temperature- and humidity- controlled) air as make-up air to the spray booth areas. Ambient temperatures of 30-40°C (86-104ºF) in paint application areas are pretty high and can be reduced. Furthermore, you are not in compliance with your customer’s painting specifications.

One of our major appliance manufacturing plants had a “glass house,” fully enclosed paint spray booth that used filtered, temperature- and humidity- controlled make-up air.

This had the added advantage of eliminating airborne dust and particulate matter.