Handling Heat and Humidity in a Paint Booth

Given that the drying process of coatings is highly dependent on the temperature and humidity in a paint booth, the setup of equipment varies widely for different climates. A paint booth set up in the perpetually hot and dry areas of southern Arizona is subject to different environmental conditions than a booth installed in the frigid Northwest Territories of Canada.

How to Handle Humidity in a Paint Booth

Heaters are commonplace in modern paint booths, but in some extreme cases, humidifiers may need to be added to create the optimum spray and cure environment. In some situations, a chiller may be needed to remove excess moisture and regulate the extreme temperatures of the outside air.

If your paint booth is located in a climate with high levels of heat and humidity, and the desired temperature set point for the spray booth is at or below the dew point in the summer, a chiller is required to attain that temperature. The outside walls of the booth may form condensation if the dew point of the outside air is at or above 73 degrees Fahrenheit.

Standard design practice is to condense the moisture out of the air by sub-cooling with a chiller, then reheating the air with indirect heat to the desired operating temperature and relative humidity set point. This practice would be done only with the use of an insulated paint booth with a vapor barrier.

There are two overarching factors — in addition to code compliance — that come into play when determining what components your paint booth needs to have in order to achieve an optimum paint environment:

What are the characteristics of the paint you are spraying?

This dictates what conditions must be achieved for the inside of the paint booth, including spray temperature, bake temperature and humidity levels. This information should be readily available from the manufacturer or supplier of the coating you use.

See: How to Safely Switch from Solvent-Based to Waterborne Paint

What are the characteristics of the external environment?

This factor determines what equipment you need to invest in to ensure the air being brought into the paint booth is conditioned to fit with the criteria set by the unique characteristics of the coating you are spraying. Questions to ask include:

• How powerful does your air heater need to be?
• Do you need a chiller?
• Do you need a humidifier?
• Does your paint booth need to be insulated?
• Do you need a vapor barrier?

Once you know exactly what equipment you need, you can create an ideal paint environment. Then your paint booth manufacturer should be able to select your paint booth configuration with equipment that best meets your business’ needs.