Handling Heat and Humidity in a Paint Booth – A Q&A from the GFS Facebook Page

Given that the drying process of coatings is highly dependent on the temperature and humidity inside the paint booth, it should come as no surprise that paint booth equipment varies widely when looking at different climates all over the world. For example, a paint booth setup in the perpetually hot and dry areas of southern Arizona will be subject to very different environmental conditions than a booth installed in the northern territories of Canada.

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 other situations you may even need a chiller to remove excess moisture and regulate the extreme temperatures of the outside air.

Recently we received a technical question from a member of the GFS Facebook community concerning operating a paint booth in Malaysia, a country with a climate that is subject to very high levels of heat and humidity.

Here is the question we received from our friend, Jacob Kow in Malaysia:

“Hi, I’m in Malaysia with the temperature of 32 degrees Celsius. How to I maintain the spray temperature of 23 degrees Celsius inside the painting booth? Do I need to install a chiller and humidifier?”

We posed this question to the GFS Engineering team, and here’s the response we received for Jacob:

“Due to the conditions in Malaysia the temperature set-point being asked for is at or below the dew point in the summer months, a chiller would be required to attain that temperature. But it is important to consider that the outside walls of the booth may form condensate if the dew point of the outside air is at or above 23°C. Humidity is a large issue in Kuala Lumpur, according to the most detailed weather information available for Malaysia. Cooling the air would cause for other conditions such as condensate on the booth walls or a high relative humidity in the booth since the air is being cooled down to the saturation temperatures in the summer time.

Standard design practice would be to condense the moisture out of the air by sub-cooling with a chiller and 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 booth with a vapor barrier in the environment of Malaysia.”

As you can see, there are really two overarching factors (in addition to code compliance and regulations) that come in to play when determining exactly what components your paint booth needs to have in order to achieve the optimum paint environment:

1. What are the characteristics of the paint you are spraying?

This will dictate exactly what conditions need to 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.

2. What are the characteristics of the external environment?

This factor will determine exactly what equipment you need to invest in to ensure that the air being brought in to the paint booth is conditioned to fit with the criteria set out by the unique characteristics of the coating you are spraying. How powerful does your heater need to be? Do you need a chiller? Do you need a humidifier? Does your booth need to be insulated? Do you need a vapor barrier? Etc.

Once you know exactly what equipment you need in order to create the environment that you need, your paint booth supplier should be able to begin easily selecting your paint booth configuration simply by checking that the equipment fits with the items on that list.

Does your shop have any special equipment in its paint booth to account for unique climate conditions? Let’s hear about it in the comments!

For more information, or to contact GFS, please visit www.globalfinishing.com.

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