Paint spray booths are pressure-controlled enclosed spaces for painting vehicles. Temperature, airflow and humidity must all be controlled by means of the ventilation system, which will include fans and burners to heat the air.

Excess paint removal is essential. “Overspray”, or excess paint that is not deposited on the surface being sprayed, is a fact of life in spray booths. Most of this mist of paint is invisible, but it nevertheless presents a health risk for workers (isocyanate paint mists are known to cause occupational asthma) and can harm the quality of the finish on the product. To remove the airborne paint, chemical detackifying agents are normally used. The removal of overspray and detackifiers puts an additional load on the HVAC system.

High airflow rates are needed to properly ventilate the space to remove the overspray and improve visibility. The ventilation system of the booth also needs to introduce make-up air to replace the large volumes of air that are exhausted from the booth. The larger the booth, the higher the required airflow rating of the fans used to ventilate them. Modern ventilations are often tasked with offering a curing mode as well. Typically, large centrifugal fans are used to accomplish this task.

Cross-draft booths draw the air towards the booth opening. While they are easy to build, the air moves over the painted surface and dust contamination is therefore more likely to be a problem. Down-draft booths draw the air into filters at the bottom of the booth and are less likely to cause dust contamination problems, but are more difficult to build.

The ventilation systems used in the spray booth may use cyclones to prevent the introduction of pollutants or to recover powder in the case of powder spraying. Filters may also be used to control dust.

The design of spray booths depends on the particular requirements of the application, as well as the efficiency that can be achieved. An extremely wide array of paints is available, and their different properties entail the need for different designs to optimise paint elimination. The method of application used in the booth also has an influence on design. For lighter spray applications, the booth may be constructed of aluminium, whereas a more robust material such as steel or concrete is required for medium to heavy applications.

With years of experience in fan and cyclone building, CFW is able to offer optimal solutions for spray booth engineering and construction.