OSHA defines a spray booth as a power-ventilated structure provided to enclose or accommodate a spraying operation to confine and limit the escape of spray, vapor and residue, and to safely conduct or direct them to an exhaust system.
In simpler terms, a spray booth moves air through a working chamber and exhaust system to capture overspray and harmful vapors created during a paint spray operation.
Paint booths come in many different configurations. The biggest difference between those configurations is the airflow. There are four main airflow designs for paint booths:
Downdraft Paint Booths
The best airflow style, downdraft paint booths do an excellent job controlling overspray and contamination. Air enters the booth through a full-length, filtered ceiling plenum or intake chamber and flows vertically over the product or vehicle and into the filtered exhaust pit in the floor. The intake and exhaust filter layout is designed for even air velocity throughout the working area.
Semi-Downdraft Paint Booths
Semi-downdraft paint booths are a hybrid, combining features of crossdraft and downdraft booths. Air is introduced to the booth through the ceiling or an intake plenum in the first 25 to 30 percent of the booth. It is then pulled across the working chamber, over the product or vehicle and into the filtered exhaust chamber at the rear of the booth.
Side Downdraft Paint Booths
Side downdraft paint booths are an economical solution for shops that are not able or do not want to install an exhaust pit. Air comes into the booth through a full-length, filtered ceiling plenum or an intake chamber and flows downward over the product or vehicle. The intake and exhaust filter layout is designed for even air velocity throughout the working area. When air reaches the floor, it’s pulled into floor-level, filtered exhaust plenums on both sides of the booth.
Crossdraft Paint Booths
The simplest, most cost-effective configuration, crossflow airflow starts at the front of a crossdraft paint booth, with air entering the booth through filtered product doors or an intake chamber. Air flows horizontally, parallel to the floor and over the product or vehicle. The intake and exhaust filter layout is designed for even air velocity throughout the working area. Air exits the booth through an exhaust plenum at the rear of the booth.
Other Finishing Equipment
Prep workstations and mix room systems work in a similar fashion. Moving air transports particles and vapors through filtration. In a mix room, the moving air stream also transports harmful and dangerous vapors out of the working area, minimizing exposure to harmful vapors and reducing the risk of explosion.