Troubleshooting Spray Booth Airflow

Troubleshooting Spray Booth Airflow

May 28th 2019

Making spray booths work exactly the way you want can be a challenge because of space and ventilation constraints. Spray booths can take up a lot of space on shop floors, so finding the right spot that will also vent exhaust properly is key. Also important are choosing the right type of spray booth, installing proper ventilation, replacing paint filters regularly, adjusting for unusual jobs, and keeping an eye out for poor airflow issues.

Types of Spray Booths

There are four main categories of spray booths:

  1. Open Front Spray Booths offer a safe and clean environment for any type of finishing operation for both batch and conveyorized production systems. Airflow is drawn in through the open front, across the work area and exhausted through a filter bank in the back of the booth.
  2. Open Front Bench Booths are a structural variation of Open Front Spray Booths with similar airflow that are also suitable for both batch type and automated production systems. Conveyor pass-through openings can be as much as 25% of the booth open front area, without requiring additional exhaust fan capacity.
  3. Batch Powder Booths have an open front design that is ideal for powder applications. Air is drawn in through the open front of the spray booth and passes through the booth's working area into the filtered exhaust plenum. The air is filtered in three stages and discharged back into the room.
  4. Cartridge Batch Powder Booths also have an open front design ideal for small- to mid-size powder applications. To ensure cartridge filters remain clean, the booth has a purge control feature, which assures the safe operation of the coatings enclosure by maintaining the airflow at design levels.

Fans, Ducts, Controls, and Extension Kits

Spray booth exhaust fans typically run at speeds in the thousands of cubic feet per minute (CFM) range. To accommodate that airflow, common ductwork comes in diameters ranging from 12 inches to 48 inches in six-inch increments. These size ranges can also be found in 45° and 90° elbows, duct cleanout doors, and automatic roof ventilators. To gain even more control over airflow, you might consider motor starters, multi-fan control panels, and VFD control panels.

If you need to expand capacity, you don’t always need to install an entirely new spray booth system. You can economically upscale your business with spray booth “extension kits” customized to handle the particular equipment being coated within your spray space limitations. Instead of paying to make permanent changes for a temporary job, extension kits offer a more flexible alternative that keeps your work space versatile while maximizing productivity.

Preventing Powder Drift

Even if you have installed all your spray booth systems correctly, you may find powder drifting out of your spray booth openings. Here are some possible causes and solutions of this unwanted issue.

  • Cause: Insufficient airflow through the booth and the recovery system.
    Solution: Position powder guns away from booth openings and check air volume control.
  • Cause: Cartridge filters are not failing to receive adequate cleaning.
    Solution: Increase air pressure or the volume.
  • Cause: Cartridge filters at end of life.
    Solution: Replace cartridge filters.
  • Cause: Final filters clogged.
    Solution: Check the final filters for leakage; repair or replace filters as needed.