Troubleshooting Spray Booth Airflow

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.