Does airflow affect your spray booth’s operational capabilities?

Does airflow affect your spray booth’s operational capabilities?

In a word, yes. Airflow is one of the most important factors that can affect your spray booth's operational capabilities. If you do not maintain proper airflow, you will compromise the efficiency and performance of your spray booth.

What else can be affected by poor/incorrect airflow?

• The overall quality of the finish: Inadequate or unbalanced airflow will produce a non-uniform finish, incomplete drying, and the possibility of dust or particles getting into the wet coating.
• Items near the booth could collect overspray and cause rework of completed jobs.
• Excessive energy bills

What affects airflow?

• Dirty air filters
• Paint buildup on the fan
• Improper booth ventilation
• Undersizing of the fan and motor from the get go…

How do you calculate airflow?

If you have a cross draft booth, use the calculation WxHx100 fpm (ft. per min.), which will give you the minimum cfm (cubic ft. per min.) of exhaust.

If you have a downdraft booth, use the calculation LxWx50 fpm, which will give you the minimum cfm.

Make sure you rate the fan's static pressure at 0.5” of static pressure. This is the static load rating that most spray booth exhaust filters have, which allows you to use the filters to full capacity without sacrificing your airflow. It is very common in the automotive industry to only rate the fan for 0.25" of static pressure, which does not necessarily meet code, but it does make the booth less expensive, initially.

Never put a 45/90 degree bend on the exhaust stack until you have traveled 2.5 times the fan's diameter in distance away from the exhaust fan. Many times we have seen a bend right after the fan, which gives too much static pressure on the fan and drastically affects the airflow Also use long sweeping bends, never sharp or square turns, in your exhaust stack.

How can I tell if I have the right airflow in my existing spray booth?

A good rule of thumb is when you spray into the air you should be able to count to three (3) seconds and no longer see any visible overspray. If you still see a swirling cloud of spray, there is an incorrect amount of air movement, or you have a turbulence that is disrupting the smooth flow of air to the filters.

The bigger the booth, the higher CFM rating you'll need.