Q. We are in the process of setting up a painting system for our products. Our application involves spray painting of large castings 3 × 2 × 1.8 m in size and spray painting of medium castings 2 × 0.5 × 0.1 m. I would be obliged if you could advise me on which of the following two spray booths is best for my application:
1) Down draft booth(air in from top and out from bottom; with a pit for exhaust air, or
2) Semi-down draft booth (air in from top and out from side; without a pit)
A. If you decide to use a down draft paint spray booth, I recommend it be exhausted into a pit rather than through a side. Although the cost of providing a pit will add to the expense of the installation, the booth will be more efficient due to laminar airflow in the spray booth. On the other hand, using a down draft booth having a side vent will be less efficient due to turbulence of the booth air. This turbulence could possibly result in painters being painted. If you decide to install a paint spray booth having side exhaust, it must also have a side made-up air intake to be more efficient owing to laminar airflow in the spray booth.
However, considering the configuration of the products being painted, a side draft (side intake and side exhaust) paint spray booth may be a better choice than the two aforementioned choices. Again, owing to laminar airflow, the side draft-side exhaust paint spray booth will be more efficient than choice No. 2.