Retrofitting a
Paint Spraybooth

Back to Spray Paint Booths

During the past few months I have visited numerous installations where the owners have retrofitted water-wash spray booths and converted them to dry filter, or they have converted single stage dry filter booths to three-stage.

That is understandable.  Water-wash booths for low-volume paint usage went out in the 1980s and 90s, because it became evident that dry filter booths were less expensive to operate and the filtration efficiency was often higher under practical conditions.  While water-wash booths can be as efficient as dry filter booths, they require more attention and maintenance, and when left unattended the efficiency can drop quite dramatically.

The need to convert dry filter booths from single stage to two or three stage filtration arose when EPA and state regulations started to place limits on filtration efficiency, especially when chromate-containing (inorganic HAP) coatings were being used.

It is easy to understand the motivation to retrofit, but what boggles my mind is when I find that all the old steelwork behind the filters has not been removed.  Let me give you just one example. One of my clients was frustrated that he couldn’t get sufficient airflow through his booth despite the fact that the fan was operating, he had increased its RPM and there was a decent differential pressure across the filtration system.  When I removed the three-stage filters I too was baffled.  Behind the filters I found the entire water curtain, water trough and all the bells and whistles from the original water-wash booth.  Whoever “retrofitted” the booth had simply inserted a new layer of filters in front of the curtain and expected the “new” booth to operate just fine.  When my client saw this, he wanted to pull the hair from his head! Trust me, within 24 hours every scrap of unnecessary metal was removed and the booth did perform just fine.

If you have already retrofitted a spray booth, or if you intend to do so in the future, please make sure that you minimize any unnecessary restrictions to air flow in the exhaust section of the booth.  Remember, the easier it is for the air to travel through the filters and up through the exhaust stack, the better the booth will perform … and at a lower energy cost.

HOME | TRAINING | CONSULTING | EXPERT WITNESS | ASK THE EXPERT | LINKS