Ask the Expert Question-and-Answer Archive

by Ron Joseph

September, 2003

Spray Booths and Water Based Coatings

Q. Is there a conversion formula or chart that can be utilized to convert from Zhan to Ford ratios as well as the converse.

A. Water-based coatings are considerably safer than solvent based paints, but they nevertheless contain a small quantity of solvents. I have not recently read the OSHA and NFPA (National Fire Protection Association) guidelines on spray booths for water-based coatings, but there are certain requirements you will in any case want to follow. For instance, you will want a reasonable air flow rate to allow the paint overspray to be captured by the spray booth filters. The current OSHA guideline is 100 fpm, whereas the NFPA guideline is <25% LFL.

My suggestion is that you read through OSHA 1910 and also

purchase a copy of NFPA Bulletin 33 at www.nfpa.org. I will be happy to assist you in this, but will need to charge a small fee for consulting.