Spray-booth separation and material handling

December 28, 1976

Mr. George A. Horne
Industrial Hygienist
ACF Industries, Incorporated
[Recipient address omitted]
Dear Mr. Horne:

This is in reply to your letter of December 1, 1976, concerning interpretations you have received regarding paint spraying operations.

The present General Industry Standards, 29 CFR 1910.107(c)(2), Minimum Separation, (6) Wiring Type Approved and (7) Lamps, all require definite specifications that are to be met within the spray area itself, as well as 20 feet from a spraying operation, unless separated by a partition.

Your questions will be answered in sequence as presented in your letter.

1. The minimum separation distance of 20 feet as stated in 1910.107(c)(2) is from the 1969 edition of the NFPA 33 Code and is interpreted to mean 20 feet from the spray area and/or a 20 feet radius from the frontal vertical egress of a spray booth. The variables that you describe are from the 1973 edition of the NFPA 33 Code. This agency is considering adopting parts of the 1973 Code with some restrictions. Some of our field personnel may have been giving out guidance according to the 1973 edition which is technically not the official standard being enforced.

2. An adequate partition is one that would be vapor proof, and of such a height that the vapors and/or spray material could not go over the top. For most operations, eight feet should be sufficient.

3. Yes, parts may be moved in and out of a spray booth by a material handling device that is not explosion proof for Class 1, Group D Locations, if the following steps are followed:

a. Spraying operations are halted.

b. Booth purged of flammable or combustible vapors.

c. Ventilation equipment is in operation.

Under no circumstances will the device be allowed in the spray booth during spraying operations.

If I can be of any further assistance, please feel free to contact me.

Sincerely,
Morton Corn
Assistant Secretary of Labor