Ventilation rate for aircraft spray painting areas

April 8, 1997
Ms. Elsie L. Munsell
Deputy Assistant Secretary of the Navy
(Environment and Safety)
Department of the Navy
[Recipient address omitted]
Dear Ms. Munsell:
This is in response to your letter of March 14 requesting an interpretation of the Occupational Safety and Health Administration (OSHA) standard for the airflow rate required for a spray painting area.
29 CFR 1910.94(c) and 29 CFR 1910.107 both apply to spray areas. These sections are currently under revision and will be combined into one area of 29 CFR 1910.107. There is no specific flow rate mentioned in either standard for spray areas, OSHA uses National Fire Protection Association Publication, NFPA 33, 1995 edition, (copy enclosed) Spray Application Using Flammable or Combustible Materials, paragraph 5-2, which requires that "each spray area be provided with mechanical ventilation that is capable of confining and removing vapors and mists to a safe location and is capable of confining and controlling combustible residues, dusts, and deposits. The concentration of vapors and mists in the exhaust stream of the ventilation system shall not exceed 25% of the lower flammable limit." This means that the airflow may be variable depending on the job being performed. This also means that under the circumstances that you have described, OSHA considers these corrosion-control hangars to be spray areas as opposed to spray booths. The determining factor in this decision is that other work is also performed in the area and painting is incidental to the specific area that is being treated (wing, rudder, etc.), and not the entire aircraft on a repetitive basis.
The employees must also be fully trained in the hazards to which they are exposed and in the emergency action and fire protection plans required by 29 CFR 1910.38 [and 1910.39], in personal protective equipment as required in 29 CFR 1910 Subpart I and also in the health requirements listed in 29 CFR 1910 Subpart Z.
Should you have further questions, please contact [the Office of General Industry Enforcement at (202) 693-1850].
Thank you for your continued interest in occupational safety and health.
Sincerely,
John E. Plummer, Director
Office of Federal Agency Programs
Enclosure

[Requester letter reproduced on OSHA page; omitted here.]