OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

March 17, 1978

                    REGIONAL ADMINISTRATOR

ATTN:               HAROLD WHITE Technical Support

THRU:               DONALD E. MACKENZIE Field Coordinator

FROM:               BRUCE HILLENBRAND Acting Director 
                    Federal Compliance and State Programs

SUBJECT:            Transparent Welding Curtains and the Requirements of 29
                    CFR 1910.252(e)(2)(iii)

This is in response to your letter dated August 18, 1977, on the above subject and confirms conversations between Mr. Wasko and Mr. Harold White. The transparent welding curtains referred to are of plastic composition. You wish to be advised if such curtains may be used to meet the requirements of the subject standard.

Standard 29 CFR 1910.252(e)(2)(iii) states:

Protection from arc welding rays. Where the work permits, the welder should be enclosed in an individual booth painted with a finish of low reflectivity such as zinc oxide (an important factor for absorbing ultraviolet radiations) and lamp black, or shall be enclosed with noncombustible screens similarly painted. Booths and screens shall permit circulation of air at floor level. Workers or other persons adjacent to the welding areas shall be protected from the rays by noncombustible or flameproof screens or shield or shall be required to wear appropriate goggles.

In reference to the requirement in the first sentence of the standard, the employer would be in violation if the plastic curtain forms a booth to enclose the welder since the curtain is not noncombustible, as required. There is no known treatment which will make organic plastics noncombustible.

In reference to the requirement of the second sentence of the standard, the transparent plastic welding curtain could easily be installed to meet the ventilation requirement.

In reference to the requirement of the third sentence of the standard, a transparent plastic screen or shield would be permitted since it can be made flameproof as well as sufficiently absorptive and non-reflective of the welding rays.