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.

November 8, 1988

Mr. Jack Cannova
Tempe Industrial Supply
412 Orion Street
Tempe, AZ 95283

Dear Mr. Cannova:

With regard to the use of plastic pipe for unprotected, above ground gas transmission and distribution piping systems, it is our understanding that only one type of plastic pipe is acceptable for such uses. That pipe, Acrylonitrile-Butadiene-Styrene (ABS), is marked on the pipe as approved for compressed air supply. Otherwise, the above ground portion of such a system must be enclosed in a conduit or casing of sufficient strength to provide protection from external damage and deterioration.

Hopefully the above information satisfies your request of October 27, 1988.



[Corrected 10/22/2004]