Albert Switzer & Associates, Inc. — Pipeline Safety Interpretation

Page 1PI-72-0102 February 8, 1972 Mr. J. M. Kidd Albert Switzer & Associates, Inc. Consulting Engineers P.O. Box 14658 Barton Rouge, Louisiana 70808 Dear Mr. Kidd This letter is in regard to your inquiry to and subsequent discussions with Mr. Marshall Taylor of our Houston field office relative to the use of plastic pipe. You stated that your firm is designing a natural gas distribution system for a predominately rural area (Class Locations 1 & 2), and supplied design information that shows sizes ranging from 6”to 12” and pressures from 36 to 150 psig. In your letter you state, “The DOT regulations appear to be silent on pressure above 100psig and pipe sizes larger than 6” ASTM D2513, Thermoplastic Gas Pressure Pipe, Tubing and Fittings referenced in Section I of Appendix B of 49 CFR, part 192 includes specifications for thermoplastic pipe. Section 4.1.1.4 of ASTM D2513 references specifications for Poly Vinyl Chloride (PVC) Plastic pipe (SDR-PR and Class T) with the noted limitations. With regard to your comment on pressures above 100 psig, we refer you to Sections 192.121 and 192.123 which specify the design limitations for the operating pressures of plastic pipe meeting all other requirements of the regulations. If you have further questions, please advise. Sincerely Joseph C. Caldwell Acting Director Office of Pipeline Safety#

Page 2Albert Switzer & Associates, Inc. P.O. Box 14658 3150 Valley Street Baton Rouge, Louisiana 70808 August 24, 1971 Mr. Marshall W. Taylor USDT Office of Pipe Line Safety 201 Fannin Street - Suite 315 Houston, Texas Re: Plastic Pipe ASA Job No. 326 Dear Mr. Taylor: Please refer to our conversation this date concerning the use of plastic pipe. Our firm is designing a natural gas distribution system for a predominately rural area (Classes 1 and 2). The following is the design information. ASTM D 2513 Class 200 Station Size Miles PSIG PVC – 2 Wall Thick A 150 12” 19.6 0.606” B 123 10” 8.3 0.511” C 92 8” 9.3 0.410” D 81 8” 4.2 0.410” E 65 8” 6.2 0.410” F 43 6” 2.9 0.316” G 36 The DOT regulations appear to be silent on pressures above 100 psig and pipe sizes larger than 6". We would appreciate your review of this information and solicit your recommendations. Your s truly, ALBERT SWITZER & ASSOCIATES, INC. Consulting Engineers J. M. Kidd, P. E.#