Public Service Commission of Nevada — Pipeline Safety Interpretation

Page 1Mr. Jeffrey L. Maples Gas Pipeline Safety Engineer Public Service Commission of Nevada Regulatory Operations Staff Capitol Complex 727 Fairview Drive Carson City, NV 89710 Dear Mr. Maples: Thank you for your letter of April 20 requesting clarification of a variety of issues regarding liquefied petroleum gas (LPG) systems and master meter systems. We have analyzed your questions and explain our conclusions below. For simplicity, we have used the same headings as on your letter. 49 CFR 192.11(a) As we interpret the term in relation to LPG, a "system" normally consists of a tank storing petroleum, gas in liquid form, appurtenant facilities, and piping used to deliver gas to one or more customers. Separate tanks and piping serving separate sets or customers within a mobil home park would not constitute a single system, but separate systems. The example presented in your letter, two tanks serving line customers each, with no interconnection and no equipment in a public place, would be two separate systems. Neither would be subject to §192.11(a) because each system serves fewer than 10 customers. Were the tanks or associated piping interconnected, they would constitute a single system serving 18 customers and would be subject to §192.11(a). Similarly, were some part of either system located in a public place, that entire system would be subject to §192.11(a). 49 CFR 192.199 As used in Part 192, the phrase "district regulator station" refers to a pressure limiting device that is designed and installed to limit the downstream pressure in a distribution system or part of a distribution system. In an LPG system a pressure regulator on the outlet of the supply tank would be enforced §192.199(g) against LPG operators. Doing so could be problematic in the absence of a clear understanding of the meaning of "district regulator station." We have scheduled a rulemaking proceeding to begin next March to clarify which facilities the Part 192 regulator- station rules cover. We suggest that you defer decisions on compliance actions against LPG operators regarding §192.199(g) until the conclusion of that proceeding. DB C:\WP51\INTERPRT\192\11\89-07-31 1#

Page 2The party who actually operates the distribution system has primary responsibility for compliance with the regulations, regardless of ownership. In the examples you cited, it is possible for the supplier to perform the maintenance of the tank/regulator combination under an agreement with the operator, but the primary responsibility for compliance remains with the operator. NFPA 58 - 2213 The question here is whether it is acceptable, in the absence of a waiver, to set relief valves to start to discharge at 275 psi rather the 250 psig as specified in NFPA (1979) Section 2213. Assuming the tanks in question were manufactured, designed, or installed after the 1979 edition of NFPA 58 was incorporated by reference in Part 192 (Amendment 192-37, 46 FR 10160, effective March 4, 1981), tank relief valve settings that are not in accordance with NFPA 58 (1979) requirements would violate §192.11(a), and the system operators would be liable to appropriate penalties or other sanctions for the violations. tanks manufactured, designed, or installed before the 1979 edition was referenced would be subject to the relief valve setting requirements in earlier editions of NFPA5 8 referenced in §192.11. An operator may apply for a waiver of the NFPA setting requirement to avoid continuing violations. As a certified State agency under the Natural Gas Pipeline Safety Act of 1968, the Nevada Public Service Commission is authorized to grant waiver requests, subject to the approval of this office (See 40 app. U.S.C. 1672(d). We would not approve such a waiver unless there in an adequate explanation why the NFPA setting requirements is inappropriate to apply in a particular case and why a higher setting does not reduce safety. I hope that the preceding discussion clarifies these issues for you. If you need any further information, please contact me. Sincerely, /signed/ Richard L. Beam Director Office of Pipeline Safety DB C:\WP51\INTERPRT\192\11\89-07-31 2#