Public Utilities Commission of Ohio — Pipeline Safety Interpretation

Page 1October 18, 1994 Mr. Edward M. Steele Chief, Gas Pipeline Safety Section The Public Utilities Commission of Ohio 180 E. Broad Street Columbus, Ohio 43266-0573 Dear Mr. Steele: I am responding to your letter of May 11, 1994, concerning the maximum allowable operating pressure (MAOP) of a distribution system. The operator established an MAOP of 5 psig, based on a maximum safe pressure under § 192.621(a)(5). However, as shown on an MAOP worksheet, the system was operated at 10 psig on a peak day during 1970. The operator now alleges the MAOP was mistakenly set at 5 psig and should have been 10 psig. You ask if the operator may increase the MAOP to 10 psig without uprating under Subpart K of Part 192. When we addressed this issue in our letter to you dated May 2, 1994, we said the operator must uprate the system under Subpart K. We still believe that is a correct application of the regulations. System MAOP is governed by the lowest value determined under § 192.619 and § 192.621. The worksheet shows that 5 psig was the lowest value. Thus, 5 psig was unmistakenly [sic] the correct MAOP, and any increase in MAOP must meet Subpart K. However, inasmuch as the system has been operated at 10 psig every winter since 1970, the operator may wish to seek a waiver of Subpart K based on this history of operation. Sincerely, Cesar De Leon Director for Pipeline Safety Regulatory Programs dal/192.619 94-10-18#