Interpretation Response #PI-96-009
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Mr. H. Russell Frisby, Jr.
Maryland Public Service Commission
William Donald Schaefer Tower
6 St. Paul Street
Baltimore MD 21202-6086
Dear Mr. Frisby:
We have considered your letter of May 6, 1996, notifying us the Commission will grant the Baltimore Gas and Electric Company (BGE) a waiver from compliance with 49 CFR 192.557(c) and 192.619(a)(3). The waiver will apply to certain gas pipeline systems constructed before 1970 that operate at less than 30 percent of specified minimum yield strength. BGE requested the waiver to authorize prior upratings of these systems that were based on pressure tests done at the time of construction instead of at the time of uprating.
Our review of this matter indicates that a waiver is unnecessary. The regulations in 49 CFR Part 192 do not require that upratings of these systems be based on pressure tests done concurrently with uprating.
BGE said it was requesting the waiver because of a March 11, 1974, letter we sent the Tennessee Public Service Commission. That letter says a strength test must be performed in uprating to a pressure permitted by § 192.619(a)(2)(ii). This statement was intended to indicate that because § 192.619(a)(2)(ii) requires a pressure test as a basis of maximum allowable operating pressure (MAOP), any system uprating to a pressure permitted by § 192.619(a)(2)(ii) must be based on a pressure test.
Apparently, the statement has been misconstrued to mean the test must be performed concurrently with uprating. But there is no doubt that § 192.619(a)(2)(ii) permits operators to rely on previous test pressures in calculating MAOP. And there is nothing in the regulations that alters this policy when MAOP is determined by uprating.
Richard B. Felder
Associate Administrator for
cc: Alex Dankanich
Assistant Chief Engineer
Gas Pipeline Safety
|§ 192.557||Uprating: Steel pipelines to a pressure that will produce a hoop stress less than 30 percent of SMYS: plastic, cast iron, and ductile iron pipelines|