Memo: Internal — Pipeline Safety Interpretation

Page 1INFORMATION: Section 192.611 Richard L. Beam Associate Director for Pipeline Safety Regulation, DMT-30 James C. Thomas Chief, Southern Region Office of Operations and Enforcement, DMT-16 The following responds to the three questions in your memo of September 10, 1982, about the proper application of §192.611: 1. Under §192.611(a), an MAOP equivalent to 72 percent of SMYS may be confirmed for a new Class 2 location. The design pressure referenced in §192.619(a)(1) is based on original conditions, and does not change with changes in Class location. 2. Under §192.611(b), a preexisting MAOP must be reduced to provide a hoop stress that is not more than that allowed for new pipe in the new class location. In accordance with §§192.105 and 192.111, the maximum hoop stress allowed for new pipe in a Class 2 location is 60 percent of SMYS. 3. Under §192.611(c), if the operator tests to 90 percent of SMYS, an MAOP equivalent to 72 percent of SMYS may be confirmed. Section 192.553(d) would not apply since uprating would not be needed for an MAOP based on 72 percent of SMYS. # DB C:\WP51\INTERPTR\192\611\82-10-07 1#

Page 2Date: September 10, 1982 Subject: ACTION: Clarification of interpretation of Sections 192.611 amd 192.619 From: James C. Thomas, Chief Southern Region, Pipeline Safety, DMT-16 To: Richard L. Beam Associate Director for Pipeline Safety Regulation, DMT-30 Following your August 10, 1982 response to my request for interpretation, I discussed the answers with Mr. Mel Judah and now request further clarification of question 2. If a transmission operator has an MAOP established under Section 192.619(a)(1) for a Class 1 Location and is operating at a pressure equivalent to 72% SMYS, and the class location subsequently changes to Class 2 - 1. If the operator qualifies under 192.611(a) can the MAOP be confirmed at the same pressure (equivalent to 72% SMYS) i.e. is the design pressure limitation under 192.619(a)(1) calculated using the original 72% class location factor or the new 60% factor after the class location change? 2. If the operator qualifies under 192.611(b), would the MAOP be revised to a pressure equivalent to 60% SMYS? 3. If the operator qualifies under 192.611(c), could the operator confirm the pressure equivalent to 72% SMYS or must it be reduced to 60% SMYS in accordance with Section 192.533(d)? DB C:\WP51\INTERPTR\192\611\82-10-07 2#