Mountain Fuel Supply Company — Pipeline Safety Interpretation

Page 1January 4, 1978 Mr. F. F. Bassani Gas Engineer Mountain Fuel Supply Company P.O. Box 1129 Rock Springs, Wyoming 82901 Dear Mr. Bassani: You have asked our opinion on whether the installation of a 10-inch branch connection on a 24-inch O.D., 0.281-inch wall, grade X-52 pipe in a Class 1 area, using a hot tap and a split full encirclement saddle for reinforcement, would require a reduction in the pipe's maximum allowable operating pressure (MAOP) of 850 psig. We apologize for the unusual delay in responding to your inquiry. Under the applicable regulations governing MAOP in this situation (§192.619(a)(1), §192.13(b), §192.105, and §192.111), the pipe's MAOP would be reduced only if installing the 10-inch branch connection "changes" the pipe within the meaning of §192.13(b) and, if it does, the hot tap with split saddle constitutes a "fabricated assembly" within the meaning of §192.111(d). We have not addressed the second issue because in our opinion installing the branch connection as you have described would not "change" the existing pipe as intended by §192.13(b). Thus, the installation would not require reassessment of the pipe's design under Subpart C and the MAOP prescribed by §192.619(a)-(c) likewise would remain the same. Although the term "change" is not defined in Part 192, since it is used in §192.13(b) in the same context as "replace" and "relocate," a reasonable inference is that "change" means a substantial alternation of an existing pipeline. Ordinarily, a branch connection made by hot tap with reinforcement would not substantially alter the pipe to which it is attached. This view is supported by §192.155 which specifically requires that a branch connection be designed "to ensure that the strength of the pipeline system is not reduced." Sincerely, Cesar DeLeon Acting Director Office of Pipeline Safety Operations dal\192\619\78-01-4 1#

Page 2April 27, 1977 Mr. Cesar DeLeon Acting Director Office of Pipeline Safety Operations Department of Transportation Washington, D.C. 20590 Dear Mr. DeLeon: We would like to have an official interpretation on the following question: Would the installation of a 10-inch hot tap on a 24-inch O.D., 0.281-inch wall, grade X-52 pipe in a Class I area using a split full encirclement saddle for reinforcement cause us to lower our maximum allowable operating pressure of 850 psig? Attached is a copy of an interpretation received from Mr. J. C. Overly, Chief of the Western Region, Office of Pipeline Safety Operations. By using this method of installation, we would not have to blow any gas to atmosphere, and thereby conserve a valuable source of energy. An early reply would be appreciated. Very truly yours, F. F. Bassani Gas Engineer Attachment dal\192\619\78-01-4 2#

Page 3April 21, 1977 Mr. Roy E. Spann Mountain Fuel Supply Co. P.O. Box 1129 Rock Springs, Wyoming 82901 Dear Mr. Spann: I am writing in reply to your question raised at the industry seminar held in Casper, WY on April 13 and 14 of this year. Your question concerned making a 10" hot tap on a 24" line in a class 1 location with a M.A.O.P. of 850 psig utilizing a full encirclement welded split sleeve as reinforcement. I told you at the time you asked the question that I thought that the split sleeve would be considered reinforcement but that I wanted to verify that. I have since checked with our headquarters office and have received concurrence with my opinion. As such this would not lower the design factor as stated in 192.111(b). This is, as mentioned to you on the phone, the opinion of the Western Regional office. An official interpretation must be requested in writing and directed to OPSO headquarters in Washington, D.C. I hope I have been of some assistance and if you have any further questions please feel free to contact me. Thank you for your continued interest in gas safety. Sincerely, dal\192\619\78-01-4 3#

Page 4Jack C. Overly, Chief Western Region Office of Pipeline Safety Operations dal\192\619\78-01-4 4#