Missouri Public Service Commission — Pipeline Safety Interpretation

Page 1July 28, 1981 Mr. Dale W. Johansen Assistant Director, Gas Department Engineering Section Missouri Public Service Commission P. O. Box 360 Jefferson City, Missouri 65102 Dear Mr. Johansen: We apologize for the lateness of our response to your letter of April 14, 1981, asking whether §192.357(d) requires nonrelief type service regulators, which would release gas only upon failure to have their breather vents vented to the outside atmosphere. As indicated by the enclosed interpretations (dated October 12, 1973, and November 1, 1976), §192.357(d) does not apply to nonrelief type service regulators because they do not release gas during operation. Nevertheless, nonrelief type service regulators that have breather vents are subject to the requirements of §192.355(b)(2) and must be installed so that gas escaping from the vents in the events of diaphragm or other failure is released into the outside atmosphere. We trust that this response will satisfy your concerns. Sincerely, /signed/ Melvin A. Judah Acting Associate Director for Pipeline Safety Regulation Materials Transportation Bureau dal\192\355\81-07-28 1#

Page 2October 12, 1973 Mr. A. C. Singer Vice President of Operations The Gas Service Company 700 Scarritt Building Kansas City, Mo. 64142 Dear Mr. Singer: In your letter of September 24, 1973, you requested an interpretation of Paragraph 192.357(d), Title 49, Code of Federal Regulations, which reads as follows: "Each regulator that might release gas in its operation must be vented to the outside atmosphere." Your specific question was whether the above paragraph requires an outside vent on service regulators which are installed inside, and which are not equipped with relief facilities. Since they do not release gas in their operation, you have considered such regulators as constituting a closed system. Your interpretation is correct. Since there is no release of gas in the operation of such a service regulator, that regulator need not be vented to the outside atmosphere. If we may assist further, please let us know. Sincerely, /signed/ Joseph C. Caldwell Director Office of Pipeline Safety dal\192\355\81-07-28 2#

Page 3November 1, 1976 Mr. Leonard M. Coffelt Missouri Public Service Commission P. O. Box 360 Jefferson City, Missouri 65101 Dear Mr. Coffelt: This responds to your letter dated September 21, 1976, asking that we review a previous interpretation dated October 12, 1973, regarding 49 CFR 192.357(d). You ask whether that interpretation permits "service regulators to be installed within a building without venting the diaphragm breather vent to the outside atmosphere." Section 192.357(d) reads: "Each regulator that might release gas in its operation must be vented to the outside atmosphere." The October 12, 1973, interpretation essentially provides that Section 192.357(d) does not apply to a regulator which does not release gas in its operation. That interpretation was not intended to permit installation of a regulator with a diaphragm breather vent inside a building without placing the discharge end of the vent outside the building. Sections 192.199(e) and 192.355(b)(2) are clear that the outlet of each regulator vent must be located outside. Sincerely, /signed/ Cesar DeLeon Acting Director Office of Pipeline Safety Operations dal\192\355\81-07-28 3#