Missouri Public Service Commission — Pipeline Safety Interpretation

Page 1August 13, 1980 Mr. B. J. Washburn, Manager Electric and Gas Departments Missouri Public Service Commission P.O. Box 360 Jefferson City, Missouri 65102 Dear Mr. Washburn: Thank you for your letter of June 3, 1980, in which you asked for an interpretation of Title 49 FR 192.747. Enclosed is our interpretation of the specific questions you raised, i.e., are curb-cock valves considered necessary for the safe operation of a distribution system and, if so, what effect if any does the operating pressure of the service line or the presence or absence of other service line valves outside of the building have on this determination. If I may be of further help in this matter, please let me know. Sincerely, /signed/ Melvin A, Judah Acting Associate Director for Pipeline Safety Regulation Materials Transportation Bureau Enclosure DB C:\WP51\INTERPRT\192\747\80-08-13 1#

Page 2No. 80-11 Date: August 13, 1980 DEPARTMENT OF TRANSPORTATION RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION MATERIALS TRANSPORTATION BUREAU PIPELINE _________________________________________________________________ SAFETY REGULATORY INTERPRETATION NOTE:A _________________________________________________________________ pipeline safety regulator interpretation applies a particular rule to a particular set of facts and circumstances, and, as such, may be relied upon only by those persons to whom the interpretation is specifically addressed. SECTION: 192.747 SUBJECT: FACTS: Are curb-cock valves included in those valves which may be necessary for the safe operation of a distribution system? Section 192.747 requires that each valve, the use of which may be necessary for the safe operation of a distribution system, must be checked and serviced at intervals not exceeding one year. The valves referred to in §192.747 are those necessary for the sectionalizing of the distribution system so that an operator can isolate a particular section of the distribution system in an emergency. DB C:\WP51\INTERPRT\192\747\80-08-13 2#

Page 3The manual used by the Transportation Safety Institute (TSI) in conducting the course on "Safety Regulation for Gas Pipeline Systems" states that valves for sectionalizing should be considered at the following locations: 1. 2. 3. 4. Control(s) at each pressure regulation station. Principal feed(s) to business districts and class 4 locations. All single valves on mains within (2) above. Valves that meet the following criteria. Reasonable for a sectionalizing plan. Consider - number of customers - Volume of gas - environment - response time/valve accessibility A curb-cock valve could only be used to isolate the service line in which it is installed. It could not be considered as being capable of sectionalizing the distribution system. Therefore, because of its limited capability, a curb-cock valve would not be considered under §192.747 as being necessary for the safe operation of a distribution system. Since a curb-cock valve would not be considered necessary for the safe operation of a distribution system, the operating pressure of the service line or the presence or absence of other service line valves outside of the building would have no effect on making a determination. Melvin A. Judah Acting Associate Director for Pipeline Safety Regulation Materials Transportation Bureau DB C:\WP51\INTERPRT\192\747\80-08-13 3#