Memo: Internal — Pipeline Safety Interpretation

Page 1Interpretation of §192.741 Associate Director for Pipeline Safety Regulation, DMT-30 Chief, Central Region, DNT-14 In your memo of June 22, 1979, you ask several questions with regard to a piping schematic. First, you would like to know at what regulator stations telemetering or recording pressure gages are required under §192.741(a). Section 192.741(a) provides: "Each distribution system supplied by more than one district pressure regulating station must be equipped with telemetering or recording pressure gages to indicate the gas pressure in the district." As indicated by §192.741(c) the purpose of paragraph (a) is to identify any high or low pressure within a distribution system district which would indicate unsatisfactory operation of a pressure regulator or auxiliary equipment supplying the district with gas. Section 192.741(a) does not require that pressure gages be placed at regulator stations; they may be located there or at other places within the district. However, the number and location of the telemetering equipment or recording pressure gages must be such that the performance of the regulator(s) and auxiliary equipment is adequately monitored to detect unsatisfactory operation. Secondly, you asked if it is the intent of §192.741(a) to require telemetering or pressure recording devices only when the entire distribution is supplied by more than one regulator station, or does it also apply to districts within one distribution system. As indicated in answer to the first question, the intent of §192.741(a) is to require operators to monitor the gas pressure in each district of a distribution system if the district is supplied by more than one pressure regulating station. Thirdly, you asked whether each pressure district within a system is a separate distribution system. In accordance with the intent of §192.741(a) the terms "distribution system" and "district" refer to pipelines located downstream from regulator stations used to maintain pressure in the pipelines. These pressure districts may be considered separate distribution systems within a larger more complex system. Finally, you asked if Part 192 requires the installation of overpressure protection at regulator stations D, E, F, and G, shown on your schematic, which were installed in the 1950's with MAOP based on §192.619(a)(3). Since the regulator stations D, E, F, and G were installed in the 1950's the overpressure protection requirements of §192.195 would not apply to them unless they have been replaced, relocated, or otherwise changed within the meaning of §192.13. Since MAOP is DB C:\WP51\INTERPRT\192\741\79-08-31 1#

Page 2governed by §192.619(a)(3), they need not have overpressure protection in accordance with §192.195, as they would if §192.619(b) or §192.621(b) applied. Cesar DeLeon DB C:\WP51\INTERPRT\192\741\79-08-31 2#