San Diego Gas & Electric Company — Pipeline Safety Interpretation

Page 1Mr. Paul L. Hathaway Vice President - Gas San Diego Gas & Electric Company P. O. Box 1831 San Diego, Ca 92112 Dear Mr. Hathaway: Referring to your letter of February 21, 1975, and figures attached thereto, the redesigned riser shown in Figure 2 with a protective sleeve covering all plastic materials aboveground appears to meet the requirements of 49 CFR 192.375(a) for protection of plastic service lines. Although we do not have enough information to opine whether the riser shown in Figure 2 would meet all the requirements of 49 CFR 192.123, we have particular misgivings about its meeting the temperature limitations of section 192.123(b) under ordinary aboveground operating conditions. The two 4-inch PVC lines which are shown in Figure 3 are mains. This is so because in accordance with the definition of the term "main" in 49 CFR 192.3 each 4-inch line serves as a common source of supply for more than one service line. We trust this adequately responds to your inquiry. Sincerely, Joseph C. Caldwell Director Office of Pipeline Safety Mr. Joseph C. Caldwell, Director Office of Pipeline Safety DB C:\WP51\INTERPRT\192\3\75-03-21 1#

Page 2Washington, D. C. 20590 Dear Mr. Caldwell: Thank you for your response to my letter of November 7, 1974, concerning risers used in privately owned (non-utility) gas systems subject to the OPS regulations. Your comments were most helpful; however, we would like additional clarification on two points. Both questions again relate only to privately owned gas distribution on systems subject to the OPS regulations. 1. You pointed out that when used on a service line, the PVC riser shown in Figure 1 (attached) would not comply with the OPS regulations since the PVC flange was exposed. If the riser was redesigned to extend the protective sleeve beyond the PVC flange, as shown in Figure 2 (attached), would the riser then comply with paragraphs 192.123 and 192.375(a)? 2. Figure 3 (attached) shows a master-metered housing project. The gas is metered by a utility master meter, and then enters a privately owned distribution system supplying gas to a number of multi-unit apartment buildings. The two 4-inch PVC lines connect to the utility master meter, and extend throughout the development. These 4-inch lines do not connect directly to the multi-unit apartment buildings; gas reaches each building through a smaller diameter pipe which taps into the 4-inch line nearest the building. Figure 3 shows typical 1-1/2 inch PVC pipes supplying individual buildings. As shown in Figure 3, are the two 4-inch lines connecting to the utility master meter "mains" or are they "service lines," according to OPS definition of these terms? Thank you for your assistance in resolving these questions. Yours very truly, Paul L. Hathaway NOTE: ATTACHED TWO PAGES - DIAGRAMS DB C:\WP51\INTERPRT\192\3\75-03-21 2#