National Gas and Oil Corporation — Pipeline Safety Interpretation

Page 1March 12, 1992 Mr. John B. Hartnett Vice President and Chief Operating Officer National Gas and Oil Corporation 1500 Granville Road P.O. Drawer AF Newark, Ohio 43055-0693 Dear Mr. Hartnett: This responds to your letter of December 13, 1991, asking for our interpretation of 49 CFR 192.167(a). National Gas and Oil Corporation (National) operates two natural gas compressors at the Perry Storage site. Compressors No. 1 and No. 5 are rated at 415 and 634 horsepower, respectively. The compressors are located in separate buildings approximately 35 feet apart. Perry Storage is a gas storage field where gas is injected in the off season and withdrawn for use in periods of high demand. You ask for our interpretation whether an emergency shutdown system is required for Perry Storage pursuant to 49 CFR 192.167(a). Section 192.167(a) states: "Except for unattended field compressor stations of 1,000 horsepower or less, each compressor station must have an emergency shutdown system. . . ." You describe the Perry Station as unattended with a continuously manned control center for your entire pipeline system located 92 feet from the nearest compressor. Although personnel are not assigned to the compressors during operation, we view the station as being attended, because personnel are immediately available to respond to problems that may arise at the station. The Research and Special Programs Administration (RSPA) interprets "field compressor stations" in § 192.167(a) to mean temporary installations operating in rural areas. These compressors are often skid mounted for ease in moving from site to site as the need arises. Field compressor stations usually do not have electricity available to power emergency shutdown systems. In such cases, it is not practical to install emergency shutdown systems. Because National's Perry compressors are permanently installed, they do not qualify as field compressors. You state that the term "field compressor stations of 1,000 horsepower or less" is unclear regarding whether each compressor horsepower rating should be considered individually or if the horsepower ratings of all compressors in a station should be added when making a determination. Since both of National's compressors boost pressures for injecting natural gas into the Perry Storage, the horsepower is additive. The total compressor capacity at National's Perry Station is 1,049 horsepower. jt 192.167/92-03-12#

Page 2Because National's compressors are attended, permanently installed and overall compressor capacity exceeds 1,000 horsepower National's Perry Station is not excluded from complying with the provisions of § 192.167(a). We trust that this responds sufficiently to your request. Sincerely, Cesar De Leon Director, Regulatory Programs Office of Pipeline Safety jt 192.167/92-03-12#