Enstar Natural Gas Company — Pipeline Safety Interpretation

Page 1U.S. Department ofTransportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue SE Washington DC 20590 OCT 2 2 2019 Mr. Steve Cooper Director of Operations Enstar Natural Gas Company 3000 Spenard Road P.O. Box 190288 Anchorage, AK 99519-0288 Dear Mr. Cooper: In a June 18, 2019, letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), you asked for reconsideration of PHMSA's March 11, 2019, response to your request for interpretation on external corrosion control under§ 192.467. You based your request for reconsideration on the remoteness of the casing/pipeline location, low operating pressure (MAOP of 60 psig), leak survey frequency, and class location of the 8- inch pipeline diameter, 0.277-inch wall thickness distribution pipeline located in a Class 1 location. PHMSA provides written clarifications based on current Federal pipeline safety regulations. As to the referenced interpretation (PI-86-004), please refer to PHMSA's March 11, 2019, response letter. After examining your latest information, PHMSA does not believe remoteness of a pipeline location and the quarterly leak survey frequency are justification for not complying with the pipeline safety regulations. PHMSA still believes the March 11, 2019, interpretation response letter correctly reflects the current pipeline safety regulations. Therefore, Enstar must perform inspections, tests, and remediation with procedures that are in accordance with § 192.467. lfwe can be of further assistance, please contact Tewabe Asebe at 202-366-5523. ale Director, Office of Standards and Rulemaking The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations (49 CFR Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the specific facts presented by the person requesting the clarification. Interpretations do not create legally-enforceable rights or obligations and are provided to help the public understand how to comply with the regulations.#

Page 2J UN 2 7 2 0\9 3000 Spenard Road P.O. Box 190288 Anchorage, AK 99519-0288 www.enstarnaturalgas.com June 18, 2019 '•,.•: > I • I U.S.DOT PHMSA Office of Hazardous Materials Standards Attn: John A. Gale East Building 1200 New Jersey Avenue, SE. Washington, DC 20590-0001 RE: Interpretation Decision Letter Pipelinl ; safety Officer~ . ' The following _is.in response to your March 11, 2019 l~tter t? ENST AR Natural Ga&· Co~pany , (ENSTAR) regarding the interpretation request for shorted pipeline casings. Based on langq.age in the PHMSA response, and afl:er discussions withPHMSA staff, it was appa,rent that information impm1:ant to thj,s request was not being considered; or may not have been properly understood when. PHMSA made th~ir decisjon on this matter. ENSTAR wishes to clarify some points and respectfully-requests that PHMSA reconsider this intetpretation request dated November 14~ 2016. Jn. the initial request ENST AR asked to be granted an interpretation similar to an existing one (PI-86-004) regarding shorted casings. In two of the locations where this request would apply, the remoteness of the casing/pipeline location, the maximum. operating pressure of the pipeline, leak survey frequency, and pipeline class location are all important factors that should be considered. In these cases the pipeline is an 8-inch diameter distribution pressure main (MAOP 60psi) with a wall thickness of0.277 inches and in a Class I location. The main is a one-way feed to a remote community (Whittier, Alaska) that provides natural gas to 47 customers. As describeq it:i the. following, unique challenges to remediation of the shorts at these locations have driven this request: • The first shorted casing is located between a steep mountainside and Portage Creek, buried approximately 10 feet deep and, due to its location on the opposite side of the river from the driven road, only accessible by rail. Work to correct this short would almost certain require installing a new Cfossing of the river and completing a complicated tie-in between the. railroad tracks and the river bank. • The second shorted location is a few miles downstream of the first location and near where the , pipeline transitions out of a 2-mile· long utility twmel that pa:sses t~ough a mountain on.- its way Anchorage: 907-277-5551 • Kenai, Peninsul~ Office: 907-262-9334 • Mat-Su Office: ~07 376-7979 Al/Our#

Page 3into Whittier. Repairing this short would require removing a portion of the tunnel entrance and replacing pipe back inside the tunnel. Replacing pipe inside the tunnel simply presents many challenges related to hot work in a confined space that while not impossible, are cu,mbersome and expensive. These challenges while maintaining continuity of service to the end-of-the-road community during remediation work have made resolving isolation issues difficult. ENST AR closely monitors the cathodic protection potentials of the casing and carrier pipe for deteriorating potentials, to date the potentials have not shifted. As an alternative solution to date ENST AR has performed leak surveys every quarter year to ensure the integrity of the system. This process has been completed in accordance with a previous PHMSA interpretation, PI-86-004 3(A) iii, which was given to the Public Service Commission of Kentucky in 1986. ENST AR requests that PHMSA grant the same guidance to ENST AR as described in the interpretation PI-86-004, specifically part 3. Reasonable time allowance and methods for operator correction of shorted casings. Should you have any questions regarding this request for interpretation, please feel free to call me at 907-334-7730 between 8:00 AM and 5:00 PM AST. Sincerely ENSTAR Natural Gas Company Steve Cooper, P.E. Director of Operations Steve.Cooper@enstarnaturalgas.co:rn Anchorage: 907-277-5551 • Kenai Peninsula Office: 907-262-9334 • Mat-5~ Offi' ce ; 90/316· ~79'7~ · Al/Our#