Mardi Gras Transportation System — Pipeline Safety Interpretation

Page 1PI-01-0108 U.S. Department of Transportation Research and Special Programs Administration 400 Seventh St., S.W. Washington, D.C. 20590 AUG 2 1 2001 Mr. Les Owen Pipeline Operations Coordinator Mardi Gras Transportation System 10777 Clay Road Houston, TX 77041 Dear Mr. Owen: I am responding to your letter of July 10, 2001, regarding the federal safety standard in 49 CFR 192.619(a)(2)(ii). You asked if we concur with your understanding of that standard as it applies to piping that connects facilities on an offshore platform to an underwater pipeline. As described in your letter and attached drawing, the piping is in two parts. The first part includes a pig launcher assembly and traditional fixed riser piping that begins at the hull deck and extends below the waterline to a hang off point. The second part consists of a flexjoint and steel catenary piping that begins at the hang off point and connects to a pipeline on the water bottom. You would like to comply with §192.619(a)(2)(ii) by applying a safety factor of 1.5 to the first part of the piping and a factor of 1.25 to the second part. Section 192.619(a)(2)(ii) requires a safety factor of 1.25 for certain offshore pipeline segments not located on an offshore platform. For segments that are located on an offshore platform, including a pipe riser, the factor is 1.5. Based on our evaluation of the design, it appears that the first part of the piping is the only part that is actually "on an offshore platform." The second part is not in contact with or supported by the platform itself. Therefore, we believe your intended application of § 192.619(a)(2)(ii) is correct. I hope this information is useful to you. If I can provide any further assistance, please contact me at (202) 366-4595. Sincerely, Stacey L Gerard Associate Administrator for Pipeline Safety#