{"operation":"document","citation":"PI-81-0101","title":"Pipeline Safety Interpretation PI-81-0101","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1981-02-25","effective_on":null,"summary":"PI-81-0101 concerning 192.13.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-81-0101.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-81-0101.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-81-0101","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1981/g81-03-10_Chen_192.13%20-%20lmxs.pdf","body":"<<<PAGE 1>>>\n\nPI-81-0101\nDATE: 25 Feb 1981\nSUBJECT: ACTION: Interpretation – Section 192.311\nFROM: Robert L. Paullin\nAssociate. Director for Operations & Enforcement, DMT-10\nTO: Melvin A. Judah\nActing Associate Director for Pipeline Safety\nRegulation, DMT-30\nSection 192.311, a general construction requirement for transmission lines and mains, limits\nplastic pipe repair to the use of a patching saddle or removal. Also, Paragraph 192.13(b)\nrequires that when a segment of pipeline is replaced, relocated, or otherwise changed, then\nthat replacement, relocation, or change must be made in accordance with this part. With\nthese requirements in mind, would the existing Part 192 permit the addition of a band clamp\n(compression fitting) on an operating pipeline to permanently repair damage or a leak (1) on\na plastic transmission line or main? (2) on a plastic service line?\n\n<<<PAGE 2>>>\n\nFebruary 27, 1981\nMr. Keith A. Chen, P.E.\nDirector - Research\nWisconsin Gas Company\n£26 Last Wisconsin Avenue\nMilwaukee, Wisconsin 53202\nDear Mr. Chen:\nYour letter to this office of February 6, 1981, concerns the use of full encirclement stainless steel band\nclamps for permanent repair of damaged plastic pipe. We agree with your interpretation that Subpart G of\n49 CFR Part 192 (and, thus, §192.311) is only applicable during the construction of a transmission line or\nmain. However, as further discussed below, even if the band clamp were considered a “patching saddle,” as\nintended by §192.311 (which it is not), its use to permanently repair plastic pipe either during construction\nor after operation nay be prohibited under §192.703(b).\nIn regard to the term “patching saddle” as used in §192.311, these words were added to the final rule as a\nresult of comments to the proposed rule stating that defective plastic pipe should be permitted to be\nrepaired. These comments clearly had in mind the use of a saddle made of material similar to that of the pipe\nbeing repaired that would be joined to the pipe by fusion, solvent cement, adhesion, or similar methods.\nTypical comments that prompted the Office of Pipeline Safety to permit use of a “patching saddle” were\n\"We feel that patching of a plastic vain should be allowed. Should be no difference between a\npatch over a gouge or the installation of a service tee.\" (Iowa Public Service Company)\n\"The use of solvent weld half-soles on polyvinyl chloride pipe has proven to be a safe,\neconomical method of repair for scratches, gouges, and grooves on mains in service. (Central\nTelephone and Utilities Corporation)Thus, a band clamp is inconsistent with the meaning\nintended by \"patching saddle.\nAnother reason why \"patching saddle\" does not mean a band clamp is that when §192.311 was issued,\n§192.281(e)(2) was also issued, requiring a rigid internal tubular stiffener to be used in conjunction with each\ncompression type mechanical coupling. This requirement recognizes the compressive forces of the sealing\ngasket used in a compression coupling and the fact that plastic materials under constant stress will tend to\ncold flow. A full encirclement stainless steel hand clamp, like a compression coupling, subjects the plastic pipe\nto compressive stress but does not provide internal support for the pipe that may be needed to prevent cold\nflow of the plastic.\nBecause of the question of cold flow of plastic pipe, we believe that the safety of a permanent repair by use of\na band clamp is questionable under some conditions, depending on the stiffness of the elastic pipe involved.\nWhere unsafe conditions would result, §192.703(b) would forbid use of the band clamp as a repair method.\nIn your letter, you state that “Wisconsin Gas conducted tests on tile, stainless steel clamp, used as a\npatching saddle which determined that the performance met the required safety and serviceability tests of\nthe code.\" We would appreciate your sending us these data and any other data available on the problem\nof cold flow of plastic pipe under continuous gasket pressure as discussed above.\nSincerely,\nSIGNED\nMELVIN A. JUDAH\nMelvin A. Judah\nActing Associate Director for\nPipeline Safety Regulation\nMaterials Transportation Bureau","truncated":false,"body_characters":4167}