{"operation":"document","citation":"PI-82-0109","title":"Pipeline Safety Interpretation PI-82-0109","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1982-11-03","effective_on":null,"summary":"PI-82-0109 concerning 192.13.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-82-0109.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-82-0109.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-82-0109","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1982/g82-11-03_Reifschneider_192.13%20-%20lmxs.pdf","body":"<<<PAGE 1>>>\n\nPI-82-0109\nNovember 3, 1982\nMr. Tom Reifschneider\nPeoples Engineering\nSupervisor of Standards\nPeoples Natural Gas Company\n25 Main Place\nCouncil Bluffs, IA 51501\nDear Mr. Reifschneider:\nThis responds to your letter of October 12, 1982, regarding the use of an encapsulation method to repair leaks\nin PVC fittings. You asked whether the method would qualify as a \"patching saddle\" under §192.311.\nThe enclosed copy of a letter dated February 27, 1981, to Keith Chen Discusses the meaning of \"patching\nsaddle.\" Based on that discussion, it appears that the encapsulation method does not qualify as a \"patching\nsaddle\" in its ordinary sense.\nWe presume that your primary use of the method would be to repair existing pipelines in place. In this case,\n§192.311 would not apply since it only governs the construction of new transmission lines and mains or\nexisting ones that are being relocated, replaced, or otherwise changed (see §§192.13 and 192.301). The only\nrestrictions under Part 192 on use of the encapsulation method for repairing an existing plastic pipeline are\nthe provisions in §192.703(b), which essentially require that the repair method used remit in a safe pipeline.\nSincerely,\nOriginal signed by\nRichard L. Beam\nAssociate Director for\nPipeline Safety Regulation\nMaterials Transportation Bureau\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 clamps\nfor permanent repair of damaged plastic pipe. We agree with your interpretation that Subpart G of 49 CFR\nPart 192 (and, thus, §192.311) is only applicable during the construction of a transmission line or main.\nHowever, 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 or\nafter 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 patch\nover 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, economical method of\nrepair for scratches, gouges, and grooves on mains in service. (Central Telephone and Utilities Corporation)\nThus, a band clamp is inconsistent with the meaning intended 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 patching\nsaddle which determined that the performance met the required safety and serviceability tests of the code.\"\nWe would appreciate your sending us these data and any other data available on the problem of cold flow of\nplastic pipe under continuous gasket as discussed above.\nSincerely,\nMELVIN A. JUDAH\nMelvin A. Judah\nActing Associate Director for\nPipeline Safety Regulation\nMaterials Transportation Bureau\n\n<<<PAGE 3>>>\n\nPeoples Natural Gas Company\n25 Main Place\nCouncil Bluffs, Iowa 51501\nOctober 12, 1982\nMr. Richard Beam\nAssistant Director\nOffice of Pipeline Safety Regulations\nMaterial Transportation Bureau\nDepartment of Transportation\nWashington, DC 20590\nDear Mr. Beam:\nPeoples Natural Gas Company, Division of InterNorth, Inc., operates 1,800 miles of Polyvinyl Chloride (PVC)\npipeline distribution systems. Presently, leak areas are replaced with transitions from PVC plastic to\nPolyethylene plastic rather than being repaired. Replacement methods of repair are costly because they\nrequire that a large area be dug to work within.\nWe are presently considering a repair method which is very similar to the AVON Series Four procedure used to\nrepair leaking cast iron systems as an alternative to replacement of pipeline. A reusable mold would be fitted\naround the leaking PVC fitting and injected with a two-part epoxy mixture and a heat-absorbing material to\nprevent the PVC from overheating. With this encapsulation method, only a small area would be needed to\nwork within, thus substantially reducing our repair expenses.\nEnclosed for your information, are several hand sketches which I drew demonstrating the encapsulation\nmethod. In addition, I have enclosed two photographs of a portion of pipeline which had to be replaced in\nArlington, Iowa. The intersection, parking, and yard had to be dug up in order to install stopping units before\ntwo leaking 1 1/2\" tees could be replaced. Utilizing the encapsulation method, the intersection would be kept\nin service except for a bell hole which would be needed to clean the leaking joints and to place the mold\naround the pipe.\nSection 192.311, Repair of Plastic Pipe, states: \"Each imperfection or damage that would impair the\nserviceability of plastic pipe must be repaired by a patching saddle or removed.\" We are interested in knowing\nwhether this PVC encapsulation method is the equivalent of patching saddle.\nYour prompt response will be greatly appreciated.\nVery truly yours,\nTom Reifschneider\nPEOPLES ENGINEERING\nSupervisor of Standards","truncated":false,"body_characters":6694}