{"operation":"document","citation":"PI-92-038","title":"Memo: Internal — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1992-08-12","effective_on":null,"summary":"PI-92-038 response to Memo: Internal concerning 192.121, 192.273.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-92-038.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-92-038.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-92-038","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1992/PI92038.pdf","body":"<<<PAGE 1>>>\n\nAugust 12, 1992\nINFORMATION: Plastic Pipe\nCesar De Leon\nDirector, Regulatory Programs, DPS-10\nRichard E. Sanders\nManager, Pipeline Safety Division, DMA-607\nThis memo responds to your list of concerns, dated November 16, 1991, about plastic pipe,\nstemming from discussions at TSI seminars, pipeline safety inspections, and pipeline accidents.\n1. 2. 3. Section 1, issue 1, (Present Part 192 Code Sections ... Where Temperatures Will Not Go\nBelow -20° F or Above 140° F) and Section 6, (Pressure Testing of Polyethylene Systems),\nof your memo expressed concerns over existing temperature limits for design and testing\nof plastic pipe. As you know, 49 CFR 192.123, Design limitations for plastic pipe, sets a\nminimum operating temperature in plastic pipe at -20° F, and 49 CFR 192.513 limits the\ntemperature of thermoplastic material during pipeline tests to a maximum of 100° F.\nWe agree with your recommendations concerning the need to relax the regulations to\nreflect advancements in technology of polyethylene piping. We are currently developing a\nNotice of Proposed Rulemaking to address these issues.\nSection 1, issue 2, expressed a concern over the need to derate plastic pipe whose\ntemperature exceeds 73° F to be commensurate with the design formula for that\ntemperature. We agree that unless the pipe in your example was qualified for use above\n73° F, its MAOP could not be set at 60 psig.\nIn Section 2, (qualification Procedures in § 192.283), you expressed concern over §\n192.283(a)(1)(i) which governs the qualification of procedures for joining polyethylene\npipe. This Section references ASTM D2513, 1987 edition, which does not identify fiber\nstress amounts for polyethylene pipe when conducting an acceptable quick burst test.\nWe intend to address this issue through staff participation on the ASTM D2513\ncommittee. Meanwhile, we have issued an interpretation on the issue. (See attached letter\nto Glen Smith.)\nDB\nC:\\WP51\\INTERPRT\\192\\121\\92-08-12\n1\n\n<<<PAGE 2>>>\n\n4. 5. 6. Additionally, in Section 2, you recommended that an organization, such as PPI, undertake\nresponsibility for receiving and reviewing all joining procedures, and publishing all\nqualified joining procedures. Although we see some potential benefit to such action, we\ndo not think it's necessary for RSPA to take the lead in bringing it about.\nIn Section 3, (Maintenance of Equipment Used to Join Plastic Pipe), you identified the\nneed for equipment specifications and maintenance requirements regarding permissible\ntolerances in the operation of equipment used to join plastic pipe.\nWe agree with your concerns about the use of proper equipment. However, we think a\nrequirement to use such equipment is implicit in existing standards under § 192.273 and §\n192.283, which govern plastic pipe joining. Equipment that is in obviously poor condition\nprobably would not be able to produce the requisite joints.\nSection 4, (Qualification of Persons to Join Plastic Pipe), expressed the need for\nclarification of 49 CFR 192.285(c). This rule requires persons to be requalified if, during\nany 12 month period, (1) the person does not make any joints under a given procedure; or\n(2) 3 joints or 3 percent of the joints made, whichever is greater, are found unacceptable\nby testing under § 192.513.\nUpon review of this regulation, we find that it does not require an operator to review a\nperson's joining performance based on a running 12-month period. In other words, each\nnew day does not mark the end of another 12-month period requiring another review.\nrather, in cases where a person is qualified or requalified to join plastic pipe, the 12-month\nperiod would begin at the time of the qualification.\nIn Section 5, (NFPA Standard 58), you indicated that there sometimes arises confusion\nover which requirements take precedence, NFPA 58 or the Part 192 regulations. You said\nthe NFPA code, referenced in § 192.11, permits only butt or socket fusion for\npolyethylene pipe; whereas, the Part 192 regulations, otherwise, permit mechanical\nfittings.\nNFPA 58 expressly prohibits the use of mechanical fittings on certain pipe in petroleum\ngas systems. The use of mechanical fittings on all gas systems is allowed under Subpart F,\n\"Joining of Material Other Than by Welding.\" We are aware that some operators view\nthis as a conflict. Thus, we are presently evaluating the issue as part of our regulatory\nreview process and hope the review will resolve this matter.\nLastly, you indicated that NFPA requires all plastic materials used in LP gas systems to be\nregistered with NFPA. A review of the 1979 edition of NFPA 58, adopted by our\nregulations, and our subsequent conversations with NFPA, regarding interpretation,\nconfirm your assertions. At present, this NFPA requirement cannot be satisfied because\nDB\nC:\\WP51\\INTERPRT\\192\\121\\92-08-12\n2\n\n<<<PAGE 3>>>\n\n7. 8. 9. there exists no listed authorities for use of polyethylene plastic pipe. Consequently, NFPA\nhas amended the standard to eliminate this requirement from the 1992 edition of NFPA\n58, and we have begun effort within DOT to reference this latter edition in our\nregulations.\nSection 7, Plastic Casings, raises a concern over the use of plastic casings with steel\ncarrier pipe. The plastic casing would act as a high dielectric materials, thus not\npermitting cathodic protection currents to be driven through the casing to the carrier pipe.\nIf a pipeline does not have an adequate level of cathodic protection because of shielding by\na pipe casing, the operator must remove the casing or modify the cathodic protection\nsystem to provide the required level of protection. We believe this interpretation is clear\nunder the Part 192 corrosion control rules.\nSection 8, Use of Plastic Pipe for Temporary Bypass During Emergencies and\nMaintenance, expressed concerns over existing regulations (§ 192.321) which prohibit the\nuse of aboveground plastic pipelines. The regulations prohibit the use of aboveground\nplastic pipelines for any reason, including temporary applications needed for quick\nresponses to emergencies and maintenance problems.\nWe agree with you concerns, and we are currently developing a Notice of Proposed\nRulemaking to address this issue.\nSection 9, Material Not Covered Under Present DOT Code or Industry Standards,\nindicated that no industry standards exist for nylon or composite plastic materials. You\nsuggested that standards or procedures be established which would parallel existing\nstandards or procedures for other plastic material.\nAs you know, Subpart B-Materials of Part 192 of the DOT Pipeline Safety Regulations\nprescribes minimum requirements for the selection and qualification of pipes used in\nnatural gas pipelines. It requires that all pipe be manufactured in accordance with a listed\nspecification. For plastic pipe, ASTM D2413 and ASTM D2517 are two such listed\nstandards for manufacture and use of thermoplastic and thermosetting plastic pipe in\nfederally regulated gas pipelines. No other standards are listed for plastic pipe use, and\nneither ASTM D2413 nor ASTM D2517 incorporate nylon or composite plastics into the\nstandards. Thus, nylon or composite plastic pipe may not be used in federally regulated\ngas pipelines. We assume, however, that standards comparable to thermoplastic and\nthermosetting materials will be developed with sufficient economic or industrial demand.\nWe would then consider amending Part 192 to reflect these changes.\nYour continued support for this office is very much appreciated.\nDB\nC:\\WP51\\INTERPRT\\192\\121\\92-08-12\n3\n\n<<<PAGE 4>>>\n\nAttachment\nDB\nC:\\WP51\\INTERPRT\\192\\121\\92-08-12\n4","truncated":false,"body_characters":7597}