1、1Generic Saddle FusionJoining Procedure forPolyethylene Gas PipingTR-41/20021825 Connecticut Ave., NW Suite 680 Washington, DC 20009P: 202-462-9607F: 202-462-9779www.plasticpipe.org2FOREWARDThis report was developed and published with the technical help and financialsupport of the members of the PPI
2、 (Plastics Pipe Institute, Inc.). The members haveshown their interest in quality products by assisting independent standards-makingand user organizations in the development of standards, and also by developingreports on an industry-wide basis to help engineers, code officials, specifying groups,and
3、 users.The purpose of this technical report is to provide important information available toPPI on a particular aspect of polyethylene pipe saddle fusion to engineers, users,contractors, code officials, and other interested parties. More detailed information onits purpose and use is provided in the
4、document itself.This report has been prepared by PPI as a service of the industry. The information inthis report is offered in good faith and believed to be accurate at the time of itspreparation, but is offered without any warranty, expressed or implied, includingWARRANTIES OF MERCHANTABILITY AND F
5、ITNESS FOR A PARTICULARPURPOSE. Consult the manufacturer for more detailed information about theparticular joining procedures to be used with its piping products. Any reference to ortesting of a particular proprietary product should not be construed as an endorsementby PPI, which does not endorse th
6、e proprietary products or processes of anymanufacturer. Industry members in fulfilling their own compliance responsibilitiesoffer the information in this report for consideration. PPI assumes no responsibility forcompliance with applicable laws and regulations.PPI intends to revise this report from
7、time to time, in response to comments andsuggestions from users of the report. Please send suggestions of improvements tothe address below. Contacting PPI directly or visiting the web site can obtaininformation on other publications.The Plastics Pipe Institute, Inc.Toll Free: (888) 314-6774http:/www
8、.plasticpipe.orgOctober 20023I. IntroductionIn 1994, representatives of the U.S. Department of Transportation (DOT), Office ofPipeline Safety requested that the Plastics Pipe Institute assist in promoting greateruniformity in the joining procedures utilized by gas utilities in the butt and saddlefus
9、ion of polyethylene (PE) gas piping products. DOT reported that it had encountereda proliferation of similar but slightly varying joining procedures from individual PE pipeproducers. The slight differences in the various procedures made it more difficult forpipeline operators to qualify persons with
10、 appropriate training and experience in theuse of these procedures, and more difficult for DOT to enforce the joiningrequirements in 49 C.F.R. Part 192.285 (Plastic pipe; qualifying persons makingjoints) of the Code of Federal Regulations.In response to DOTs request, PPI established a task group to
11、review the fusionprocedures currently used and develop a more uniform, or “generic” joining procedurethat could be qualified by pipeline operators This joining procedure would bringgreater consistency to this aspect of gas pipeline installation, facilitate the pipelineoperators efforts to qualify th
12、e procedure, reduce costs, and simplify DOTsenforcement duties.II. ScopeThe program undertaken by the PPI Task Group for the testing of representativematerials under a generic set of conditions was designed to reflect the fusionconditions and parameters specified in most joining procedures recommend
13、ed bypipe producers and qualified by pipeline operators. It produced a PPI TechnicalReport (TR-33/99) that reflects a Generic Butt Fusion Procedure that most of thePolyethylene Gas Pipe manufacturers recommend. At the conclusion of the buttfusion phase of the program, the task group started its test
14、ing to develop a GenericSaddle Fusion Procedure that is based on common interfacial pressures and heateradapter surface temperatures. In anticipation of a change in the Maximum AllowableOperating Pressure (MAOP) and the design factor from .32 to .40, it was felt that thisprocedure was needed to insu
15、re safety in saddle fusion on live gas mains. It wasintended to provide a technical basis for the development of a proposed genericsaddle fusion procedure (see Appendix A) that can be offered to the industry for usewith selected PE piping products. The procedure would be available for use bypipeline
16、 operators who would determine whether the procedure is appropriate fortheir use with the PE piping products they employ. Pipeline operators may considerrecommendations and testing performed by others in their efforts to comply with thefusion procedure qualification requirements of 49 C.F.R. Part 19
17、2.283 (Plastic pipe;qualifying joining procedures).4It is important to emphasize that the testing performed by the PPI Task Group wasintended only to establish a technical basis for developing and proposing a genericfusion joining procedure that may be qualified and used by pipeline operators with a
18、broad range of PE piping products. The testing was not intended to qualify theprocedure for use with any particular pipe product, and PPI offers no opinion onwhether the procedure is properly qualified for use with any particular PE pipe product.PE pipe producers remain solely responsible for any re
19、presentations that they maymake about the use of this generic procedure or any other joining procedure with theirproprietary PE piping products. Pipeline operators remain solely responsible forcompliance with the requirements of 49 C.F.R. Part 192.283 (Plastic pipe; qualifyingjoining procedures) whe
20、n qualifying any procedure for use with the products theyselect for their pipelines.PPI hopes that the inherent value of greater uniformity will provide an incentive formanufacturers and pipeline operators to evaluate the proposed generic procedure inAppendix A as a first option for saddle fusion jo
21、ining of PE piping products. Use ofthis procedure is not mandatory, and each PE pipe producer and pipeline operatorretains the option of developing different procedures for its particular products andpipelines. However, PPI believes that its work in developing this procedure willpromote the use of e
22、ffective, qualified procedures for saddle fusion joining of PE pipe.III. Testing Program to Evaluate Use of PPI-Proposed GenericSaddle Fusion Joining Procedure with Polyethylene GasPiping ProductsThe PPI Task Group consisted of representatives from the following equipment, fitting,and pipe manufactu
23、rers: Performance Pipe, Rinker PolyPipe, Central Plastics,Uponor, Charter Plastics, North American Pipe, KWH Pipe, Rahn Plastics, McElroyManufacturing, and T.D. Williamson.The Task Group collected and examined a large number of diverse procedures nowin use by gas pipeline operators or recommended by
24、 pipe producers for specific PEpiping products. It then identified those conditions and fusion parameters that werecommon to the majority of those procedures. The Task Group proposed the followingsaddle fusion parameters as representative of the conditions in the individualprocedures that they revie
25、wed:Heater Adapter Surface Temperature 500 10FInitial Interfacial Pressure 80 PSIHeat Soak Interfacial Pressure 0 PSIFusion Interfacial Pressure 40 PSINote: “Interfacial pressure” is the force per unit area applied between the fitting saddlebase and the main pipe. Most saddle fusion equipment provid
26、es a gauge reading thatis the actual force applied in pounds (Newtons). To determine the applied force for a5particular saddle fitting design, multiply the interfacial pressure by the saddle fittingbase area.From its review of the different procedures collected from PE gas pipe producers, theTask Gr
27、oup further developed the “generic” joining procedure set out in Appendix A,based on its assessment of the common elements in the individual procedures. Itwas agreed that proprietary products such as Uponors Aldyl A MDPE products andPhillips Driscopipes 8000 HDPE piping products (both of which have
28、beendiscontinued) were sufficiently different from the remainder of the materials beingdiscussed that they were not included in the test program. The manufacturers shouldbe contacted for more information on particular joining procedures for those products.Using these proposed parameter ranges and pr
29、ocedures, the Task Group initiated atesting program to evaluate whether a representative cross-section of marketed PEgas piping products would qualify under the qualification requirements of Part 192when joined in accordance with this “generic” joining procedure. The evaluation wasconducted using pi
30、pe and fittings from MDPE and HDPE materials deemed suitablefor fuel gas applications per ASTM D 2513. These materials have a gradedesignation, in accordance with ASTM D3350, of PE24 and PE34, respectively.Grade Density Melt Index Pipe(grams/cc) (grams/10min.) Marking_PE24 .926/.940 .15 to .40 PE240
31、6PE34 .941/.955 .05 to .15 PE3408After saddle fusion of the fittings onto pressurized gas main pipe, destructive testswere conducted in accordance with the requirements of DOT and ASTM. The resultsof the test program are described in the following sections. PPIs Conclusions andRecommendations, based
32、 on the Task Groups work, are noted at the end of thetesting report. Test data are maintained at PPI headquarters.Part 1 - Saddle Fusion and Testing - (Like Materials) By an independent lab.Part 1 of this project was to evaluate the generic procedure for use in fusing PE pipefittings to the same pip
33、e main material (e.g., MDPE to MDPE) using different heatingtimes. An independent lab was used to saddle fuse the samples using theproposed interfacial pressure combinations and different heating times at both 32 Fand 120 F temperature conditions. The following parameters were used to makesamples th
34、at were destructively tested and evaluated by the independent lab tonarrow down the proposed fusion procedure and parameters for saddle fusingdifferent fittings on ASTM D 2513 gas mains. The Task Group members supplied 2“SDR 11 pipe samples and tapping tee fittings for this saddle fusion testing. Al
35、l6fusions were made on pipe mains under 0.40 design factor pressures - that is, MDPE-100 psig and HDPE -125 psig to observe any leakage or blowout problems (Note -the 73F HDB may be used only for temperatures below 100F; for 100F and above,elevated temperature ratings must be used). The Task Group a
36、greed to use thesesame fusion parameters for both the MDPE and HDPE (shown in Appendix A).Approximately (210) saddle fusion joints were made and evaluated by visualinspection, quick burst testing per ASTM D1599, knock off testing per ASTM F905 andSection/bend testing per ASTM D 2657. From this, the
37、task group decided to use thesame parameters shown above and ask each pipe manufacturer to do the next roundof testing by varying the heating times and keeping the heater temperature andinterfacial pressures the same.Part 2 - Saddle Fusion and Testing - (Like Materials) By Pipe ManufacturersPart 2 o
38、f this project was to evaluate the proposed generic saddle fusion procedureon2”IPS main pipe and larger using the same parameters as in Part 1 but varying theheating times. Each pipe manufacturer saddle fused tapping tees onto 2” IPS straightand coiled 2” IPS DR11 main pipe using both serrated and s
39、mooth heater adapters at73F. All fusions were made on pipe mains under 0.40 design factor pressures (thatis, MDPE -100 psig and HDPE -125 psig at 73F) to observe any leakage or blowoutproblems. The Task Group agreed to use these same fusion parameters for both theMDPE and HDPE (shown in Appendix A).
40、 Again, the saddle fusion joints were madeand evaluated by visual inspection, quick burst testing per ASTM D1599, knock offtesting per ASTM F905 and Section/bend testing per ASTM D 2657. The results werevery encouraging the fusion parameters and heating times were narrowed as shownbelow:Heater Adapt
41、er Surface Temperature 500 10 FInitial Interfacial Pressure 60 PSIHeat Soak Interfacial Pressure 0 PSIFusion Interfacial Pressure 30 PSITotal Heating Times 20,30 and 40 seconds(Note: Total heating times include the time required for initial heating and heat soak.During initial heating, the main is o
42、bserved and when an indication of melt is visibleon the crown of the main, the pressure is reduced for the heat soak time. Typically,initial heating takes from 3 to 5 seconds.)Part 3 - Saddle Fusion and Testing - 2“ IPS DR11 (Like Materials)7Part 3 of this project was to evaluate the proposed generi
43、c saddle fusion procedureon2”IPS and larger main pipes using the same parameters from Part 2 and varying theheating times. Each pipe manufacturer saddle fused tapping tees onto 2” IPS straightand coiled 2” IPS DR11 main pipe using both serrated and smooth heater adapters at73F. All fusions were made
44、 on pipe mains under 0.40 design factor pressures (thatis, MDPE -100 psig and HDPE -125 psig at 73F) to observe any leakage or blowoutproblems. The Task Group agreed to use these same fusion parameters for both theMDPE and HDPE (shown in Appendix A). Again, the saddle fusion joints were madeand eval
45、uated by visual inspection, quick burst testing per ASTM D1599, knock offtesting per ASTM F905 and Section/bend testing per ASTM D 2657. The task groupmember reported no failures using a 25-35 second total heating time, 60 psi InitialHeat interfacial pressure and 30 psi Fusion Interfacial Pressure.
46、The Task Grouptherefore decided to do cross fusion testing of HDPE fittings on MDPE mains anddifferent manufacturers fittings on other manufacturers pipe. A test matrix wasdeveloped for (186) samples to be made and tested as in earlier parts.Heater Adapter Surface Temperature 500 10 FPre-Heat Interf
47、acial Pressure 60 PSISoak Interfacial Pressure 0 PSIFusion Interfacial Pressure 30 PSIHeating time 25-35 secondsPart 4 - Saddle Fusion and Testing - (Unlike Materials)Part 4 of this project was to evaluate the proposed generic saddle fusion parametersshown in Part 3 above and the generic saddle fusi
48、on procedure shown in Appendix Aon different combinations of “standard” tapping tee fittings and pipe manufacturerspipe (brands and material types). Each pipe manufacturer saddle fused “standard”tapping tees onto 2” IPS DR11 straight and 2” IPS DR11 coiled main pipe using bothserrated and smooth hea
49、ter adapters at 73F. All fusions were made on pipe mainsunder 0.40 design factor pressures (that is, MDPE -100 psig and HDPE -125 psig at73F) to observe any leakage or blowout problems. The Task Group agreed to usethese same fusion parameters for both the MDPE and HDPE (shown in Appendix A).Again, the saddle fusion joints were made and evaluated by visual inspection, quickburst testing per ASTM D1599, knock off testing per ASTM F905 and Section/bendtesting per ASTM D 2657. Approximately (1
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