Generic Saddle Fusion Joining Procedure for Polyethylene Gas Piping
|Publication Date:||1 January 2018|
The program undertaken by the PPI Task Group for the testing of representative materials under a generic set of conditions was designed to reflect the fusion conditions and parameters specified in most joining procedures recommended by pipe producers and qualified by pipeline operators. It produced a PPI Technical Report (TR-33/99) that reflects a Generic Butt Fusion Procedure that most of the Polyethylene Gas Pipe manufacturer's recommend. At the conclusion of the butt fusion phase of the program, the task group started its testing to develop a Generic Saddle Fusion Procedure that is based on common interfacial pressures and heater adapter surface temperatures. In anticipation of a change in the Maximum Allowable Operating Pressure (MAOP) and the design factor from .32 to .40, it was felt that this procedure was needed to insure safety in saddle fusion on live gas mains. It was intended to provide a technical basis for the development of a proposed generic saddle fusion procedure (see Appendix A) that can be offered to the industry for use with selected PE piping products. The procedure would be available for use by pipeline operators who would determine whether the procedure is appropriate for their use with the PE piping products they employ. Pipeline operators may consider recommendations and testing performed by others in their efforts to comply with the fusion procedure qualification requirements of 49 C.F.R. § Part 192.283 (Plastic pipe; qualifying joining procedures).
It is important to emphasize that the testing performed by the PPI Task Group was intended only to establish a technical basis for developing and proposing a generic fusion joining procedure that may be qualified and used by pipeline operators with a broad range of PE piping products. The testing was not intended to qualify the procedure for use with any particular pipe product, and PPI offers no opinion on whether the procedure is properly qualified for use with any particular PE pipe product. PE pipe producers remain solely responsible for any representations that they may make about the use of this generic procedure or any other joining procedure with their proprietary PE piping products. Pipeline operators remain solely responsible for compliance with the requirements of 49 C.F.R. § Part 192.283 (Plastic pipe; qualifying joining procedures) when qualifying any procedure for use with the products they select for their pipelines.
PPI hopes that the inherent value of greater uniformity will provide an incentive for manufacturers and pipeline operators to evaluate the proposed generic procedure in Appendix A as a first option for saddle fusion joining of PE piping products. Use of this procedure is not mandatory, and each PE pipe producer and pipeline operator retains the option of developing different procedures for its particular products and pipelines. However, PPI believes that its work in developing this procedure will promote the use of effective, qualified procedures for saddle fusion joining of PE pipe.