McElroy Discussion Forums

Is there a maximum amount of time permitted between facing pipes and fusing them?

There are specifications for the amount of time between HEATING and fusing, but NOT between FACING and fusing. Once the pipe ends have been heated (according to the pipe manufacturer’s recommended procedure), you must “Bring melted ends together rapidly”. Rapidly is best defined as ONLY the amount of time required to remove the heater and quickly move the jaws of the fusion machine to bring the ends of the pipe together. This can and should be accomplished in only a few seconds.
The purpose of facing the pipe is to clean and square the ends of the pipe prior to fusing. The facing operation exposes clean material and (when properly done) removes any cuts or gouges caused by the rough cut or sawing of the pipe. I am not aware of a procedure that specifies a maximum amount of time between FACING and fusing the pipe ends. However, there is a practical limit. The pipe ends need to be kept clean prior to heating and they will never be any cleaner than when they have been freshly faced. SO, you don’t want the faced ends sitting around collecting dust and dirt while the crew goes off to lunch. If the pipe can’t be fused immediately after facing, then it’s best to re-face.

You can find links to various pipe manufacturers and there recommended procedures at:
http://www.mcelroymfg.com/fusion/solution/links.htm

You might also find helpful the PPI “Generic Butt Fusion Joining Procedure for Polyethylene Gas Pipe” at:
http://www.plasticpipe.org/pubs/downloa ... r33-01.pdf

While there is no given time between facing pipe and fusing the pipe ends, it should be done in a reasonable period of time, especially in larger sizes.
Large diameter PE pipe has a tendancy to "neck down" on the ends after they are cut (due to the hoop stress) alignment of the pipe ends will be easier to achieve if the ends are fused soon after they are faced.