Additional information and details on mechanical couplings are provided in Chapter 9 of the Plastic Pipe Institute (PPI) Handbook of Polyethylene Pipe.

Flexible Restraint

A PE pipe may be connected to a bell end of a DI or PVC pipe using a flex restraint section on the PE pipe, typically including a stiffener within the PE pipe end. These flex restraint pieces are electro-fused to the PE pipe to achieve the proper stab depth in the PVC or DI bell and the restraint harness plate is attached behind them. The opposite end of the restraint harness is attached behind the DI/PVC hub. For a non-bell end on the DI or PVC pipe, PE bell adapters are available, up to 24" IPS, that are machined to the standard MJ adapter internal configurations and have an external stainless steel backup ring installed to ensure positive seal contact. This connection incorporates a back- up flange behind the PE adapter and a MegaLug flange on the PVC or DI pipe.

(a) PE Connection to DI/PVC Bell Using Flex Restraints on the PE Pipe and (b) Use of PE Bell Adapter to Connect to DI or to PVC Pipe End