Dismantling joints when used on PE pipe spigots MUST have wide flat seals or lip seals. O-rings or circular compression seals must not be used on PE spigots as they create a pressure ridge on the surface of the PE spigot over time, leading to leakage.
Use of restrained mechanical joints such as Hawle system 2000 are NOT recommended as dismantling joints, as the restraint system grips the spigots surface, damaging the spigot and limiting the times the joint can be dismantled and re-seal successfully.
Mill-Pro recommends 316 Stainless steel dismantling joints to provide equivalent maintenance free performance to the PE pipe
Some examples are AVK - Wang Vari-gib type Spigot and flanged dismantling joints:
Wang Vari-gib Dismantling Joints - Spigot
Wang Vari-gib Dismantling Joints - Flanged