Transition from Plastic to Other Materials

Transition from plastic to other materials sometimes becomes unavoidable. Depending on the situation, the transition can be made using flanges, threaded fittings or unions. The following are just a few helpful points to remember when making such a transition.

  • Flange connections are limited to 150 psi.
  • Threaded connections are limited to 50% of the rated pressure of the pipe.
  • When mating to a threaded metal piping system, it is recommended that a plastic male thread be joined to the metal female thread. Since the two materials have different co-efficient of expansion, the plastic male fitting will actually become tighter within the female metal fitting when expansion occurs.

Westlake Pipe & Fittings has Schedule 40 and/or Schedule 80 threaded couplings, nipples, unions, male and female threaded adapters and 150 psi rated flanges for effecting these transitions.