17 Thermoplastic Pipe and Fittings Lined with Polyurethane Elastomer, Pipe and Fittings Made of Solid Polyurethane Elastomer, Pipe and Fittings Made of Polyurethane Elastomer Reinforced with Synthetic Fibers, Pipe and Fittings Made of Polyurethane Elastomer and Overlaid with Fiberglass Reinforced Epoxy and/or Polyester and/or Other Thermoset Plastic Resins