Reinforced Thermoplastic Pipe (RTP) RTP(Reinforced Thermoplastic Pipe) is a high pressure plastic pipe system. Reinforced Thermoplastic Pipe (RTP)Products structure:RTP(Reinforced Thermoplastic Pipe) is a high pressure plastic pipe ... coating of balck for underground use.Three types of reinforced material: Aramid fiber, Polyester or steel wire. ... , 4, 4.5, 5, 5.5, 6 Reinforced Thermoplastic Pipe (RTP)