Covers pipes and fittings for use in gas mains and services for direct burial and reliner applications, for use with natural gas, LP gas, and air and LP gas mixtures. Three types of pipe are provided for: Type 1, Unmodified UPVC, Class 100; type 2, Modified (improved impact) UPVC, Class 100 (for use with pressures up to 100 kPa and temperatures of 40 degrees C), and Type 3, Modified (high ductility) UPVC, Class 100 and 450 (for use with pressure up to 100 kPa for Class 450 and temperature of 40 degrees C). Dimensions and performance requirements are specified.