167. Nonmetallic piping must meet the requirements of any of standards ULC/ORD-C107.7-1993 Glass-Fibre Reinforced Plastic Pipe and Fittings for Flammable and Combustible Liquids, ULC/ORD-C107.4-1992 Ducted Flexible Underground Piping Systems for Flammable and Combustible Liquids and ULC/ORD-C971-2005 Nonmetallic Underground Piping for Flammable and Combustible Liquids, published by Underwriters’ Laboratories of Canada. Piping that meets the requirements of ULC/ORD Standard C971-2005 Nonmetallic Underground Piping for Flammable and Combustible Liquids must also be installed so that there are no joints in the ground.