The executive standard of polyurethane prefabricated directly buried thermal insulation pipe is GB/T29047-2012 national standard for high-density polyethylene outer protective pipe, rigid polyurethane foam plastic prefabricated directly buried thermal insulation pipe and pipe fittings, which is applicable to hot water with long-term operating temperature of transmission medium not higher than 120 ℃ and occasional peak not higher than 140 degrees centigrade.