FIELD: construction of pipelines; applicable in heat insulation and waterproofing of pipes of heating systems with their underground trenchless laying. SUBSTANCE: method includes installation of pipe into waterproofing polyethylene shell, shell sealing and application to pipe of liquid heat-insulating composition, its foaming and hardening. Internal surface of polyethylene shell is treated with spark discharge at 28,000 V during extrusion. Steel pipe external surface is treated by shot blasting machine for producing the required roughness. Heat-insulating polyurethane foam composition is prepared by mixing of polyol component and polyisocyanate in ratio of 1:1.53-1.67. Weight of composition for filling of interpipe space is calculated by formula P = V x J x K, where P is calculated weight of polyurethane foam composition, kg; V is volume of interpipe space, cu.m; J is calculated apparent density of polyurethane foam, kg/cu.m; K is foam excess coefficient. Duration of filling of isolated volume is determined by calculated weight of composition. EFFECT: higher quality of pipe structure and improved adhesion of insulating layer to polyethylene shell.
