Comparison and analysis of thermal insulation materials and thickness of heating pipeline in utility tunnel

For ensuring the heat loss of heating pipeline in utility tunnel less than the prefabricated directly buried insulating pipeline, proposes a concept of equivalent thickness of insulation layer. Through the calculation and analysis of different thermal insulation materials and their thicknesses, concludes that when the heating pipeline adopts the thermal insulation material with the heat conduction coefficient not greater than that of the flame retardant rigid polyurethane, the heat loss at the economic insulation thickness is greater than that at the equivalent insulation thickness. Whereas when the heat conduction coefficient of insulation material is greater than that of the flame retardant rigid polyurethane, the calculation method of economic insulation thickness is suitable. The flame-retardant rigid polyurethane outer galvanized iron sheet is suitable as insulation material for heating pipeline in utility tunnel.