Aidtherm 716 is a mixture of polyether polyol, water, stabilizers, accelerators, etc., mixed with polymer MDI in a ratio of 1:1, and then poured into the cavity between the steel pipe and the outer protective tube to form rigid polyurethane Foam. The system is developed for the thermal insulation of regional heating pipelines and land oil pipelines with a temperature resistance of not more than 100 degrees.