In a settlement near the Arctic Circle, the air temperature sometimes drops to -70C. The result is a disrupted water supply. They solved the problem by installing a floating pump with a deep suction pipe in the lake. A pipe with a diameter of 12.5 cm that connects the pump to a tank 5 meters away km, we want to insulate with a 5 cm thick layer of polyurethane foam. The water flow in the pipe is 675 L/min. It determines the necessary coefficient of thermal conductivity of the foam to pump water without additional heating temperature 2.5C.