There is a steam pipe with a 10mm thick thermal insulation coating on a steel pipe with an outer diameter of 45mm. The temperature of the pipe wall and the surface temperature of the film are measured and are 170℃ and 20℃, respectively. The thermal conductivity of the insulation film is 0.25 [BTU/m-min "F]. Find the heat loss per 1m of pipe length. (However, the thermal resistance of steel is ignored.)