A pipe consists of 100 mm internal diameter and 8 mm thickness carries steam at 170C. The convective heat transfer coefficient on the inner surface of pipe is 75 W/m2C. The pipe is insulated by two layers of insulation. The first layer of insulation is 46 mm in thickness having thermal conductivity of 0.14 W/mC. The second layer of insulation is also 46 mm in thickness having thermal conductivity of 0.46 W/mC. Ambient air temperature = 33C. The convective heat transfer coefficient from the outer surface of pipe = 12 W/m2C. Thermal conductivity of steam pipe = 46 W/mC. Calculate the heat loss per unit length of pipe and determine the interface temperatures. Suggest the materials used for insulation.