3-in S40 pipe (O.D. = 3.5 in.) is insulated with 2-in thickness of insulation having a mean thermal conductivity of 0.050 and a 1.25-in thickness of insulation having a mean thermal conductivity of...

3-in S40 pipe (O.D. = 3.5 in.) is insulated with 2-in thickness of insulation having a mean thermal conductivity of 0.050 and a 1.25-in thickness of insulation having a mean thermal conductivity of 0.037. If the temperature of the outer surface of the piper is 670°F and the temperature of the surface of the outer insulation is 100°F, calculate the heat loss in Btu per hr-ft of pipe.