A4-in. schedule 80 steel pipe (id = 3.826 in., od = 4.5 in.) carries a heat-transfer fluid at 600°f and is covered with a 1/2-in. thick layer of pipe insulation. the pipe is surrounded by air at 80°f. the vendor's literature states that a 1-in. thick layer of the pipe insulation has an r-value of 3. neglecting convective resistances, the resistance of the pipe wall, and thermal radiation, estimate the rate of heat loss from the pipe per foot of length.