A gas at 450 K is flowing in a 2-in steel pipe, schedule 40. The pipe is insulated with51 mm of lagging having a mean k=0.0623 W/m/K. The convective heat-transfer coefficient of the gas inside the pipe is 30.7 W/m2/K and the convective coefficient of air on the outside of the lagging is 10.8. The air is at a temperature 300K. Calculate the heat loss per unit length of pipe, and overall heat transfer coefficient based on outside area.
