Insulated steam lines in power plants are lagged to protect the insulation from damage to prevent absortion of moistuire into the insolation. Cavas cloth or thin aluminum sheet is currently used. The aluminum is typically 1.5 mm thick, whereas the cloth may be 1.5 to 3 mm thick. Use aluminum, with its lower emittance, reduces the heat loss but increases the surface temperature by 5 to 15C . To avoit skin burns, it is recomended that maximun safe lagging surface temperatures are 40C for metalic jackets and 60C for cavas jackets. A 36 cm-0.D., 7 cm wall-thickness steel steam line is insulated with a 10 cm thickness of calcium cilicate. The steam temperature is 560C, and the ambient temperature is 26C. The inside convective resistence is negligible and the outside convective heat transfer coeficient can be taken as 10 W/m K. a) Calculate the rate of heat loss per meter and surface temperature for a 1.5 mm-thick aluminum sheet lagging. b) Calculate the rate of heat loss per meter and surface temperature for a 3 mm-thick cavas lagging. Take = 0.9 for cavas. c) If aluminum is painted with an oil-based paint with a emittance of 0.9 calculate the increase in heat loss and the reduction in surface tempearure. %3D Use e = 0.1 for the aluminum, k 0.04 W/m K for cavas, and k 0.085 W/m K for calsilite insulation.