Astandard schedule 40, 2-in. steel pipe (inside diameter 2.067 in., and wall thickness 0.154 in.) carrying steam is insulated with 2 in. of 85% magnesia covered in turn with 2 in. of cork.
estimate the heat loss per hour per foot of pipe if the inner surface of the pipe is at 250°f and the outer surface of the cork is at 90°f. the thermal conductivities (in btu∕hr * ft * °f) of the substances concerned are:
steel, 26.1; 85% magnesia, 0.04; cork, 0.03