Question: A standard 1 in. Schedule 40 iron pipe carries saturated steam at 250°F. The pipe is lagged (insulated) with a 2-in. layer of 85 percent magnesia, and outside this magnesia layer there is a 3-in. layer of cork.
The inside temperature of the pipe wall is 249OF, and the outside temperature of the cork is 90°F. Calculate
(a) the rate of heat loss from 100 ft of pipe, in Btuh, and
(b) the temperatures at the boundary between metal and magnesia and between magnesia and cork.