Heat Transfer - Calculate daily rate of heat transfer and the temperature on the outside surface

Superheated steam at an average temperature 200°C is transported through a steel pipe (k = 50 W/m·K, Do = 8.0 cm, Di= 6.0 cm, and L = 20.0 m). The pipe is insulated with a 4-cm thick layer of gypsum plaster (k = 0.5 W/m·K). The insulated pipe is placed horizontally inside a warehouse where the average air temperature is 10°C. The steam and the air heat transfer coefficients are estimated to be 800 and 200 W/m2·K, respectively. Calculate (a) the daily rate of heat transfer from the superheated steam, and (b) the temperature on the outside surface of the gypsum plaster insulation. answer (15957 W, 17.9°C)