Question - Hot water at 110oC flows in a cast iron pipe (k 52 W/m · oC) whose inner radius is 2.0 cm and thickness is 0.3 cm. The pipe is to be covered with adequate insulation so that the temperature of the outer surface of the insulation does not exceed 30°C when the ambient temperature is 22oC. Taking the heat transfer coefficients inside and outside the pipe to be hi 80 W/m2 · oC and ho 22 W/m2 · oC, respectively, determine the thickness of fiber glass insulation (k 0.038 W/m · oC) that needs to be installed on the pipe.