water heater that has water at 55°C. The rage temperature is the inner and outer , respectively. The 219 CHAPTER 3 the temperature rise of water to 0.25°C, determine the required thickness of the insulation. 3-81 Steam at 230°C is flowing through a steel pipe (k-15.1 W/m-°C) whose inner and outer diameters are 9 cm. and 10 cm, respectively, in an environment at 13°C. The pipe is insulated with 5-cm-thick fiberglass insulation (k = 0.035 W/m-°C). If the heat transfer coefficients on the inside and the outside of the pipe are 170 and 30 W/m²-"C, respectively, determine the rate of heat loss from the steam per meter length of the pipe. What is the error involved in neglecting the ther- mal resistance of the steel pipe in calculations? 3-82 Hot water at an average temperature of 70°C is flowing