Chilled water enters a thin-shelled 5-cm-diameter, 150-m long pipe at 7°C at a rate of 0.98 kg/s and leaves at 8°C. The pipe is exposed to ambient air at 30°C with a heat transfer coefficient of 9 W/m2·°C. If the pipe is to be insulated with glass wool insulation (k = 0.05 W/m·°C) in order to decrease the temperature rise of water to 0.25°C, determine the required thickness of the insulation