Chilled water enters a thin shelled 4 cm diameter, 200 m long pipe at 7 deg. Celsius at a rate of 0.98 kg/sec and leaves at 8 deg. Celsius. The pipe is exposed to an ambient air at 30 deg. Celsius with a heat transfer coefficient of 9 W/m^2*K. If the pipe is to be insulated with glass wool insulation (k=0.05 W/m*K) in order to decrease the temperature rise of water to 0.25 deg. Celsius, determine the required thickness of insulation.