A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m².°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be

• A. Equal to that of the uninsulated steam pipe
• B. Less than that of the uninsulated steam pipe
• C. Less than the steam pipe with 5 cms insulation
• D. Greater than that for uninsulated steam pipe

Answer: (B)