The outside surface temperature of a pipe (radius -0.1m) is 400K. The pipe is losing heat to atmospheric, which is at 300K. The film heat transfer coefficient is 10 W/m2K. To reduce the rate of heat loss, the pipe is insulated by a 50 mm thick layer of asbestos (K= 0.5 W /mK) .

Calculate the percentage reduction in the rate of heat loss.