Chapter 8, Problem 8.71P

A $\text{5}0-\text{mm}$ -diameter, thin—walled metal pipe covered with a $25-\text{mm}$ -thick layer of insulation $\left(0.085\text{W/m}.\text{K}\right)$ and carrying superheated steam at atmospheric pressure is suspended from the ceiling of a large room. The steam temperature entering the pipe is $\text{12}0°\text{C}$ , and the air temperature is $\text{2}0°\text{C}$ . The convection heat transfer coefficient on the outer surface of the covered pipe is $10{\text{W/m}}^2.\text{K}$ . It the velocity of the steam is $\text{1}0\text{ m}/\text{s}$ . at what point along the pipe will the steam begin condensing?