In a processing plant, cold water at 3°C is pumped through a 20 mm (outside diameter) galvanized steel pipe. The pipe passes through a room where the air temperature can be as high as 30°C and the relative humidity as high as 90%. To prevent condensation on the pipe surface, it is insulated with a sleeve of foam rubber (thermal conductivity of 0.03 W/mK). What thickness of insulation is needed to prevent condensation? Hint: begin by assuming laminar airflow around the pipe.