$\dot{Q}=10 \times \pi \times 0.08 \times 5 \times (150-20)=3719W$
Assuming $h=10W/m^{2}K$,
$\dot{Q} {cond}=\dot{m} {air}c_{p,air}(T_{air}-T_{skin})$
The heat transfer due to radiation is given by:
The heat transfer from the not insulated pipe is given by: