Heat Loss from an Uninsulated Surface to Air.

Ta (air temperature, deg F)
Ts (surface temperature, deg F)
ε (emissivity of the pipe)
do (pipe diameter outside, in)
L (pipe length, ft)
c (specific heat of air, BTU per hr lb per deg F)
v (wind velocity, mi per hr)
ρ (density of air, lb per ft3)