Thermal resistance of insulation

Symbol
$T_{ins}$
Unit
K.m/W
Formulae
$\frac{\rho_i}{2\pi} \ln\left(\frac{D_{ins}}{D_{ins}-2t_{ins}}\right)$cable
$\frac{1}{2k_{ins} \pi} \ln\left(\frac{D_{ins}}{do_{pipe}}\right)$heat source
Used in
$U_{wall}$
OHTC of pipe wall [W/(K.m$^2$)]