Thermal resistance of armour bedding

Symbol
$T_{ab}$
Unit
K.m/W
Formulae
$\frac{\rho_{ab}}{2\pi} \ln\left(\frac{D_{ab}}{F_x D_{shj}}\right)$Multi-core cables type SS
$\frac{\rho_{ab}}{2\pi} \ln\left(\frac{D_{ab}}{D_{shj}-\Delta d_{sh}}\right)$otherwise