Substitution coefficient u

Substitution coefficient for the calculation of the thermal resistance to ambient.

Symbol
$u$
Formulae
$\frac{2 L_{cm}}{D_{o}}$standard case
$\frac{2 L_{cm} + 2 d_{psc}}{D_{o}}$considering point source correction
$\frac{2 L_{cm} + 2 d_{im}}{D_{o}}$considering non-isothermal soil
$\frac{2 L_{cm} + 2 d_{im} + 2 d_{psc}}{D_{o}}$considering point source correction and non-isothermal soil
$\frac{2 L_{deep}}{D_{o}}$considering equivalent depth for deep burial
Related
$d_{im}$
$D_{o}$
$L_{cm}$
Used in
$T_{4iii}$