According to IEC, the losses in ferromagnetic steel pipes are part of the armour losses $W_A$ for pipe-type cables. We consider them with a separate loss-factor for cables in a common pipe.

Symbol
$W_{\mathrm{p}}$
Unit
W/m
Formulae
$W_{\mathrm{c}} \lambda_{\mathrm{3}}$
Related
$\lambda_{\mathrm{3}}$
$W_{\mathrm{c}}$
Used in
$F_{\mathrm{out}}$
$W_{\mathrm{t}}$