Thermal resistivity of filler

The IEC 60287 does not list materials for filler but states: depending on the filler material and its compaction, the thermal resistivity is in the range 6 to 13 K.m/W for cables with extruded insulation, 10 K.m/W is suggested for fibrous polypropylene.

Following values are taken from IEC 60287-2-1 Ed.2.0 for insulation or jacket with following additions:

Symbol
$\rho_{f}$
Unit
K.m/W
Related
$M_{f}$
Choices
MaterialValue
fPOC6.6
fPP9.0
fPE7.0
fPVC12.0
sPVC6.0
sPE3.5
PRod8.0
PTube12.0
TY5.3
Jute6.0
tape6.0
Air38.2
Ot10.0