Thermal resistivity of armour bedding

Typical values for different materials are listed below.

Values are taken from IEC 60287-2-1 Ed.2.0 with following additions or deviations:

• For Natural Rubber (NR) the value was taken from matweb.com (value for Rubber acc. IEC is 5.0)
• The value for fibrous polyolefin copolymer (fPOC) is taken from the book 'Handbook of Polyolefins' by C. Vasile (2000)
• The value for fibrous polypropylene (fPP) is taken from Table 1 Thermal conductivity of various fibres (Hearle and Morton, 2008) whereas the IEC 60287-2-1 Ed.2.0 suggests a slightly higher value.
• The value for fibrous polyethylene (fPE) and polyvinyl chloride (fPVC) is considered to be twice the value used for insulation.
• The value for the water-blocking tapes is an approximative mean value based on different sources

Note: The value is the average of the thermal resistivities of 1st and 2nd armour bedding layer weighted by their thicknesses.

Symbol
$\rho_{ab}$
Unit
K.m/W
Formulae
$\frac{\rho_{ab,1} t_{ab,1}+\rho_{ab,2} t_{ab,2}}{t_{ab}}$
Related
$\rho_{ab,1}$
$\rho_{ab,2}$
$t_{ab}$
$t_{ab,1}$
$t_{ab,2}$
Used in
$T_2$
$T_{ab}$
Choices
MaterialValue
PE3.5
PVC5.0 (U_n <= 3kV)
6.0 (U_n > 3kV)
EPR3.5 (U_n <= 3kV)
5.0 (U_n > 3kV)
POC5.0
IIR5.0
NR7.0
PP5.0
SiR5.0
CR5.5
CSM9.1
CJ6.0
RSP6.0
BIT6.0
fPOC6.6
fPP9.0
fPE7.0
fPVC12.0
tape6.0