Cableizer

Thermal resistivity armour bedding

Typical values for different materials are listed below.

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

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
Formulas
$\frac{\rho_{ab,1} t_{ab,1}+\rho_{ab,2} t_{ab,2}}{t_{ab}}$
Related
$M_{ab}$
Armour bedding material
$\rho_{ab,1}$
Thermal resistivity armour bedding 1 [K.m/W]
$\rho_{ab,2}$
Thermal resistivity armour bedding 2 [K.m/W]
$t_{ab}$
Thickness armour bedding [mm]
$t_{ab,1}$
Thickness armour bedding 1 [mm]
$t_{ab,2}$
Thickness armour bedding 2 [mm]
Used in
$a_{shj}$
Factor $a_{shj}$ for jacket around each core
$b_{shj}$
Factor $b_{shj}$ for jacket around each core
$c_{shj}$
Factor $c_{shj}$ for jacket around each core
$T_{2}$
Thermal resistance armour bedding [K.m/W]
$T_{ab}$
Thermal resistance armour bedding [K.m/W]
Choices
CodeValueMaterialReference
PE3.5Polyethylene (LD/MDPE, ST3)IEC 60287-2-1
PVC5.0 (U_n <= 30kV)
6.0 (U_n > 30kV)
Polyvinyl chloride (PVC, ST1/2)IEC 60287-2-1
EPR3.5 (U_n <= 30kV)
5.0 (U_n > 30kV)
Ethylene-propylene rubber (EPR)IEC 60287-2-1
POC3.5Polyolefin copolymer (POC)= PE
IIR5.0Butyl rubber (IIR isobutylene isoprene rubber)IEC 60287-2-1
NR7.0Natural rubber (NR)matweb.com
PP5.9Polypropylene (PP)Polypropylene - The Definitive User's Guide and Databook
SiR5.0Silicone rubber (SiR)shinetsusilicone-global.com
CR5.5Polychloroprene (CR, Neoprene)IEC 60287-2-1
CSM9.1Chlorosulphonated polyethylene (Hypalon)IEC 60287-2-1
CJ6.0Compounded juteIEC 60287-2-1
RSP6.0Rubber sandwich protectionIEC 60287-2-1
BIT6.0PVC/bitumen tapesIEC 60287-2-1
fPOC6.6fibrous (Polyolefin copolymer)Handbook of Polyolefins
fPP9.0fibrous (Polypropylene)Hearle and Morton 2008
fPE7.0fibrous (Polyethylene)2 x PE
fPVC12.0fibrous (Polyvinyl chloride)2 x PVC
tape6.0tapemix
Ot10.0Otherfibrous polypropylene, IEC 60287-2-1