The absorption coefficient of solar radiation for the cable surface is used to calculate the temperature rise due to solar radiation.
The coefficient is material-dependant, typical values are given in standard IEC 60287-1-1 for different cable jacket materials and in standard IEC 60287-2-1 for different duct materials.
No reference values were found for Polypropylene (PP), Silicone rubber (SiR) and Chlorosulphonated polyethylene (CSM) and they are assumed to be similar to PVC.
| Code | Cable | Duct | Tray | Material |
|---|---|---|---|---|
| PE | 0.4 | 0.4 | 0.4 | Polyethylene (LD/MDPE, ST3) |
| HDPE | 0.4 | 0.4 | - | High density polyethylene (HDPE, ST7) |
| XLPE | 0.4 | 0.4 | - | Crosslinked polyethylene (XLPE) |
| PVC | 0.6 | 0.6 | 0.6 | Polyvinyl chloride (PVC, ST1/2) |
| PP | 0.6 | 0.6 | - | Polypropylene (PP) |
| PPY | 0.6 | 0.6 | - | Polypropylene yarn (PP) |
| FRNC | 0.8 | 0.4 | - | Flame-Retardant Non-Corrosive polyethylene (FRNC) |
| HFS | 0.4 | 0.4 | - | HFS-110-TP (AS/NZS 3808:2000 R2016) |
| POC | 0.6 | - | - | Polyolefin copolymer (POC) |
| SiR | 0.6 | - | - | Silicone rubber (SiR) |
| CR | 0.8 | - | - | Polychloroprene (CR, Neoprene) |
| CSM | 0.6 | - | - | Chlorosulphonated polyethylene (Hypalon) |
| CJ | 0.8 | - | - | Compounded jute |
| RSP | 0.8 | - | - | Rubber sandwich protection |
| BIT | 0.8 | 0.8 | - | PVC/bitumen tapes |
| WPE | - | 0.4 | - | duct made of plastic filled with water |
| Metal | - | 0.2 | - | duct made of steel |
| Alu | - | - | 0.1 | tray made of aluminum |
| StN | - | - | 0.64 | tray made of galvanized steel (new) |
| StW | - | - | 0.8 | tray made of galvanized steel (weathered) |
| Fibre | - | 0.6 | 0.6 | duct made of fibrous material (glass-reinforced plastic, GRP) |
| Cem | - | 0.7 | 0.75 | duct made of cement |
| Earth | - | 0.75 | - | duct made of earthenware (vitrified clay, VCP) |
