Design Guide for Hazardous / Industrial
Self-regulating trace heating systems
21-5400-7D0001/-
05/2023-EHT-466854
Notice Technical data subject to change without notice.
No claims for damage arising from alternations, errors or misprints shall be allowed.
Page 10 / 40
Finally. you must apply the following correction factors depending on your insulation material:
Table B: Insulation Correction Factors
Correction Factor*
thermal conductivity at 20 °C
in W/m
×
K
Insulation
material
Rockwool / Mineral Fibre (ASTM C547-15 Type II)
1.00
0.0370
Calcium Silicate (ASTM C533 Type I)
1.47
0.0567
Cellular glass (ASTM C552-15 Type II)
1.46
0.0481
Rigid cellular urethane (ASTM C591-13 Type I)
0.83
0.0275
Foamed elastomer Grade 2 (ASTM C534-14)
1.29
0.0425
Expanded perlite (ASTM C610-15)
2.06
0.0678
Pyrogel XT (ASTM C1728-12)
0.56
0.0206
→ Example
Pipe diameter: DN25
Insulation thickness: 20 mm
Insulation material: calcium silicate
Minimum ambient temperature: -20 °C
Maintain temperature: 25 °C
We obtain the basic heat loss in W/m from Table A on page 9:
Now. the correction factors from Table B must be checked and. if necessary. applied:
The effective heat loss of the setup is determined as follows:
effective heat loss = basic heat loss
×
correction factor insulation
= 13.9 W/m
× 1.47
= 20.4 W/m
correction factor insulation: 1.47
ΔT = 25 °C - (-20 °C) = 45 °C
}
basic heat loss: 13.9 W/m
