Dampness factor u insulation materials used to measure water vapor infiltration capability of the anti-u = § air / § material which breathable air coefficient § (air) = 1.82 * 10 -10 Kg / msPa , Armstrong Rubber and Plastic foam insulation materials, water vapor permeability coefficient § = 4.0 * 10 -10 Kg / msPa. Dampness in the air factor u = 1, Armstrong Rubber and Plastic foam insulation materials wet resistance factor u ≥ 4500.
in the same test under the condition of insulation materials commonly used wet resistance factor u for
|
insulation materials commonly used |
Dampness factor u value |
|
glass wool, rock wool
Aluminum foil (paste glass wool before)
Aluminum foil (after paste glass wool)
Polyethylene (plus former flame retardants)
Polyethylene (plus after flame retardants)
Polystyrene
Polyurethane
Phenolic foam
Other (NBR / PVC)
Other (EPDM)
|
3-5
∞
Numerous pinhole
3000-4000
~ 1000
80
100
150
400
≤ 4000 | Dampness
factor u value the higher the water more difficult to infiltrate into insulation materials, thermal conductivity increased income t slower, longer service life. Foam rubber materials
only as an example:
|
use of t-year |
different u value of thermal conductivity of materials into the t (W/mk) |
|
400 |
1000 |
3500 |
4500 |
7000 |
|
0
2
4
5
6
8
10 |
0.0358
0.0451
0.0543
0.0589
0.0635
0.0727
0.0819 |
0.0358
0.0395
0.0432
0.0451
0.0469
0.0506
0.0543 |
0.0358
0.0369
0.0380
0.0385
0.0390
0.0401
0.0411 |
0.0358
0.0367
0.0375
0.0379
0.0383
0.0391
0.0400 |
0.0358
0.0364
0.0369
0.0372
0.0374
0.0380
0.0385 |
* ambient temperature of 30 ℃, relative humidity of 80 percent, ￠ 219 of chilled water (7 ℃) effective 25mm thick material (the surface coefficient of 9W / m 2 k) when insulation. |
