| class 1 | class 2 | class 3 | class 4 |
Water penetration resistance
| ≥ 8000 Pa | ≥ 8000 Pa | ≥ 13.000 Pa | ≥ 20.000 Pa |
1 Pa corresponds approximately to 0.1 mm water column. Some manufacturers of rain protective clothing significantly exceed this value and therefore often specify the water column (in addition to the class). It is not unusual, for example, for a 10,000 mm or 20,000 mm water column to be advertised. These values clearly exceed the minimum requirement of EN 343 and are an indication of maximum waterproofness.
Water vapour transmission resistance (breathability/ret value):
First a short explanation of the "Ret-value "(Resistance to Evaporating Heat Transfer). The Ret value defines the resistance that a fabric offers to water vapour. It is therefore used as a unit of measurement for breathability. In practice, this means: the lower the Ret value, the more breathable the material.
The following applies to water vapour transmission resistance:
| class 1 | class 2 | class 3 | class 4 |
Water vapour transmission resistance | Ret > 40 | 25 < Ret < 40 | 15 < Ret < 25 | Ret ≤ 15 |
R = Finished garment tested in the rain tower (optional).
If the garment has not been tested, "R" is replaced by "X".