Resistance to water penetration is the most important quality for an adequate protection. The resistance to water penetration is expressed in Pa.
The classification of the products is done as per the below table :
|Specimen to be tested||Class 1||Class 2||Class 3|
|Before Pre-treatment||≥ 8000 Pa||no test required*||no test required*|
|After Pre-treatment||no test required||≥ 8000 Pa||≥ 13000 Pa|
|Seams before Pre-treatment||≥ 8000 Pa||≥ 8000 Pa||≥ 13000 Pa|
|*no test required because the worst case situation case for Class 2 and 3 is after Pre-treatment|
Also referred to as the Breathing property of the clothing, Ret of all layers of the garment shall be in accordance to the below table.
|Class 1||Class 2||Class 3|
|Water Vapour Resistance||Ret > 40||20 < Ret ≤ 40||Ret ≤ 20|