Water resistance: The EN ISO 20345:2011 standard featured ‘WRU’ markings for shoes/boots with ‘water-resistant uppers’. However, this did not indicate that the footwear was waterproof as the test requirement is, that no more than 3cm2 of water penetration is allowed. This is because only the upper itself was tested to obtain WRU certification; when the upper is included in a shoe, the shoe as a whole can lose its water-repellent ability because water penetrates into the seams
Under the new 2022 standard, WRU has been replaced by WPA. ‘WPA’ now indicates that footwear can allow for some ‘water penetration and absorption’. WPA footwear offers some breathability and can be used in working conditions that do not require the feet to be submerged in water.
Also, under the new 2022 standard the ‘WR’ (water resistant) marking is the same test for water penetration that is used during the 2011 test, but it is the result that differs. In order to be marked as ‘WR’ the 2022 standard states no water penetration inside the footwear shall be detected where, as above, the 2011 test allows for 3cm cubed of water to penetrate the footwear and therefore, the new WR standard is more stringent. To help equate one standard to another, a previous S2 model with WR has now become an S6, and a previous S3 model with WR has become an S7.
Often a membrane is used to achieve this however, footwear without a membrane could pass the water resistance testing but the seams would need to be very watertight. The test itself is referred to as “water resistance” and not waterproof, a term often used by wearers. The term “waterproof” would insinuate that the footwear would never allow water to enter, which over time cannot be guaranteed by any manufacturer due to use, wear and tear, also via the tongue and seams of the footwear, depending on depth of water submersion.