The EN 343 protective clothing standard

Examining the testing of rain-resistant garments.

The EN 343:2019 – ‘Protective clothing – protection against rain’ standard covers garments designed to safeguard the wearer from wet weather – anything from light rain to snow or a cloudburst. It outlines performance requirements and provides guidance on wearer times via Annex I in the standard. In regard to PPE certification, EN 343 is a CAT I claim and so is usually a ‘bolt-on’ claim to other clothing standards’ such as EN ISO 20471 (high visibility) or EN 342 (cold).

While safety is the primary aspect that testing investigates, comfort is also a key part of a garment’s real-world performance. Wearing such apparel for several hours can pose comfort issues, and the intention here is simply – keep the wearer dry.

Water penetration

Avoiding water ingress is the primary concern. Creating a waterproof garment is achieved by designing the clothing correctly, choosing the right materials, and using correct seam-sealing techniques.

The water penetration test in EN 343 is carried out via a hydrostatic head testing machine, which exerts hydrostatic pressure onto the face of the test material and the pressure is gradually increased. This is done by a diaphragm underneath the water column being filled by air and expanding. As water does not compress at these pressures, it only has one way to go – to try to pass through the surface of the material that is being tested.

Most materials used in EN 343 garments are woven. These are then made waterproof with either coatings (front or back), membranes or laminated. There are four different classifications for water penetration, each affording different levels of protection (level four being the highest). Naturally, higher classifications have harsher requirements. However, EN 343 outlines not just the requirements of each level, but also the pre-treatments to which the material must be exposed.

The table in this article (‘table 2’ in the standard) outlines the requirements. Depending on the level of performance claimed, testing will be required before or after certain pre-treatments listed in the standard.

Classification of resistance to water penetration
Water penetration resistance (WP)	Class
	1	2	3	4
Specimen to be tested Material before pre-treatment Material after each pre-treatment (see clauses 5.2 to 5.5)	WP ≥8,000 Pa –	– WP ≥8,000 Pa	– WP ≥13,000 Pa	– WP ≥20,000 Pa
Seams before pre-treatment	WP ≥8,000 Pa	WP ≥8,000 Pa	WP ≥13,000 Pa	–
Seams after pre-treatment by cleaning (see clause 5.2)	–	–	–	WP ≥20,000 Pa
Note: 1,000 Pa is approximately 102 mmH20

For a Class 1 garment, materials and seams must be tested as new with a requirement of >8,000 Pa. Anything Class 2 or above requires further pre-treatments, which include abrasion, flexing, fuel and oil exposure, and laundering. These are to simulate real-world use from the wearer moving around, cleaning the garment and any detrimental contamination to which the garment might be exposed during use.

Breathability

Although there are numerous materials and techniques available to create a highly water-resistant fabric, there needs to be a balance between keeping water out while letting water vapour out. When wearers exerts themselves, they naturally sweat. Heat from the body and mechanical movement of the wearer accelerates the vaporisation of perspiration. If this has no route to leave the garment, it simply condenses back into water as this is its lowest energy state.

As with most protective garment specifications for breathability, EN 343 references the ISO 11092 ‘sweating guarded hotplate’ method. This tests a material’s breathability under steady conditions which include temperature, relative humidity and air flow for the environment around the wearer, as well as a constant body temperature which is simulated by the hotplate device.

A porous membrane to simulate skin is placed over a sintered plate. The water bath below this is heated which slowly evaporates the water, changing its molecular state into vapour. This passes through the membrane and through the material under test, and out into the chamber’s atmosphere. This vapour is then condensed and removed to keep the chamber’s relative humidity consistent.

The more water vapour that passes through the material, the more breathable the sample is – usually expressed as its R_et value. The sweating guarded hotplate method can also be used to determine the R_ct value, which represents how thermally insulative a material or composition is. Both the R_ct and R_et value can be used to calculate the i_mt figure. This is the water vapour permeability index – that is, the relationship between breathability and how insulative a material is. However, EN 343 only requires the R_et to be determined. There are four classes of breathability – ‘1’ to ‘4’ – with the higher number being the best.

Although there are other mandatory tests, such as general, mechanical and innocuousness requirements for most PPE garments, EN 343 also has an optional test: EN 14360:2004. This simulates a cloudburst, using a shower of high-energy rain drops. While the materials and seams used in a garment’s construction may be performing very well, the garment’s design may fail as shown by this test.

The cloudburst test is conducted by measuring the amount of water that wicks into the garment (such as through the cuffs and up the arms), or examining specific design failures, such as the garment’s pockets filling with water.

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