What does an 8,000 mm waterproof rating mean? EN 343 classes, 5,000 vs 10,000 vs 20,000 mm, and what the figures mean in heavy rain
An 8,000 mm rating means the fabric held back a column of water 8,000 mm (8 meters, about 26 feet) tall before water came through, in the hydrostatic head test (EN 20811 / ISO 811). The higher the figure, the more pressure the fabric resists: 5,000 mm is where manufacturers start calling a fabric waterproof, 10,000 mm holds up to steady rain and the pressure of a strap or a knee on wet ground, and 15,000 to 20,000 mm is heavy, wind-driven rain over a long shift. Is 5,000 mm waterproof? It is: the fabric passed the test at that pressure, and Portwest lists its 5,000 mm Classic Rainwear at EN 343 class 3 for water penetration, the top class under the 2019 edition’s test. The millimeter figure says nothing about breathability, which is the second EN 343 digit (1 to 4), or about the seams and zips, which the optional rain-tower test (R) covers. Portwest prints both the millimeters and the EN 343 class on each rain garment here.
Portwest DX4 DX463 Rain Jackets, 20,000 mm Waterproof, PolyesterRated 20,000 mm and EN 343 4:4:X, as Portwest states it (Portwest data)Why two different numbers describe one jacket. The millimeter figure is a laboratory result on the fabric alone: water is pushed against a swatch at rising pressure and the height of the water column at the moment it leaks is the rating. EN 343 turns that and the breathability result into classes, 1 to 4 for water penetration (the 2019 edition tests the fabric and the seams, before and after pre-treatment) and 1 to 4 for water vapour resistance, printed as two digits with a third position for the rain-tower test on the finished garment, R for passed and X for not run. So one garment can read 5,000 mm and class 3:1:X, another 10,000 mm and 3:3:X, another 20,000 mm and 4:4:X. Heavy rain raises the pressure on the fabric (wind, a wet strap, kneeling), which is where the higher millimeter figures earn their keep; the second digit decides whether the wearer stays dry from the inside over a long shift, and the EN 343 user sheet puts a wearing-time limit on the lower breathability classes in warm weather.
The figures, one by one
What each number on a Portwest rain garment page is, from its data sheet.
How to read EN 343 on the page
- First digit, water penetration (1 to 4): tested on the fabric and the seams; the 2019 edition added class 4 and tests after pre-treatment (washing or dry cleaning, flexing, abrasion, fuel and oil).
- Second digit, water vapour resistance Ret (1 to 4): class 1 is above 40 m²·Pa/W (least breathable), class 4 at 15 or below (most breathable); the user sheet’s wearing-time table below is built on it.
- Third position, R or X: R means the finished garment passed the rain-tower test (water sprayed on a moving mannequin for an hour, no leaks inside); X means the test was not run. Every Portwest rain garment here is marked X, so the figure speaks for the fabric and seams, not a whole-garment spray test.
- The millimeter figure and the first digit are related but not the same: Portwest lists 5,000 mm fabrics at class 3 and 20,000 mm fabrics at class 4, because the class also depends on the seam test and the pre-treatments.
- Hi-vis rainwear carries both ratings and the ANSI/ISEA 107 class: a Class 3 rain jacket at 15,000 mm and 3:1:X reads all three on the product page.
EN 343:2019 recommended maximum continuous wearing time for a complete unlined rain suit, from the Portwest user information sheet
| Working temperature | Class 1 | Class 2 | Class 3 | Class 4 |
|---|---|---|---|---|
| 25 °C (77 °F) | 60 min | 105 min | 180 min | no limit |
| 20 °C (68 °F) | 75 min | 250 min | no limit | no limit |
| 15 °C (59 °F) | 100 min | no limit | no limit | no limit |
| 10 °C (50 °F) | 240 min | no limit | no limit | no limit |
| 5 °C (41 °F) | no limit | no limit | no limit | no limit |
The class in this table is the second EN 343 digit, water vapour resistance (breathability), 1 to 4; the first digit is resistance to water penetration, 1 to 4; the third position is R when the finished garment passed the optional rain-tower test and X when that test was not run. Portwest prints the two digits and the X on each rain garment page here, for example 3:1:X on the 190T Essentials and 300D Industry rainwear and 4:4:X on the PW3 Extreme styles.
Source: Portwest user information sheet for EN 343:2019 rainwear (the wearing-time table and the X, Y and R positions)
Questions people ask
What does 8,000 mm waterproof rating mean?
The fabric held back an 8 meter column of water in the hydrostatic head test (EN 20811 / ISO 811) before it leaked. Portwest lists its softshell rain jackets at 8,000 mm with a 3,000 g/m²/24h breathability figure.
Is 5,000 mm waterproof?
Yes by the test: the fabric resisted a 5 meter water column, and Portwest lists its 5,000 mm Classic Rainwear at EN 343 class 3 for water penetration. It is the entry figure for rainwear; higher figures resist the extra pressure of wind, straps and kneeling.
What waterproof rating is needed for heavy rain?
The standards do not set a figure by weather. Manufacturers list 10,000 mm and above for steady or wind-driven rain and 15,000 to 20,000 mm for long shifts in it; the EN 343 second digit, breathability, decides comfort over those shifts, and the user sheet limits wearing time for class 1 and 2 fabrics in warm weather.
Are Portwest rain pants waterproof?
Portwest lists its rain pants with a millimeter figure and an EN 343 class on each page: 5,000 mm (3:1:X) on the 190T Essentials and Classic styles, 15,000 mm on the PW3 insulated pants, 20,000 mm (4:4:X) on the S165. The figure on the product page is the one Portwest states.
What is the difference between EN 343 class 3 and class 4?
Class 4 is the top class the 2019 edition added for both digits; for water penetration it means the fabric and seams held a higher pressure after pre-treatment, and for breathability it means a Ret of 15 m²·Pa/W or below. Portwest lists 4:4:X on its 20,000 mm DX4 garments.
Is a 25,000 mm or 20,000 mm waterproof rating good, and what is the highest?
By the hydrostatic head test, 20,000 mm and above is the top of the range manufacturers publish for work rainwear; Portwest’s highest figure on this site is 20,000 mm on its DX4 rain jackets and S165 rain pants, with EN 343 class 4:4:X. Higher figures resist more pressure (wind, straps, kneeling); comfort over a long shift is the second EN 343 digit, breathability, not the millimeters.
What does EN 343 mean?
EN 343:2019 is the European standard for protective clothing against rain. It grades water penetration (1 to 4, tested on fabric and seams, after pre-treatment in the 2019 edition) and water vapour resistance or breathability (1 to 4), printed as two digits with a third position for the whole-garment rain-tower test: R for passed, X for not run. Portwest prints the code with the millimeter figure on each rain garment page.
How long does a rain jacket last?
The standards set no life; the fabric and seams do. A PVC-coated 5,000 mm jacket is replaced when the coating cracks or peels at the folds or a seam leaks; a laminated 10,000 to 20,000 mm jacket lasts until the laminate delaminates or the seam tape lifts, and is washed by its care label without softener. Hi-vis rainwear also carries the wash count for its retroreflective tape, which Portwest prints as a maximum of 25 or 50 washes.
The ratings, test results and standards shown here are the manufacturers' published values, reproduced as published. Nothing on this page is a recommendation by Bayshore Safety that any product is suitable for a particular task, hazard or workplace. Selecting safety products and protective equipment is the responsibility of the end user and the employer, based on their own hazard assessment and the regulations that apply to their work. Confirm every value on the manufacturer's own documentation before use.