How to Read a JIS L 1092 Water Resistance Figure
What the water column number on an outerwear specification means, and what it does not tell you.
What the test measures
JIS L 1092 is a Japanese Industrial Standard for the water resistance of textiles. The method most often quoted for outerwear, method B, is a hydrostatic head test: water pressure is raised against one face of the fabric until it passes through. The figure reported in millimetres is the pressure the fabric withstood. A style quoted at 15,000mm held a 15 metre column of water before the first drops appeared.
Why the same standard produces different numbers
The figure belongs to the fabric, not to the finished garment. Seams, zips and pockets are where a jacket usually leaks first, which is why taped seams and covered plackets appear in construction notes. Two jackets can carry the same water column and behave differently in rain because one is sealed and the other is not.
What figure is enough
For a commuting shell, figures around 10,000mm are common in the market. For sustained exposure, buyers usually look higher. Styles in our range record figures from 2,000mm to 30,000mm, and the specification table on each product page states which.
The DWR rating is a separate number
You will also see a DWR rating quoted to JIS L 1092, written as a spray test grade such as 5.5.5. That describes how well the surface sheds water before it wets out. It is a surface finish figure and it is not interchangeable with the water column.
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Read the guide →Frequently Asked Questions
Is a higher water column always better?
Not always. Higher figures usually come with a heavier or stiffer laminate and a higher price, so the target should follow the end use.
Does the rating change after washing?
The surface repellency degrades with washing and abrasion before the membrane does. Reproofing restores the surface behaviour.
Have a Question This Guide Did Not Answer?
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