WATERPROOF OR WATER REPELLENT

how is that to be understood?

Suppose I have the misfortune to be followed by rain and thunderstorms during my ten-day hut hike. Now the saying proves true: There is no bad weather, only bad clothing. In such a situation, only the right layer of rain can save me from wetness, cold, blisters and pressure points.

But which material keeps really tight? How can I understand the difference between good and bad rainwear?

THERE IS A STANDARD : THE WATER COLUMN

How quickly does a material let water through? The water column determines which criteria are used to measure the water permeability of a membrane. The outside of the material is exposed to water pressure and is measured in millimeters of water column.

This is where the European standard DIN EN 343:2010-05 for clothing comes into force. Several factors are taken into account, not only the water column but also the water vapor transmission resistance, called RET value. Because it makes no big difference whether you get wet from the outside or the inside. But more about this later.

Here are some examples of water columns and what the values mean:

1.500 mm: from this value textiles in Germany are generally considered waterproof
4.000 mm: considered waterproof in Switzerland according to the Swiss Federal Laboratories for Materials Testing and Research (EMPA)
5.000 mm: Pressure caused by a person weighing 80 kg while sitting
10.000 mm: Waterproofness for good outdoor clothing
14.000 mm: Pressure caused by an 80 kg person kneeling

WHICH WATER COLUMN VALUE DO YOU REALLY NEED?

The decisive factor here is what to do in heavy rain and what the fabric has to withstand, i.e. whether it is exposed to higher pressure in addition to water. It makes a difference whether I'm just standing in the rain with a rain jacket, whether strong wind is also pressing on it, or whether the straps of a bagpack exert pressure on rain-wet shoulders and backs, pressing the water through the fabric. When sitting and kneeling, there is a high pressure on the clothing, the same applies when sitting, lying down and standing in a tent. In these cases the water column should be as high as possible.

Some examples:

Tent floor and tarpaulin: at least 5,000 mm water column
Weatherproof trousers with which you kneel or sit on a wet surface: from 15,000 mm water column
Hardshell jacket designed for carrying a heavy backpack: from 20,000 mm water column
If, on the other hand, weatherproof textiles are not exposed to any particular pressure, a significantly lower water column is sufficient
Tent tarpaulins, outer tents and tarps: minimum 3,000 mm water column
Waterproof trousers, which should mainly protect against splash water 10.000 mm water column
Wind- and bicycle jackets, which are used without carrying a backpack 10.000 mm water column
Hardshell jackets, which are designed to carry heavy backpacks, become waterproof from a water column of 20,000 millimeters. Without a backpack, jackets with a lower water column of 10,000 millimeters are sufficient.

Thus, the border between WATERPROOF and WATERREPELLENT is fluid and depends on the following factors: the strength and duration of the water exposure and the pressure of the water on the fabric (by backpack, wind and the wearer himself in different situations)

SO WHICH WATER COLUMN DO I CHOOSE WHEN BUYING A JACKET?

The good news: Actually all hardshell jackets are waterproof, at least in our shop. Most of the established manufacturers such as Mammut or Jack Wolfskin start with a water column of at least 10000 mm and are well above what the standard defines as waterproof. Most of the rain jackets even have a value of 20.000 to 30.000 mm.

These values refer to new garments. Used, worn out textiles no longer have the same properties as when they were purchased.

In addition, when choosing waterproofing, it is essential to consider the intended use.

IMPORTANT: Waterproof your jacket regularly! On a well impregnated garment, water rolls off before it can be pushed through by the wind, for example.

I WANT YOU TO KNOW THAT TOO:

Breathable but waterproof: The 3-layer laminate GORE-TEX® Pro.

A decisive factor is the BREATHABILITY, the so-called water transmission resistance of a fabric. What good is a jacket that is so tightly impermeable on the outside that it does not wick away the sweat you produce and you get wet on the inside? The decisive factor here is a membrane such as GORE-TEX, which allows a minimum of breathability.

AND FINALLY:

While the water column only tests the water transfer resistance of the textiles, other important components must also be taken into account in order to achieve an optimum protective function: A poor front zipper can allow water to penetrate, especially in headwinds, and seams can also be weak points if they are not properly welded. Even badly cut hoods can be a problem.