In addition to comfortable and non-slip shoes, the backpack is the hiker’s most important tool. Even on bike tours, a small model is usually enough to store the essentials for the day. Some provisions for the rest at the summit, personal documents and, depending on the season and weather conditions, a dry shirt, hat and gloves. You don’t need much more to be on the safe side. But what if the weather changes along the way and dark clouds appear? Then a waterproof backpack is worth its weight in gold.

In the following article you will find out what waterproof means, what the water column stands for and which backpacks stay tight on short and long tours on foot or by bike.

Regardless of whether it’s a rain jacket, backpack, cell phone case or hiking boots: waterproof means nothing more than that no water penetrates through the material and thus onto the smartphone, into the socks or into the inside of the hiking backpack. As a rule, special membranes ensure that only the surface of the backpack or jacket absorbs the water, meaning that even large amounts of rain “stay outside”. Like this model from Proviz, which is also made from 100 percent reflective material.

Now you might ask yourself why there are additional items of clothing whose material is declared “water-repellent” or “waterproof”. The crucial difference: Waterproof fabrics allow raindrops to bounce off them. However, if it rains continuously and heavily, they will eventually have to give in to the water masses. This calls for standards that customers can follow so that they don’t suddenly find themselves standing in the woods like watered poodles on vacation. With this lightweight design from 4Monster, the zipper should be waterproof and the fabric itself should be at least water-repellent.

The water column is the international standard that the textile industry uses to make transparent how the water permeability of a fabric is measured. Or to put it another way: how long it takes until a certain material or membrane can no longer hold back. In Europe, DIN EN 343:20210-05 is authoritative here. To determine the water column, the substance to be tested is exposed to water in the laboratory and the pressure is gradually increased. The so-called Suter test ends as soon as the third drop has penetrated the material and is visible on the inside. If this happens at a water pressure of 0.5 bar, this corresponds to a water column of 5000 millimeters. In Germany, textiles with a water column of 1500 millimeters or more are considered waterproof. At least when no additional pressure is put on the fabric. For example, if the straps of the backpack press on the rain-soaked shoulders, a larger water column is necessary in order to get home dry. The wind can also play a role.

For some backpacks (here a model from Semptec), instead of the water column, an IP class provides information about how well the material protects against shocks and water. For example, the protection class IPX6 means that the material used is protected against jets of water and temporary flooding. You can read what the protection classes mean in detail here. A waterproof backpack is also important for outdoor fans who plan tours with a canoe or other boat. But be careful: very few backpacks stay tight even during a longer dive. This YEAZ backpack for day trips is made from tear-resistant tarpaulin. It should be extremely water-resistant, but not completely waterproof. The weak point in such backpacks is often the so-called roll-top closure. In classic backpacks, the zippers are usually the first to lose their battle against the water.

If you already have a fair-weather backpack (without a water column) in your closet, you don’t necessarily have to buy a new one. To be prepared for unexpected rain showers, all you need is a rain cover that is placed over the backpack and lashed to the back with an elastic or drawstring (there is a flexible model from Vaude here). Before you buy the rain cover, be sure to check the volume and pack size of your backpack so that the cover fits properly.

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