What are waterproof membranes?

WATERPROOF MEMBRANES

A waterproof breathable jacket. Ideal, of course, especially in harsh conditions. But how can a jacket be waterproof and still be breathable? A special membrane makes this possible. But how exactly does that work and what different waterproof membranes are there? We are going to tell you all about it in this blog!

THE MAGIC OF A WATERPROOF MEMBRANE

In technical jackets, a waterproof membrane is a must. It keeps you dry and fresh. This is because the structure of a waterproof membrane contains holes thousands of times smaller than a drop of water. This prevents water from penetrating the membrane. On the other hand, the holes are hundreds of times larger than moisture vapour molecules from your body, so sweat can be discharged. Moreover, the molecular structure of the membrane is so complex that most air molecules cannot penetrate the membrane either.

The structure of a waterproof membrane.

WHAT DIFFERENT MEMBRANES ARE THERE?

There are an awful lot of different membranes on the market today. The best-known membranes are Gore-Tex and Dermizax. In addition, many clothing brands today also have their own waterproof membrane. For example, Mammut's DRYtechnology or Jack Wolfskin's eco-friendly Texapore membrane. Each membrane has its own qualities. Some are more resistant to water and others have better breathability. water resistance is calculated according to the following system.

WATER COLUMN

Waterproofness of a garment is expressed in millimetres. And that quantity is called the garment's water column. This is measured by placing a tube with a diameter of 2.5 cm on the material. After this, we see how high the water can rise in the tube before the material starts to leak. If this happens after 20 metres, it means that the material is water-resistant up to 20,000 mm. So the jacket's water column is 20,000 mm.

Important to know if you want to buy a good waterproof jacket is that the jacket has a minimum water column of 10,000 mm. A jacket with a lower value than 10,000 mm is not called waterproof, but water-repellent. This means that you do get wet in a heavy downpour.

BREATHABILITY

Jackets with a water column of more than 30,000 mm or higher may be fully waterproof, but that doesn't mean you will stay completely dry. After all, you can still get wet from the inside as well. This is why it is also important to look at the breathability of a membrane. The more intense your activity, the more you sweat and the more important the breathability is.

The breathability of a membrane can be indicated in different ways. The best known are "g/m²/24h" and "RET". g/m²/24h tells you how many grams of moisture pass through one square metre of fabric in 24 hours. In this case, the higher this value means the more breathable the fabric is. Where 10,000 g/m²/24h is fairly breathable and good for static activities and from 20,000 g/m²/24h or higher is good for dynamic activities and therefore highly breathable.

RET stands for Resistance to Evaporating Heat Transfer and thus tells the fabric's resistance to moisture measured in m²Pa/W (Pa = moisture pressure in the air). With RET, it is good to know that the lower this value is, the more breathable the fabric is. So an RET value of up to 6 is good breathability and from 20 or higher the fabric is almost to non-breathable.

DIFFERENT LAYERS

Besides the water column, most waterproof jackets also have a layer system. Of course, the number of layers again affects the waterproofness of the jacket. The three different types are a 2-layer, 2.5-layer or 3-layer system.

In a 2-layer system, the membrane is only connected to the jacket's outer material. This makes the jacket light and flexible but also vulnerable. In a 3-layer system, the membrane is connected to the outer material and the inner material. This reduces movement between the layers and protects the membrane, making it more durable and sturdy. In a 2.5-layer system, the outer material is attached to the membrane and a thin inner layer is attached to the inside. This combines the strength of the 3-layer system with the lightness and foldability of the 2-layer system.

WHY THE HIGHEST WATERPROOF RATING IS NOT ALWAYS THE BEST CHOICE

A jacket with a high waterproof rating is not always the best choice. This is because you also sacrifice breathability, wearing comfort and flexibility. Brands often do say that the jacket is reasonably breathable and flexible but compared to soft shells and fleece jackets, the jackets are still less so. If you go to an area where it hardly rains, a jacket without a waterproof membrane is also sufficient.

SCORES VERSCHILLENDE MEMBRANEN

Hopefully this article has helped you find your way around the world of waterproof membranes. If you still have a question, please let us know! Drop by our shop or contact us by phone or email. At Twinseasons we are happy to help.Onderkant formulier