One of the wettest season of the year, autumn, is coming, therefore it could be useful to know which garments are really waterproof, how the tests for waterproofness and breathability of fabrics work and, above all, what is the difference between waterproof and water-repellent clothing. Let's see them together in this mini-guide, to get ready for buying the right jacket for your needs.
Key Points
• Waterproofness test
• Breathability test
• Waterproof VS Water-repellant
2' reading
• Waterproofness test
One of the main tests that are carried out to evaluate the level of impermeability of a fabric is the so-called water column test, which is performed by machinery following a simple principle. The water column is the measure of the water pressure that a material can withstand before water penetrates inside it and get absorbed, and it is expressed in millimeters. Imagine placing a glass tube on top of a fabric and filling it up to 20,000 mm (or 20K). If the material absorbs water, it means that garment has a water column of 20,000 mm (or 20 meters), which corresponds to an excellent level of impermeability.
How to read waterproof test results with reference to jackets? Generally, the various levels of waterproofness of jackets are:
- 0 K: No waterproofing. If you catch rain, you'll get soaked. Good luck!
- 0-1K: Lightweight protection, suitable for short journeys in the rain. This means that, if it rains, you can go to have breakfast at the bar downstairs at most.
- 1-5K: Moderate protection, suitable for intermittent and non-prolonged rain. If you live in London, it's not for you then.
- 5K-20K: Well, this is a very good level of waterproofing!
- 20K-40K: Advanced waterproofing, can withstand prolonged rainfall.
- +40K: The ultimate waterproofing: you could face the tidal waves of Interstellar's planet Miller and still stay dry!
Note: Even an excellent level of impermeability is not enough. In fact, the more waterproof a fabric is, the more likely it's heavy and not very breathable. Final result? We would not get wet because of rain, but our own sweat. How does breathability work?
• Breathability test
As for the water column, breathability is also measured in laboratory, through the MVTR test, an acronym for moisture vapor transmission rate, i.e. the ability of a material to release the water vapor produced by sweating, measured in grams/meter/day.
How to read breathability test results with reference to jackets? Usually, the standard levels of breathability for jackets are:
- 0-3,000 g/m2/24h: Breathability level: ice cream. Not because you'll stay cool. In fact, you will soon melt like ice cream in the sun.
- 3,000-10,000 g/m2/24h: Medium breathability.
- 10,000-15,000 g/m2/24h: High breathability.
- +15,000 g/m2/24h: Excellent breathability. No worries, you will stay cool and dry all the time.
Note: These are not meant to be absolute values, as breathability is influenced by several factors, such as the design of the garment itself. Often, pockets are responsible for lack of breathability. But, on the other hand, a jacket without pockets is uncomfortable and impractical, isn't it? Actually, there are a few tricks to make a waterproof garment also breathable. For example, the Integrity Shell Jacket by Vertx is a 100% waterproof jacket, with the following features:
- 20,000 mm at water column test
- 18,000 g/m2/24h at breathability test
- Taped seams to resist water
- Storm-flaps to protect zippers
There's more. This jacket is in fact equipped with 2-way side zippers with hem snaps for ventilation.
In addition, to guarantee additional breathability, the Integrity Shell Jacket is also equipped with 37.5® technology. Many of the common fabrics, to counteract sweat in perspiration, tend to distribute liquid sweat on the fabric; The 37.5 technology, on the other hand, works by absorbing the radiant energy (heat) that your body emits naturally, in this way manages to eliminate vapor before it turns into liquid sweat, and keeps your body temperature stable at 37.5°C, which is the ideal level regardless of the intensity of the effort.
• Waterproof VS Water-repellent
What's the main difference between a waterproof fabric and a water-repellent fabric? The waterproof fabric is a total barrier against water and snow; the water-repellent fabric, on the other hand, also provides an excellent protection thanks to the DWR treatment (Durable Water Repellent, lets the water droplets slip away from the fabric), but only up to a certain amount of water. Before buying your jacket, make sure it is waterproof or water-repellent depending on what you are looking for.
Both types are available on Tactyka: the waterproof Vertx Integrity Shell Jacket and the water-repellent Vertx Integrity +P Shell Jacket.
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Image 1: Vertx Integrity Shell Jacket
Image 2: Vertx Integrity +P Shell Jacket