Water-repellent,” “Water-resistant” and “Waterproof,” are terms commonly printed on raingear labels. Many consumers aren’t able to tell the difference between these three features, naturally assuming that they all suggest water impenetrability. The truth of the matter is this; waterproof, water-repellent, and water-resistant indicate varying degrees of water protection. Knowing the difference between them will help you choose the right product for inclement weather.
Water repellency is a term used to describe the characteristic of both water-resistant and waterproof products once a durable water repellent (DWR) is applied. If a product is labeled as “water-repellent”, it means that it is hydrophobic, or repels water on contact. A feature of water resistant and waterproof fabrics, water repellency measures how much water pressure a material can withstand before water begins to permeate.
Water-repellent fabrics depend on something called surface area angling in order to repel liquid. If a droplet makes contact with the fabric at an angle less than 90 degrees, some water will be absorbed into the fabric. If a droplet hits an angle greater than 90 degrees, less water will be absorbed.
Put simply; once a liquid hits the surface of the fabric, depending on the angle of impact and how much surface area is covered will determine how well water is repelled. Scientists have, over the years, come up with a definitive list to explain how naturally water-repellent some fabrics are. Evaluating the results based off four variables, fabrics are graded on how water droplets form on their surfaces.
The list takes into consideration...
When it comes to testing fabrics for water-repellent qualities, factors like permeability (the trait of a material or membrane that causes it to allow liquids to pass through it) and penetration (the measure of how much surface area a liquid can cover as it is absorbed) play major parts in these experiments. In controlled laboratory environments, fabrics are tested in four classes to determine whether they can inherently repel water:
If a fabric is able to effectively pass these four classes of testing methods, it can be deemed usable for companies to use in outerwear production.
Apart from synthetic alternatives, refined fabrics are not inherently water-repellent. In order to make a fabric used in the production of outerwear repel water, a DWR is coated onto the exterior shell or infused with the fibers of a garment. DWR is a specifically manufactured chemical that, once applied to the surface of fabric, repels water.
If a product is labeled as “water-resistant,” it was designed specifically to resist contact by light water (rain showers/light rain and snow flurries) but are not designed to withstand any heavy exposure to the elements. From a technical standpoint, any water-resistant fabric should be able to withstand a water pressure of roughly 1,500 mm or more, according to the Hydrostatic Head Test (abbreviated as HH). The test is fairly simple. A double open-ended cylinder is placed on top of a DWR treated fabric and gradually filled with water. Measurements (in millimeters) are recorded to see how much water the fabric can withstand before permeation (or liquid penetration) occurs. The ratings vary, and the higher the number, the better the quality of waterproofness.
Becoming familiar with HH statistics is another handy tool to use when deciding what outerwear grade best suits your needs.
|HH Grading Scale (mm)||“Best Used In” Weather Conditions|
|1,500mm to 5,000mm||Light to average conditions: rain showers and light snow dustings|
|5,000mm to 10,000mm||Moderate Conditions: steady rain and snowfall|
|10,000mm to 40,000mm+||Extreme Conditions: heavy rain and snowstorms|
To sum it up,
A product labeled “waterproof” provides the highest quality level of protection from water amongst all outerwear. When companies design waterproof products, they target water-resistant features and enhance them to increase the amount of water being repelled.
Think of it this way, waterproof garments...
These garments are specifically made with synthetic membranes that are inserted under the fabric, forming layers. These layers increase the amount of water that can be repelled while extracting moisture from the interior of the garment.
An additional feature of waterproof garments are sealed seams. Through the process of seam sealing, interior seams are sealed from external conditions, preventing water seepage. This is accomplished by covering the stitch holes and seams with a state-of-the-art waterproof tape in order to prevent water infiltration due to wet weather. The tape is then heated to a certain temperature, and the end result is an airtight and watertight sealed seam.
Now that you know that “water-repellent” is a characteristic, and understand the differences between water-resistancy and waterproofness in fabrics, you should have a newfound sense of reassured confidence when purchasing the perfect product that meets your needs. Being mindful of label descriptions can greatly assist you in deciding whether a product will be suitable for the conditions that you expose it to. Truly know your product and how to clean and store it, because product awareness will help you prolong its usage for years to come.