Do you know the difference between waterproof vs water resistant vs water repellent outerwear?

FIRSTLY, WHAT DOES “WATER-REPELLENT” MEAN?

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 amounts of water begins to permeate.

HOW WATER DROPLETS FORM ON FABRIC

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 outer 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 on four variables, fabrics are graded on how water droplets form on their surfaces.

The list takes into consideration...

1. The chemical compounds present in the fabric.
2. The roughness of the surface area.
3. The porous qualities of the fabric.
4. How substances like oil, sweat, and dirt affect water-repellency.

WATER-REPELLENCY TESTING METHODS FOR FABRICS

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:

• Class A: Permeability is tested against water pressure.
• Class B: Penetration is tested in simulated rainstorms.
• Class C: Levels of absorbance are measured.
• Class D: The fabric is tested by means of angled liquid contact.

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.

SO HOW DOES A FABRIC BECOME TRULY WATER-REPELLENT?

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 a fabric, repels water.

WHAT IS “WATER-RESISTANCE”?

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 water 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 exposure to 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.

To sum it up,

Water-Resistant fabrics…

1. Are treated with a DWR to repel light water on contact.
2. Have a general HH grade between 1,500mm and 5,000mm of water pressure resistance.

And Waterproof fabrics…

1. Are treated with a DWR to repel water on contact.
2. Have a general HH grade minimum of 10,000mm+ of water pressure resistance.

WHAT MAKES A GARMENT TRULY “WATERPROOF”?

A product labeled “waterproof” like the shell provides the highest quality level of water protection from rain or 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...

1. Are treated with a DWR coating or laminate to ensure high-grade water repellency (10,000mm+)
2. Have layers that are designed to increase the amount of possible water-resistance.
3. Have sealed/heated seams that help ensure better water-resistance functionality.
4. Utilize waterproof zippers that are more durable and withstand harsh conditions.
5. Cost more due to these innovative technical features.

CLOSING REMARKS 

Now that you know that “water-repellent” is a characteristic, and understand the major 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 use for years to come.