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uv protection in fabrics: your total guide

UV Protection In Fabrics: Your Total Guide

Having UV protection in fabrics is a great way to protect your skin from the sun. Many clothing items are made with materials that naturally absorb much of the sun’s rays. They don’t absorb all of them, but they provide a great deal of protection against sunburns, cancer, and other issues that exposure to the sun can cause.

Today’s blog is your complete guide to UV protection in fabrics. We’re explaining how UV testing is done, how to know the level of protection you’re getting, and how light and dark colors differ in the protection they offer, among other things.

Keep reading to learn everything you need to know about UV protection in fabrics.

The Difference Between UPF and UV Ratings

To start, it’s essential to understand the difference between UPF (ultraviolet protection factor) and UV (ultraviolet) ratings. Without properly understanding the difference, you’ll get confused about how much protection you’ll get. 

The UPF rating indicates how much of the sun’s ultraviolet rays (where “UV” comes from) are absorbed by the fabric instead of your skin. A higher UPF rating will provide more protection, but a lower rating is better than nothing. It will provide some protection, just not as much.

If you purchase fabric with a UPF 20 rating, only 1/20th of the UV radiation will go through the fabric. That means that 20 times less radiation exposure reaches the part of your body covered by the material.

How UV Testing Works

Another important aspect of UV protection in fabrics is understanding how UV testing works. There are some misconceptions about testing that we’ll demystify in this section.

First, UV testing is done on a single layer of fabric, meaning that materials with multiple layers will have even better UPF ratings. But while it might seem like you’d just add the UPF ratings together, the math is more complicated. 

Let’s look at an example.

A piece of fabric with a UPF rating of 15 means that approximately 93% of UV rays are blocked. About 7% of those rays can get to your skin. 

Now, imagine that your second piece of fabric also has a UPF rating of 15. That means the combined materials have a UPF rating of 30, right? 

Nope, that’s not how it works. The UPF rating would be UPF 50+ because of the second layer of fabric. That second layer will block out an additional 93% of the 7% of UV rays that the first layer of fabric allowed through. That means that a mere 7% of that 7% would actually reach your skin. That’s a lot of protection from UV rays!

If you’re a math person, the calculation is 100 - (0.07*0.07) = 99.9951%.

What UPF 10 vs. 50 Really Means

There are three categories of UPF ratings: good, very good, and excellent.

  • Good: UPF 10 to 24
  • Very Good: UPF 25 to 39
  • Excellent: UPF 40 to 50 

The protection is beyond excellent if you see a piece of fabric with a 50+ rating. Less than 2% of the sun’s UV rays will get to your skin. You won’t get better protection than that!

The better the UPF rating, the more protection your skin gets. But even a low rating like UPF 10 offers significant protection against ultraviolet rays.

How Different Colors Absorb The Sun’s Rays

Various colors absorb the sun’s rays differently. Darker and brighter colors absorb UV rays instead of allowing them through the fabric to your skin. If you’re out hiking all day, a black or red shirt will provide more protection than a white shirt. 

Lighter colors still absorb the sun’s rays, but not to the same extent, so they don’t provide the same level of protection as darker colors. 

Colored fabrics have better UV protection because of the benzene atoms contained in the dye molecules. Those atoms absorb ultraviolet rays. So, wearing a light-colored, dyed shirt will provide more protection than a light-colored shirt that hasn’t been dyed. 

How Fabric Structure Affects UPF Ratings

It’s not safe to assume that two black shirts will have the same UPF ratings. That’s because the structure affects how much of the UV rays are blocked. 

Unbleached cotton contains natural lignins that act as UV absorbers. A single knit fabric has a lower rating than a double knit. A flat-knit design has a lower UPF rating than a raised fiber structure. 

Take fleece and french terry, for example. Since they are double knits and the fibers are entangled with each other, not as much light can get through. As a result, they provide excellent UV protection. 

Wool is another example. It can block UVA and UVB rays, while some fabrics can only block UVA or UVB rays, but not both. Tightly knitted or woven fabrics provide better protection than loosely constructed fabrics. You could have one black shirt with UPF 15 and another with UPF 30. Never assume!

Again, that’s not to say that fabrics with looser weaves don’t provide any UV protection. They just don’t provide as much as those with a tight weave. Looser weaves often have gaps and holes that let UV rays pass through. 

On the other hand, looser-fitting clothes offer better protection than tight-fitting ones because tight-fitting clothes stretch the fabric and expose holes that can allow rays to pass through. 

What Is the Difference Between UPF and SPF?

The SPF (sun protection factor) number tells you how long the sun’s UV radiation would take to redden your skin when using the product exactly as directed versus the amount of time without any sunscreen. The term SPF is not used for clothing but rather for skin applications such as sunscreen, creams, or lotions when your skin is exposed to the sun’s rays.

UPF measures the amount of protection a fabric will provide to your skin from UV rays and how much UV radiation it will absorb so that it cannot affect your skin.  

As an example, a UPF 50 fabric will block 98% of the sun's UV radiation and allows only 2% (1/50th) to penetrate, thus reducing your exposure risk significantly. Whereas, when you use an SPF 50 product on skin exposed to the sun it would take you 50 times longer to burn than if you weren't wearing the cream.  

UV Protection in Wazoodle Fabrics

Wazoodle Fabrics is actively working to provide our customers with more information on UPF ratings. Our process includes testing all our fabrics for their ratings and adding those ratings to the Specs tab on all our product pages. 

To check a fabric’s UPF rating, check the Specs tab to see if we’ve tested that fabric yet. Or, you can look for the UPF Rating icon on the product page that signifies the fabric's rating. 

If you see two icons displayed – one for UPF 10 and UPF 20 – the fabric has a range of UPF ratings from 10 to 20. The rating is 10 for lighter colors and 20 for darker colors. 

Wazoodle Fabrics offers many fabrics with the best combination of fiber, construction, and color to offer the most UV protection. 

Our Zorb line provides the most. The entangled structure of the super absorbent Zorb fibers ensures most UV rays are blocked out. In fact, it was the close-knit construction of our fabrics that made them ideal for masks for blocking out germs during the height of the coronavirus pandemic.

Our ProECO and ProCool fabric lines also provide Good to Excellent protection. The ProCool polyester fabrics contain an ester (benzene) ring that absorbs UV light and allows the fabric to last for a long time without breaking down or exposing you to the sun’s rays.

During the dyeing process for our polyester fabrics, the material is colored by heating the solid dye to a vapor, opening the pores, and allowing the pigments to sink in. This exponentially increases UV protection. 

Try Wazoodle Fabrics.

Are you looking for UV protection in fabrics? Even without a current UPF rating, many of our fabrics offer excellent protection against ultraviolet rays. Look for dyed fabrics with a tight knit/weave for the best protection. 

If you have questions regarding UPF ratings for a specific fabric, don’t hesitate to reach out to us. We’ll be happy to assist you. We also offer 4x4 swatches of our fabrics if you want to test them before making a larger purchase. Get started with Wazoodle Fabrics today!

Skin Cancer

University of Utah Health

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