You are probably wondering why I have started to write a category like Tuesday Tech Talk on my blog. Well, as you might now, besides going crazy making stuff, photographing and writing about it, I am still a designer. And my aspiration for I ♥ Design is to become – over time – a resource for designers in the athletic and outdoor apparel industry. A place where not only I share my inspirations and personal projects but also the knowledge I have researched and built up over the last 15 years as a designer in the athletic apparel industry.
So here is part 2 of the Sun Protection Series. Last week we discussed the meanings and differences of UVA, UVB, SPF and UPF and the best option we currently have to protect ourselves from harmful UV Rays.
This week, I’ll be focusing on the UPF component. UPF – Ultraviolet Protection Factor rates how much of the suns radiation is absorbed. A UPF 50 only lets 1/50th of the UV rays pass through. So in other words, the UV rays are reduced to only 2%.
Determination of UPF Ratings:
In the past, UPF ratings were determined by placing a piece of fabric on top of human skin and expose it to UV radiation up to 60 times higher then the Sun. The resulting degree of sunburn determined the UPF rating. Ouch! These days Spectrometers are used to determine the UPF with much less pain for any testing subject.
Now, look at some test results with only white test matter from an Australian study in the mid 90s:
And here a table of the UPF ratings and what they mean:
So, a UPF of 20 lets only 20% of the UV rays through which in other words means, only 5% of the UV rays are passed through. UPF 15 is the minimum rating a fabric has to achieve before it can be labeled sun protective.
General Observations:
Generally, the lighter the color of a material, the less UV absorption. If a fabric has a tight weave, it’s UPF rating will be higher than a loose weave. Also note that once a fabric is stretched, the weave or knit structure becomes more dense and more rays can pass through. Easy testing method for everybody at home: Hold the fabric up to the light: If you can see through it, the rating will be less then when it’s dense. Also, if fabric gets wet, the UPF rating is instantly cut in half. So a white cotton tee has a UPF rating of 7, once you pull it over your kid’s head to let it play in the water for a couple of hours, the rating immediately goes down to only a UPF 3!
Treatments:
For designers, creating UPF apparel lines with a restricted fabric palette might seem stifeling. Fortunately, a lot of fabrics are now available that have chemical sun blocks washed into them.
And Nanotechnology offers even better solutions: I found a manufacturer that invented a way to create a water based starch and Zinc Oxide solution that bonds to the fibers and creates superior UV protection. As we found out last week, Zinc Oxide has extensive UVA and UVB absorption ratings and is in terms of health concerns the superior option as it isn’t absorbed into the skin like chemical filtering agents could, yet creates a barrier on top which reflects the rays before entering into the skin.
photo by nanowerk
This enlargement shows three different scenarios:
A is cotton fiber without treatment
B shows cotton fiber with Zinc Oxide being clumped up in certain areas which doesn’t offer the same protection as
C where the Zinc Oxide is washed in with a starchy water based solution. The even coverage of the Zinc Oxide Particles offers good UV protection
And for everybody who’s at home and would like to enhance the UV protection abilities of existing clothing, there are solutions: iDye for example offers a simple solution in which everybody can wash extra (chemical based) sun protection into our clothes. The protection lasts for about 20 washes before it has to be repeated.
Concept thoughts that come to mind besides covering up all skin areas:
- Use of dark colored fabric at the bottom of visors
- Use of silver threads for a melange look and reflection in fabrics
- Insertion of reflective fabric at shoulder and/or neck areas to reflect the sun.
