Do windows and/or windshield have UVA and UVB protection?

Toyota’s New Car Features book (NM3200U, available by subscription to techinfo.toyota.com) says some of the glass is of a “UV Cut” type:

• Front Fix Window Glass
• Front Door Glass Sub-assembly
• Rear Door Glass Sub-assembly
• Rear Quarter Window Glass
• Back Door Glass

The “UV Cut” designation, which is not explained further, is not shown for the Windshield Glass, Sliding Roof Glass (if present), or Back Window Glass.

I couldn’t find any other discussion of UV transmission in Toyota’s publications for the fourth-generation Prius. If you need more information, I’d suggest contacting Toyota through their website or by letter to ask.

 

i'll be interested to read their response.

 

I'd be interested in their response to why so many Gen 4 and Prime windshields keep cracking.

I doubt there's much UVA/UVB protection in the factory glass. I went and added my own.

 

don't tell me that, i thought there were federal requirements for windshields.

 

Do some Internet searching.
Plain window glass passes almost NO UVB or UVC.
My 30 second search found that the blocking of UVA isn't as good.......but that A isn't as big a problem either.
I'm pretty sure that spending more than 30 seconds on a search will give you the answer you need.

 

G'day,
I'd agree with Sam S.'s post.

Window glass generally has a significant iron content (the ferric ion is the UV absorber giving glass a yellowish tint because it absorbs blue as well as UV, the ferrous ion is more of a near IR absorber giving a blue tint because of its red light absorbance - together they combine to give commercial glass a greenish hue - if there is nothing else added by the glassmaker to decolourise the glass). In a thick section (edge-on), window glass looks green.

So the short wavelength UV (C and B) won't get through at the thickness of most windows, so no sun-tan inside the car .
From memory, UV-A is less of a biological problem and would still be absorbed to some extent by the thickness of car window glass, certainly more than with no glass in the way. Again, inside the car is not a place to get a sun-tan . Eye damage is maybe a slight risk with life-time prolonged exposure to UV-A but a negligible one compared to simply being outside in summer with no sun-glasses. Drive with polarised UV-rated sunglasses - no UV of any wavelength and no glare from reflections off the road or dash.

I don't know if you can find transmission spectra for window glass on any window-glass manufacturers' sites (try Pilkington?). Such spectra would show how much UV and even blue light is absorbed by the glass - thickness is an important variable in this, of course. Window glass is usually about 3mm thick.

David S.

 

I could be mistaken, but think that means 'cut out' rather than 'cut down,' but you're right. It is, unlike the glass, not perfectly clear.

 

G'day,

I agree with RCO that it was intended to read 'cut out' or 'cut off' - maybe an expression 'lost' in the translation.

The values in the table make sense given they're for 'laymen' not nit-picking glass technologists or physicists.

The transmission (the light that gets to you into the cabin) is what's left after about 10% is reflected back at the air/glass interfaces and what's absorbed in the the glass, and to a minor extent absorbed by the very thin polymer film between the two glass sheets of the laminated windscreen.

The side and rear windows are just mono-layers of glass. These windows should be of tempered glass, heat treated to shatter into little bits if broken, not sharp slivers like normal domestic window glass. The stress 'islands' or zones produced by tempering often show as greyish patches up if you're wearing polaroid-type sunglasses and looking through them, say, in your rear-view mirror.

David S.

 

a bit of googling shows 99% cut, cuts out 99% of uv rays. but nothing scientific, and toyota doesn't give a percentage in that chart.

 

Yes. But "worry thresholds" are a very personal thing.
Continue to worry if you wish.

 

check with your dermatologist.

 

So helpful!!! I wonder what "UV" means, UV-A or UV-B, or...?

What's interesting is this study from 2016 that looked at 29 cars from 15 manufacturers of varying ages, price range, car types, etc. and they reported the actual %UV-A reduction. 2014 Prius measured 96% UV-A blockage of front windshield and 79% UV-A blockage of front side windows... much less than the specified 100% / 91%. Guess I'm getting my windows tinted!

full article here