Do older canopies also protect against UV, or is it only the newer ones?
Maybe you could do this test on some of older canopies at your
gliderport?


Eric Greenwell wrote:
I recently bought an Oregon Scientific UV888 Personal UV Monitor (~$30).
Among other things, it measures the UV flux and computes the UV Index
(UVI), then determines a "safe exposure time" based on your input of
skin type and the SPF of the sunscreen you are using.

Naturally, I made a measurement in the sun (UVI = 8), then another one
inside the cockpit (UVI = 0), indicating the canopy provides quite a bit
of protection. Testing other kinds of plastic, like baggies, plastic
wrap, Lexan, etc., gave readings from 0 to 7, so not every kind of
plastic is protective.


Looking at an "erythemal dose rate" chart, you can see almost all (99%)
of the dosage in the direct sun occurs below about 330 nm. Since our
canopies block UV below about 360-370 nm, they provide essentially
complete protection from damaging rays. The fraction of the UVA that
comes through will still give you some tanning, and some fabrics will
fade slowly, but your skin is protected from the UVB. This is very good
news, that the canopy affords even more protection than I first thought.