The message
from "Franz Heymann" contains these words:

In the 80's when I was being treated for multiple malignant
melanoma,
I asked about UV transmission through glass. The reply was that
single
glazing,(car windows for example) and standard double glazing at
that
time, offered virtually no protection at all.

I don't believe that. Most glasses have quite a sharp cut-off just
beyond the visible blue end of the spectrum. If not, the near-UV
photodetectors which I used for decades would not have had to be
constructed with fused silica windows.

I've been burned through car windows, and I see many parents
protecting their children from that risk with stick-on screens.

Janet.