[shvcko99]

Does most glass (transparent one) normally used to make windows already block uv light partly or totally or do we have to ask for specific glass?

[Borek]

Try googling for "uv blocking properties of common glass".

[Enthalpy]

It depends on the undesired UV wavelength.

For instance, ordinary car glass lets the longest-wavelength UV pass, but blocks enough of the spectrum to avoid Sun burns. I tried in Guyana, so that's safe science.