The effectiveness of glass in blocking UV rays depends on the type and thickness of the glass, as well as the specific wavelength of the UV rays. Ordinary clear glass blocks most ultraviolet C (UVC) rays due to the shorter wavelength of UVC (100-280 nanometers), and ordinary glass absorbs UVC rays in this wavelength band better.

A single layer of ordinary glass about 2 mm thick can block about 80% of UVC light, and if two such layers are used, UVC can be almost completely blocked. However, for ultraviolet A (UVA, 320-400 nanometers) and ultraviolet B (UVB, 280-320 nanometers) rays, ordinary glass is less effective in blocking them. UVA, in particular, can penetrate ordinary glass, which is one of the reasons why sun protection is still needed indoors or in the car.

If you are referring to UV lamp beads used for sterilization, usually in the UVC band, then ordinary glass does effectively block this type of UV light. However, UV-transparent glass made of specialty quartz glass or other special materials may allow more UV light to pass through. 

Therefore, if you want to use glass to protect against UV lamp beads, ordinary window glass should be effective, especially for UVC. note, however, that if there are special needs, such as a UV application that requires a high transmittance, then specially designed UV-transparent materials will need to be used.