Laminated glass is a type of safety glass that holds together when shattered. In the event of breaking, it is held in place by an interlayer, typically of polyvinyl butyral (PVB) or ethylene-vinyl acetate (EVA), between its two or more layers of glass. The interlayer keeps the layers of glass bonded even when broken, and its high strength prevents the glass from breaking up into large sharp pieces. This produces a characteristic "spider web" cracking pattern when the impact is not enough to completely pierce the glass. Laminated glass is also used to increase the sound insulation rating of a window, where it significantly improves sound attenuation compared to monolithic glass panes of the same thickness. An additional property of laminated glass for windows is that a PVB and EVA interlayer can block essentially most ultraviolet radiation.
