Sheets of glass are heated to about 700°C in a furnace, then chilled rapidly by cold air blown onto both surfaces. Toughened glass is four to five times stronger than float glass and, if broken, disintegrates into small fragments with dulled edges which are unlikely to cause serious injury.

A steel wire mesh is embedded within the glass and is intended to hold it in place if cracked. The glass breaks in almost the same way as ordinary glass into sharps dagger-like pieces. The visual quality of the glass is impaired by the wire mesh but this has traditionally been accepted in low-cost fire resistant and roof glazing. Wired safety glass only qualifies to Class C and should be regarded primarily as a fire-rated rather than a safety glass.

The principal benefit of laminated glasses is their performance under impact. The glass may fracture but any broken fragments will remain firmly bonded to the polyvinyl butyral (PVB) interlayer. The interlayer also absorbs impact energy, reducing the risk of penetrating the panel. When properly glazed, even safety grade laminates will resist attack, acting as a deterrent to burglars and normally remaining in place until replacement is convenient. The interlayer in laminated glass provides two additional benefits: sound transmittance is reduced, particularly at the higher frequencies and ultra-violet radiation (between 320 and 380 nanometres) is reduced by at least 97%.