Why does shower screen glass shatter by itself? What heat-soaked glass does

The toughened glass used in shower screens is several times stronger than ordinary glass, and if it breaks it shatters into small granules, reducing the risk of injury. Occasionally, though, a shower screen breaks "for no reason". The cause is usually a tiny impurity inside the glass.

1. What causes it

Raw glass can contain microscopic nickel sulphide (NiS) inclusions. After the glass is toughened, these inclusions can slowly expand with time and temperature changes until the glass breaks without warning. Damaged edges or uneven stress during installation can also cause breakage.

2. How heat soak testing helps

Heat soak testing places toughened glass in a heat-soak oven at about 290°C for around two hours, so panes containing inclusions break in the factory and are weeded out before delivery. LE-RELAX runs its own heat-soak oven, and our process meets the European standard BS EN 14179-1. Heat soaking greatly reduces the chance of spontaneous breakage, but cannot rule it out completely.

3. Extra protection

• Laminated glass: two panes bonded with an interlayer, so fragments stay in place if it breaks.
• Safety film: applied to the back of the glass to stop fragments scattering.

4. Everyday care

• Avoid knocking the glass with hard objects, especially at the edges and corners.
• Fix loose hinges or screws promptly so the glass is not left under uneven stress.
• Check the seals and glass edges regularly for chips or cracks.