Toughened and laminated safety glass
What Part K requires, and where laminated beats toughened.
Toughened and laminated are both called safety glass and they do completely different jobs. Getting them the wrong way round means either failing the building regulations or paying for security you did not get.
Toughened
Heat-treated so it is several times stronger than ordinary glass, and when it does break it shatters into small blunt granules rather than shards. That makes it safe — it will not lacerate someone who falls against it. It does not make it secure: once broken the whole pane is gone and the opening is open.
It cannot be cut, drilled or edge-worked after toughening. Every hole and cut-out has to be specified before manufacture.
Laminated
Two or more panes bonded to a plastic interlayer. When it breaks the fragments stay stuck to the interlayer, so the pane holds together and the opening stays closed. That is what makes it the security glass, and it is also why it is used where glass overhead could fall on someone.
Where the regulations require safety glass
Part K calls these critical locations, and safety glass is mandatory in them:
- Glazing in doors, and in side panels within 300mm of a door, up to 1500mm from floor level
- Glazing below 800mm from floor level anywhere else
- Glazing in and around bathrooms and shower enclosures
- Overhead glazing, where laminated is generally required rather than toughened
Glass in a critical location must be marked, permanently, showing the standard it meets — which is how a building control officer checks it.
Choosing between them
If the requirement is safety, toughened is cheaper and sufficient. If the glazing is out of sight from the road, in a door, or protecting something worth taking, laminated is the better spend. Overhead, laminated.
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Questions
Is toughened glass more secure than ordinary glass?
It is harder to break, but once broken the entire pane granulates and the opening is clear. Laminated is the security choice because it holds together.
Where do I legally need safety glass?
Critical locations under Part K: in doors, within 300mm beside doors up to 1500mm high, below 800mm generally, and around baths and showers.
Can toughened glass be cut to fit?
No. It has to be made to final size with all holes and cut-outs specified before toughening. Cutting it afterwards shatters it.
Why does my glass have a stamp in the corner?
That is the safety marking showing which standard it meets. Glass in a critical location must carry it — it is how building control verifies compliance.
Which should I use overhead?
Laminated. If overhead glazing breaks, laminated stays in the opening instead of falling on whoever is underneath.