Toughened and laminated safety glass

Where Part K actually applies

Critical locations are defined by height and proximity to a door. Broadly: anything glazed below 800mm from floor level, and anything within 300mm of a door edge up to 1500mm from floor level. Those are the positions where someone walking into the glass is likely.

In practice this catches shopfronts, entrance screens, side panels beside doors, low-level office partition glazing and most balustrade work. Older commercial buildings frequently have annealed float glass in all of these positions, which is a live liability rather than a cosmetic issue.

Toughened or laminated — they fail very differently

Toughened glass is four to five times stronger than annealed and, when it does break, disintegrates completely into small blunt pieces. That is safe for the person, but it clears the opening instantly — no security, no weather protection, and anything above it is now unsupported.

Laminated glass is not as strong but holds together on its interlayer when cracked. It keeps the opening closed, keeps the building secure, and stays in place overhead. For anything at street level, overhead, or where a fall is possible, laminated is normally the right answer even though it costs more.

Everything is decided before toughening

A toughened pane cannot be cut, drilled, notched or edge-worked afterwards — any of those will shatter it. Every hole, cut-out and edge finish has to be right on the order.

This is why accurate site survey matters more here than almost anywhere else, and why a 5mm error on a measured opening means a remake rather than a trim on site.