Toughening glass at a Hampshire college

Modern buildings are often made with a lot of glass, to let in light and create a positive, airy feel.

However, did you know that toughened glass panels can shatter spontaneously, due to a phenomenon called Nickle Sulphide Inclusion (NSI). This is caused when Nickle Sulphide atoms expand and there is no way to predict if and when this may happen. If it does it will result in a failure of the entire panel.

The spontaneous shattering of the glass is of course a huge health and safety issue, causing danger to those who regularly use these buildings with falling glass.

CEMAST Technology College in Lee-on-the-Solent in Hampshire took a proactive step in addressing this issue when a toughened glass pane broke in one of the workshop skylights

They called in structural consultants so that they could understand the issue further. The consultants’ recommended solution was that the college have its high-level panes fitted with a 200-micron clear security film and an edge retention bead.

This method would hold glass fragments within the frame, if a breakage did occur, protecting staff and students and allowing time for glaziers to be called to safely replace the panel.

Bonwyke’s involvement

As local stockists of a range of window film and architectural vinyl, Bonwyke were invited to specify an appropriate film and supplied AV8mil clear 200micron thick film, along with Dow Corning 995 structural silicone, which was successfully installed on each of the high-level glass panes at the College.

Just three months after the film installation, another pane shattered due to NSI. Crucially, this time all the glass was held in position by the film and didn’t cascade to the floor, helping to avoid a health and safety risk.

John Field, Head of Estates Management at CEMAST, said: “It’s a very worrying problem for us, as our focus is to protect our staff and students at all times. The installation of the film was quick, clean and as an operational centre, issue free. It’s been so amazing to see how effective the film was when the last pane broke. It takes the worry and risk out of the situation.”

If you work in a building with toughened glass panels and are concerned about safety, contact us by telephone on 01329 222299 or by email at for a quote.

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