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What Is Toughened/Tempered Safety Glass?

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As a leading door supplier we are often asked about the type of glass used in door manufacturing. Below we've compromised a list of your most common questions regarding safety glass.

What Is Toughened Glass?

Toughened or tempered glass is a type of safety glass made by using a controlled thermal or chemical treatment to increase its strength. It therefore offers better protection against break-ins, flying objects and severe winds as it is up to five times stronger than standard glass.

Toughened glass gets this strength from the tempering process which sees it subjected to intense heating followed by rapid cooling.

Why Is Toughened Glass Used?

Along with being much stronger than regular plate glass, when toughened glass is put under significant pressure it shatters into small granular pieces as opposed to sharp glass shards and so is much less likely to cause injury.

Toughened glass is therefore commonly used in public infrastructure for its strength and safety benefits. It has many industrial and domestic applications. For example, toughened glass is used for protective eyewear, tabletops, office doors, shower screens, phone screen protectors, phone boxes etc.

What Are The Different Types of Glass Available?

As well as toughened glass, laminated glass is also superior to standard glass. Laminated glass is most popular for being used in car windscreens. This type of glass has a plastic interlay (polyvinyl butyral) wedged between two glass sheets, which prevents the screen from breaking. The plastic inlay works like glue to keep the fragments together even when the glass breaks. This means the glass keeps in place long enough for a replacement to be found. So, where laminated glass holds in place when shattered, toughened glass breaks up into hundreds of tiny pieces.

This practical safety feature is highly effective and the reason blast-resistance glass, fire-resistance glass, bullet-resistance glass and solar control laminated glass exist.

However, toughened glass still has a far higher load and breakage point and can withstand temperature changes up to 250°C.

How Can You Tell Toughened Glass Apart?

Toughened glass has smooth edges due to the extra processing it goes through, and this is one of the ways you can tell it apart - as well as a ‘bug’ label in the glass’s corner.

Another way to tell toughened glass apart is using polarised glasses in the sunlight and you may see dark, shady spots or lines that are formed by machine rollers during the tempering process.

Are There Any Disadvantages of Using Toughened Glass?

Whilst toughened glass has major safety benefits, it does have some disadvantages. It must be cut to shape or size before the tempering process as any modifications afterwards could weaken the glass and cause it to inevitably break down the line. This means that the edge of the glass cannot be laminated to get the shine and look of real glass.

The question of whether to opt for toughened glass or laminated glass often comes down to preference if strength is not the definitive factor. It depends largely on whether it is safer to have the area left exposed after a breakage or if it needs to stay in place until a replacement can be found. E.g. A car windscreen being a perfect example of this.

However, toughened glass is much stronger and therefore requires a greater force to break, so the likelihood of this happening is considerably less.

What Are The Benefits of Using Toughened Glass?

As well as being a lot less fragile, toughened glass could save lives with its great safety and strength benefits. As it does not shatter into sharp glass shards, injuries are much less likely to cause severe injuries.

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