Toughglaze (UK) Ltd - Leaders in glass

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Welcome to the latest Toughglaze (UK) website which has been updated with new and useful information about the glass that we manufacture. The many different applications and services Toughlaze (UK) has to offer include Digital Printing on Glass & Solar Panels.

Heat Soaked Glass

At Tough Glaze we are finding the use of toughened glass in buildings is increasing with the now routine construction of large glazing screens, glass roofs and curtain walls, nickel sulphide inclusions is now an issue.

Glass is produced from bulk natural materials which are then processes to an extremely high standard but these naturally occurring products inevitably contain a level of low level of impurities. Nickel Sulphide is one of the causes of failure of toughened glass. The presence of Nickel Sulphide in a batch of glass is variable and it is quite likely that large quantities of glass may contain comparatively low levels of Nickel Sulphide and the reverse is true.

An understanding of the problem by the manufacturers has caused them to take steps to eliminate this impurity.

When Nickel Sulphide impurities are present they are in the form of small crystals. There differing crystalline forms each stable within various temperature ranges. They are not generally a problem in annealed glass but become an issue in toughened or heat strengthened glass. When rapidly cooled the glass is hardened around a shrunken version of the crystal. This process is so fast that it does not allow the crystal to revert to its more stable form.

The modified Nickel Sulphide crystal must revert to its low temperature form but as it is trapped in the glass it can only do this slowly and as it does so the crystal expands and it is this process that places intolerable stresses on the hardened glass and failures result. This will only happen if the crystal is large enough to place sufficient stress on the glass.

The actual rate of occurrence of Nickel Sulphide is low but the user of the glass must consider the effect and threat to Health & Safety of such an inclusion in all the glass specified.

Toughglaze offer a heat soaking process that complies with BS EN 14179. In this process the glass is heated and maintained at a temperature then slowly cooled in a heat soaking oven which encourages the conversion of the Nickel Sulphide inclusion to its more stable form.

Please note that even heat soaking to the most rigorous category will not guarantee the conversion of all Nickel Sulphide so there is still an inherent possibility of failure however the failure rate is greatly reduced.

Based upon the European rate of Nickel Sulphide inclusion, there will be one critical inclusion in every 4 tons of glass. The table to the right provides a guide to the levels of heat soaking required.

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Products & Services

Toughglaze provide a variety of products and services, have a look at our range below for more insight:

		Digital Printing on Glass (New)

		Solar Panels (New)

		Toughened Glass

		Laminated glass

		Fire Rated Glass

		Glass Doors

		Balustrading

		Screen Printing

		Sandblasting

		Acoustic Glass

		Antibacterial Glass

		Partitioning

		Heat Strengthned Glass

		Heat Soaked Glass

		Glass Floors