Safety Glass

Safety Glass is the generic name for glass which has been treated to make it safer than normal glass.

Normal float glass can be dangerous. It is brittle, so it breaks easily. When broken, the pieces form razor sharp edges that can cause serious injury. How many times have you accidentally broken a drinking glass and the pieces spread across the room? Everyone is warned to stay away until it is cleared up and no-one is allowed near it with bare feet.

In places with the biggest likliehood of serious injury, safer alternatives are employed.

The main types of safety glass are:

Toughened Glass

When toughened glass breaks, it forms little cubes which are much safer than glass shards. It can still cuase injury but usually it causes scratches rather than deep cuts.

This is often found in the side windows of cars and in glazing in buildings. It is made from normal float glass. After float glass has been manufactured, it is then heat treated.

Laminated Glass

Laminated glass consists of 2 layers of glass held together by a 'sticky' film. It is safer than normal glass because if broken, the pieces of glass stay together attached to the film rather than scatter all over.

This glass is used to make windscreens in cars and public transport. It is common to break the windscreen with a chip from the road for instance. The glass, however, remains intact.

Specialist Glass

Glass can be specifically built for a specific purpose, for example, being able to withstand high impact. Bullet proof glass and riot shields are examples of when this may be required.

The construction of this glass varies depending on the use. Laminated glass using special films or extra layers to add strength may be employed. Other materials, such as polycarbonate may also be used. This is a specialised field requiring specialist equipment to manufacture and test the glass.

Other Coatings

Glass is sometimes coated in a film to make it safer. The coating binds the glass together if it gets broken in a similar way to laminated glass, but the coating is applied to one side only. An example of this is Pilkington Optimirrorâ„¢ Protect which is a mirrored coating applied to the glass.

Standards and Markings

In the European Union, Safety Glass must comply with relevant standards:

EN 12600 refers to impact strength. The glass must be tested using the methods prescribed in the Standard and the results within the specified acceptable range.

EN 12150 - This standard must be reached for 'Thermally toughened soda lime silicate glass'. A company that manufactures Toughened Glass must comply with this standard. It checks that correct and accurate processes are being carried out to ensure the quality and consistency of the product.

EN ISO 12543 and EN 14449 - These standards must be reached for laminated glass.The manufacturer must comply with the manufacturing standards which ensure that the glass reaches the correct quality.

In the EU, safety glass needs to be marked to show what type of glass it is and that it complies with the relevant manufacturing standards. This is done with CE Marking. A CE Mark has the following information:

The CE Logo

The Notified Body Number - A Notified Body is the organisation which audits the manufacturer to ensure compliance with the standards

The Manufacturers name and address

The year that the CE mark was affixed

The Certificate Number - a certificate provinbg compliance following assessment by the Notified Body

The Product Standard NUmber, eg, EN12600

Product data not in the standard - For example, thermal conductivity or thermal strength information.

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