Security Glass
Architectural Armour supply security glass and a wide range of security products for the protection of people and assets. Our comprehensive glazing products include
Physical Attack Resistant Glass
Security Glass is produced worldwide for a range of applications using many different manufacturing methods, as a result there is often some confusion as to which construction is most suited to which application.
To help explain it’s probably best to give a brief guide of the most commonly used types of glass, and how some are used in the manufacture of security glazing systems.
Float Glass
Float glass is a single monolithic piece of flat glass; it’s made by floating molten glass on a bed of molten metal to give the sheet a uniform thickness and very flat surface. When used on its own, float glass has almost no security value as it’s easily broken and breaks into large, jagged shards.
Toughened Glass
Toughened glass is manufactured by subjecting the float glass to a heating and cooling treatment. A balance of high compressive stresses at the surface and tensile stresses in the centre of the glass increases its strength. The result is a glass that is approx. 5 times stronger than ordinary glass of the same thickness, but it can be easily broken by an impact such as a ball hammer, where upon it breaks into small, blunt-edged fragments instead of splintering into jagged shards. When used alone it could be considered safety glass but has little security value as it leaves nothing in place to protect your assets.
Laminated Glass
Laminated glass is manufactured by bonding together two or more layers of high quality float glass under heat and pressure using an interlayer of polyvinyl butyral (PVB). The PVB serves to maintain the integrity of the glass following deliberate or accidental damage. Dependent on the make up of the laminated glass, it could be considered a safety, attack or bullet resistant glass:
Laminated Safety Glass is intended for use in architectural applications where in the instance of accidental damage the use of monolithic glass would present a hazard. Laminated safety glass may craze locally following impact, but will retain its integrity. Typically Laminated Safety Glass is a 3 ply construction, consisting of two layers of glass sandwiching an interlayer, the thickness of both the glass and PVB are adjusted to give a number of differing options dependent on application, but even when laminating toughened or heat strengthened glass they do not provide the level of integrity of the multiply constructions.
Laminated Security Glass
Laminated Security Glass is a broad term to describe a range of multiply constructions to give either Physical or Bullet Resistant protection. Constructions vary but are generally designed to offer products to comply with physical attack standards such as EN 356 and LPS 1270, or bullet standards like EN 1063 or BS 5051.
These more complex assemblies can range from 5 ply constructions such as 11.3mm 5ply, i.e. 3 layers of glass and 2 pvb interlayer’s, to 13 ply constructions over 70mm thick. In addition to varying the thickness of glass and pvb interlayer’s, the use of heat strengthened, chemically toughened or polycarbonate layers can achieve improved performance.
The following pages give more detail into attack and bullet resistant glass, but if there was one point to get across, it would be not to assume that safety glass has the same physical strength as security glass. Toughened glass is stronger than float but will disintegrate when attacked and 3 ply laminated glass will not stop a determined criminal for long.
Please contact us to discuss your project requirements.
