Safe glasses, which do not cause injuries when breaking – these are laminated glasses, which in case of an accidental impact maintain their shape and do not fracture. Another variant is a toughened glass pane, which breaks into small blunt glass pieces. But regarding deflection properties, the toughened glass pane is almost five times harder than an ordinary glass with the same thickness. In explosive hazardous rooms thicker, multiple toughened laminated glass panes should be used.
Vandalism-resistant glasses, which should resist impacts of accidental objects (external appearance of the glass is maintained) – these are preferably toughened glass panes with the thickness starting from 8 mm or laminated and toughened glass panes, whereas in the laminate the external glass pane is toughened, minimum thickness 6 mm and the second glass pane may be ordinary glass with the minimum thickness 4 mm.
Burglary-resistant glass panes are designed to make physical attack more complicated and to prolong it – it is recommended to use thicker laminated glass panes or glass panes laminated from several thinner glass panes. Implementation of toughened glass panes in the laminate will make the glass pane even harder. A safety film may be applied on the internal surface of the glass pane. The film is evaluated per peel strength (N/m), which is equal to the respective value of the laminated glass pane. To protect against armed attack special laminated glass panes are manufactured, where toughened glass panes laminated with a special flexible film are used. According to the security category bullet-resistant glass panes may also be manufactured so that they do not form glass pieces, so that when the bullet enters the glass, the glass pieces will not drop out from the other side.
Data communications protection. Radio waves are the most known type of electromagnetic radiation. Frequency ranges UHF and VHF are used in computers, FM radio, TV and radars. All computers emit electromagnetic radiation with different spectrum. Part of this radiation can be received decoded and with listening devices. The same system also functions vice versa and gives a possibility to send signals to the computer. It is possible to build rooms that would restrict undesired data exchange and limit radiation. In such a case walls should contain metal. Efficiency of this system can be controlled the same way as voice strength – in decibels. Electromagnetic protection efficiency of glass is close to zero. But if the glass surface is covered with electrically conductive coating, it turns into a protective material.
The efficiency of the structure may be increased by adding one more glass pane with special protective film either by laminating or by manufacturing an insulating glass unit. All Pilkington DataStop products are provided with double protective coating on all glass surfaces. Non-transparent parts of walls and floors and ceilings of rooms should be covered with metal mesh (usually made of copper), which with window frames, glasses and doors would form a continuous surface. Each slightest interruption reduces protective efficiency. Thus there should be no openable windows in the protected, covered room. Coated glass such as Pilkington DataStop gives the most efficient protection against high-frequency FM wave and radars.
One-sided visual contact. There is no such glass that is transparent from one side and not from the other. The approximate effect may be achieved only artificially by changing the environment where glass is installed and its optical impact on the glass. Reflection capacity of a glass pane depends on the light intensity of the glass from both sides. By creating a proper environment one-sided transparency can be achieved with each glass pane. In many glass types it is created when natural daylight is imposed on the side to be viewed but the opposite side is as dark as possible.
For instance 12 mm Optifloat body tinted glass (gray) creates one-sided transparency in the light conditions 60:1. In reality the usable product would need higher surface reflection. Pilkington Surveillance Mirror is a glass characterised by high surface reflection properties and extraordinarily low light transmittance. Reflection and light transmittance is similar on both sides. In case of Pilkington Surveillance Mirror glass the ratio is 7:1 and in case of an ordinary float glass with a thickness of 6 mm it is 250:1. To achieve effect an insulating glass unit or laminated glass plane with reflective surface coating and a thicker Optifloat body tinted glass plane (light absorbs on both sides) may be combined.
Mesh curtain effect. The surface of the glass pane is covered with a special mesh. When light on one side is more dull/darker, back reflection effect is created on the side where the light is lighter. The strength of the back reflection effect depends on the observation distance. During daytime the light level outside the room is much higher than inside and this would make it very difficult to see through the mesh curtain, except in cases the viewer is so close that he/she can ignore reflection and look through a mesh opening. Yet the viewer looking from the side the light is darker sees very little back reflection. To get a good idea look at the ads on the tram windows.
Laminated security glass panes
Laminated security glass panes are used in places where ordinary glass panes do not give sufficient protection against weather, mechanical load or burglary. Usually glass panes are bonded with hard and flexible clear or coloured PVB film or with resin, if CIP manufacturing process is used. By increasing the number of glass panes and films laminated glass panes can also be used in more demanding requirements. For extreme conditions the toughened glass panes harder than normal glass panes are laminated with a film with a thickness of 0.76 mm or more. Laminated glass panes can also be manufactured in bended shapes, to be used in corner windows of a building for instance.
Toughened security glass panes
For manufacturing toughened glass panes horizontal tempering method and oscillating devices are used. The optical properties of glass are of high quality and the plane is with precise measures. A toughened glass pane is a pre-tensioned glass pane, manufactured in precisely controlled heat processing. The bending strength of a toughened glass pane (s = 5171 kp/cm²) is five times bigger than of an ordinary glass plane. When broken the toughened glass pane breaks into small blunt glass pieces, which do not cause cut injuries. Toughened glass panes are normally recommended to be used in skylights, façade glazing or in the structural insulating glass unit.
Application of security glass
1. Car glazing
2. Engine room glazing
3. Ship and yacht glazing
5. Balcony glazing
7. Table glazing
8. Interior glazing
9. UV-resistant glazing
10. Door glazing
11. Doors made of full glass