The higher the required safety level of safety glass for facades, the heavier the panes. This is where a development by Silatec and the Technical University of Siegen comes in to produce lighter safety glass. Silatec Managing Director Christoph Hahn explains the details.
GW News: Why is the demand for safety glass currently increasing, and is it aimed more at facade glass or glass for interiors?
Christoph Hahn: I think there are several factors responsible for this: the gap between rich and poor is widening and there is also a feeling of insecurity. In addition, the increasing propensity to violence, especially in cities, probably plays an important role. Also, it is important to take into account the major terrorist attacks of the last few years.
Why is the weight of safety glasses of a higher safety level so relevant?
Essentially for two reasons: With turn-tilt elements, the maximum weight is limited by the fittings. With triple insulating glass, the weight of the glass has increased anyway. In addition, architects want ever larger glass surfaces - this weight must be absorbed constructively and also be able to be handled logistically.
Technical University of Siegen
In a research project with the Technical University of Siegen, Silatec has developed a thin safety glass with polycarbonate that achieves the P8B resistance rating against manual attack. Here on the right, seen as basic glass for an insulating glass pane.
How did the joint research project with the Technical University of Siegen come about? What are the results?
We have been researching and working successfully with the Technical University of Siegen for a very long time. In addition, we have been dealing with the question of how to construct attack-resistant glazing more efficiently for about 30 years. And so it was actually logical for us to tackle this topic together. The result is a P8B glazing with a nominal thickness of 20 mm and a weight per unit area of approx. 28 kilograms per square metre. In addition, the Ug-value is improved because plastics are less thermally conductive than glass.
What does the structure of the new pane look like? And why is the combination of polycarbonate and glass a good alternative?
The construction of the pane depends on the glass structure and the size of the pane. In principle, thin glass only makes sense for relatively small pane areas. Where the need for protection is particularly high, the combination of thin glass and polycarbonate makes a lot of sense, for example in burglar-resistant escape doors.
The result of our latest research project together with the Technical University of Siegen is a P8B glazing with a nominal thickness of 20 mm and a weight per unit area of around 28 kilograms per square metre.
What happens in the event of glass breakage, in terms of residual load-bearing capacity and splinter bonding?
Tests conducted as part of the research project have shown that the intermediate layer binds glass splinters sufficiently well. Together with the glass fragments, polycarbonate ensures the residual load-bearing capacity in the compression zone of glass that is subjected to bending stress.
Can the newly developed glass also be used for emergency exit doors?
Yes, especially for burglar-resistant fire escape and panic doors of resistance classes RC2, RC3 and RC4, as these types of doors place much tougher demands on the glass than those defined in EN 356. Conventional laminated safety glass solutions would not be able to obtain approval here.
The interview was conducted by Matthias Rehberger.
How does the lightweight safety insulating glass from Silatec work exactly?
The new triple insulating glass with thin glass and polycarbonate achieves a heat transfer coefficient of less than 0.7 W/(m2K) and a total energy transmittance of 56 per cent with its 12 mm intermediate space and a gas filling of krypton as well as a thermal insulation coating. This means that it meets the current energy requirements. These thermal and safety properties can be achieved with a cross-section that is 33 per cent slimmer and a structure that is up to 64 per cent lighter.
