Safety glass are the most desirable which an average user would like to have in their windows. What makes the glass used in the window qualify for the safety glass? Colloquially, the term safe panes is usually assigned to laminated panes, consisting of two panes of glass with a standard thickness of 3 mm separated by a layer of 0.38 mm thick PVB film. Currently, this construction is called VSG 33.1. This name replaced the once-used classes O1 and O2.
Legal norms for safety glazing.
From April 23, 2012, there are norms in Poland determining whether a given glass can be classified as safety glass. These are among others:
- PN-EN 356:2000 – Polish Norm- Glass in construction – Protective window panes – Research and classification of resistance to manual attack.
- PN-EN 12600:2004 – Polish Norm- Glass in construction- Pendulum research – Impact test method and classification of flat glass.
- PN-EN ISO 12543:2011 – Polish Norm- Glass in construction- Laminated glass and laminated safety glass. Part 1: Definitions and description of components. Part 2: Safe laminated glass. Part 3. Laminated glass.
- PN-EN 12150:2002 – Polish Norm- Glass in construction- thermally tempered safety glass soda-lime-silicate. Part 1. Definitions and description and Part 2. Assessment of conformity of the product with the standard.
- PN-EN 1627:2011 – Polish Norm- Doors, windows, curtain walls, grates and blinds. Resistance to burglary – Requirements and classification.
The term “safety window glazing” is mentioned in the above-mentioned provisions many times. Applies not only to VSG 33.1 glass, but also laminated glass, laminated glass with fire-resistant properties, tempered glass and others. It follows from this conclusion that the term safe glass can be assigned to various types of ready-made glazing sets, both window and door.
Conditions for classification of safety glass.
One of the conditions for classifying glass to the category of safety glass is accomplishment the conditions contained in the above-mentioned Standards PN-EN ISO 12543: 2011 and PN-EN 12150: 2002 which determining their properties under the influence of a pendulum impact test method. This test determines the glass’s resistance to being hit by a soft body weighing 50 kg with different energy. Behavior of the glass after such impact can be sorted by type. Depending on the method of cracking occurring, the glass can be divided into type A, type B and type C, where type C is characteristic for tempered glass, which after impact breaks down into numerous, harmless, small fragments. An additional division is the division into three classes, where class 3 is the weakest class. The characteristics of safety glass fully describe the symbols used:
- α – means the highest falling height of the pendulum at which the glass pane has not been broken. It can have values 190, 450 and 1200 mm.
- β – means the way of cracking and takes on the values of A, B or C.
- φ – determines the highest fall height in a given class, at which the glass pane has not been broken or has been broken down in accordance with the product requirements.
Examples of safety glass signs.
To include glass in a safe group called “safety glazing” it must at least meet the requirements of class 3 (B). For example, tempered glass classified as safety glass will be described as 3 (C) 0 or 1 (B) 1 or 1 (C) 1. We can noticed that the safety glass can be both a regular sheet of laminated glass and reinforced glass, polished reinforced glass, annealed glass with a foil glued, thermally or chemically strengthened glass or float-type glass.
