Building glass
Building glass (also called silicate glass ) is a material that is melted from quartz sand , soda , limestone and dolomite .
Glass is a multiple mixture of different silicates (e.g. Na - Ca - Mg - silicates ), which has a large softening range, but no fixed melting point . When it cools down from its molten state, it is malleable up to 600 ° C. Its softening range depends on the chemical composition. For example, pure quartz glass remains usable up to around 1,000 ° C. In the solid state, glass is an amorphous substance, which is also physically referred to as a supercooled liquid. In Austria, sales of building glass in 2013 were 310 million euros.
In addition to glass blocks and concrete glass, building glass groups I and II belong to the area of building glass .
Building glass I
Glass ceramic
Glass with a proportion of small crystals is called glass ceramic . Because of its high softening point and its high thermal shock resistance, it is u. a. used for hotplates.
Window glass
Window glass (F) is a clear alkali-lime glass, which is mainly manufactured using the float glass process. Therefore it has a high surface quality, similar to polished mirror glass.
Clear garden glass / clear garden glass
Bare garden glass according to DIN 11 525 is a lower quality float glass that meets the requirements of gardening and landscaping. Garden clear glass is a cast glass with a light-diffusing underside and is standardized in DIN 11 526.
Toughened safety glass
Single-pane safety glass (ESG) was quickly cooled on the surface when it was hot, and thus toughened. It is therefore particularly unbreakable against impact , impact and bending . In mechanically verursachtem break it breaks into small glass crumbs. It is used for glass doors, parapet and facade panels , as well as z. B. also windows in sports halls.
Laminated safety glass
Laminated safety glass (VSG) consists of two or more glass layers that are glued together with highly elastic plastic films (PVB) or with the help of cast resin (soundproofing), which have a splinter-binding effect. VSG is therefore bulletproof and break-through resistant. It is also made with wire inlays and as multi-pane insulating glass . With so-called alarm glass in accordance with DIN 52 290, inserted wires enable a connected alarm system to be triggered in the event of a break.
Cast glass
This is a glass with structured surfaces, e.g. B. Ornamental glass (O), which has a decorative and creative effect and can be used to diffuse light and see-through. With an inlaid wire mesh, it is also known as wire glass (D) or wire ornament glass (DO).
Heat-resistant glasses for use
They consist of borosilicate glass and are used for cookware and roasting utensils (e.g. Jenaer Glas ) or for laboratory vessels.
Building glass II
Thermal insulation glass
Thermal insulation glass consists of several panes one behind the other, between which, depending on the type of glazing, there are one or more intermediate spaces filled with noble gas . It also has thin precious metal coatings on the glass surfaces. They are protected in the space between the panes and ensure that long-wave heat rays are reflected outwards, while short-wave rays are allowed into the room. Today, double thermal insulation glass achieves a U-value of 1.1 W / (m 2 K) (watts per square meter Kelvin). In the case of triple thermal insulation glass, this value is around 0.7 W / (m 2 · K) today . By way of comparison: for single glazing installed well into the 1970s, the value was still 5.8 W / (m 2 · K) and for double-pane insulating glass used before 1995 it was around 3 W / (m 2 · K).
Solar control glass
Solar control glass has a low total energy transmittance g-value as well as good thermal insulation and the highest possible light transmission.
It is available in different coatings .
- Reflective , with a metal or metal oxide coating on the inside of the outer pane, which mainly reflects the infrared part of the sunlight . The total energy permeability value g thereby drops to a value of up to 0.18. The coatings are blue or silver reflective on the outside and slightly brownish when viewed through. The key figures z. B. 60/40 means that 60% of the visible light, but only 40% of the total radiation energy (light + infrared) is allowed through.
- Absorbent , in which the outer pane is weakly colored ( green , yellow or gray ) and so absorbs part of the solar radiation. The expansion of the outer pane, which is heated more strongly as a result, must be observed. The inner pane is usually coated and therefore reflective.
- Opaque ones in which the space between the panes is filled with a fiberglass spun or a plastic honeycomb body. The light transmission is reduced by up to 50%, but this is required for skylights and commercial buildings or sports halls .
Soundproof glass
Soundproof glass consists of two panes of different thicknesses that measure up to 14 mm and 4 mm respectively to prevent resonance . The air gap is 12 to 24 mm and is partially used to further improve the sound insulation with a noble gas , e.g. B. argon or krypton filled. With increasing demands on sound insulation, the demands on the tightness of the window frames also increase .
Fire protection glass
According to German building law, fire protection glass is divided into two classes, F and G. The letter "F" stands for fire-retardant (F30), highly fire-retardant (F60) and fire-resistant (F90 and F120). The letter "G" stands for fire-resistant glazing (G30 to G120). The time indicated indicates the duration of the protective effect in a test according to DIN 4102 or EN 1364-1 in a fire test. A classification of fire resistance is only possible for a complete component, ie a system such as fire protection glazing consisting of fire protection glass, a suitable frame system, fastening elements and glazing materials (special blocks, seals, etc.). Transparent fire protection was only made possible and widespread 30 years ago due to the development of special glass products. F-class fire protection glass consists of several panes of silicate glass or single-pane safety glass, between which at least one transparent fire protection layer is embedded, which foams at temperatures> 120 ° C. The interlayer or layers become opaque. In the event of a fire, the fire-resistant glazing must remain effective as a room seal, prevent the passage of fire and smoke and must not let any heat radiation through, ie it must have an insulating effect (<140 K temperature increase). Glasses G-Class , wired glass, especially toughened glasses, other special glasses and glass-ceramics have fire protection layers and protect usually just before the passage of fire and smoke. They are therefore considered to be less resistant, secure the room closure, but offer little or no protection from heat radiation, which , if turned away from fire, can lead to high temperatures and spontaneous combustion of combustible materials such as carpets or furniture.
swell
- Werner Vogel: Glass chemistry . 3. Edition. Springer-Verlag, Berlin 1992, ISBN 3-540-55171-9 .
- Josef Wessing: Construction technology tables . 12th edition. Westermann-Verlag, Braunschweig 2007, ISBN 978-3-14-225034-2 .
- Construction engineering . 21st edition. Wiley-VCH Verlag, Darmstadt 2007.
Web links
Individual evidence
- ↑ Falling demand for building glass , gff-magazin, March 27, 2014