Saint-Gobain’s introduction to glazing know-how
Glass has existed for more than 5500 years since its discovery during early civilizations. The term “glass” was not used until the Roman empire who developed and perfected the technics of glass-making. Since Saint-Gobain’s creation in 1665, then known for the famous Hall of Mirrors at Louis XIV’s Versailles Palace, we have improved glass composition, in order to respond to different market needs.
Today, we wish to share our knowledge with you.
The flat glass used for Building and Automotive (Transport) applications is made thanks to a process called float glass.
It consists to melt raw materials: Silica, Lime, Soda, Oxide/aluminia/magnesia and nowadays recycling glass (cullet) at a very high temperature from 1000° to 2000°. Then, the glass is poured onto a tin bath. The glass, less dense than tin, "floats" on it and forms a ribbon.
The glass obtained is perfectly flat with a regular thickness, the glass ribbon is cut in large panes of 6 000 × 3 210 mm ready to be transformed by our Transport plant.
Saint-Gobain develops in-house coatings to add functionalities on glass-like heating, Solar control, antireflection ...
The coated glass is obtained by Magnetron process: the glass is coated with nanometriclayers: an ionized gas is projected onto blocks of targeted raw material tearing off its molecules, which are deposited on the glass.
There is 2 kinds of coating :
- Soft coat Ag-based to be protected as it can corrode (insulated glass for example)
- Hard coats like Comfortsky & Reflexcontrol to be in contact with passengers.
These coatings are thin film(nm), invisible.
Laminated glass was discovered in 1909 by French chemist Edouard Benedictus. It consists of two glass panes bonded together by an interlayer: PVB (Polybutyral de vinyl). In the event of breaking, the glass fragments are held in place by the interlayer.
Since the 1980 's the regulation requested that on-road vehicle's windshield has to be laminated. The regulation has evolved and some driver doors or side windows are allowed in laminated glass mainly for truck and rail vehicles.
Laminated Glass Process
The main benefits of laminated glass are
- Safety and security
- Repairable in case of crack (not in the driver area)
- UV filter
- Strong stress resistance
- Ideal to add optical functions, thermal and acoustic insulation
Tempered or Toughened glass
Is a safety glass processed by a controlled thermal treatment to increase its strength compared to normal glass (6 times more). After the thermal process, the outer surfaces are in compression, and the inner surfaces are into tension. In addition, this reduces the risk of injury because glass breaks into small, circular pieces instead of sharp, jagged shards.
Tempered glass is used in every transport and off road vehicles, mainly for doors, side and driver windows, roof and backlight.
We supply zone tempered windshield as well for the agricultural market.
Tempered Glass Process
The main benefits of tempered glass are
- tougher than ordinary glass
- heat resistance
- scratch resistant
- easy to clean
Insulated glass (Double Glass Units)
It consists of 2 sheets of glass separated by an air (or gas) gap and assembled together by a peripheral spacer to assure an optimal thermal and acoustic insulation.
Some basics about glass
Glazing is a unique material thanks to its incredible intrinsic properties :
- Optical transparency (refractive index:1,5)
- Mechanical resistance: heat, pressure, breakage and chemicals
- Thermal insulation
- (AU) AS NSZ 2080
- (BE) L47/L48
- (BR) IMMETRO
- (CN) TB T1451 / CCE
- (DE) BN TL 918511
- (EU) EN15152 / UIC 651-566 / TSI ECE R43
- (FR) NFF15-818/NFF31-129/NFF31-250 / NFF31-314 / NFF01-492
- (IN) IS 2553
- (JP) JIS R 3213
- (KR) KSL 2004
- (RU) GOST 5727
- (SE) TB20/100
- (UK) GMRT 2100
- (USA) ANZI FRA
The norms governing Transport vehicle glass are becoming ever stricter and more demanding.
For several years now, we benefited from our own test installations that are accredited.These tests and controls are carried out in accordance with established European and International norms and operators specifications .
Every Sekurit Transport plants are Iso certified and IRIS for rail .