There are 3 types of glass that can be used as glass canopy.
Single-pane Tempered glass
Heat-tempering/Fully-tempered Laminated Glass
Heat-strengthening Laminated Glass
1. Single-pane Tempered Glass
When glass is tempered, it is heated beyond glass softening point of 600℃, then the glass is cooled rapidly creating a higher surface compression and edge compression in the glass.
This tempering process will make the glass up to 4X stronger and safer than annealed or untreated glass. Tempered glass is also less likely to experience breakage through thermal shock.
The disadvantage of tempered glass is prone to spontaneous breakage due to inclusions or tiny impurities in the glass such as nickel sulfide or if a treatment such as machining was applied to the edge post-tempering causing the glass to break.
In recent years, to avoid spontaneous glass breakages,heat soaking has been widely used. Heat soaking is a process that may expose NiS inclusions in tempered glass. The process involves placing the tempered glass inside a chamber and raising the temperature to approximately 550°F or 287° to accelerate NiS expansion.
2. Heat-tempering/Fully-tempered Laminated Glass
Entrance canopies are overhead glazing by definition and the selection of an impact-resistant durable glass panel is essential.
Heat-tempering laminated glass has the benefits of both tempered glass and laminated glass, not only owning a stronger mechanical strength but also glass fragments won’t fall down in case of breakage, and all glass fragments will stick to the interlayer PVB or SGP film.
3. Heat-strengthening Laminated Glass
As the name suggests, heat-strengthing laminated glass consists of two heat-strengthing glass panes laminated by interlayer PVB film or SGP film.
Heat-strengthened glass undergoes a slower cooling process than tempered glass resulting in lower compression strength. Heat-strengthened glass is approximately 2X stronger than annealed, or untreated glass. Heat-strengthened glass provides a better surface quality as compared to tempered glass, as it is less prone to cosmetic defects potentially incurred during the strengthening process. See ASTM C-1048-4 for further details.
Which kind of glass is suitable for canopy depends on the project environment, location and project needs.
To know more about our glass products, or find building glass suppliers and manufacturers, please contact us:
www.migoglass.com
