What is Tempered Glass?

Summary:Tempered glass is glass made by heat treatment to increase i...

Tempered glass is glass made by heat treatment to increase its strength. Tempering compresses the outer surface and pulls them inside. But, when it breaks, it will turn into small pieces instead of big pieces like regular tempered glass.


Tempered glass can use for many purposes like in car windows, aquariums, shower doors, etc.


Process in creating tempered glass


Made on heating glass with a temperature of 650 - 700 degrees celsius and then using rapid air cooling. It will be 4 - 6 times better and stronger than regular glass.

When the tensile strength of ordinary glass is 40 MPa (N / mm2), the same value for toughened glass is 120-200 MPa (N / mm2). The safety of tempered glass depends on the thickness of the glass, the treatment of the edge of the glass, and whether the glass has holes.


As a result of thermal hardening, we thus get a so-called harmless glass.




Tempered glass is 4 times stronger than regular glass. The more accurate the manufacturing process, the stronger the glass is. Strengthened 6 mm thick glass must have either the smallest surface compression of 69 MPa (10,000 psi) or the least edge compression of 67 MPa (9,700 psi). To know safety glass, the surface compressive stress must exceed 100 megapascals (15,000 psi). Because of the increased surface tension, the glass breaks into small round lumps when it breaks, as opposed to sharp pieces.

Compressive surface stresses give tempered glass increased strength. Annealed glass has little internal stress and usually forms fine cracks on the surface. The stress applied to the glass can speed up the spreading of the crack, and when this is started, the stress focus on the tip of the crack, facilitating the spreading of the crack through the glass at the speed of sound. As a result, tempered glass is fragile and breaks into irregular, sharp shards. The compressive stress on the surface of tempered glass contains defects that prevent the glass from propagating and expanding. Before tempering, it must be cut or ground. Cutting, grinding and sharp impacts after tempering will destroy the glass.


The strain pattern due to annealing can be observed by looking through an optical polarizing element such as a polarizing element. Consider polarized sunglasses.




Tempered glass is used when strength, heat resistance, and safety are important considerations. For example, a passenger car has all three requirements. Because they are stored outdoors, they are exposed to constant heating and cooling throughout the year, as well as temperature changes. It also needs to withstand small impacts from road debris such as rocks and road accidents.


Large, sharp pieces of glass pose an extra risk to passengers, so use tempered glass to make the pieces dull and almost harmless if broken. Yet, the windshields are made of laminated glass that won't shatter when broken, while the side and rear windows have been made of tempered glass. Some new cars have laminated side windows to meet occupancy restrictions, anti-theft purposes

Other typical applications of tempered glass include:


l  Balcony doors

l  Athletic facilities

l  Swimming pools

l  Facades

l  Shower doors and bathroom areas

l  Exhibition areas and displays

l  Computer towers or cases

l  Mobile phone screen protectors

l  Buildings and structures


Tempered glass is also used in buildings (for their frameless glass doors). Some buildings in the U.S. have standards that include skylights, glass installed near doors and stairs, large windows, windows that extend near the ground, sliding doors, elevators, fire department access panels, glass, etc.


Shower Doors


Yup, one of the uses of tempered glass is for shower doors. With its natural transparency, it can give an elegance than can always fit whatever design of your bathroom is.

Why is tempered glass used for showers?


The most used product for building shower doors is tempered glass. This glass undergoes a much more durable heating and rapid cooling process than tempered glass. The edges of the tempered glass remain vulnerable to breakage, but this product contains extra safety features.


Household uses


Tempered glass is also used at home. Some examples are Oven, Tabletops, Glass shelves, Cabinets, Fireplace, etc.




Some Restaurants use tempered glass for their plates, windows, and shelves. Some manufacturers offer tempered drinkware because of its strength and thermal shock resistance. In some countries, these products are specified in venues that must increase performance levels or need a safer glass due to intense usage.


Tempered glass has been used in bars and pubs, particularly in the United Kingdom and Australia, to prevent broken glass from being used as a weapon.


Tempered glass products can also be seen in hotels, bars, and restaurants to reduce glass breakage and raise safety standards.


Cooking and baking


Some forms of tempered glass can be used for cooking and baking. Manufacturers and brands include Glasslock, Corelle, Pyrex, and Arc International. This is also the type of glass used for ovens.

Touchscreen devices


Most mobile phones today use tempered glass for protecting their main screen from scratches. It is known as a screen protector.


Maintenance Tips


Never use abrasive cleaners on glass shower doors. Do not use polishing powder, pads, steel wool, or cleaning agents containing bleach or ammonia. These products can damage the glass and corrode the shower door hardware over time. You should clean the glass shower doors weekly with a cleaning agent that will not damage the glass. You can spray the glass with 1 part of vinegar, 4 parts of water, and a few drops of mild dishwashing liquid. Place the solution on the glass for a few minutes and then wipe it clean with a microfiber cloth.


The Explosion rate of a Glass


Shower door glass has a spontaneous explosion rate of 3 %, whether it is a frameless or framed shower door. If you are not careful, your safety is at risk.


Why Glass Explode?


In some cases, this is due to the inherent nature of the tempering process. Since the glass contains nickel sulfide, it can break naturally. Enclosures can grow over time and generate stresses that can be damaged under heat and other external stresses.


How to Identify a Tempered Glass?


Tempered glass usually has perfectly smooth edges due to the extra treatment, while other types of glass usually have worn or wavy edges. If the edges of the glass are exposed, move your finger along them.


What are the disadvantages?


Tempered glass must be cut or stamped before tempering and cannot be machined after tempering. Polishing or drilling the edges of the glass is done before the tempering process begins. The balanced stress of the glass causes the glass to eventually shatter into thumbnail-sized pieces when the part is damaged. Glass is prone to breakage due to damage at the edges where the tensile stress is most, but it can break if a strong or concentrated impact to the center of the glass plate (for example, glass). It is struck at the hardened point)


Tempered glass can pose a safety issue in some situations, as it tends to completely shatter the glass in the event of a strong impact, rather than leaving debris on the glass.


The surface of tempered glass shows surface waves caused by contact with smoothing rollers when formed using this process. This swell is a serious problem in the manufacture of thin-film solar cells. The float glass process can be used as an alternative to various glazing applications to provide low warpage sheets with very flat and parallel surfaces.


Defects in nickel sulfate can destroy tempered glass in the first few years of manufacture.


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