How Is Tempered Glass Made?

December 5, 2023
February 1, 2023

Most of the glass you come across in public and private spaces, such as microwaves, shower cubicles, doors, and windows are made of tempered glass. They are made of almost four times as strong as "regular" glass, so they won’t easily break. It is even used in hurricane windows and doors in Boca Raton, FL.  

If tempered glass does receive an impact strong enough to break it, it does not shatter into sharp shards but instead breaks into tiny granules. The frequent use of tempered glass as a safety precaution is why people opt for this type of glass.  

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Process of Making Tempered Glass  


First, the glass is cut to the appropriate size. To ensure the integrity of the glass, cutting is necessary before the tempering procedure begins. Before tempering, the glass is examined for defects to reduce the likelihood of breaking and shattering. Manufacturers use sandpaper or other examples of abrasive materials used to reduce sharp edges.  

Heat Treatment  

The glass is prepared, then heated to a temperature of more than 1,112 degrees Fahrenheit in a tempering oven. Such temperature is even more intense than the temperature of lava.  

A damaging test called the "Heat Soak Test" is applied to lessen the likelihood of unexpected tempered glass breaking. Likewise, this test is used to lessen the risk of spontaneous breakage by Nickel Sulphide (NiS) inclusions. The tempered safety glass undergoes an additional heat process in this test.  

Moreover, the heat soak test involves heating and cooling the glass in line with preset temperature curves governed by the EN 14179 European standard. This treatment removes the bulk of the at-risk glass since it is destructive. But it is impossible to remove all the impacted material at this time due to technological limitations. Nevertheless, the possibility of spontaneous breakage is much reduced.    

The heat soak test is recommended when the stability of the work, upholding closure or covering volume, and/or the safety of users may be in jeopardy owing to tempered glass breaking.  


The glass is then quickly cooled using the "quenching" method of high-pressure cooling. It is blasted with high-pressure air, which causes the external surface to cool considerably more quickly than the interior. The center tends to move away from the outside surface as it cools. As a result, the center maintains tension as the surrounding surface collapses.    

Glass is approximately five times more breakable when it is under tension than when it is compressed, which is how tempered glass gets its strength. During quenching, the outside surfaces of the glass cool more quickly than the inside. As the glass cools, the core tries to separate from the exterior surfaces. Tempered glass gains strength due to the center's tension while the outside surfaces collapse.  

Another technique for producing tempered glass is chemical tempering, in which several chemicals exchange ions on the glass' surface to induce compression. This method is not widely used because it is significantly more expensive than quenching and using tempering furnaces.  

Uses and Applications for Tempered Glass  

Tempered glass is very adaptable and is used in various products. It is used in the construction of car windows for cars. Manufacturers use this type of glass because it will break into smaller, duller pieces than annealed glass, making tempered glass the safer choice.  

Additionally, tempered glass is used in your home's heat-sensitive appliances, such as stovetops, countertops, ovens, and tabletops. It is used anywhere that requires glass that can endure lots of pressure, so if it breaks, injuries can be expressly prevented by its design.  

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Inquire About Hurricane Windows and Doors in Boca Raton, FL  

Tempered glass is ideal for high-pressure windows, illumination elements, display cases, and heat-tolerant devices or appliances. Give us a call for more information.