faceboo Understanding Toughened Glass: A Comprehensive Comparison Guide

Interesting Differences: Toughened Glass vs Tempered Glass vs Annealed Glass

May 12, 2023
Last updated on December 27, 2023

Glass is a ubiquitous material used in almost all industries. However, there are different types of glass available in the market, each with unique features and applications.

This blogpost focuses on toughened glass and a comprehensive comparison with other glass types like tempered, annealed, and heat-strengthened glass.

The Relationship between Toughened Glass and Tempered Glass

  1. Toughened glass, also referred to as safety glass, is renowned for its strength and reliability.
  2. Toughened glass is essentially a type of tempered glass, with the terms often used interchangeably.
  3. The manufacturing process involves subjecting regular glass to intense heat, followed by rapid cooling, resulting in a significantly enhanced resistance to breaking. In the unlikely event of breakage, toughened glass shatters into small, harmless pieces with blunt edges.
  4. Tempered glass undergoes a similar process, but it is further enhanced through chemical treatment.
  5. The outstanding characteristics of toughened glass include its exceptional durability, impressive strength, and ability to withstand thermal stress.
  6. It finds wide application in  architecture, (residential and commercial buildings - both interiors and exteriors 
  7. Some of the examples of interior and exterior applications of toughened glass are:


toughened glass partition

Toughened Glass vs. Annealed Glass

  1. Annealed glass is the fundamental form of glass commonly utilized in the production of various glass products. It is made by heating the glass to a high temperature and then slowly cooling it.
  2. Unlike toughened glass, when annealed glass breaks, it shatters into sharp, large, and hazardous shards. On the other hand, toughened glass shatters into small, harmless pieces that reduce the risk of injury.
  3. Toughened glass thickness varies from 3 mm to 12 mm based on the area of application. Normal thickness is 4 mm which is the same as regular/annealed glass.

window glass

Toughened Glass vs. Heat-Strengthened

  • Heat-strengthened glass is built through controlled heating and cooling techniques. Here the temperature used to heat ordinary glass is lower than that of toughened glass.
  • It breaks into larger, sharper fragments compared to toughened glass.
  • It provides improved resistance to thermal stress when compared with annealed glass. However, toughened glass has higher resistance to thermal stress when compared with heat-strengthened glass.
  • Its frequent installations are found in architectural applications, such as curtain walls and spandrel panels.

Shower cubicle

Frequently Asked Questions

Can laminated glass/glass laminate replace toughened glass?

While laminated glass may not possess the same level of physical strength as toughened glass, it is specifically engineered to prevent shattering upon breakage, ensuring safety. Toughened glass fractures into small, rounded pieces, whereas laminated glass remains intact due to the presence of a PVB layer that holds it together. They can both withstand high pressure and heat and the terms can be used interchangeably.

How to distinguish between tempered and regular glass visually?

Tempered glass can exhibit curved edges, etched logo/label, and reflections with distortions when observed from an angle. Look for the Saint-Gobain assured logo to confirm genuine glass.

Toughened glass is commonly used in which industry?

Due to its high strength and break-resistant property i.e strong durability, common usage of toughened glass is found in many decorative and architectural applications, such as in residential, commercial, automotive, technological, and sports/leisure industries. Examples range from shower cubicles, partitions, balustrades, railings, furniture i.e. table tops. 

What is the difference between toughened, heat strengthened and laminated glass?

Laminated glass consists of layers with a Poly Vinyl Butyral (PVB) interlayer between the two sheets of glass. The PVB holds them together when shattered, providing enhanced security. Toughened glass is created through rapid heating and cooling, making it more resistant to breakage. Heat-strengthened glass is subjected to controlled heating (but at a lower temperature than that of toughened glass) to enhance its strength without the intense rapid process of toughening. During the rare instance of breakage, heat-strengthened glass breaks into larger, sharper pieces when compared to toughened glass, which breaks into smaller, blunt, harmless pieces.

What is the main difference between annealed glass, heat-strengthened glass, and fully tempered glass?

Annealed glass is the most ordinary form of glass (untreated glass) and breaks into sharp shards when shattered. Heat-strengthened glass is stronger than annealed glass but breaks into larger, sharper pieces causing injury. Fully tempered glass undergoes intense heating, rapid cooling and controlled chemical treatment. This makes it stronger than both annealed and heat-strengthened glass. In rare cases, fully tempered glass breaks into small, squared, harmless fragments.

What are the two types of toughened glass?

The two types of toughened glasses are: chemically toughened and thermally toughened. Thermally toughened glass undergoes an additional heating process to minimize the risk of spontaneous breakage, while chemically toughened glass is treated with chemicals to enhance its strength.

What is the difference between annealed glass and normal glass?

Both annealed glass and normal glass are the same and the terms are used interchangeably.

Does toughened glass reduce heat?

Yes, toughened glass is heat resistant. This is why it is used in commercial buildings – schools, apartments, government buildings and offices. Double-glazed toughened glass is an excellent option for enhancing heat insulation in residential settings.

Watch a short video here about using Toughened Glass for the Toughest Ramp Walk




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