Guardian Insights

The Basics of Heat-Treated Glass

Dec 2, 2019

By Chris Dolan

From skyscrapers to shower enclosures, heat-treated glass offers a way to keep glass transparent, high performing and strong. Understanding the difference between heat-treated glass products will help you respond to trends, meet building codes and create a safe environment for occupants.

Heat-strengthened glass:

  • Two times stronger than annealed glass
  • Resists thermal stress and edge damage that may occur during installation
  • Cracks and tends to stay in the frame when it breaks
  • Best used in applications where safety glass isn’t required

Tempered glass:

  • Also called safety glass
  • Four times stronger than annealed glass
  • Breaks into small pieces that can fall out of the frame

In a Guardian float plant, the glass that comes off the line is called annealed glass. Annealed glass can be cut and processed further in many ways.

To heat treat annealed glass, the fabricator heats it up to 1000°F in a furnace and then rapidly cools it. The cool air compresses the glass surface while the interior expands—locking in a permanent state of tension that makes the glass stronger.

Basics of Heat Treated Glass

There are important considerations for both heat-strengthened and tempered glass. The glass experts at Guardian are ready to help you navigate the process every step of the way and find the best heat-treatment service for your project. Contact us to get started today.

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Chris Dolan

Chris Dolan is commercial segment director, Guardian Glass U.S. and Canada. He is responsible for growing Guardian’s presence and participation in the commercial construction market segment. Prior to his current position, he was Director of Marketing for Guardian U.S. and Canada. He has been with Guardian for 28 years in a variety of sales management and business development roles.