The basics of heat treated glass

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.