How Tempered Glass Breaks: Myths vs. Facts

Tempered glass is widely used in furniture, windows, and table tops because it is stronger and safer than standard glass. However, misconceptions about how it breaks are common. Understanding the realities of tempered glass breakage helps homeowners make informed choices for safety and design.

Myth 1: Tempered Glass Never Breaks

Many people believe tempered glass is unbreakable. Fact: Tempered glass can break if subjected to sufficient force, sharp impact at weak points, or edge damage.

According to the Glass and Glazing Federation (GGF), tempered glass is up to five times stronger than regular annealed glass, but no glass is completely indestructible.

Myth 2: Tempered Glass Breaks in Large, Dangerous Shards

Fact: One of the main safety benefits of tempered glass is that it breaks into small, blunt fragments instead of sharp shards. This significantly reduces the risk of injury.

For example, Pilkington explains that these tiny fragments are often cube-shaped or granular, making them much safer than broken annealed glass.

Myth 3: Tempered Glass Breaks Easily

Fact: Tempered glass is heat-treated to withstand daily wear, impacts, and temperature changes far better than standard glass. Most breakage occurs only under unusual stress, such as:

Edge damage or chips
Excessive point load
Sudden, uneven thermal stress

Myth 4: Tempered Glass Breakage Is Predictable

Fact: While tempered glass is designed to fail safely, it can shatter unexpectedly if its edges are weakened or if it contains inclusions such as nickel sulphide. This is why manufacturers follow strict standards such as UK Approved Document K for impact-resistant glazing.

Tips to Minimise Breakage Risk

Handle glass by the centre, avoiding direct pressure on edges or corners
Ensure installation surfaces are smooth and properly cushioned
Use tempered glass appropriate for the intended application (e.g., table tops, partitions, doors)

For more information on tempered glass types, safety, and applications, visit our detailed guide here.