Red Seal Glazier Practice Exam

What does the term “thermal stress” refer to in glazing?

1. A condition where uneven temperature causes glass to crack or shatter

2. A method for calculating glass weight

3. A type of insulation used for glass

4. An inspection process for glass quality

The correct answer is: A condition where uneven temperature causes glass to crack or shatter

Thermal stress in glazing refers to the condition where uneven temperature across a glass surface leads to cracking or shattering. This occurs because glass expands and contracts with temperature fluctuations, and when different parts of the glass experience varying temperatures, it can create internal stresses. If these stresses exceed the material's strength, the glass may fail. Understanding thermal stress is crucial for glaziers when selecting glass types and thicknesses for various installations, especially in environments with significant temperature variations. For instance, large glass panes in areas with direct sunlight can experience uneven heating, leading to the potential for thermal stress. Recognizing how to mitigate these risks, such as by using tempered glass or appropriate glazing techniques, is essential in preventing damage and ensuring safety.