Tempered glass breaks into small, relatively harmless pieces due to its manufacturing process involving extreme heating followed by rapid cooling. This treatment creates high compressive stress on the surface and tensile stress in the center, storing potential energy throughout the glass. When the balance is disturbed by damage penetrating the compressed outer layer, this stored energy is released explosively, causing the entire piece to fragment into small, cubical pieces rather than sharp shards. This predictable failure pattern is intentionally designed as a safety feature, significantly reducing injury risk compared to standard glass. Building codes specifically require tempered glass in hazardous locations precisely because of this safer breakage pattern.
