Spontaneous glass breakage: causes and the role of internal stress

Bangkok Post

3 days ago

Glass suddenly shattering on its own may seem mysterious, but it can be explained scientifically.
Last week, a Thai woman suffered a serious hand injury when a tempered glass door suddenly shattered as she tried to open it at an office building in Bangkok.
This incident highlights the potential danger even with safety glass, which is designed to reduce injury during breakage.
This phenomenon often occurs without warning and can affect bathroom glass panels, windows or even dining tables. In most cases, the issue arises with tempered glass, a type of safety glass that has been specially reinforced for use in car windows, large household panels or shower enclosures.
Tempered glass is designed to improve safety: when it breaks, it shatters into small, rounded particles (similar in size to corn kernels), which are far less sharp and reduce the risk of injury.
Tempered glass is designed to be safe. However, it can still cause harm, especially in confined spaces or at close range. This is particularly true if the broken fragments have sharp edges or if the breakage projects shards outward with force.
Common causes of spontaneous breakage:
Minor damage during installation: A small chip on the glass edge may develop into a larger crack over time. Even a slight amount of pressure later could cause the entire sheet to shatter.
Stress from tight framing: If the glass is fitted too tightly into a frame, with no room to expand or contract due to temperature changes or wind pressure, internal stress builds up. This stress may eventually lead to cracking or breakage.
Nickel sulphide inclusions: Impurities like nickel sulphide can form inside the glass during manufacturing. These particles can expand when exposed to heat, creating internal pressure that causes the glass to break from within.
Thermal stress: Sudden or extreme changes in temperature can cause rapid expansion or contraction, putting excessive strain on the glass structure.
Insufficient glass thickness: Glass that is too thin may not be able to withstand wind pressure. This can often be mitigated by using laminated safety film.
Recommended preventive measures:
Use glass products from certified and reputable manufacturers.
Carefully inspect glass edges for chips or flaws before installation.
Ensure installers leave sufficient clearance in frames, and avoid over-tightening.
Apply safety films to vulnerable areas such as car windows or large household panes.
Watch for early warning signs such as warping, rainbow-like patterns or unusual creaking sounds, which could indicate stress.
Ultimately, preventing spontaneous glass breakage requires care at every stage - from production to installation. With proper attention to detail, the risk of this type of accident can be greatly reduced, ensuring better safety and peace of mind for everyone in the space.