Spontaneous glass breakage refers to a phenomenon in which tempered glass may spontaneously shatter without any external force. This issue has become a safety concern due to the widespread use of tempered glass in daily life, particularly in locations frequently encountered by people, such as high-rise buildings, bathrooms, and glass doors.

The causes of spontaneous breakage in tempered glass can be broadly classified into external factors and internal factors, as detailed below:

1. External Factors Contributing to Spontaneous Breakage

① Shape of the Glass

Tempered glass with drilled holes or cut corners is more prone to spontaneous breakage compared to glass without such modifications.

② Surface Damage

Scratches, cracks, edge chips, or other damage caused during transportation, handling, or installation can compromise the stress balance in tempered glass, leading to spontaneous breakage.

③ Installation Issues

Improper installation, such as insufficient spacing or direct contact between the glass and its frame, may result in compressive stress at the edges or corners due to differing thermal expansion coefficients between glass and metal under sunlight. This stress can also cause localized temporary thermal stress, triggering breakage.

④ Design Deficiencies

Tempered glass that does not meet wind load resistance standards or fails to comply with local wind pressure requirements is also at risk of spontaneous breakage.

2. Internal Factors Contributing to Spontaneous Breakage

① Visible Structural Defects in the Glass

Inclusions such as stones, sand particles, or air bubbles within the glass significantly increase the likelihood of spontaneous breakage. However, spontaneous breakage caused by these issues typically occur during the manufacturing process and are rarely observed after the glass has been put into use.