After homogenization treatment, tempered glass can significantly reduce the self-explosion rate, but it cannot completely eliminate it. The specific effects are as follows
The self-explosion rate before processing
Unhomogenized tempered glass, due to the presence of nickel sulfide (NiS) impurities, impurity particles or other stress concentration issues inside, has a typical self-explosion rate of approximately 0.1% to 0.3% (that is, about 1 to 3 out of every thousand pieces of glass may self-explode).
The effect after homogenization treatment
Principle: Homogenization treatment (Heat Soak Test) involves heating the glass to approximately 290 ° C to 300 ° C and maintaining it for several hours. This causes the nickel sulfide particles that may cause self-explosion to prematurely expand and undergo phase transformation (from the α phase to the β phase) under controlled conditions, thereby prematurely ignitating the defective glass.
Reduced self-explosion rate: After treatment, the self-explosion rate can be reduced to approximately 0.01% to 0.03%, which is about one-tenth of the original risk.
International standard reference
According to the European standard EN 14179-1, the self-explosion rate of homogeneous glass should not exceed 0.01% (one in ten thousand).
In actual engineering, high-quality homogenization treatment can further reduce it to approximately 0.005% (one in fifty thousand).
Residual risk factors
Even after homogenization treatment, glass may still self-explode for the following reasons:
Non-nickel sulfide factors (such as impact from hard objects, local stress, improper installation, etc.);
A very small number of nickel sulfide particles did not undergo complete phase transformation during the homogenization process.
Stress concentration caused by damage to the edges or surface scratches of the glass.
Engineering suggestions
Homogenization treatment has become a standard process for scenarios with high safety requirements such as high-rise buildings, curtain walls, and skylights. The selection of high-quality raw plates, control of tempering stress and standardized installation can further ensure safety.
Summary: Homogenization treatment can reduce the self-explosion rate of tempered glass from approximately 0.2% to below 0.02%, lowering the risk by about 90% to 95%. It is a key process for enhancing safety, but it cannot achieve 100% self-explosion.
