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Why does tempered glass self-explode?
Why does tempered glass self-explode?


Among greenhouse covering materials, greenhouse glass has the properties of high light transmittance, long service life and very good thermal insulation performance, so glass is an ideal greenhouse covering material.


In recent years, with the improvement of the safety performance of glass, the top of most glass greenhouses now uses diffused tempered glass, which has high strength, very good bearing capacity as well as wind pressure resistance, impact resistance and temperature resistance. It is also safer to install on the top of the greenhouse. Even if it is broken, the fragments will form small obtuse particles similar to honeycombs and the edges are rounded. It is a very safe glass.


But tempered glass has a phenomenon - self-explosion.




The reasons for the self-explosion of tempered glass can be divided into the following two situations:


In the process of glass processing or installation, due to external factors, micro cracks occur on the surface of the glass, causing stress concentration, destroying the self-equilibrium state of the tempered glass and causing the glass to self-explode;


Tempered glass contains nickel sulfide crystals. The self-explosion of tempered glass is caused by the volume expansion due to the phase transformation of nickel sulfide (NiS) in the glass. Due to the limitation of production technology, most of the tempered glass currently contains nickel sulfide crystals. After heat treatment, part of the crystals will undergo crystalline changes over time and the volume will increase, which will cause micro-cracks in the glass, which may lead to self-explosion of tempered glass;


Self-explosion of tempered glass is a normal phenomenon. Because the existing production technology cannot completely eliminate the existence of nickel sulfide impurities, self-explosion of tempered glass is inevitable, which is an inherent characteristic of tempered glass. At present, there is no national standard in the world that restricts the self-explosion of tempered glass.


In response to the problem of self-explosion of tempered glass, Planti's glass quality inspection staff attaches great importance to the production process of glass, and has always followed the principle of high standards and strict inspection to reduce the content of nickel sulfide from the source, thereby reducing the self-explosion rate of tempered glass.


Planti recommends greenhouse growers to increase the number of glass when placing an order appropriately to deal with the self-explosion caused by improper handling of the glass during transportation and installation while try to maintain sufficient glass inventory to avoid affecting the installation period of the project.