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Industry standards and solutions for self-explosion rate of tempered glass

2020-2-24

 
 
Industry Standard for Tempered Glass Self-Explosion Rate

The self-detonation rates of Chinese manufacturers are not consistent, ranging from 3% to 0.3%. The original industry standard JGJ113-96 version mentioned that the glass preparation should be 3% more used. Generally, the self-detonation rate is calculated by the number of sheets, and the area and thickness of the single glass are not considered, so it is not accurate enough, and it cannot be compared with each other more scientifically.
 
In order to measure the self-explosion rate uniformly, a unified assumption must be determined. Set uniform conditions: every 5-8 tons of glass contains a nickel sulfide sufficient to cause self-explosion; the average area of ​​each piece of tempered glass is 1.8 square meters; the nickel sulfide is evenly distributed. The calculated self-explosion rate of 6mm thick tempered glass is calculated to be 0.34% to 0.54%, that is, the self-explosion rate of 6mm tempered glass is about 3 ‰ to 5 ‰. This is basically consistent with the actual value of high-level processing enterprises in China.

In fact, the self-explosion rate of tempered glass used in construction projects is usually between 8 ‰ to 3 ‰, so the average self-explosion rate of tempered glass is 5 ‰. The value of the self-explosion rate of other combined products such as tempered interlayer and tempered insulating glass (calculated based on the total thickness of each layer of tempered glass in the product structure). This can also be used as a basis to infer the average self-detonation number of a combined product of a given area and structure. Or calculate the self-detonation rate from the specific number of self-detonating pieces, the area of ​​a single piece, and the total number.

 



The above shows that: the larger the single sheet area of ​​tempered glass, the greater the possibility of self-explosion; the thicker the glass structure, the greater the possibility of self-explosion. This is also consistent with the actual situation. But at some point, there was a self-detonation every 27 films, which made it unacceptable, so we must find a countermeasure and find a reliable solution.

Is there a standard for the self-explosion rate of tempered glass? Modern float glass production technology cannot completely eliminate the existence of nickel sulfide impurities, so self-explosion of tempering is inevitable, which is an inherent characteristic of tempered glass. At present, there are no national standards in the world that limit the self-explosion of tempered glass.
 
 
 

Tempered glass self-explosion solution

Tempered glass is safety glass recognized by regulations, and is widely used in places with high requirements for mechanical strength and safety, such as glass doors, building curtain walls, facade windows, indoor partitions, furniture, close to heat sources, and locations subject to cold and heat shocks. Partition. The characteristics of tempered glass determine that self-detonation is unavoidable, and the time and conditions of self-detonation cannot be estimated. Therefore, in order to prevent the harm caused by the self-explosion of the tempered glass, some measures or methods are often taken during the glass processing and installation process to reduce the losses caused by the self-explosion of the tempered glass.

1. Hot dip treatment (homogeneous treatment):

The tempered glass is placed in a hot dipping furnace for heating, heat preservation and cooling, so that the nickel sulfide in the tempered glass reaches a stable state, and the stress in the glass is debalanced to achieve the purpose of reducing the self-explosion rate. Advantages: The self-explosion rate is greatly reduced, the cost is low, and the glass specifications and layout are not changed. Disadvantages: Self-detonation cannot be completely ruled out, and stress will be reduced accordingly.

2. Laminated glass:

The PVB interlayer is sandwiched between the glass and processed by high temperature and high pressure. The toughness of the PVB film is very good. When the laminated glass is broken by external force, it can absorb a large amount of impact energy and rapidly decay, so it is difficult for the laminated glass to break through and maintain excellent integrity. This enables buildings that use laminated glass to be kept in the door and window frames even if the glass is broken when subjected to explosions, wind disasters, earthquakes, etc., protecting personnel inside and outside the building from splashed glass fragments, wind and rain Other foreign objects are also difficult to cause damage to the interior. The disadvantages are:

1) The weight and thickness of the glass increase the load and load of the building;

2) It is not conducive to escape and rescue when a fire occurs;

3) Increase construction costs.
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3. Stick-film glass:

High-performance polyester film on glass. Polyester film is commonly known as safety explosion-proof film. When the glass is broken for various reasons, it can stick the glass fragments to prevent splashing, and protect people inside and outside the building from splashing glass fragments. Wind and other foreign objects are also difficult to cause damage to the interior. The safety explosion-proof membrane can be connected to the frame edge together with organic glue to form a glass film protection system to prevent falling. Advantages: easy processing without changing glass specifications and layout. Disadvantage: increase construction cost.

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