Tempered Glass  uses the thermal process to enhance the basic strength of float glass. Here Glass panels are fed from the loading conveyer into the furnace where it oscillates back and forth on the ceramic rollers until it reaches a temperature of approximately 620 degree Celsius. When the glass panels come out of the furnace, it moves into the quencher where it is rapidly cooled by blasting both sides with cool air.

The rapid cooling induces compressive stresses to the glass surface. While the centre remains in tension. Although the physical characteristics remain unchanged, additional stress created within it increase the strength by 4-5 times that of float glass of equal thickness.

Heat Strengthened Glass which is widely used in the construction industry differs from tempered glass by its properties and its manufacturing process. The glass panels are quenched at a slower rate. Result is lower compressive stress, increasing the strength to only twice that of float glass of equal thickness.

Tempered Glass with Heat Soak Tested
Spontaneous breakage is an inherent characteristic of tempered glass due to volume changes occurring during crystal form transformation of nickel sulfide inclusions and other defects present in the glass. Heat soak test is an effective way for bringing about spontaneous breakage before tempered glass panels are installed thus reducing risks of breakages after installation. By placing tempered glass in the heat-soak furnace, heating to a desired temperature, preserving for enough time and cooling down, the crystal form of nickel sulfide inclusions is stabilized and the internal stress is relaxed to a certain extent. During this process, tempered glass with large enough nickel sulfide inclusions and other defects will be broken by induced extra stresses. As a result, heat-soak tested tempered glass will have a much less chance of spontaneous breakage than normal tempered glass.

Meng Heng Glass has its own Heat- Soak Oven designed to reduce the risk of spontaneous breakage from Nickel Sulfide (Nis) inclusions. The process used is in compliance with both European EN14179 &  the German DIN 18516 standards. While heat-soaking does not guarantee that breakage will be completely eliminated in the installed tempered glass; it is an invaluable test for identifying batches that have a high incidence of nickel sulphide inclusions.