Is It Safe To Choose Heat Strengthened Glass For Curtain Wall Glazing
The previous article talked about the safe use of curtain wall glass, so is it safe to use heat-strengthened glass as curtain wall glass? First of all, we need to understand heat-strengthened glass before we can talk about where it is suitable for use.
(1) Characteristics of heat-strengthened glass
The heat treatment of heat-strengthened glass is similar to that of tempered glass, but the degree of tempering is low, and its surface stress is controlled not to exceed 69N/mm2. Tempered glass does not belong to the current definition of "safety glass".
The surface stress of heat-strengthened glass is low, so there is no danger of self-explosion. When it is not affected by the outside world, it will never explode by itself, so in this sense, it is safer than tempered glass. Even if it is broken under the action of external force, the fragments formed by the radial cracks will not fall easily because of the glue seams and notches around it. There is time to remove and replace.
The surface of the heat-strengthened glass is relatively flat, the image distortion is small, and it is more beautiful.
(2) heat strengthened glass has long-term application experience
Due to the above-mentioned advantages of heat-strengthened glass, it has a long history of application in glass curtain walls in Hong Kong, Macao, and abroad, and is still used in many projects. During the period from 1990 to 2000 in China, heat-strengthened glass was used in many projects, and the situation is good so far.
In the Guangzhou Mayor Building built in 1996, the outer sheet of insulating glass was made of Belgian golden coated heat-strengthened glass, and the inner sheet was made of CSG 6mm float glass; the Guangdong Public Security Command Center built in 1997 was 110m high and made of American 6mm silver. Gray-coated single heat-strengthened glass; Qingdao Everbright Bank, built in 1999, is heat strengthened glass insulating glass, and the outer sheet is 6mm silver gray coated glass made in the United States. In the several projects that the above-mentioned author has handled, ten years have passed so far, and there has been no safety accident of glass breaking.
The daylighting roof of Beijing New Dong'an Market, built in the 1990s, uses heat strengthened glass laminated adhesive (green glass and clear glass), and no self-breaking plates have been found to this day. Compared to heat-strengthened glass, its safety is relatively high.
（3） Large curtain walls adopt heat-strengthened glass one after another
The roof height of the Russian Federation Building in Moscow is 341m, making it the tallest building in Europe. It was designed by the United States, contracted by China Construction Corporation, and undertaken by Shenyang Yuanda for the glass curtain wall project. Considering that the project is located thousands of miles away, once the glass self-explodes, the cost of replacement and maintenance is extremely expensive. Therefore, it is decided to use heat-strengthened glass for all of this project. The transparent part is a laminated insulated glass(6mm+1.14PVB+6m)+16A+8mm, and all three pieces of glass are heat strengthened glass; The opaque part is 8m blue sky and white cloud-colored glaze printed single piece glass, which is also heat strengthened glass.
The Guangzhou TV Tower currently under construction is the world's tallest independent tower. The total height is 620m, the height of the curtain wall is 430m, and the total area of the curtain wall is 320000 square meters. It consists of over 5000 triangular plates and adopts a double-layered hollow structure: (8mm+1.52SGP+8mm Low E) 12A+(8mm+1.52SGP+8mm). The upper and lower parts of the tower are thick, and the middle part is reduced. The shape is a hyperbolic paraboloid. Considering the variety of glass types, it is extremely difficult to replace glass at high altitudes, and all glass is heat strengthened glass.
Another project under construction in Guangzhou, the West Tower of the Pearl River New Town, is a 432m high comprehensive building with a two-way curved facade. I have compared two options: tempered glass and heat-strengthened glass. It is extremely difficult to replace the glass at high altitudes, and preventing self-explosion is everyone's primary consideration. After discussion, it has been decided to use (8mm+1.52PVB+8mm)+12A+10mm laminated insulating glass, with all three pieces of glass being heat strengthened glass.
Look at it this way heat strengthened glass is also great for architectural use, there is no news like the tempered glass smashed down after self-explosion. There is no absolute meaning of safety glass, the use of glass has certain risks. Can be achieved through a reasonable choice of glass type, coupled with the necessary design and construction measures to maximize the use of glass safety.