Safety glass covers tempered glass which is also called toughened glass, fire-resistant glass, laminated glass and the other combination of laminated glass products according to the general building code, standards or industry rules. Tempered glass can withstand normal impact and even if it is broken, the small chips could not hurt you. But if the small chips fall down from upper air, the damage gets big and big due to accelerated speed. Don’t you think it is still a kind of safety glass? More and more cases have showed us the answers. Only for this reason, single tempered glass is not suitable for high-rise curtain wall.

1. Single tempered glass is not suitable for high-rise glass curtain wall
Safety glass covers tempered glass which is also called toughened glass, fire-resistant
glass, laminated glass and the other combination of laminated glass products according to the
general building code, standards or industry rules. Tempered glass can withstand normal
impact and even if it is broken, the small chips could not hurt you. But if the small chips fall
down from upper air, the damage gets big and big due to accelerated speed. Don’t you think it
is still a kind of safety glass? More and more cases have showed us the answers. Only for this
reason, single tempered glass is not suitable for high-rise curtain wall.
Nowadays, people seem toughened glass as safety glass and use it into glass curtain walls.
While the other types of safety glass, laminated glass always be ignored. Maybe the cost of
laminated glass is higher. But I don’t think they don’t eliminate the safety performance of
laminated glass. Ordinary glass after tempering, the strength on the surface will rise by 3 to 4
times than before. But the edges and corners are very weak, even if the impact resistance and
compressive strength is lower than float glass. When the glass edges or glass corner was
broken by cracking, the full panel of tempered glass will be broken either, but the full panel of
float glass will be fine. On the other hand, glass covers exiguity crystal, Nis that is not available
to avoid in the glass manufacturing. When the temperature gets high, the volume of Nis gets
big under the tensile stress range in the tempered glass. When the volume expands over the
tensile stress, the tempered glass will blast. That is what we called “spontaneous breakage”
Although more than 8mm thick tempered glass needs to heat soak process upon some
standards. Heat soak process systems will maximum reduce the spontaneous cracking, but
not available to avoid it happen. In the real world, if the glass falls down from curtain wall, most
of glass is tempering glass. So AJJ Glass thought the single tempered glass for curtain wall is
not suitable. It is not safety. While laminated glass is different, it is able to eliminate almost all
glass chips fall off effectively. Accordingly AJJ Glass suggest that frame supported glass
curtain wall should adopt laminated glass instead of toughened glass, point supported glass
curtain wall can use fully tempered glass. In order to satisfy energy saving, the laminated
insulated glass is the best choice for frame supported glass curtain walls. We hope all
concerned department including contractor, designer, builder and quality inspector can take
this positive suggestion in consideration and do some change to really solve the issue of glass
spontaneous broken and then falling down and hurt humans.
Sometimes we found that some people attribute all glass breakage accident into tempered
glass spontaneous broken. Maybe they won’t be responsible for anything. In fact, they don’t
seriously analyze and find out the reason to avoid the same problem in next time. AJJ Glass
do dome research on glass broken issues and found that most of broken issues are not
caused by spontaneous broken, but others. Especially for glass that has been installed into the
curtain walls for several years, even if for decades. Generally, the main characteristic of
spontaneous broken is that there is a similar butterfly lung in the position of Nis expansion.
And the more important is that spontaneous glass breakage always happens in the first two
years, it hardly happens after that. When the glass was broken but still in the wall, the butterfly
lung is the best way to recognize if it is spontaneous or not. So it is an important thing to
recode this as soon as the glass has broken. Of course, most of time we can’t found the

2. characters of brokering before the glass falls down. In this case, it is must to analyze the
reasons. It is made by spontaneous broken? Or it is made by the temperature changes? Or it
is made by mechanical crack through outside force? It has to according to the position,
direction of broken, the installation period, the structure of points of curtain walls, the material
of frame or point supported, the usage conditions, the surround circumstances, the broken
time and the broken details and so on.
It is only for reference, hoping it is useful for you. And welcome your positive comments.
By AJJ Glass Ltd, which is a leading tempered glass supplier and architectural glass
manufacturer in China for over 15 years.
Contact Info:
AJJ Glass Products Co., Ltd
No.3, Neimao 2 Road, Xinglin, Xiamen, China
P: +86-592-8099639
F: +86-592-7137951
E: sales@ajjglass.com
http://www.ajjglass.com