Heat strengthened glass is normal plate glass which is subjected to a thermal treatment and heated till its soften point (about 620℃ as tempered glass). Its process is very much similar to tempered glass. The only difference is its cooling period, which is slowly cooling and different as the rapid cooling of tempered glass. It is fit to sustain high wind pressure with its wind resistance ability. In this case, it is widely use for tall building, curtain walls, and window panes since it won't break into small fragments and injury pedestrians underneath the building.