Semi-tempered glass, also known as heat strengthened glass, is a kind of glass between ordinary float glass and tempered glass. It has some advantages of tempered glass, having strength 2 times higher than regular float glass while avoiding the disadvantages of tempered glass, such as unsatisfactory flatness and easy to explode.

Semi-tempered glass is not considered as safety glass as it will result in larger fragments and cracks in radial pattern when it’s broken. Although most of fragment will be free of sharp edges, it could still cause injury. Therefore, semi-tempered glass is not suitable for sunroof or places with high possibility of being bumped into.