You need to have the right information and tools if you are going to break a glass window or door to make an exigent entry into a structure or to rescue a trapped motorist. There are three types of glass you will encounter: tempered glass, non-tempered glass, and laminated glass.
Tempered glass is special heat-treated form of glass. Tempered glass is used where there is a likelihood of human contact and as such is made to shatter into small ¼” pieces when broken. The small pieces are not very sharp and are relatively safe to handle.
Non-tempered glass is a different animal. When broken, non-tempered glass makes large, irregular, jagged pieces that are razor sharp. Non-tempered glass is much more dangerous than tempered glass and should be handled with caution, regardless of its thickness.
Laminated glass has plastic layers sandwiched between glass layers. Because of the plastic sheeting, laminated glass tends to puncture under impact (see video where Mr. Summers tries to break the double laminate glass). Although the glass breaks, the plastic will hold the laminate together. High impact and/or cutting forces are needed to adequately defeat laminated glass. Fragmentation and spalling will also send glass flakes and powdered glass inward, which can be a danger to those on the opposite side.
Tempered Glass Break Practice
Here are some rough generalizations about glass. Car side and rear windows, newer storefront windows, and modern sliding glass doors are made of tempered glass. Many building codes require tempered glass be installed in residential and commercial windows that are within 48” of doors. Tempered glass normally has manufacturers’ Continue reading
