Why does it matter how glass breaks?

Broken glass is extremely dangerous. Anything subject to human impacts needs to break in the safest possible manner. This can be achieved by breaking into very small pieces that are less likely to severely cut or stab people, or by staying in place when broken. Any glass that is installed above where people are present, also needs to be safety glass. The abilty of glass to stay in place after breaking is also important for fire safety, as it minimizes air flow and prevents the spread of fire and smoke.