Why Do Glass Windows Shatter During Fire?

 

You might have noticed in movies and also in real life that whenever there is a fire inside a building, the glass windows crack and break. The openings of the windows in the walls of the room on fire play a key role in the spread of fire. Windows are those parts of the buildings that generally have less resistance to fire in comparison to that of the walls. During a fire,  there is a increase in temperature inside the room. The glass pane is not subjected to uniform heat from the fire. Glass windows are fitted within the frames, and the thickness of the frame is larger in comparison to that of the glass pane. There is an intense heat flow that is suddenly experienced on one side of a glass pane. As a result, the heat focussed on the central region of the glass causes it to expand. While the edges of the pane happen to be relatively cooler,  which induces stress in the material. This shifting gradient is known to shatter the glass to pieces.