A panic bar is a device attached to doors allowing for quick egress. These devices are also commonly referred to as exit bars, push bars, or crash bars.
There are many instances when these devices are required by law in school buildings, public buildings, factories, and some commercial buildings.
Most commercial buildings and offices even if not required by law have some form of a panic bar on at least one door.
Panic bars are often used for safety purposes for quick egress in the case of an emergency such as a fire or panic situation.