Most people visiting or working in commercial and public buildings give little thought to the structure or security of the building. In fact, many people aren't even familiar with the term "exit device." This is in spite of the fact that every commercial and public building in North America is outfitted with at least one, and likely numerous, exit devices (also known as crash bars or panic bars.) However, every person who enters a public building has a reasonable expectation of security and safety while inside. Fortunately, exit devices play a significant role in the safety and security of human lives as well as property.
An exit device is a type of door hardware which allows doors to remain locked from the outside. People inside the building, however, can still exit quickly without having to unlock the door. The mechanism actually makes a hands-free exit possible. In fact, the nickname "crash bar" is derived from the ability to open the door by simply applying full-body force to it ("crashing" into it.)
Exit devices are advantageous for a few reasons. First and foremost they are security and safety features. A property owner who wishes to restrict the public's ability to enter a building to just a few select doors can apply crash bars to all non-public entrances. These doors cannot be opened from the outside when locked. In the event of an emergency, such as a fire, those inside the building can use these doors as emergency exits by activating the crash bar on the inside of the door. The term "panic bar" came to be applied to exit devices because they can be opened quickly in an emergency. Panic bars are also advantageous because people with limited mobility (i.e. those in wheelchairs) and even small children can activate them.
The first crash bar was invented in the early 1900's and marketed under the brand name Von Duprin. The company continues to be the leading manufacturer of exit devices today, though other companies have since copied Von Duprin's original design. Von Duprin has also improved on its original design since its first prototype. New technology has allowed for lighter and stronger materials to be used. All of this has resulted in a wide range of quality exit devices on the market.
Three basic types of exit devices are available:
1) Rim style: This type is mounted on the inside surface of the door.
2) Mortise style: Like standard a mortise lock, this type of crash bar has its locking mechanism mounted (mortised) into a cavity in the door.
3) Surface/Concealed style: This type is constructed with vertical rods. Concealed exit devices provide additional latching at the tops and/or bottoms of doors. This type of exit device is used when aesthetics play a strong factor in door design.
Crash bars are available in various designs. The standard that most people are familiar with is the touchbar design. These are often found on utility, service and emergency exit doors. The crossbar style is also popular. The first Von Duprin exit device was a crossbar type. Other styles include lever and plate-type.
Today all industrialized countries have some type of building code standard(s) which dictates how exit devices should be applied to commercial/public buildings. Undoubtedly many lives have been saved thanks to panic bars since their invention over one hundred years ago. This unobtrusive and seemingly insignificant device changed the face of building safety and public security in a very significant way.