Crash bar

A crash bar fitted to a glass exterior door.

A crash bar (also known as a panic bar, exit device,[1] panic device,[2] or a push bar) is a device for unlocking a door during emergency conditions. The mechanism consists of a spring-loaded metal bar fixed horizontally to the inside of an outward-opening door. When the lever is either pushed or depressed, it activates a mechanism which unlatches the door allowing occupants to leave quickly from the building.[1]

Background

Following the events of the Victoria Hall disaster in Sunderland, England in 1883 in which 183 children died because a door had been bolted at the bottom of a stairwell, the British government began legal moves to enforce minimum standards for building safety. This slowly led to the legal requirement that venues must have a minimum number of outward opening doors as well as locks which could be opened from the inside.

However these moves were not globally copied. For example, in the United States, 605 people died in the Iroquois Theater Fire in Chicago in December 1903 because iron gates blocked exits. Five years later 174 people in Ohio died in the Collinwood school fire, which lead to a national outcry in the U.S. for greater fire safety in buildings.

Implementation and usage

By the end of the 20th century, most countries had building codes (or regulations) which require all public buildings have a minimum number of fire and emergency exits. Crash bars are fitted to these types of doors because they are proven to save lives in the event of human stampedes. Panic can often occur during mass building evacuations caused by fires or explosions.

In the event emergency exits are required, the crash bar works efficiently to allow people to pass through security doors without a reduction in speed. A crash bar's fast-acting mechanism reduces the risk that a rushing crowd might suddenly become a logjam at the exits. This situation, which has many historical precedents, can cause falls, crushing and injury because the rear of a crowd has no idea that the people at the front of a crowd have come across a door.

Crash bars are typically found on doors which are required emergency exits serving a particular type or quantity of occupants. Common locations include doors which provide egress from assembly areas, doors which serve many occupants, or doors serving hazardous areas. For buildings subject to the International Building Code, or a locally adopted variation, they are required for certain healthcare, education, or assembly spaces, generally related to the number of occupants exiting through a given door. [3] A door intended only for exit doesn't need a handle on the outside, and for security, an outside handle is often omitted. However a door handle can be mounted on the outside to create a two-way door. This allows the bar to be locked in a neutral (latch open) position, allowing the door to be freely opened from either side.[4]

Legal standards

United Kingdom

In the UK, British Standards BS EN 179 and BS EN 1125 apply to panic hardware for workplace access and public access buildings respectively.[5]

United States

Exiting requirements are regulated by Building Code and local fire department or fire marshal requirements. Depending on the State, the Building Code may be adopted at the city, county, or state level. Many local and statewide codes are based on the International Building Code, with amendments as adopted locally. Requirements for exit doors are also regulated by the locally adopted life safety code, generally associated with the fire marshal. Commonly, this is the Life Safety Code published by the National Fire Protection Association.

Additionally, some municipalities require this hardware when an occupancy is considered 'hazardous', as in the case of chemical storage facilities.

References

  1. 1 2 American National Standards Institute, ANSI/BHMA A156.3-2001, American National Standard for Exit Devices
  2. ↑ California Code of Regulations, Title 24, Part 2, "California Building Code." 1008.1.9
  3. ↑ 2009 International Building Code. Country Club Hills, Illinois: International Code Council, Inc. 2009. p. 1008.1.10. ISBN 978-1-58001-725-1.
  4. ↑ Von Duprin Commercial Door Hardware "Exit Devices: To Dog, or not to Dog?"
  5. ↑ British Standards relating to Panic Hardware

Further reading

United Kingdom

British Standards relating to Panic Hardware

United States
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