Editing Crash bar (section)

==Background==

=== History ===
Following  the events of the [[Victoria Hall disaster]] in [[Sunderland, Tyne and Wear|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. Motivated by the Sunderland disaster, Robert Alexander Briggs (1868–1963) invented the panic bolt which was granted a UK patent on 13 August 1892.<ref>{{cite web|url=http://www.arthurlloyd.co.uk/RobertBriggsPanicBolts.htm|title=Robert Alexander Briggs and the invention of the Panic Bolt|first=Patricia|last=Lovell}}</ref>

However, these moves were not globally copied. For example, in the [[United States]], at least 602 people died in the [[Iroquois Theatre fire]] in [[Chicago]] in December 1903 because of door latch designs that were difficult for fleeing patrons to open. A survivor of the Iroquois Theater fire, [[Carl Prinzler]], along with architect [[Henry H. Dupont
]], independently developed and were awarded a series of nine patents relating to new and improved exit door hardware. All of the patent designs focused on a single lever bar (and related hardware) that would cause a locked door to pop open when simple interior pressure was exerted upon it. The bar would be mounted waist high from the ground. Five years later, 174 people in Ohio died in the [[Collinwood school fire]], which led to a national outcry in the United States for greater fire safety in buildings. 

 
On 31 December 1929, some 37 years after the panic bolt was patented, 71 children died during the [[Glen Cinema disaster]] at a [[Hogmanay]] film screening in [[Paisley, Renfrewshire]], [[Scotland]], when a smoking [[Nitrocellulose#Film|cellulose nitrate film]] canister sparked panic. Children rushing to escape the cinema became crushed against the padlocked exit doors. Even after a police officer broke a padlock, the inward-opening doors were held shut by the mass of bodies behind them.<ref>{{Cite news|url=https://www.bbc.com/news/uk-scotland-50502446|title=The cinema panic that killed 71 children|date=2019-12-31|access-date=2020-01-01|language=en-GB}}</ref>

=== Justification for use ===
{{Quote box|In virtually all [crowd crush] situations it is usually the authorities to blame for poor planning, poor design, poor control, poor policing and mismanagement. <!--This is a verbatim quote. It must not be changed. -->
|author= Edwin Galea, professor of fire safety engineering at the [[University of Greenwich]], England<ref>{{cite news |title=Crowd crushes: how disasters like Itaewon happen, how can they be prevented, and the 'stampede' myth |work=[[The Guardian]] |date=1 November 2022 | first=Samantha |last=Lock |url=https://www.theguardian.com/world/2022/nov/01/how-do-crowd-crushes-happen-stampede-myth-what-happened-in-the-seoul-itaewon-halloween-crush}}</ref>
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By the end of the 20th century, most countries had [[building code|building codes (or regulations)]] which require all public buildings have a minimum number of [[fire exit|fire]] and [[emergency exit]]s. Crash bars are fitted to these types of doors because they are proven to save lives in the event of [[human crush]]es. 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. Such a human crush, which has [[List of fatal crowd crushes|many historical precedents]], can cause falls, crushing, and other injury because the rear of a crowd has no idea that the people at the front of a crowd are impeded by 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 expected to exit quickly through a given door.<ref>{{cite book|title=2009 International Building Code|year=2009|publisher=International Code Council, Inc.|location=Country Club Hills, Illinois|isbn=978-1-58001-725-1|page=1008.1.10}}</ref>