Editing Deadbolt (section)

==Safety==
The double cylinder design raises a safety issue. In the event of a fire, occupants will be prevented from escaping through double-cylinder locked doors unless the correct key is used. This is an avoidable cause of death in house fires.{{cn|reason = One example is not often. |date=September 2022}}<ref>{{cite web | url = http://www.smh.com.au/articles/2004/06/07/1086460240897.html | title = Deadlocked doors seen as fatal in house fire  | work = [[The Sydney Morning Herald]] | first = Les | last = Kennedy | date = 2004-06-08 | access-date = 2010-11-16}}</ref> The risk can be mitigated by locking the deadlock only when there are no occupants inside the building, or leaving the key near the keyhole. Some fire departments suggest putting the key on a small nail or screw near the door at floor level, since the cleanest air is at floor level and one may be crawling to get to the exit, thus placing the key where it is easiest to find.  

Note that single cylinder dead locks (with an unlocked twist mechanism on the inside of the door) do not have this problem, and therefore are most commonly used on fire exits.  Some areas have fire safety codes that do not allow a locked exit.<ref>{{cite web |title=Hardware requirements for access and egress |url=http://www.embc.gov.bc.ca/ofc/services/guidelines/pdf/guide.pdf |publisher=Canada government |access-date=12 June 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140327145755/http://www.embc.gov.bc.ca/ofc/services/guidelines/pdf/guide.pdf |archive-date=27 March 2014 }}</ref><ref>{{cite web|title=Building Codes (p.127)|url=http://www.nyc.gov/html/dob/downloads/bldgs_code/bc27s6.pdf|publisher=New York City|access-date=12 June 2014}}</ref>