"Who hasn't gone to inspect a fire sprinkler system and momentarily been taken aback by the confusing array of pipes, valves, gauges, fittings, and other trim? Depending upon the system configuration, some control valves should be left in the 'normally open' position, while others should be left in the 'normally closed' position. Sometimes, without tracing out the pipe path by hand, it's hard to tell which is the correct valve in the correct position. In Coffee Break Training 2008-17 (April 22, 2008) we showed how leaving an alarm control valve in the wrong position could have had disastrous consequences. That was a single incident in a small warehouse. Where a facility may have dozens or even hundreds of fire sprinkler systems--such as a college campus--the likelihood of an error in valve positioning is multiplied many times over."
Coffee Break Training - Fire Protection Series No. 2008-50
United States Fire Administration: http://www.usfa.fema.gov/