A fire sprinkler or sprinkler head is the component of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been exceeded. Fire sprinklers are extensively used worldwide, with over 40 million sprinkler heads fitted each year. In buildings protected by properly designed, and maintained fire sprinklers, over 99% of fires were controlled by fire sprinklers alone.
In 1812, British inventor Sir William Congreve patented a manual sprinkler system using perforated pipes along the ceiling. When someone noticed a fire, a valve outside the building could be opened to send water through the pipes.
A large furniture factory had repeatedly burned down, and Hiram Stevens Maxim was consulted on how to prevent a recurrence. As a result, Maxim invented the first automatic fire sprinkler. It would douse the areas that were on fire, and it would report the fire to the fire station. Maxim was unable to sell the idea elsewhere, but when the patent expired the idea was used.