Henry S. Parmalee invented fire sprinklers in 1874 to protect his piano factory. Fire sprinklers today utilize the same basic principles. Sprinkler heads are distributed throughout a building in a manner dictated by the fire codes. The sprinklers are connected to a system of pipes filled with pressurized water.
Sprinklers are rated at specific temperatures. When the heat of a fire reaches the operating temperature of the sprinkler, the heat destroys a heat sensitive device on the sprinkler, allowing the water to escape. The pressurized water then sprays directly over the heat source.
Sprinkler systems can communicate with the fire alarm system with a device called a flow switch. When water flows through sprinkler pipes, it is usually because a sprinkler has been activated. The flow switch senses the water flowing through the pipe and activates the fire alarm system. Most of the buildings at the University of Arizona have sprinkler systems. The office of the Arizona State Fire Marshal requires that sprinkler systems be tested semiannually.