The Wet Pipe System is the most common type of fire sprinkler installation. Closed sprinklers heads are connected to a water-filled piping system. The water is contained in the pipework until heat from the fire causes the sprinkler head to reach a a given temperature which activates the sprinkler, allowing the water to discharge.

Contrary to many perceptions of automatic sprinkler systems, in this type of system, the only sprinklers that will discharge water are those sprinklers whose elements have been directly actuated by the fire.

A Deluge System is a system that employs open-type sprinklers that are connected to a piping system which is connected to a water supply that is kept from filling the pipe until the deluge valve is released by the supplemental detection system. This operates much in the same way as a preaction system. However, when the deluge valve releases the water to the system, every sprinkler in the system discharges.

Deluge Systems provide fast and total wettings of protected areas, and are frequently used in extra-hazard risks such as aircraft hangars, power generating stations, and petrochemical facilities.

A Dry Pipe Sprinkler System is a system which employs automatic and closed-type sprinkler heads, which are connected to a piping system containing compressed air or nitrogen, rather than water. This type of system is used where water would freeze in the piping.

The water supply for the system is held back by the dry-pipe valve, which will only release the water after the evacuation of the air pressure from the system (such as the operation of a sprinkler). The water will then flow into the piping system, and out of the opened sprinklers.

Dry Pipe Systems are frequently installed in coolers and freezers.

Preaction Systems are similar to Dry Pipe Systems in that the water is kept from entering the piping by a valve, in this case a preaction valve. This valve is held closed electrically, only being released by the activation of the detection system (heat or smoke detectors mainly) when an electrical signal is sent to the releasing solenoid valve. The water then fills the pipe, ready for the activation of the sprinkler heads.

Preaction systems can be arranged to be activated by only one detector or many.

These systems are typically used in applications where the accidental discharge of water would be catastrophic.

A Foam Sprinkler System is any type of system-Wet, Dry, Preaction, or Deluge that has been adapted to include the injection of foam concentrate in order to combat high risks such as flammable fuels and alcohol.

The primary components added to the sprinkler system riser include bladder tanks to hold the foam concentrate, concentrate control valves to isolate the sprinkler system from the concentrate until activation, and proportioners (controllers) for mixing the appropriate amount of foam concentrate with the system supply water.