Wet pipe systems are by far the most common sprinkler system. They are constantly pressurized with water and are designed to discharge at a specific temperature depending on the occupancy, limiting and controlling the spread of the fire.

Dry pipe systems provide protection to non-environmentally controlled spaces where temperatures could be expected to fall below 40 degrees Fahrenheit. Dry pipe sprinkler systems require more maintenance than wet systems because there is additional equipment involved in dry systems.

Pre-action systems are a special class of dry pipe sprinkler systems which combines the benefits of a dry sprinkler system with the rapid response of an electronic detection system. Pre-action sprinkler systems are usually found in locations where accidental activation of the system could result in water damage to highly valuable physical assets such as in data centers, museums or libraries.

Fire pumps are required when the local municipal water supply cannot provide adequate pressure to meet the hydraulic demands of a fire protection sprinkler system. A fire pump becomes necessary when certain challenges, such as with a high-rise building (usually defined as a building over 70 feet in height), would require added pressure beyond what the normal available water supply can deliver. Sometimes, one or more fire pumps may be required in buildings that have heights at or above 40 stories or 500 feet. The upper floors of tall buildings need to be able to battle a fire immediately, and are fighting gravity to get the water up tens to hundreds of feet in a matter of seconds. Large industrial spaces and storage warehouses have systems that require to flow a large volume of water that most local water municipalities are not able to supply. Fire pumps work to get the proper amount of pressurized water to extinguish a fire in all of these situations. Fire pumps are also necessary if the sprinkler system water supply is provided from a ground-level water storage tank.

Standpipes are usually found in large high-rise buildings. They are a vertical network of piping which allows the fire department to attach hose connections to a water supply, allowing manual application of water to a fire. There is usually a standpipe found in each stairwell of a high-rise building. Usually, standpipes act as a “combination riser” that provides water to the sprinkler system at each floor level controlled by a valve and a drain apparatus, which also provides components for testing purposes. They also provide a 2 1/2″ hose valve at each level of the building to which the local fire department can connect hoses, should a fire need to be fought manually, in addition to having automatic sprinklers. In this respect, more simply, they act as indoor fire hydrants.

In industrial settings, it’s common to design and install a system using foam with open-headed deluge sprinklers or high-expansion foam generators. Foam sprinkler systems are very effective for controlling and extinguishing flammable liquid fires.