MYTH: When a sprinkler system actuates, all sprinklers on the system go off at the same time.
FACT: Each sprinkler has a heat-sensitive element with a predetermined temperature and sensitivity that responds individually to heat from a fire. Only those sprinklers in the immediate vicinity of the fire actuate and discharge water. It is not uncommon for only one or two sprinklers to go off in a fire.
Myth: Sprinkler systems cause excessive water damage.
FACT: In most cases, water flowing from a sprinkler causes much less damage than the fire would have caused in the absence of the sprinkler. A fire has the potential to completely destroy a building, and sprinkler systems have a solid record of performance in saving lives and property, with minimal water damage. It is also important to note that the water damage from a fire hose operated by the fire service during fire fighting operations in an unsprinklered building could greatly exceed water damage from a sprinkler, because the rate of discharge from a fire hose is several times the rate of discharge from a sprinkler.
Myth: Sprinkler systems don’t work.
FACT: Most studies of sprinkler system effectiveness show that sprinkler systems are between 98% and 99.8% effective in the control of fire. The majority of incidences of ineffectiveness are related primarily to the failure of building owners in keeping sprinkler control valves in the open position.
Myth: Automatic fire detection systems are an acceptable substitute for sprinklers
FACT: Automatic fire detection systems do not control or suppress a fire and are not a substitute for an automatic sprinkler system. Detection systems have a good record of providing notification, but do not provide suppression.
Myth: Accidental sprinkler discharge is common.
FACT: Sprinklers have an impressive history of reliable service in an emergency and discharge in the absence of a fire is very rare.
Myth: Sprinkler systems cost too much.
FACT: Sprinkler system are not prohibitively expensive. They usually are only a small fraction of the total cost for a building. It is not uncommon for an owner of a commercial property to recover the cost of the sprinkler system in 5 to 10 years through insurance rate reductions. A residential sprinkler system connected to a public water costs about $1.16 per square foot, less than the cost of most carpets.
Myth: Sprinklers are ugly.
FACT: Sprinkler systems can be designed to maintain the beauty of a building. Pipes can be concealed above ceilings or behind soffits, and sprinklers can be selected from a wide range of aesthetic models. Ornamental and decorative sprinklers are available that allow concealment above the ceiling with only a small plate showing below the ceiling, with a wide range of factory-applied colors. While sprinklers can be concealed, management of a building may elect to use a visible presence of sprinklers as a sales tool to emphasize life safety in a building, especially hotels.
Sprinkler Head Types
Spray sprinklers are manufactured in three basic styles. A standard spray upright (SSU) sprinkler is mounted on upright above a branch line pipe, usually in a room with exposed structural elements, and has a deflector, a metal plate whose edge is distinctively bent to deflect water downward from the sprinkler. A standard spray pendant (SSP) sprinkler is mounted below the branch line, usually mounted at or below the surface of a suspended ceiling and is characterized by a flat deflector. SSU and SSP discharge patterns are designed to be the same. Sidewall sprinklers have a specifically designed deflector that allows the sprinkler to discharge water from a wall-mounted position.Variations on upright, pendant, and sidewall sprinkler are the dry upright, dry pendant, and dry sidewall sprinklers. These special sprinklers are manufactured with a seal at the inlet that prevents water from entering the nipple until the sprinkler actuates. These sprinklers can be extended from a wet pipe system into an unheated area, such as a walk-in freezer, an outside loading dock, or an unheated attic space, or can be used in the pendant position on a dry pipe system to prevent condensation from entering the sprinkler and freezing.
Sprinkler Head Temperature Ratings