What is an automatic fire sprinkler system?
An automatic fire sprinkler system consisting of a water supply system (pumps and tank or mains water), a network of pipes (steel, plastic and other alloys) and fire sprinkler heads spaced at regular intervals throughout the protected premises. Fire sprinklers in the past were used only in warehouses, factories, offices and other commercial premises. But in recent years they are regularly installed in family dwellings, care homes, student accommodation, hospitals, libraries and historical remises.
Fire sprinkler systems are used worldwide, with well over 40 million sprinkler heads fitted each year. Automatic fire sprinkler systems are the most widely used fire protection system throughout the world. Sprinklers are designed to put a little water as possible on the seat of a fire at a very early stage of development.
Are there different types of automatic sprinkler systems?
Wet sprinkler system
These systems are installed in premises where there is no possibility of pipes freezing. The system pipework is charged with water under pressure at all times. When a sprinkler head is activated by the heat from a fire water flows immediately on to the seat of the fire.
Dry sprinkler system
Dry pipe systems are installed in premises where there is a possibility of water in pipes freezing. Dry systems are charged with compressed air or another inert gas i.e. nitrogen. When a fire sprinkler head is activated by the heat from a fire, the air pressure drops and the valve opens allowing water to fill the pipes and discharge from the sprinklers on to the seat of the fire.
Pre-Action sprinkler system
Pre-action systems are commonly installed in areas where the accidental discharge of water may be problematic i.e. when a sprinkler head is accidently damaged.
They are installed in areas such as data processing facilities, document storage or cold storage warehouses. The system can only be activated by a combination of events i.e. operation of a smoke/heat detection system AND the operation of a sprinkler in a fire condition. The pipes are normally filled with compressed air and water is only allowed to fill the pipes when the smoke/heat detection system is activated. This ensures that accidental discharge will not occur. There are several modes of operation and these can be setup in the sophisticated system control panel to suit the client’s exact requirements.
Can sprinklers operate accidentally?
Sprinklers are activated by heat from a fire and will not operate until the temperature reaches about 68⁰C. There is no risk of activation by smoke, dust, fumes or moisture in the air.
Do all the sprinklers operate if there is a fire?
Only the sprinkler or sprinklers closest to the fire source operate, they don’t all go off at the same time.
Are sprinklers effective?
When buildings are protected with a properly designed and maintained sprinkler system about 99% of fires are controlled by the sprinklers.
About 60% of fires (in commercial premises) are controlled when only 4 sprinklers operating.
Losses from fires in buildings equipped with sprinklers are 1/10 of those in unprotected buildings
Will sprinklers near a cooker operate accidentally like smoke detectors?
Smoke will not activate a sprinkler head. There must be a fire that generates enough heat to raise the temperature near the sprinkler to above 68⁰C. It is very unlikely that the heat from cooking will set off the sprinkler.
Why are sprinklers important for life safety?
Sprinklers do not rely upon human factors such as familiarity with escape routes or emergency assistance. They go to work immediately to reduce the danger.
Sprinklers prevent the fast developing fires of intense heat which are capable of trapping and killing dozens of building occupants.
How much does a new sprinkler system cost?
How much does a retrofit sprinkler system cost?
Are their "trade-offs"?
The system cost can often be offset by insurance savings, and by specific design alternatives or “trade-offs” permitted by most building codes in view of the superior protection afforded by sprinklers. These trade-offs often include reduced fire-resistant requirements for structural components, longer exit travel distances, and larger building areas and heights.
Is water damage from sprinklers as bad as fire damage?
Water damage from sprinkler operating when there is a fire is considerably less than what the Fire and Rescue hoses would need to discharge. In most cases, sprinklers operate at the very early stage of a fire and will have suppressed or extinguished the fire long before the fire and rescue services arrive.
Is water on a frying fat fire dangerous?
Sprinkler have extinguished many fire involving domestic frying fat fires. Initially the flames flare up but with the fine spray of water from the sprinkler head the heat is very quickly removed from the fat fire and surrounding area and the flames are extinguished.
WARNING: Do not ‘pour’ water directly from a container on to a fat fire.
How effective are sprinklers compared to smoke alarms?
The chances of surviving a domestic fire are about 60% where smoke detectors are fitted. When sprinklers are also present the chance of survival is about 95%.
How do sprinkler heads operate?
Sprinklers have either a small glass bulb or a solder fusible link. The bulb or link works like a plug that retains the water in the pipes. The bulb and link are coloured to denote the operating temperature (see images below). When enough heat from a fire get to the sprinkler head it either expands the liquid in the glass bulb or melts the solder of the fusible link and the bulb or link falls away allowing water to discharge on the fire. When water is discharged, it strikes a serrated deflector plate that usually distributes the water in a circular pattern, other patterns of distribution are also available.
Glass bulb operating temperatures Fusible Link operating temperatures
Can individual sprinklers be tested like smoke detectors?
Sprinklers are individually tested when they are manufactured. When installed the completed system water flow and pressure requirements are tested and water is discharged back to the storage reservoir.
How should sprinkler systems be maintained?
The ensure that the system operates as designed it must be maintained in accordance with the requirements of the system design rules used. The design and maintenance rules can could be any of the following: NFPA (LINK http://www.nfpa.org/codes-and-standards) , BS (link http://shop.bsigroup.com ) EN 12845, LPC (link http://www.bre.co.uk/certification-and-listings ), BS9251 and others. These rules specify the maintenance intervals for the system and components. The most important thing is to employ a 3rd party accredited sprinkler installer to carry out the maintenance. You can find a list of approved installers here (Link to Find an Installer)
What is the life safety record for fully sprinklered buildings?
Aside from fire fighting and explosion fatalities, there has never been a multiple loss of life in a fully sprinklered building due to fire or smoke. Individual lives have been lost when the victim or his clothing or immediate surroundings became the source of the fire.
A National Fire Protection Association study for the years 1971-1975 found that approximately 20 lives are lost each year in this country in sprinklered buildings, as compared to approximately 4,000 per year in unsprinklered buildings. Some 68% of the lives lost in sprinklered buildings were due to explosions, and an additional 18% were due to the fact that the fire originated in an unsprinklered area of the building.
What impact does automatic fire sprinklers have on the environment?
The findings of a ground-breaking study show that greenhouse gases released by burning buildings can be reduced by 98% when automatic fire sprinklers are installed. The study, a collaborative effort of FM Global (link http://www.fmglobal.com/) and the Home Fire Sprinkler Coalition (link https://homefiresprinkler.org/ ), also found that automatic fire sprinklers: reduce fire damage by up to 97%; reduce water usage to fight a home fire by upwards of 90%; and reduce the amount of water pollution released into the environment.