Automatic fire suppression systems control and extinguish fires without human intervention.

According to the National Fire Protection Association, there were 1,602,000 fires reported in the United States in 2005. There were 3,675 civilian deaths, 17,925 civilian injuries, and $9.2 billion in property damage. A fire department responded to a fire every 20 seconds and a structure fire

Structure fire

A structure fire is a fire involving the structural components of various residential buildings ranging from single-family detached homes and townhouses to apartments and tower blocks, or various commercial buildings ranging from offices to shopping malls...

 was reported every 62 seconds.

Although man has fought fire for centuries, it was not until Feb. 10, 1863 that the first fire extinguisher

Fire extinguisher

A fire extinguisher or extinguisher, flame entinguisher is an active fire protection device used to extinguish or control small fires, often in emergency situations...

 patent was issued to Alanson Crane of Virginia. The first fire sprinkler system was patented by H.W. Pratt in 1872. But the first practical automatic sprinkler system was invented in 1874 by Henry S. Parmalee

Henry S. Parmalee

Henry S. Parmalee, a piano maker from New Haven, Connecticut, invented a fire sprinkler system in 1874 to protect his piano factory. While other patents for fire sprinklers predated Parmalee's work, he is credited with the first practical automated sprinkler head.His piano company The Mathushek...

 of New Haven, CT. He installed the system in a piano factory he owned.

Types of automatic systems

Today there are numerous types of Automatic Fire Suppression Systems. Systems are as diverse as the many applications. In general, however, Automatic Fire Suppression Systems fall into two categories: engineered and pre-engineered systems.

Engineered Fire Suppression Systems are design specific. Engineered systems are usually for larger installations where the system is designed for the particular application. Examples include marine and land vehicle applications, computer clean rooms, public and private buildings, industrial paint lines, dip tanks and electrical switch rooms. Engineered systems use a number of gaseous or solid agents. Many are specifically formulated. Some, such as 3M Novec 1230 Fire Protection Fluid

Fire Protection Fluid

Fire Protection Fluid is a fluid that acts like water, looks like water, and flows like water, but does not get things wet in the same way as water. When discharged from a fire apparatus, it converts to a gas, due to its thermodynamic properties and suppresses fire when used at its extinguishing...

, are stored as a liquid and discharged as a gas.

Pre-Engineered Fire Suppression Systems use pre-designed elements to eliminate the need for engineering work beyond the original product design. Typical industrial solutions use a simple wet or dry chemical agent, such as potassium carbonate

Potassium carbonate

Potassium carbonate is a white salt, soluble in water , which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid...

 or monoammonium phosphate (MAP), to protect spaces such as paint rooms and booths, storage areas and commercial kitchens. In Europe, a small number of residential designs have also emerged. These units often employ water mist with or without a surfactant

Surfactant

Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...

 additive, and target retrofit applications where the risk of fire or fire injury is high but where a conventional fire sprinkler system would be unacceptably expensive.

Components

By definition, an automatic fire suppression system can operate without human intervention. To do so it must possess a means of detection, actuation and delivery.

In many systems, detection is accomplished by mechanical or electrical means. Mechanical detection uses fusible-link or thermo-bulb detectors. These detectors are designed to separate at a specific temperature and release tension on a release mechanism. Electrical detection uses heat detectors equipped with self-restoring, normally-open contacts which close when a predetermined temperature is reached. Remote and local manual operation is also possible.

Actuation usually involves either a pressurised fluid and a release valve, or in some cases an electric pump.

Delivery is accomplished by means of piping and nozzles. Nozzle design is specific to the agent used and coverage desired.

Extinguishing agents

In the early days, water was the exclusive fire suppression agent. Although still used today, water has limitations. Most notably, its liquid and conductive properties can cause as much property damage as fire itself.

Agent	Primary Ingredient	Applications
FM-200	Heptafluoropropane	Electronics, medical equipment, production equipment, libraries, data centers, medical record rooms, server room Server room A server room is a room that houses mainly computer servers. In information technology circles, the term is generally used for smaller arrangements of servers; larger groups of servers are housed in data centers... s, oil pumping stations, engine compartments, telecommunications rooms, switch rooms, engine and machinery spaces, pump rooms, control rooms
3M Novec 1230 Fire Protection Fluid	Fluorinated ketone	Electronics, medical equipment, production equipment, libraries, data centers, medical record rooms, server rooms, oil pumping stations, engine compartments, telecommunications rooms, switch rooms, engine and machinery spaces, pump rooms, control rooms
Argonite Argonite Argonite is a name brand and registered trademark owned by Ginge-Kerr for a mixture of 50% argon and 50% nitrogen . It is an inert gas used in gaseous fire suppression systems. Ginge-Kerr is part of United Technologies Fire & Security...	Argon Argon Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...  and nitrogen	Same applications and FM-200 and Novec 1230 fluid; less Class B style hazards
FE-13	Fluoroform Fluoroform Fluoroform is the chemical compound with the formula CHF3. It is one of the "haloforms", a class of compounds with the formula CHX3 . Fluoroform is used in diverse niche applications and is produced as a by-product of the manufacture of Teflon...	Police evidence freezers, inerting natural gas pumping stations or trains/trucks/cranes operating in cold weather, electronics, medical equipment, production equipment, libraries, data centers, medical record rooms, server rooms, oil pumping stations, engine compartments, telecommunications rooms, switch rooms, engine and machinery spaces, pump rooms, control rooms
Wet Chemical	Potassium carbonate Potassium carbonate Potassium carbonate is a white salt, soluble in water , which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid...	Commercial kitchens
ABC Dry Chemical ABC Dry Chemical ABC or multi-purpose dry chemical is a dry chemical extinguishing agent. It uses a specially fluidized and siliconized monoammonium phosphate powder. ABC dry chemical is usually a mix of monoammonium phosphate and ammonium sulfate, the former being the active one. The mix between the two agents is...	Monoammonium phosphate	Paint booths, dip tanks, coating operations, flammable liquid storage areas, paint mixing areas, exhaust ducts
Regular Dry Chemical	Sodium bicarbonate Sodium bicarbonate Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula Na HCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda . The natural mineral form is...	Gasoline, propane and solvents, live electrical equipment, flammable liquids
Carbon Dioxide	Carbon Dioxide Carbon dioxide Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...	Non-occupied control rooms, coating operations, paint lines, dust collectors, transformer vaults, live electrical equipment, flammable liquids, commercial fryers
Foam	Synthetic detergent, polysaccharide Polysaccharide Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,... , fluoroakyl suffaccant	Flammable liquids
Purple K Dry Chemical	Potassium bicarbonate Potassium bicarbonate Potassium bicarbonate , is a colorless, odorless, slightly basic, salty substance...	High hazard commercial and industrial applications, especially with flammable liquids
Solid aerosol particulate	Potassium nitrate Potassium nitrate Potassium nitrate is a chemical compound with the formula KNO3. It is an ionic salt of potassium ions K+ and nitrate ions NO3−.It occurs as a mineral niter and is a natural solid source of nitrogen. Its common names include saltpetre , from medieval Latin sal petræ: "stone salt" or possibly "Salt...	Used in condensed aerosol fire suppression Condensed aerosol fire suppression Condensed aerosol fire suppression is a particle-based form of fire extinction similar to gaseous fire suppression or dry chemical fire extinction. The aerosol employs a fire extinguishing agent consisting of very fine solid particles and gaseous matter to put out fires... , high hazard commercial and industrial applications, no ozone depletion or global warming potential
Halotron 1	2,2-dichloro-1,1,1-trifluoroethane 2,2-Dichloro-1,1,1-trifluoroethane 2,2-Dichloro-1,1,1-trifluoroethane or HCFC-123 is considered as an alternative to CFC-11 in low pressure refrigeration/HVAC systems, and should not be used in foam blowing processes or solvent applications....	Live electrical equipment, flammable liquids
Water Mist	Water	Ordinary flammables (Paper, wood, cloth)
Water	Water	Ordinary flammables (Paper, wood, cloth)

Health and environmental concerns

Despite their effectiveness, chemical fire extinguishing agents are not without disadvantages. In the early 20th century, carbon tetrachloride

Carbon tetrachloride

Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...

 was extensively used as a dry cleaning solvent, a refrigerant and as a fire extinguishing agent. In time, it was found carbon tetrachloride could lead to severe health effects.

From the mid 1960s Halon 1301 was the industry standard for protecting high value assets from the threat of fire. Halon 1301 had many benefits as a fire suppression agent; it is fast acting, safe for assets and required minimal storage space. Halon 1301s major drawbacks are that it depletes atmospheric ozone

Ozone

Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

 and is potentially harmful to humans.

Since 1987, some 191 nations have signed The Montreal Protocol

Montreal Protocol

The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances believed to be responsible for ozone depletion...

 on Substances That Deplete the Ozone Layer. The Protocol is an international treaty designed to protect the ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion. Among these were halogenated hydrocarbons often used in fire suppression. As a result manufacturers have focused on alternatives to Halon 1301 and Halon 1211 (halogenated hydrocarbons).

A number of countries have also taken steps to mandate the removal of installed Halon systems. Most notably these include Germany and Australia, the first two countries in the world to require this action. In both of these countries complete removal of installed Halon systems has been completed except for a very few essential use applications. The European Union is currently undergoing a similar mandated removal of installed Halon systems.

Modern systems

Since the early 1990s manufacturers have successfully developed safe and effective Halon alternatives. These include DuPont FM-200, American Pacific’s Halotron and 3M Novec 1230 Fire Protection Fluid. Generally, the Halon replacement agents available today fall into two broad categories, in-kind (gaseous extinguishing agents) or not in-kind (alternative technologies). In-kind gaseous agents generally fall into two further categories, Halocarbons and Inert Gases. Not in-kind alternatives include such options as water mist or the use of early warning smoke detection systems.