Automatic fire suppression

Automatic fire suppression systems control and extinguish fires without human intervention. Examples of automatic systems include fire sprinkler system, gaseous fire suppression, and condensed aerosol fire suppression. When fires are extinguished in the early stages loss of life is minimal since 93% of all fire-related deaths occur once the fire has progressed beyond the early stages.

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

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 pressurized 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.

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.

Despite their effectiveness, chemical fire extinguishing agents are not without disadvantages. In the early 20th century, carbon tetrachloride 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 1301's major drawbacks are that it depletes atmospheric ozone and is potentially harmful to humans. Since 1987, some 191 nations have signed The 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.

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