Gaseous fire suppression

Canisters containing argon gas for use in extinguishing fire in a server room without damaging equipment.

Gaseous fire suppression is a term to describe the use of inert gases and chemical agents to extinguish a fire. Also called Clean Agent Fire Suppression. These Agents are governed by the National Fire Protection Association (NFPA) Standard for Clean Agent Fire Extinguishing Systems – NFPA 2001 in the USA, with different standards and regulations in other parts of the world. The system typically consists of the agent, agent storage containers, agent release valves, fire detectors, fire detection system (wiring control panel, actuation signaling), agent delivery piping, and agent dispersion nozzles. Less typically, the agent may be delivered by means of solid propellant gas generators that produce either inert or chemically active gas.

Theory

There are four means used by the agents to extinguish a fire. They act on the "fire tetrahedron":

Application

Broadly speaking, there are two methods for applying an extinguishing agent: total flooding and local application:

In the context of automatic extinguishing systems, local application generally refers to the use of systems that have been emplaced some time prior to their usage rather than the use of manually operated wheeled or portable fire extinguishers, although the nature of the agent delivery is similar and many automatic systems may also be activated manually. The lines are blurred somewhat with portable automatic extinguishing systems, although these are not common.

Safety precautions

Suffocation

Warning sign for fire suppression system

An extinguishing system which primarily is based on inert gases in enclosed spaces presents a risk of suffocation. Some incidents have occurred where individuals in these spaces have been killed by carbon dioxide agent release. When installed according to fire codes the systems have an excellent safety record. To prevent such occurrences, additional life safety systems are typically installed with a warning alarm that precedes the agent release. The warning, usually an audible and visible alert, advises the immediate evacuation of the enclosed space. After a preset time, the agent starts to discharge. Accidents have also occurred during maintenance of these systems, so proper safety precautions must be taken beforehand.[1]

During a fire in an essentially closed space, individuals within a closed space during a fire are safer with INERGEN than without given the design of the system.[2]

Barotrauma

Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with the body, and the surrounding environment.[3] The positive pressure caused by these gases may be sufficient to break windows and walls. Humans and structures must be adequately protected and ventilation/blow-off must be considered when designing the system.

See also

References

  1. ↑ "Gas extinguishing system may blow out walls and windows". blog.anta.net. 2009-04-14. ISSN 1797-1993. Retrieved 2009-04-14.
  2. ↑ Lambertsen, Christian J. "INERGEN: Summary of Relations, Physiologic Factors and Fire Protection Engineering Design". Environmental Biomedical Research Data Center Technical Report No. 4-14-94 (2nd ed.). Retrieved 2015-12-28.
  3. ↑ US Navy Diving Manual, 6th revision. United States: US Naval Sea Systems Command. 2006. Retrieved 2008-05-26.
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