Gaseous fire suppression is a term used to describe the use of inert gases and chemical agents to extinguish a fire. It also referred to as Clean Agent Fire Suppression. Gaseous fire suppression systems are particularly used in high-risk areas where a minor fire within a critical area could have serious financial repercussions or a critical effect on the ability to deliver services. These fire suppression systems consists of the agent, agent storage containers, release valves, fire detection system (fire detectors, wiring control panel, and actuation signalling), agent dispersion nozzles and agent delivery piping.
Types of Gaseous Fire Suppression Systems
There are two main types of gaseous fire suppression systems: inert gas and chemical agents.
1. Inert Gas Fire Suppression Systems
The inert gases that are used include ARGONITE (IG55), ARGOGEN (IG55), INERTSAFE (IG541) and INERGEN (IG541).
These gases extinguish fires based on the principle of oxygen depletion where the oxygen concentration is reduced below 15%, which is an acceptable level for human exposure, but insufficient to allow fire to grow.
2. Chemical Fire Suppression Systems
The chemical agent acts not by the removal of oxygen, but they extinguish fire primarily by cooling at the molecular level. The widely used chemical agents include; NOVEC 1230, FM200 (HFC-277ea), FS 49 C2 and HFC-125. The molecules of these chemicals are capable of physically absorbing heat so that the temperature of the flame falls to a point to which it cannot grow, therefore, suppressing any further propagation.
Methods of Application
Generally, there are two methods of applying an extinguishing agent:
1. Total flooding: Gaseous fire suppression systems working on this principle by apply an extinguishing agent throughout an enclosed space. This is meant to achieve an agent concentration that is adequate enough to put out the fire.
2. Local application: Systems working using the principle of local application apply an extinguishing agent directly onto a 2-D fire area, but can also be applied into the 3-D region immediately surrounding the object on fire. However, in this case, there’s no physical barriers enclosing the fire space.
Gaseous fire suppression systems activation can be manual or automatic. The gas is discharged through a pipe network system and enters the protected environment through the appropriately designed nozzles.