Inergen

INERGEN is a blend of inert atmospheric gases that contains 52% nitrogen, 40% argon, 8% carbon dioxide, used for fire suppression system agent. It is considered a clean agent for use in gaseous fire suppression applications. Inergen does not contain halocarbons, and has no ozone depletion potential. It is non-toxic. Inergen is used at design concentrations of 35-50% to lower the concentration of oxygen to a point that cannot support combustion, but still safe for humans.

Inergen has replaced the use of CO₂ in fixed firefighting applications due to the dangers associated with lack of oxygen following activation of a CO₂ system. The name is a portmanteau of the name of the lead engineer on the project, Dr Innes R. Geneson.

A component of Inergen is carbon dioxide, which allows the human body to adapt to the environment of reduced oxygen that is present after discharge of agent. Discharge of Inergen results in an approximate 2% concentration of carbon dioxide within the space. This directs the human body to take deeper breaths and to make more efficient use of the available oxygen.

The nitrogen and argon components offset the weight of the carbon dioxide, which allows the Inergen blend to have the same density as normal atmosphere. This eliminates the need for special considerations to prevent agent leakage.

Advantages

• Inergen contains no halocarbons. It has no ozone depletion potential, and unlike halocarbon agents, it will not produce toxic or corrosive decomposition.
• Inergen is safer than carbon dioxide in applications where evacuation may not be possible prior to the application of the agent. Inergen systems reduce oxygen concentration only enough to suppress combustion while stimulating breathing efficiency to a disproportional advantage (although human evacuation is clearly recommended).
• Inergen is non-toxic, and does not threaten the health, as halocarbon agents do. In some concentrations, halocarbon agents palpitate the heart.
• Inergen has almost the same density as normal atmosphere. No special considerations are needed to prevent agent leakage.
• Because Inergen creates no 'fog' during discharge, escape routes remain visible.

Disadvantages

• Unlike carbon dioxide or halocarbon agents, Inergen agent does not liquify under pressure. Hence Inergen requires more space for storage tanks.

See also

• Argonite
• FE-13
• FM-200
• Halon 1211
• Halon 1301