Inert extinguishing agents are the most environmentally friendly gas extinguishing agents available. Inert gases extinguish a fire by removing the oxygen concentration below 14% such that the fire cannot be sustained. All inert gases are stored as a gas in cylinders at between 150 bar and 300 bar. The cylinders can be stored at distance from the application. Multiarea protection systems can also be used with inert gases. If more than one area within a building needs to be protected, a single inert gas system designed to extinguish a fire in the largest room can be used with automatic valves directing the agent into the required area. Provided there is a low risk of more than one fire within the facility at any one time, this can provide cost and storage space.

Most inert gas installations will require the provision of pressure relief. All inert agents supplied by Firepro Systems Ltd are suitable for use in occupied areas, subject to fire type and application.

Firepro Systems Ltd can provide inert gas systems based on an argon/nitrogen mix, (IG-55), or on pure argon (IG-01). These systems require a nominal design concentration of 38% for a Class A surface fire, and 40% for fires within a computer room application. The No Observed Adverse Effect Level is 43% and Lowest Observed Adverse Effect Level is 52%, equivalent to residual oxygen concentrations of 12% and 10% respectively.