FS 49 C2 acts similarly to an inert gas. It absorbs the heat produced from the combustion process. This mechanism is consistent with the observation that the fire heat release rate does not decrease until sufficient gas is released.
The difference from inert gases and FS 49 C2 is that it takes less gas to suppress a fire, and therefore gas storage takes less space, depending on the storage pressure. Savings may vary between a 50-90%.