This standard lays down the minimum general requirements for the design, installation, testing, commissioning, and maintenance of gaseous fire extinguishing systems. It covers systems using halocarbon and inert gas agents intended to protect enclosed spaces and assets where water-based suppression is not desirable.
Gaseous Fire Extinguishing Systems - General Requirements
Quick Reference Values
Maximum discharge time for Halocarbon agents10 seconds
Maximum discharge time for Inert Gas agents60 seconds
Minimum holding time for agent concentration10 minutes
Minimum safety factor for Class A fire design concentration1.2
Maximum oxygen concentration for Inert Gas system design (for normally unoccupied areas)12.5%
Piping hydraulic pressure test1.5 times the maximum working pressure for 2 min
Key Formulas
W = (V/s) * [c / (100 - c)] — Formula for calculating mass of halocarbon agent required
X = 2.303 * (Vs/V) * log10(100 / (100 - C)) — Formula for calculating volume of inert gas agent required
Practical Notes
Enclosure integrity is the single most critical factor for system success. Always perform a Door Fan Test (Annex C) to ensure the room can hold the gas concentration for the required duration (typically 10 minutes).
For liquefied gases like HFCs, the cylinder pressure gauge only indicates the presence of vapor pressure and not the amount of agent. The only reliable method to check the agent quantity is by weighing the cylinders during maintenance.
Ensure all automatic ventilation (HVAC) and dampers are automatically shut down and closed upon system activation to prevent the extinguishing agent from being diluted or removed from the protected space.