Technical Glossary

40 technical terms used in gas fire suppression engineering, explained.

Get support from our expert team for your project.

Phone+90 212 945 7465 WhatsApp+90 542 144 10 42 E-mailinfo@gazliyanginsondurme.com

Alarm Unit: The component that alerts anyone in the space with audible and visual warnings during the pre-alarm and discharge stages, triggering evacuation.
Burst Disc: A safety element that ruptures in a controlled way under excess pressure, protecting the system against sudden pressure spikes and preventing damage to the piping.
Check Valve: A one-way valve in multi-cylinder banks that prevents gas from flowing backward, ensuring each cylinder's discharge is routed into the correct line.
Clean Agent: The general term for extinguishing gases that leave no residue after discharge and are electrically non-conductive. Chemical agents such as FM-200 and FK-5-1-12 fall into this category.
CO2 (Carbon Dioxide): A gas that extinguishes through both cooling and oxygen displacement. Because its effective extinguishing concentration corresponds to an oxygen level that threatens human life, its use is restricted to spaces that are normally unoccupied or where access is tightly controlled.
Control Panel: The system's central unit, which evaluates signals from detectors and manual release stations, manages pre-alarm and time delay, and issues the final discharge command to the actuators.
Cylinder: The pressure vessel in which extinguishing gas is stored under pressure. It is manufactured under pressure-equipment regulations (TPED/PED) and is subject to periodic hydrostatic testing.
Cylinder Bank: An arrangement in which multiple cylinders are grouped together and connected to a single shared line. In Multi-Zone systems, a shared bank serves multiple zones through selector valves.
Design Concentration: The target gas percentage, calculated to extinguish a given fuel class, obtained by adding a safety margin to the extinguishing concentration defined in the relevant standard.
Detection Unit: A detector that monitors a protected space for abnormal conditions (smoke, heat, flame) and generates the first signal of a fire event.
Discharge Time: The time it takes for gas to travel from the cylinders into the protected space and reach the standard-defined majority of the design concentration. It is determined through hydraulic calculation based on pipe diameter, nozzle placement, and cylinder pressure.
Discharge Valve: The main valve at a cylinder's primary outlet that controls gas flow and opens on the discharge command.
Door Fan Test: A room integrity test that pressurizes and depressurizes a room with a calibrated fan to measure total equivalent leakage area, from which the expected retention time is calculated. It verifies room performance without ever performing a real gas discharge.
EN 15004: The design standard governing gas suppression systems in Europe, forming the technical basis for CE-marked products.
FK-5-1-12 (Novec 1230): A chemical clean agent that, like FM-200, works through heat absorption and chain-reaction interruption. With a global warming potential (GWP) of 1, it is the lowest-environmental-impact agent among clean agents.
FM (Factory Mutual): A US-based approval and certification body that documents, through independent laboratory testing, that components meet performance criteria, and is also referenced widely in the insurance industry.
FM-200: A clean agent known by its chemical name HFC-227ea. On discharge it draws heat out of the space and chemically interrupts the chain reaction in the flame zone, delivering effective suppression at a low design concentration.
GWP (Global Warming Potential): A measure of how many times more effectively a gas traps heat in the atmosphere compared with carbon dioxide. Inert gases sit near zero, FK-5-1-12 has a GWP of 1, and FM-200 has a notably higher value.
Hold Time: The minimum period the extinguishing atmosphere must remain in the protected space, without ventilation, to prevent re-ignition. Achieving it depends directly on how well the room is sealed.
IG-55 (Argonite): An inert extinguishing gas made from a blend of nitrogen and argon. It works on the same oxygen-dilution mechanism as IG-541 and has a near-zero global warming potential (GWP).
Inergen (IG-541): An inert gas blend made from nitrogen, argon, and carbon dioxide in fixed proportions. It extinguishes by physically diluting ambient oxygen rather than through a chemical reaction, and leaves a margin that a person can briefly breathe even at its extinguishing concentration.
Inert Gas: Gas blends that don't react chemically and extinguish purely by physically diluting ambient oxygen. IG-541 and IG-55 are the leading examples of this category.
ISO 14520: An internationally recognized standard series for gas suppression systems, similar in scope to NFPA 2001.
LPCB: Loss Prevention Certification Board; a UK-based certification body that independently tests and certifies gas suppression system components, widely referenced in insurance risk assessment.
Manifold: The connecting piece that gathers the outlets of multiple cylinders in a bank into a single shared line.
Manual Release Station: A station that lets personnel activate the system by hand when needed, usually paired with a nearby manual abort button.
Multi-Zone System: A system architecture that delivers gas to multiple zones from a shared cylinder bank through selector valves. Because simultaneous fire across multiple zones is not a design scenario, the shared bank is sized for the single largest zone.
NFPA 2001: A US-originated design standard for clean agent fire suppression systems, widely referenced worldwide, defining design concentration, safety factors, and test procedures.
Nozzle: The final component through which extinguishing gas from the piping is released into the protected space. Its count, diameter, and placement are determined by hydraulic calculation.
Oxygen Dilution / Displacement: The principle by which gas delivered into a protected space lowers the ambient oxygen level to a point where combustion can no longer be sustained. Inert gases and CO2 both work through this mechanism, though the oxygen level they reach — and the safety margin left for occupants — differs significantly between them.
Panel Suppression: A suppression method designed for localized spaces such as electrical panels and control cabinets, in which a polymer detection tube, typically filled to around 25 bar, bursts at a hot spot at approximately 100–110°C, triggering discharge directly.
Pilot Actuator: A mechanism that uses pneumatic pressure from a triggered pilot cylinder to simultaneously open the valves of the other cylinders in a bank.
Pressure Switch (Manometer Switch): A component that monitors cylinder pressure drops and signals the control panel in the event of a leak or discharge, enabling remote pressure monitoring.
Room Integrity: A protected room's capacity to retain the extinguishing gas for the full hold time. Leaks at points such as door-bottom gaps, cable/pipe penetrations, and ceiling voids reduce this capacity.
Selector Valve: In Multi-Zone systems, the valve that determines which zone the gas from a shared cylinder bank is routed to, opening on the signal from the alarming zone.
Solenoid Actuator: An electromechanical trigger that opens a cylinder valve directly, or activates a pilot actuator mechanism, in response to an electrical signal from the control panel.
Stand Alone System: An independent system architecture in which each protected zone is served by its own dedicated cylinder group, piping, and control panel.
TPED/PED: European Union directives that govern the design, manufacturing, and transport safety of pressure equipment (PED) and transportable pressure equipment, such as extinguishing gas cylinders (TPED).
UL: Underwriters Laboratories; a US-based independent testing and certification body that documents whether components (valves, nozzles, detectors, control panels) have been tested to the relevant standard and meet its performance criteria.
VdS: A Germany-based approval body that provides independent testing and certification of fire safety products, widely recognized across Europe.