Gas Fire Suppression Systems
Automatic Gas Fire Suppression Systems are designed for unmanned detecting and extinguishing of class А, В, С fires and live electric equipment.
Gaseous extinguishing agents are used in Gas Fire Suppression Systems: Halons (HFC-125, FM-200, HFC-318); Novec 1230 (FK-5-1-12); CO2 and inert gases.
The complete list of gaseous fire extinguishing agents can be found in SP5.13130.2009 Automatic Fire Alarm and Fire Suppression Systems, Part 8.
Main characteristics of gaseous fire extinguishing agents:
HFC-125
(C2F5H)
HFC-125 has gained wide acceptance in Russia basically because of its low cost. HFC-125 is used in applications aiming to protect locations with no permanent human presence.
Advantages:
- Low cost
- High Effectiveness
- High thermal stability (900°С)
- Ozone friendly (ozone destruction factor of HFC-125 is zero)
Disadvantages:
- Human presence is not allowed in an environment with HFC-125 in the air.
- Low refill coefficient (0.9kg/l)
- Low dielectric conductance (0.95)
FM-200
(C3F7H)
Advantages:
- Safe for humans
- Environmental friendly
- High refill coefficient (1.1kg/l)
- Low dielectric conductance (2.0)
Disadvantages:
- Low safety limit (relative surplus over NOAEL concentration is 25%).
HFC-318
(C4F8)
Advantages:
- Safe for humans
- Environmental friendly
- High refill coefficient (1.1kg/l)
Disadvantages:
- High cost
- Low effectiveness
Novec 1230 (FK-5-1-12)
(CF3CF2C(O)CF(CF3)2)
Advantages :
- Non-toxic operational concentration and the largest margin of safety for manned spaces
- Zero ozone destruction factor
- Short life cycle (exists in atmosphere 3-5 days)
Disadvantages:
- High cost
CO2
(carbon dioxide)
Advantages :
- High-performance extinguishing
- Low refill costs
- Effective cooling of surfaces at flame
Disadvantages:
- No human is allowed in CO2 environment
- Additional CO2 mass control devices are needed
There different kinds of gaseous extinguishing agents; and their features differ, though extinguishing properties are very alike. When choosing right agent for a specific project the following criteria are to be considered: type of protected space, safety issues, environmental issues and cost-effectiveness
Comparison table :
| Agent | Use concentration, % | NOAEL2 % | Safety margin |
Global Warming
Potential
|
Atmospheric
Lifetime, years
|
| HFC-125 | 9,8 | 7,5 | -23% | 3 500 | 34,2 |
| FM-200 | 7,2 | 9 | 25% | 3 220 | 29 |
| HFC-318 | 7,8 | 9 | 15% | 9 100 | 35 |
| FK-5-1-12
(Novec 1230) |
4,2 | 10 | 138% | 1 | 3-5 days |
| СО2 (carbon dioxide) | 34,9 | 5 | -85% | 1 | — |
Use concentration – concentration of agent that creates non-combustion environment
NOAEL — (no-observed-adverse-effect level) — the highest agent concentration that is without adverse effect
Margin of safetyс – relative surplus of NOAEL over inerting concentration
Cylinders are filled with agent at special-purpose refill stations. Agent is stored under the pressure of replacement gas – normally nitrogen is used for Novec 1230 systems. CO2 is stored under the pressure of its own vapors
Gas Fire Suppression Cylinder includes high-pressure container, a lock unit, siphon and actuator device.
Cylinders design allows combining them into a pile to use jointly. In this case, the first cylinder (pilot cylinder) is actuated from the firefighting control station, and all the others are actuated with pneumatic pressure in start manifold after the pilot cylinder has triggered.
Depending on the volume of agent and system design Gas Fire Suppression Systems can be one-directional and multi-directional.
Gas Fire Suppression System consists of two parts:
The mechanical part includes the following devices:
- Cylinder (pile of cylinders) with agent;
- High-pressure hose;
- Check valve – for preventing entering agent from manifold into adjacent cylinders;
- High-pressure manifold;
- Pressure annunciator
- Distribution headers
- Distributing manifold
- Nozzles
- Blinds, adaptors and test device
- Pressure relieve valve
- Smoke suction device
When an alarm goes off agent discharges through the nozzles providing jet forming and uniform distribution over a protected area.
Mechanical part sample diagram:
Electrical part includes the following components:
- Control device
- Display and control unit
- Detectors (smoke, thermal, aspirating, flame, thermocable)
- Manual annunciator
- Light boards “Gas! Escape!”; “Gas! Do not enter!”; “Automatic is disabled!”.
- Card reader for switching on/off automatic mode
- Magnetic contact detector
- Backup power supply
- Battery
Agent release can be accomplished in different modes:
- Automatic – with detectors
- Remote – with manual annunciators located on the entrance to protected rooms.
- Manual – by pulling by hand manual release lever on a cylinder
The principle of operation of Gas Fire Suppression System:
In case two detectors trigger signaling of a fire in a protected room, the control device switches on light indication boards GAS, ESCAPE THE ROOM located inside and outside the room. After the delay in personnel escape has elapsed, electromagnetic release device receives impulse to open agent cylinders. Consequently, agent enters distribution pipeline and discharges into the protected area through the nozzles. After agent has entered distribution pipeline pressure annunciator signals control station of agent discharge
Scope of application of Gas Fire Suppression Systems:
- Data Centers
- Radio Centers
- Mobile Communications Rack Rooms
- Archives and Museums
- ACS Rack Rooms and Server Rooms
- Gas Pumping Plants
- Industrials Robots Control Equipment
- Engine Rooms
- Generator Rooms
- Diesel Generators
- Switchboard Rooms
- Warehouses
- Power Transformers Room
- Electric Power Plants Facilities
- Electric Motors and other Household Electric Devices
- Railway Control and Communications Facilities
- Air Traffic Control Halls
- Transportation Companies Data Processing Centers
- Pump Rooms and Compressor Rooms
- Cargo Holds and Tanks
- Transport Vehicles Cabins
- Passengers Cabins
Our friendly well-qualified staff will assist you in choosing all system components and making the right decision. We will do our best to protect your valuable property and to save your money.
