Ever wondered how a gas suppression system gets activated?
A Gas Suppression System can be activated manually (at the cylinder valve) and electrically via one of the devices that forms part of the detection system. The other way is to set the detection system to activate automatically. The detection part is what we are going to focus on…
The typical fire detection system used in conjunction with a gas suppression system consists of the following:
1. Gas Control Unit or Conventional Detection and Gas Combination Panel
3. Gas Release Manual Call-Point
4. Gas Test Interface
6. Sounder/Strobe Combination Devices
The Gas Control Unit does exactly what it says, it controls the gas. When one fire detector gets activated, it activates the bell inside the room that gets protected to warn the occupants that a fire had been detected. When another detector in the same room activates as well, then we call it a “Double-knock” which will cause the Sounder/Strobe devices inside and outside the rooms to activate. Note that this is only possible when the status of the panel or gas control unit is on “Automatic”. When the sounder/strobes activate you will have anything from 30-60 seconds to leave the room before the gas will discharge depending on the settings. The “Gas Discharge Initiated” or “Gas Discharge Pending” light will activate at the gas control unit upon a “Double-knock”.
When this time expires, the gas control unit or combination panel will activate its gas discharge output which will send 24 VDC to the actuator so that the gas can discharge. Some gas suppression systems have a small “Pilot Cylinder” which is connected to one of the cylinders containing the fire extinguishing agent. If the actuator triggers the pilot cylinder discharges and causes the other cylinders containing the agent to trigger pneumatically. Please also see our article about gas suppression systems. Other systems do not have a pilot cylinder and the valve of the gas extinguishing cylinder activates electrically.
Another way of activating the gas release is to trigger the yellow Gas Release Manual Call-Point at the gas control unit. This will function even if the status of the panel is on “Manual”. On “Manual” the detectors in the room cannot cause a “Double-Knock”. This is why it is important that when someone enters the room, he/she puts the panel on “Manual” and when they leave on “Automatic”. It will prevent the gas from discharging when someone is in the room.
It is very important to note that should there be another entrance to the room a Gas Status Unit needs to be installed to mimic the status of the gas control unit or panel. People entering through the other door need to know in what status the other panel is.
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Arno van den Berg