Carbon Dioxide Flooding System
Carbon dioxide is an inert gas used for putting out fire. It does this by displacing the oxygen that is necessary for combustion. Because it is a gas, care must be taken to ensure that fresh air is not allowed to interfere during the process of putting out a fire. Carbon dioxide is particularly useful when dealing with electrical fires.
Carbon dioxide flooding system is used for switch rooms containing high voltages. If there is a fire in these rooms, it is rather dangerous for the firefighters to handle. The rooms will contain live and high voltage electrical supplies. The transformers may contain oil that can burn or explode.
The only sensible thing to do when fighting this type of fire is to close off all the air and displace it with carbon dioxide. With no oxygen available, the fire will eventually die off.
Carbon Dioxide Panels
These systems are installed for any room with important electrical or highly inflammable equipment. They are powered by AC mains supply. Stand-by batteries provide 72 hours of operation in case of power interruption.
Each system consists of a control panel connected to one or several heat detectors, smoke detectors, CO2 cylinders, actuator devices and indicating lights. These panels are located near to the rooms to be protected. Both heat and smoke detectors are installed for such a flooding system. They have to be activated together before the CO2 will discharge. This is to prevent false signals activating the discharging mechanisms.
The status of any CO2 panel can be monitored at the Main Fire Control room.
There are two different modes to activate the alarm of the CO2 panels and subsequent discharge of CO2 from the cylinders into the room on fire:
- Automatic mode Activation of the alarms starts when both the heat and smoke detectors – paired up into 2 zones – have been activated by fire occurring in the protected room. When one detector senses the fire, the alarm bell of the system rings intermittently. Once both types of sensors are activated, the alarm bell becomes continuous. After 20 to 30 seconds a signal is sent to the cylinders plunger-actuating device. The CO2 is discharged into the room.
- Manual mode Activation is made with the breakglass key switch. By turning the key switch, the alarm bell rings, and the CO2 is discharged immediately.
In rooms that contain ventilation louvers, it is important to seal them off when discharging CO2 gas. In these cases, the signal for discharging the gas also activates a fire curtain in the room. The curtain above the louver drops down and covers up all of them.
Sometimes the signals may be activated accidentally. All the rooms that are so protected have red and green indication lamps installed above their doors. A room that is filled with CO2 does not support combustion. Anyone who goes into such a gas-filled room can become unconscious due to lack of oxygen. Whenever gas is discharged, the red lamp above the door will be lighted. Persons must enter only when the green light is on.