CO2 (CARBON DIOXIDE) FIRE SUPPRESSION SYSTEM - THE WORLD HEAVYWEIGHT CHAMPION

Fire suppression systems are designed to suppress or extinguish a fire in sensitive environments where water from a fire sprinkler is not a desired extinguishing agent. Common areas where you will find fire suppression systems include server rooms, engine rooms, flammable storage areas, museums, data centers, factories or warehouses with (fuels, chemicals, gasoline, paintings, petroleum, flammable gases, paper, garbage, plastics, fats, oils, tar, rubber, rims, tires, etc.)

There are a few different types of agents that are used in a suppression system to suppress the fire. In server rooms and environments where you have personnel working in the area, you will usually find clean agent or inert gas suppression systems. In environments where there are few personnel or none at all, you will typically find CO2 fire suppression systems. The areas that you’ll find CO2 fire suppression systems include engine rooms, generator rooms, power stations, flammable liquid storage rooms, and around large industrial machines.

While CO2 fire suppression systems are highly effective at suppressing fires, the CO2 agent also poses a health risk when compared to the other agents. For this reason, you’ll find CO2 fire suppression systems most often in non-occupied environments.

A fire needs oxygen, fuel, and heat to continue to burn. By eliminating one of these three elements, a fire can be suppressed or extinguished. While some suppression agents reduce the heat of the fire, a CO2 fire suppression system eliminates the oxygen to suppress the fire. When the suppression system detects smoke or fire, it then releases the CO2 agent into the space it is protecting. The CO2 level in the space quickly increases as the oxygen level quickly drops causing the fire to be suppressed or extinguished.

CO2 is a colorless, odorless, and electrically non-conductive gas that leaves no residue behind. This means any sensitive equipment that is in the protected space is not damaged by the CO2, which reduces downtime and costs. Once the CO2 has dispersed to safe levels from the protected space, personnel can access any damage from the fire or smoke and quickly get back to work with no cleanup needed.

At 7.5% concentration, CO2 can cause asphyxiation to humans. Most CO2 fire suppression systems are designed to have 34% CO2 concentrations for a total flood of the protected space. Due to the obvious dangers of CO2, the CO2 fire suppression systems are required to have certain life safety devices to protect personnel around or near the protected spaces. One of the life safety devices is a pneumatic siren that warns people around the area that the CO2 will be discharging from the suppression system. It is important to properly train all personnel on the dangers of the CO2 fire suppression system and how to evacuate safely if the system is preparing to dump the CO2 to suppress the fire.

Below are some of the life safety devices and parts that you will find on a CO2 fire suppression system to reduce the risks of CO2 exposure to personnel.

Pneumatic Time Delay: When the CO2 fire suppression system is activated, a pneumatic time delay is first initiated. The pneumatic time delay works from the pressure of the CO2. The time delay operates for 30 or 60-seconds in order to allow personnel to evacuate before discharging the CO2.

Pneumatic Siren: The pneumatic siren is first activated by the pneumatic time delay and creates an audible warning that the CO2 fire suppression system is activated. The pneumatic siren will continue to go off during the CO2 discharge as well. Only when all of the CO2 has been discharged, will the siren go silent.

Supervised Lock-Out Valve: Whenever general maintenance is being performed, personnel can activate the lock-out valve to prevent accidental discharge of CO2. The lock-out valve is activate by turning a lever which effectively closes off the line between the CO2 cylinder/s and the discharge nozzles. The lock-out valve is monitored at the control panel to ensure the valve is reopened and in operating condition after maintenance has been performed.

Pneumatic Wintergreen Odorizer: CO2 is a colorless, odorless gas that is undetectable by humans. To ensure personnel are aware that CO2 has been discharged or that the system is leaking CO2, a pneumatic wintergreen odorizer is added to the system. The odorizer injects a small amount of wintergreen scent into the CO2 agent as it flows out of the system. Personnel that work around or near the CO2 fire suppression system should be instructed that when the wintergreen scent is detected, that there is carbon dioxide gas in the area and to evacuate immediately.

Warning Signs: In NFPA 12, Standard on Carbon Dioxide Extinguishing System, Chapter 4.3.2, it states that warning signs shall be affixed in a conspicuous location in every protect space; at every entrance to protected spaces; and in spaces near the protected spaces where carbon dioxide could migrate, creating a hazard to personnel. Signs state that carbon dioxide gas can cause injury or death. They also mention that when alarm operates or wintergreen scent is detected, to not enter protected space until fully ventilated.

Smoke Detectors: If a fire begins in the protected area, the smoke detector will detect the fire and send a signal to the control panel. Smoke detectors will usually sense the fire before it has had time to escalate.

Control Panel: The control panel is the brains of the system. When it receives a signal from the detectors, it then sends a signal to sound the notification devices and activate the release device to suppress the fire.

Notification Devices: To warn those around or in the protected area that the fire suppression system is preparing to activate and release the clean agent, the control panel activates the alarm horns and strobes. The horns create a loud audible alert while the strobes create a bright visual alert.

Release Device: The release device is attached to the cylinder and is activated by the control panel. The control panel activates the release device after a fire is detected, allowing the clean agent to escape from the cylinder and flood the protected area.

Cylinder/s: The cylinder is where the clean agent is stored. Depending on the size of the protected space, there can be multiple cylinders or one very large cylinder. Some clean agents are stored as a gas while others are stored as a liquid gas.

Nozzles: Once the clean agent has been released from the cylinders, it travels down the pipes and exits out of the strategically placed nozzles. Nozzles in the middle of the protected space will be 360 degree nozzles allowing the clean agent to disperse all around the nozzle. Nozzles installed near walls will usually be 180 degree nozzles which disperses the clean agent away from the wall.

Abort Switch: The abort switch is usually a large button that is located near the clean agent system or near the door of the protected space. By depressing the button and holding it, the system is paused allowing personnel to evacuate of the area before the clean agent is dispersed. Once everyone has evacuated, the button can be released and the system will continue the process of activating the clean agent system. Note that this button will not stop the system from activating. It will only delay the system from activating.

Maintenance Switch: All fire suppression systems require routine inspections and maintenance. The maintenance switch can be used during the inspections to turn off the system so it doesn’t accidentally discharge during maintenance.

Manual Release: The manual release allows personnel to bypass the normal process described above and activate the system and release the clean agent manually. Once the release has been pulled, the clean agent fire suppression system will activate, sending the agent through the system and out the nozzles to suppress the fire.