1. CXS490 Carbon Dioxide Systems

2. History CO2 recognized as a fire extinguishing agent for many years
Used in fixed systems since before World War I.

3. CO2 Applications
Hazards and equipment satisfactorily protected include:
Flammable liquid materials
Electrical hazards (transformers, switches, circuit
breakers,rotating equipment, and electronic equipment)
Engines utilizing gasoline & other flammable liquid fuels.
Ordinary combustibles (paper, wood, and textiles)
Hazardous solids

4. Static Electricity
When used to protect areas where explosive atmospheres could exist
metal nozzles must be used, and
entire system must be properly grounded.
In addition, objects exposed to discharge from CO2 nozzles
must be grounded to dissipate electrostatic charges.

5. Properties Carbon dioxide colorless odorless
electrically nonconductive
inert gas
Suitable medium for extinguishing fires.
Carbon dioxide gas is 1.5 times heavier than air.
Liquid forms solid dry ice (“snow”) when released directly into the atmosphere.
It can be easily liquified by compression and cooling.

6. Properties

7. Additional Properties
Non Combustible
Does not react with most substances
Provides its own pressure for discharge
Does not produce residues

8. } } Physical Properties Gas HP 850 psi LP 300 psi Liquid/Gas
Triple Point
Solid/Gas
Gas
Solid

9. Physical Properties At normal temperature and pressure, CO2 is a gas.
Above critical temperature (87.8° F), CO2 is a gas, regardless of the pressure.
Between 87.8° F and - 69° F (Triple point), carbon dioxide is partly a liquid and partly a gas.
Below the triple point (- 69° F, and 75 psi), it is either a solid or a gas depending on pressure and temperature.
Solid carbon dioxide is obtained below - 110° F.

10. Toxicity At extinguishing concentrations, CO2 has a:
• suffocating effect that can produces
unconsciousness and
death.

11. Use
Carbon dioxide fire-extinguishing systems are useful within limits of NFPA 12 standard in extinguishing fires involving specific hazards or equipment in the following occupancies where:
an inert electrically nonconductive medium is
essential or desirable
cleanup of other media presents a problem
they are more economical to install than other media

12. Use

13. Limitations Carbon dioxide cannot be used on chemicals
containing their own supply of oxygen
(such as cellulose nitrate)
reactive materials (sodium, potassium, etc.) and
metal hydrides.
Carbon dioxide's low cooling effect limits its use for
deep-seated fires.
Deep-seated fires require higher concentrations to be maintained for longer periods

14. Components Storage High Pressure Containers:
designed to store carbon dioxide at room temperature
850 psi at 70° F
Pressure rises rapidly with temperature
maximum temperature for storage container limited to 130° F
limitation of filling density to 68 %.
single hazard - discharges all agent
35, 50, 75, 100 & 120 lb or 16, 23, 34, 45 & 54 kg cylinders

15. Components Storage - High Pressure

16. Components Storage Low Pressure Containers: 1,000 lbs up to many tons
Vessels maintained at 0° F, 300 psi
by means of insulation and mechanical refrigeration
Filling densities can be as high as 95 %
Relief valves on container prevent pressure exceeding
safe limits due to refrigeration failure.
Multiple hazards - can be operated for a discharge time

17. Components Storage - Low Pressure

18. Components - Pipes & Fittings
Piping and fittings shall be able to withstand high pressure developed in system.
Carbon dioxide enters piping as a liquid.
Due to friction, the pressure drops, and consequently part of liquid boils, creating a mixture of liquid and gas in piping (two phase).

19. Components - Pipes & Fittings
Piping must be designed and dimensioned so that pressure never drops under 75 psi (triple point) to avoid formation of solid ("snow") which could block the nozzles' orifices.
In practice, systems are calculated so that pressure never drops under:
150 psi for low pressure systems, and
300 psi for high pressure systems.

20. Components - Nozzles Must be used within listing's limits
Mainly two types: low or high velocity
For local application
must cover entire surface involved in fire.

21. Hand Hose Line System
Fixed supply of carbon dioxide supplying hose lines

22. Standpipe System & Mobile Supply
Mobile supply of carbon dioxide capable of being quickly moved to position and connected to a system of fixed piping supplying fixed nozzles and /or hose lines.