Carbon Dioxide (Class B & C Fires)
Pressurized Water Fire Extinguishers User Guidelines
Use for Class B Fires
What types of fires can be extinguished with carbon dioxide (CO2) fire extinguishers?
Class B fires which involve flammable liquids and gases, solvents, oils, greases (excluding cooking oils/greases in depth) tars, oil-based paints and lacquers. Class C fires which involve energized electrical equipment.
What is the proper way to use a Class BC, CO2 fire extinguisher?
There are four basic operating steps. Think of the word "PASS" to remember the steps.
Pull the pin. Holding the extinguisher by the handle with the nozzle pointing away from you, pull out the pin located below the trigger. Note: Lifting the extinguisher by the handle will not activate the CO2 stream.
Aim low. Standing up to 10 feet away from the fire, point the extinguisher discharge horn at the front edge of the base of the fire (the lowest point of the fire nearest you). Remember - extinguishers are designed to be operated in an upright position. Always hold the extinguisher vertically. Never cradle it horizontally or at an angle in your arms. If the extinguisher is too heavy to hold properly, place on the floor next to you and operate.
Squeeze the trigger. Squeeze slowly and evenly. This action will release CO2 and expel it through the discharge horn.
Sweep from side to side. As the CO2 is expelled, sweep the hose from side to side. As the fire closest to you goes out, you may move closer to the fire and continue the sweeping motion until the fire is extinguished. Continue discharging to prevent reignition. Remember, hold or place the extinguisher upright. If the fire does not diminish immediately, get out of the building.
How far will the CO2 stream reach?
The horizontal range of the CO2 extinguishing stream is limited to a range of 3 to 10 feet.
How long will it take to use up the 10 to 15 pounds of CO2?
The approximate time of discharge for the 10 to 15 pounds of CO2 ranges from 8 to 30 seconds.
Once activated, can a CO2 extinguisher be shut off?
Yes, stop squeezing the trigger and the stream of CO2 will stop. This may be appropriate if you must reposition yourself in relation to the fire.
How does the CO2 put out a fire?
As the CO2 gas is expelled it turns into a cloud of dry ice, commonly referred to as "snow". This cloud reduces the amount of oxygen in the air around the fire and smothers it.
What are the advantages and disadvantages of CO2 fire extinguishers?
CO2 is clean, non-corrosive and leaves no residue on expensive computers and electronic equipment. The extinguishers are heavy, from 30 to 46 pounds, and they have short discharge ranges. CAUTION: Do not handle the expelled CO2 "snow" because it can cause frostbite.