CO2 is a clean, safe, non-conductive, and naturally-occurring environment-friendly gas that won’t damage delicate electronic equipment.
CO2 fire extinguishers are very effective in putting out fires caused by flammable liquids and electrical equipment.
However, they can’t extinguish class A fires, have cold discharge that may cause injury or frostbite, cause limited visibility with a dense fog, and are not ideal for large or persistent fires.
Let’s get to know more the advantages and disadvantages of CO2 fire extinguishers.
Different Types of Fire Classes and Fire Extinguishers
Here’s a quick overview of the different classes of fire and different types of fire extinguishers to give you a clear idea.
There are mainly five types of fire extinguishers:
- Water extinguisher (for Class A fires)
- Foam extinguisher (for Class A and B fires)
- Dry chemical extinguisher (for Class B and C fires)
- CO2 extinguisher (for Class B and C fires)
- Wet chemical extinguisher (for Class F fires)
Fire classes are categorized based on the kind of fuel burning and causing the fire. The most common fire classes are:
Class A – ordinary combustibles e.g. cloth, paper, wood, rubber, and plastics.
Class B – flammable liquids e.g. gasoline, oil, and grease.
Class C – fires associated with electrical equipment, such as appliances, wiring, and machinery.
Class D – fires where flammable metals e.g. magnesium, titanium, and potassium are involved.
Class F – fires associated with cooking oils and fats, often found in commercial kitchens.
CO2 Fire Extinguishers
CO2 fire extinguishers contain extremely pressurized carbon dioxide gas, which is non-flammable, clean, non-contaminating, and odorless in nature. They also leave no residue on the applied area.
CO2 extinguishers commercially come in cylinders that are black and typically weigh 5 lbs to 100 lbs.
Fire needs three elements to burn – Oxygen, heat, and fuel.
When the CO2 is released, it works by displacing the oxygen in the surrounding area, reducing the oxygen concentration to a level that is insufficient to support combustion. The lack of oxygen effectively smothers the fire, extinguishing the flames.
Since solid carbon dioxide is extremely cold, this also helps cool down the heat generated by fire.
However, as stated above, these types of extinguishers are suitable only for Class B and Class C fires.
Class B fires refer to fires that involve flammable liquids, such as gasoline, oil, alcohol, ether, grease, and paint. These types of fires can spread rapidly and be difficult to extinguish.
On the other hand, Class C fires are fires that involve electrical equipment, such as electronic appliances, wiring, and machinery. Water should not be used to extinguish Class C fires because it conducts electricity and can pose a shock hazard.
CO2 fire extinguishers are suitable for places like paint booths, electrical rooms, kitchens, power plants, laboratories, mechanical rooms, research facilities, and flammable liquid storage areas.
CO2 Fire Extinguisher Advantages and Disadvantages
- Clean gas
The CO2 gas is clean in nature due to being non-corrosive and not containing any solid material.
- No residue
CO2 is odorless and colorless, which means there is no need for cleaning after use as there will be no residue.
CO2 is non-conducting in nature, making it safe for use on all types of electrical equipment if a fire breaks out.
- Long shelf life
If your CO2 fire extinguisher has been stored under proper conditions and has not reached its expiration date, it should still be effective after a decade or so.
However, if it has been subjected to extreme temperature changes, physical damage, or has not been properly maintained, it may not function as expected when needed.
The shelf life depends on several factors though, including the manufacturer, type of extinguisher, and storage conditions. In general, it is recommended that you inspect your fire extinguisher annually and hydrostatically every 5 to 12 years, depending on the type and manufacturer.
Carbon dioxide (CO2) gas is not harmful to health but high concentrations of CO2 can cause headaches, dizziness, nausea, and unconsciousness.
- Fast acting
CO2 fire extinguishers are designed to put out small fires quickly. Such an early and effective fire control helps minimize costs, save time, and reduce damage.
- Easy to apply
You can easily use your fire extinguisher in small surfaces and hard-to-reach areas.
- No water damage
Co2 fire extinguishers don’t contain any water in them, which helps minimize additional water damage to your properties.
As CO2 is naturally-occuring, it doesn’t do any harm to the environment. There is also no ozone depletion or global warming effects.
- Cheap to refill
You won’t have to spend a fortune to refill your fire extinguisher.
- Food grade
Carbon dioxide (CO2) does not typically contaminate food though there is concern and we recommend that you too stay careful.
In case of a fire, you can safely use it in kitchen areas except for Class F fires (e.g. cooking oils).
However, CO2 can be used as a propellant in food packaging and as a cooling and preservation agent in some food storage containers, such as modified atmosphere packaging. In these cases, the CO2 levels need to be carefully controlled to avoid affecting the taste, appearance, and safety of the food.
- Deadly in confined spaces
Carbon dioxide can be dangerous in confined spaces and even a 9% concentration can suffocate living organisms within minutes
This is because it can displace the oxygen in the air and lead to asphyxiation. CO2 is an odorless and colorless gas, so it is not easily detected, making it even more hazardous.
- Can’t tackle Class A fires
They are not suitable for Class A fires (flammable gasses and solids), and Class F fires (cooking oils and fats), which are actually the most common causes of fire outbreaks.
- Post-fire risks
There is no post-fire security, so the flammable liquids may reignite any time.
These fire extinguishers are very noisy when in action, though that’s not a matter of concern when there is a fire.
- Too cold
Frostbite can happen if you use it improperly, especially if you hold the horn of the extinguisher while using it.
- Not instantly refillable
You have to return the cylinder to the refilling depot when the need arises.
- Refill may get expensive
Although refilling is cheap, if the refilling depot uses a cylinder exchange service, you may have to bear extra cost.
- Not for large
They can effectively put out small fires in just 10-15 seconds. So you’ll have to look for other options for large fire breakouts.
- Not for outdoor use
Since CO2 depletes the oxygen around the fire, these extinguishers won’t do any good outside or in windy areas.
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