How CO2 works as a fire extinguisher ?

Question

I wonder if somebody could tell me how CO2 working as a fire extinguisher, regarding that it is full of oxygen?
Or, is it possible that there are is some type of substance that is not possible to extinct with CO2.
Is it possible that CO2 make an opposite reaction and enlarge fire?

Answer 1

A CO2 fire extinguisher works by eliminating oxygen and replacing it with CO2. You could do the same thing with just about any non-oxidizing gas (nitrogen, for example), but carbon dioxide is inexpensive and easy to store.CO2 works best on class B and class C fires. They don't work very well on class A fires because the material usually reignites. CO2 extinguishers have an advantage over dry chemical in that they leave behind no harmful residue.
Class A B and C fires are:

Class A fires are ordinary materials like burning paper, lumber, cardboard, plastics etc.

Class B fires involve flammable or combustible liquids such as gasoline, kerosene, and common organic solvents used in the laboratory.

Class C fires involve energized electrical equipment, such as appliances, switches, panel boxes, power tools, hot plates and stirrers.

Answer 2

First, a CO2 extinguisher utilizes carbon dioxide as an agent, not oxygen. Carbon dioxide, unlike oxygen does not feed the fire in any way. A carbon dioxide extinguisher works on two elements in the fire tetrahedron. It affects the oxygen content in the area of the fire by diluting the oxygen levels to a point below which combustion can be sustained. Also, CO2 is very cold and helps disipate the heat.

Secondly, there are many substances on which CO2 will not work. Class A fires - wood, paper, trash - often will have deep seated embers that cannot be extinguished by CO2. Also, Class D materials - flammable metals such as magnesium - cannot be suppressed using carbon dioxide. CO2 can be used to fight Class B fires - flammable liquids and gases and is also rated for use on Class C electrical fires. Don't be fooled by the size of CO2 extinguisher - they are very limited in their ablilty to fight a fire of any size. For example, a CO2 extinguisher with a 10B rating will only fight a flammable liquid spill of approximatley 10 square feet. Picture a 2 foot by 5 foot block on the floor and you will quickly see how small an area that really is.

Lastly, CO2 can enlarge fires. If used on a Class A or Class D fire, the force of the CO2 discharge can cause burning material to be dispersed over a larger area.

Answer 3

Suffocation.

Fire need oxygen to spread, if oxygen level is reduced during fire, the fire will suffocate.

The lack of air circulation would probably kill the flames from CO2 suffocation without extra oxygen. Carbon dioxide will not burn and displaces air. Carbon dioxide can be used on electrical fires because, being a gas, it does not leave residues which might further harm the damaged equipment. (Carbon dioxide can also be used on class A fires when it is important to avoid water damage, but in this application the gas concentration must usually be maintained longer than is possible with a hand-held extinguisher.) Carbon dioxide extinguishers have a horn on the end of the hose. Due to the extreme cold of the carbon dioxide that is expelled from an extinguisher, it should not be touched.

Answer 4

In CO2 the carbon is combined with all the oxygen it can take and so it is not combustible (ie. it does not burn).

When we direct CO2 from a fire extinguisher on to a fire, it forms a blanket over it, as it is heavier than air. The fire is then deprived of oxygen and is extinguished.

It is not possible for CO2 to enlarge a fire.

Answer 5

CO2 works on classes B and C/E and works by suffocating the fire.
Carbon dioxide will not burn and displaces air.
Carbon dioxide can be used on electrical fires because, being a gas, it does not leave residues which might further harm the damaged equipment. (Carbon dioxide can also be used on class A fires when it is important to avoid water damage, but in this application the gas concentration must usually be maintained longer than is possible with a hand-held extinguisher.)
Carbon dioxide extinguishers have a horn on the end of the hose.

Due to the extreme cold of the carbon dioxide that is expelled from an extinguisher, it should not be touched.

Answer 6

A fire needs 3 things, oxygen, heat and fuel. Remove one of these and you put the fire out. CO2 removes the O2 from the area. It is very cold also. You can not put out a metal fire such as magnesium with an extinguisher. The O2 in the CO2 is held tightly, it could not enlarge a fire.

Answer 7

CO2 and O2 are very different compounds. In simple terms, CO2 will blow all the combustible oxygen away from the area. I think oxyhydrogen flame can't be extinguished by CO2 because it's so hot. Any fire that's hotter than the energy required to decompose CO2 won't be extinguished by it, but no, CO2 will never enlarge a fire.

It's like when you breathe. Like us, fires need O2, and they produce CO2 just like we do when we exhale. You can breathe in CO2, but your body can't use it. In the same way, although CO2 won't extinguish all fires, it will never feed a fire.

Hope that helps.

Answer 8

CO2 is stored in compreseed, solid form ("dry ice"). When released, it takes a lot of energy to evaporate it and it therefore cools the fire, hopefully enough to stop it.

The oxygen in CO2 has a very low energy level (unlike free (atmospheric) oxygen which has a high energy level) and therefore cannot feed the fire.

Answer 9

When we hit hard on top of the extinguisher an acid bottle breaks and acid (sulphuric acid) comes in contact with sodium bicarbonate solution. A reaction takes place and carbon dioxide and water are evolved. Water helps in lowering the temperature of the burning substance. CO2 heavier than air cuts down the air supply and extinguishes it. (Note:- Oxygen is necessary for burning.)

Answer 10

there are three principles for putting out fire
1.remove the combustible substance
2.remove oxygen/air supply
3.reduce the temperature of the combustible substance below the fire point
CO2 is used for putting out the fire based on the second principle.CO2 being heavier than air forms an envelope around the burning substance and thus cuts out the oxygen. simple as that