Which chemical is used in a fire extinguisher?
Fire risks come in different types, so do the fire extinguishers. It's because different fire hazards need their unique extinguishers that can effectively extinguish the fire, ensuring higher safety and accuracy. Some of the most common types of fire extinguishers include water, foam, CO2, dry chemical, and wet chemical extinguishers.
So, if you are wondering which chemical is used in fire extinguishers, keep on reading. Here we will discuss common fire extinguishers and chemicals used in them.
Different fire extinguishers and chemicals used in them
There are several types of fire extinguishers, each of which consists of different chemicals to meet different fire hazards. Here are some more details on which chemical is used in a fire extinguisher-
1. CO2 fire extinguishers
They are one of the most common and widely used for dealing with electrical equipment fires and class B fires that include flammable liquids like oil, petrol and paint.
- How do they work?
A carbon dioxide fire extinguisher has a cooling effect on the fire to reduce heat. On the other hand, it effectively displaces the oxygen supply that fuels the fire, leading to the removal of all kinds of flames. These kinds of fire extinguishers are ideal for electrical fires.
- Chemicals used
Chemical used in carbon dioxide or CO2 fire extinguishers includes carbon dioxide. It is quite useful in removing flame and extinguishing fire entirely. However, they can be harmful and hazardous if used in enclosed spaces. As the fire extinguishers use carbon dioxide to displace oxygen to stop the fire, there is a significant chance of users suffocation in enclosed spaces.
2. Powder extinguishers
Another popular fire extinguisher that contains a chemical is powder extinguishers. It is also one of the most versatile fire extinguishers that works for class A (organic flammable materials like paper, cardboard, fabrics, and wood), class B (flammable liquids like paint, oil, etc.), and class C (flammable gases) fire risks. Therefore, this type of fire extinguisher is also known as ABC fire extinguishers.
- How do they work?
Powder fire extinguishers work by smothering the fire by releasing a special powder that displaces the oxygen supply that fuels the fire.
- Chemicals used
Powder fire extinguishers contain chemical compounds called sodium bicarbonate or potassium bicarbonate. This makes them suitable for class B and C fire risks but not for class C. However, the modern or advanced versions contain mono-ammonium phosphate powder and can be used for class A fire risks.
3. Foam extinguishers
Foam fire extinguishers are primarily used for class A (organic combustible materials such as paper, cardboard, fabrics, and wood) and class B (flammable liquids such as oil, petrol, and paint).
- How do they work?
Foam fire extinguishers create a visible barrier to cut off the supply of oxygen, leading to the extinguishment of the flames.
- Chemicals used
Like most other fire extinguishers, the chemical compound in foam extinguishers is not obvious. It contains a compound called perfluorohexanoic acid, or PFHxA for short. It is a safer version of per- and polyfluoroalkyl substances or PFAS (which have a negative impact on human health). Even though perfluorohexanoic acid, or PFHxA, is not 100% safe, it is still a reliable option fit for extinguishers. Its chemical formula is C6HF11O2.
4. Dry powder extinguishers
Dry powder fire extinguishers are one of the most versatile and widely used fire extinguishers. They are suitable for class A ( flammable solid materials like wood, textile, coal, paper, and cardboard), class B (flammable liquids like oil, paint, and petroleum), and class C (flammable gases).
- How do they work?
Dry powder extinguishers help to cut down flames by suffocating the fire and displacing the oxygen supply.
- Chemicals used
Dry powder extinguishers contain chemicals called sodium bicarbonate or potassium bicarbonate. As a result, dry powder extinguishers are ideal for class B and C fire risks. However, they are not suitable for class A fire hazards. But advanced dry powder extinguishers contain mono-ammonium phosphate powder. It makes advanced dry powder extinguishers suitable for class A fire risks.
5. Wet chemical extinguishers
Wet chemical extinguishers are mostly used for kitchen fires or class F fires that can deal with oil, kitchen gases, fats, and more. Wet chemical extinguishers create a barrier of wet chemical on the surface to stop the flame and also prevent it from reigniting.
- How do they work?
Wet chemical extinguishers are used to smother the fire by stopping the flames and preventing the scope of re-ignition.
- Chemicals used
Wet chemical extinguishers contain a chemical called Potassium acetate (CH3CO2K). It is also a known food acidity regulator. Sometimes this type of extinguisher also contains potassium bicarbonate. These types of fire extinguishers are gently sprayed as a mist to cool down the flames and prevent oxygen supply that fuels the fire.
6. Lithium-ion battery extinguishers
Lithium-ion battery extinguishers are used to extinguish fires involving lithium-ion batteries in devices such as laptops, mobile phones, and so on.
- How do they work?
This kind of extinguisher sprays a fine mist of chemically exfoliated vermiculite. Its water content cools the fire, and exfoliated vermiculite creates a film barrier to put out lithium-ion battery fires.
- Chemicals used
This kind of fire extinguishers generally contain Aqueous Vermiculite Dispersion or AVD with the chemical formula (Mg, Fe2+, Fe3+)3[(Al, Si)4O10](OH)2·4H2O.
Conclusion
Most fire extinguishers use different chemicals to deal with different fire risks. Above, we discussed which chemical is used in a fire extinguisher (for each extinguisher). Also, to know more about fire extinguishers and which one is right for you, visit Technohead India.