A fire extinguisher is a device used to control small fires often in emergency cases. It consists of a handheld cylindrical pressure can that contains an agent that can be used to put out a fire.
Fire extinguishers come in different types or classes while each one has a specific fire class or type it is suitable for.
Below are details on the various classes of fire.
a) Class A Fires
The first category consists of fires caused by combustible materials such as flammable solids like wood, fabric, and paper.
b) Class B Fires
These are fires caused by flammable liquids such as petrol, paint or turpentine.
c) Class C Fires
Class C fires are fires caused by flammable gases like hydrogen methane, butane.
d) Class D Fires
These are fires caused by combustible metals, including magnesium, aluminum or potassium.
e) Electrical Fires
It consists of fires caused by electrical equipment’s. Once the electric material is removed, the fire changes its class.
f) Class F fires
Class F fires are fires caused by cooking oils, for example, a chip-pan fire.
It is important to note that every type of fire has the following elements; fuel, heat, oxygen and chain reaction.
Each class of fire has a variation of fuel, heat source and chain reaction. Hence there must be different types of extinguishers depending on the type of fire.
Types of Fire Extinguishers
1. Water Extinguishers
They are the most common fire extinguisher for class A fires. It is advisable to avoid using electrical equipment while the water extinguisher is in use.
The water in the fire extinguisher brings a cooling effect on the fuel causing it to burn slowly until the fire vanishes.
Water extinguishers are suitable for places where organic materials can be found; they include the school’s hospitals, offices, residential areas.
2. Foam Extinguishers
Foam extinguishers can be suitable for both class A and B fires. It is used in areas where there are organic materials like wood and coal, cardboard or paper.
In addition, these extinguishers can be used to put out fires caused by flammable liquids, for example, petrol and paint.
It works by releasing a type of foam that expands when it reacts with air and blankets the fire. Since foam has water in it, it brings a cooling effect.
3. Dry Powder Extinguisher
Also known as ABC powder fire extinguisher. The extinguisher has a number of advantages since it is a multipurpose extinguisher and also very common.
It works by spraying a fine chemical powder that is composed of mono-ammonium phosphate which acts a blanket of the fire hence suffocating it.
The powder extinguisher can also be used for class A, B, and C fires. It works effectively since it is not an electrical conductor and it has an ability to break a chain reaction in a gas or liquid fire; water extinguishers cannot do that.
4. Carbon Dioxide Fire Extinguisher
The carbon dioxide extinguisher works by removing the oxygen element of fire and also it removes heat with a cold discharge.
It is considered as a clean extinguisher since it leaves no residue behind. Hence it requires no cleanup.
The extinguisher can be used on class B fires which involve flammable liquids and also electrical fires.
It is ideal for electrical fires since carbon dioxide is not a good conductor of electricity.
5. Wet Chemical Fire Extinguisher
Wet chemical fire extinguishers are specifically designed to put out fires that involve combustible cooking oils or vegetable fats.
It works by spraying a liquid mist that cools the fire. Secondly, the chemical reaction of the potassium solution and the cooking media forms a soap-like substance hence sealing of the liquid to halt re-ignition.
It is therefore ideal for a kitchen setting and class F fires. Additionally, it can be used to put out class A fires when materials like wood or paper have caught fire.
6. Clean Agent Fire Extinguisher
Clean agent or halogenated fire extinguishers consist of halon agents and less ozone depleting halocarbon agents.
The extinguisher is stored in a liquid form and once sprayed to the air it converts to gas form. It is beneficial due to the following reasons:
i) It does not conduct electricity.
ii) It is safe for use even when humans are present.
iii) It leaves behind no residue.
iv) It has a short atmospheric span hence making it eco-friendly.
It works by altering the chemical reaction and removing the heat from a fire triangle. It is common for class B and C fires.
In summary, the content above enlightens you on different types of fires and the fire extinguishers suitable for each class.
You should beware of the type of extinguisher that you would likely need in your premises I case of a fire emergency.
It is important to note that you may need to have different types of fire extinguishers in different places on your premises.
Finally, fires are hazardous and can harm human beings, when putting out a fire there is a need for proper training to avoid failure or misuse of the fire extinguisher.