Fire Extinguisher Types:

How to choose the right fire extinguisher type for your fire class?

It’s critical to choose the right fire extinguisher for the right type of fire.
Because each type of fire extinguisher is effective on different classifications of fire, no one extinguisher can be used to put out every fire.

It is crucial to select the appropriate fire extinguisher for the fire class. Because each type of fire extinguisher is efficient in different classifications of flames, not every extinguisher can be used to put out every fire.

Main types of fire extinguishers

• Water, water mist or water spray
• Foam
• Dry Powder – standard or specialist
• Carbon Dioxide (‘CO2’)
• Wet Chemical

The first step is to look at the materials presented in the area to be protected from fire. These can be divided into six categories of fire involving different substances:

• Class A, combustible carbon-based solids. Example: wood, paper or textiles
• Class B, flammable liquids. Such as. petrol, diesel or paraffin
• Class C, flammable gases. Such as propane, butane or methane
• Class D, burning metals, Such as aluminum, lithium or magnesium
• Fires caused by electrical equipment (indicated by an electric spark symbol and not the letter E)
• Class F, fats and cooking oils.

 

Fire extinguisher types chart

This chart shows the types of fire and the fire extinguisher types for which they are suitable

Fire extinguishers Types and Applications

Water Fire extinguishers
Water extinguishers are only effective against fires involving paper, wood, straw, coal, rubber, solid plastics, and soft furnishings, which are classified as Class A. They are the most basic, common, and affordable sort of extinguisher. Water extinguishers are the easiest to keep in stock and are the safest to use because they simply contain water. They douse the flames and the items in water to cool them down. This puts out the fires by absorbing the heat from the burning materials.

They’re common in stores, offices, retail establishments, schools, hotels, warehouses, and private residences.

Foam Extinguishers
In solids and liquids (Class A and B), the foam smothers the fire, but not in burning fats or cooking oils (Class F). If they’ve been tested and fired from a distance of one metre, they can be used on some electrical fires.

Dry powder extinguishers
These can be used to put out fires in solids, liquids, and gases (Class A, B and C fires). Type D fires containing flammable metals such as lithium, magnesium, or aluminum require special powder extinguishers.

They function by generating a crust around the fire, which suffocates it and prevents it from spreading.

The powder does not soak into the materials and does not have an efficient cooling impact on the fire, which can cause the fire to reignite.

CO2 extinguishers.
Because they solely contain pressurized carbon dioxide gas, they leave no residue. They are useful in offices since they are acceptable for use on fires involving burning liquids (Class B) and electrical fires, such as those involving huge computer equipment. CO2 works by stifling the flames and does not harm the electrical components or short circuit the system.

CO2 extinguishers, on the other hand, get extremely cold during discharge, and those without double-lined, frost-free swivel horns may cause fingers to freeze to the horn during deployment. They are not suited for deep fat fryers, as the strong jet from the extinguisher might propel the burning fat out of the fryer, and they can asphyxiate in confined places. Because fires can re-ignite fast once CO2 has dispersed into the atmosphere, they do not provide post-fire protection.

Wet chemical extinguishers
Apart from water mist, these are the only extinguishers appropriate for Class F fires (fats and cooking oils) and are mostly employed in kitchens with deep fat fryers. They can also be used on Class A and Class B fires in specific cases. They are made out of a pressurized solution of alkali salts in water that, when turned on, produces a thin mist that cools the flames and prevents splashing.