6 Fire Types and Their Extinguishers

Whether it is chemical or a pharmaceutical company, industrial safety has got utmost importance considering products and people.

There are a number of fire incidences that happen regularly for those industries who don’t follow safety practices.

Either they don’t have proper knowledge or they don’t give importance to safety at all. And focus on producing heavy commercial batches to meet their business needs compromising safety.

What they don’t understand is their negligence may cause business as well as human loss.

Fire, if not appropriately handled, may turn into a disaster. The right knowledge of fire and its mitigation is necessary to all working individuals.

Let’s see some basics in fire and safety and then we’ll talk about fire types and extinguishers.

Safety stands on two pillars, i.e. Risk and Hazard.

Hazard is something that can cause harm or damage to business assets or humans. For example, Chemicals, Electricity, Noise, Fire, Stress, working on height or in a confined space, etc.

Risk is the probability of any hazard actually causing the harm. The risk depends on the number of factors that can put us in danger. For example, in a gasoline storage area, an electrical spark can cause harm through fire. The likelihood of the actual incidence happening is a risk.

We can say that fire is a hazard and has risk potential if not addressed correctly.

What is Fire? How does it differ from Flame?

Fire: Rapid oxidation of material because of the process of chemical combustion, liberating different energies such as light, heat, smoke, and chemicals.

Flame: Visible portion of the fire that can be seen through the naked eyes. Red-Orange flame shows incomplete combustion while Blue flame shows complete combustion.

Let’s first understand how the fire starts and what elements lead to fire when they come into contact.

Fire Triangle

The term ‘Fire Triangle’ might be familiar to you, but let’s take another look at it.

There are 3 necessary elements required to cause a fire.

1. Source of Ignition (Heat)
2. Fuel (Wood, Plastic, Clothes etc.)
3. Oxygen

According to the above diagram:

• All elements (Heat, Fuel, and Oxygen) depend on each other.
• The fire can be caused if and only if all elements are present at the same time.
• Fire will not ignite if any one of the elements is absent.

To prevent fire, you need a tool that eliminates any one component from the fire triangle and ultimately breaks the fire triangle.

Below are the 5 classes of fire and their applicable extinguishers that’ll answer the following questions.

• What are the fire types or classes?
• How do we decide the classes?
• What type of extinguisher mitigates a particular fire type?

Fire Types and Extinguishers

Here’s the summary of different classes of fires, their examples, and which extinguisher is capable to eliminate them.

The following are the types of available fire extinguishers.

• Water
• Dry Powder
• CO₂
• Foam
• Wet Chemical

You see? No single fire extinguisher can extinguish every kind of fire. Instead, each fire extinguisher is designed to combat a distinct type of fire.

Let’s brief down.

Water Extinguishers

Compatible to mitigate Class A fires. Includes fire due to wood, paper, cardboard, coal, fabrics, or dry pulps. Installed near exit locations of hospitals, offices, etc.

When water is sprayed on the fire it has a cooling effect, reducing heat transfer (remember fire triangle) gradually eliminating heat element.

Label color on fire extinguisher is Red.

There are 3 types of water extinguishers:

• Jet: Extend less surface area, consuming more time and water to mitigate fire.
• Spray: Covering more surface areas requires less time to diminish fire but may require more water.
• Mist: They are lightweight and have proper flow control. The rate of spraying ranges between 250-300 microns of water droplets forming a layer of heat with high precision. A droplet size of fewer than 250 microns can cause water droplets to evaporate and cannot mitigate the fire. On the other hand, higher particle size results in more water wastage. Sometimes able to handle Class B fires when added with suitable additives.

Dry Powder Extinguishers

They are compatible to mitigate Class A, B, C, D, and E fires. It is not recommended for use in confined spaces, which may cause more confusion, difficult cleaning, and suffocation issues. We may find these types of fire extinguishers in the chemical, pharmaceutical, petroleum industries, etc.

Just like water type, they too cause barriers but in between oxygen and fuel ultimately breaking the fire triangle.

Label color on fire extinguisher is Blue.

CO2 Extinguishers

They are compatible to mitigate Class B and E fires. We can find these types of fire extinguishers in paint industries or construction sites wherever flammable liquids or electrical fire hazards may occur.

Carbon dioxide is typically stored in a liquid form. When released from the nozzle, it converts into gas. CO2 gas, when it comes in contact with fire, replaces oxygen with the help of high pressure. This eliminates the oxygen in the fire triangle, which results in a mitigated fire.

Label color on fire extinguisher is Black.

Foam Extinguishers

Compatible to mitigate Class A and B fires. These types of extinguishers are found in all places mentioned in the water extinguisher plus flammable metals.

Foam when applied on fire, reduces the heat and creates a barrier between fuel and heat, eventually mitigating the fire.

Label color on fire extinguisher is Cream White.

Wet Chemical Extinguishers

Compatible to mitigate Class A and F fires. Found in commercial and industrial kitchens and restaurants, wet chemicals effectively handle fires caused by combustible cooking media such as oils and fats.

Wet chemicals when sprayed, convert to foam and form a barrier between oil and heat, which mitigates the fire gradually.

Label color on fire extinguisher is Yellow.

Finally…

Each fire type requires a different extinguisher to mitigate. Hence, the fire extinguishers must be used after detailed and optimized analysis of suitability, cost, resources, and practical.