Types of Fire Extinguishers: Complete Guide to Uses, Classes, Color Codes and Selection
Fire extinguishers are among the most essential fire safety tools used in homes, offices, industries, hospitals, schools, warehouses, workshops, and public places. Understanding the different types of fire extinguishers, their working principles, color codes, and application areas is a mandatory skill for fire students, safety officers, emergency responders, and anyone responsible for workplace safety.
A fire extinguisher is not a universal tool. Each extinguisher is designed to fight specific classes of fire, and using the wrong one can worsen the fire or create new hazards. For example, using water on an oil fire can cause massive splashing and spreading, while using a foam extinguisher on an electrical fire can cause electrocution.
This comprehensive guide explains the main types of fire extinguishers, their uses, limitations, working mechanisms, advantages, disadvantages, color codes, and selection guidelines. It is written in a clear and practical manner based on international standards such as NFPA, OSHA, and IS.
What Is a Fire Extinguisher?
A fire extinguisher is a portable or fixed device designed to extinguish or control small fires during the initial stage. It works by removing one or more elements of the fire triangle: heat, fuel, or oxygen. Some extinguishers also interrupt the chemical chain reaction, forming the fire tetrahedron.
Extinguishers work through four basic mechanisms:
- Cooling
- Smothering
- Starving
- Chemical chain reaction inhibition
Understanding these mechanisms helps in choosing the right extinguisher for each situation.
Fire Classes and Their Importance in Extinguisher Selection
Before selecting the right extinguisher, it is crucial to understand the classes of fire:
- Class A: Solid combustibles (paper, wood, cloth, rubber)
- Class B: Flammable liquids (petrol, diesel, solvents)
- Class C: Flammable gases (LPG, propane, methane)
- Class D: Burning metals (magnesium, sodium, titanium)
- Class K/F: Cooking oils and fats (commercial kitchens)
- Electrical Fire: Energized electrical equipment
Each extinguisher type is designed to fight specific classes.
Types of Fire Extinguishers
There are six major types of fire extinguishers commonly used worldwide:
- Water
- Foam (AFFF)
- Carbon Dioxide (CO₂)
- Dry Chemical Powder (DCP)
- Wet Chemical
- Clean Agent (HFC/FM-200/NOVEC)
Each category is explained below in complete detail.
Water Fire Extinguishers
Water fire extinguishers work by cooling the burning material below its ignition temperature. They are among the oldest and simplest types of extinguishers.
How Water Extinguishers Work
The water absorbs heat from the fuel, cooling it rapidly. Once the temperature drops below its fire point, combustion stops.
Suitable For
- Class A fires (wood, paper, cloth, plastics)
Not Suitable For
- Class B flammable liquid fires
- Class C flammable gas fires
- Electrical fires
- Kitchen oil fires
- Metal fires
Using water on flammable liquids or electrical fires can cause violent reactions.
Advantages
- Effective on deep-seated Class A fires
- Inexpensive
- Readily available
Disadvantages
- Limited to Class A
- Electrical shock risk
- Can cause water damage
Color Code
Red
Foam (AFFF) Fire Extinguishers
Foam extinguishers use AFFF (Aqueous Film Forming Foam). They work by smothering the fire and forming a vapor-sealing film.
How Foam Extinguishers Work
Foam forms a thick layer on burning liquid surfaces, cutting off oxygen and preventing vapor release. Foam also cools the fuel surface.
Suitable For
- Class A solid combustibles
- Class B flammable liquids (petrol, diesel, kerosene)
Not Suitable For
- Electrical fires (unless dielectric-tested)
- Gas fires
- Metal fires
- Kitchen oil fires
Advantages
- Effective on liquid pool fires
- Prevents re-ignition
- Provides surface cooling
Disadvantages
- Not suitable for kitchen fires
- Requires careful application
- Can damage sensitive materials
Color Code
Cream
Carbon Dioxide (CO₂) Fire Extinguishers
CO₂ extinguishers release carbon dioxide gas stored at high pressure.
How CO₂ Extinguishers Work
CO₂ displaces oxygen around the fire and cools the burning material. It also leaves no residue, making it ideal for electrical equipment.
Suitable For
- Class B fires
- Electrical fires (control panels, server rooms, IT areas)
Not Suitable For
- Class A deep-seated fires
- Kitchen fires
- Gas fires
Advantages
- No residue
- Safe for electronics
- Non-conductive
Disadvantages
- Short discharge time
- Ineffective outdoors due to wind
- Risk of cold burns from the horn
Color Code
Black
Dry Chemical Powder (DCP) Fire Extinguishers
DCP is one of the most widely used extinguishers in commercial and industrial environments.
How DCP Works
DCP interrupts the chemical chain reaction of fire and forms a blanket over the fuel. It works on multiple fire classes.
Suitable For
- Class A
- Class B
- Class C
- Electrical fires
Not Suitable For
- Class K/F kitchen fires
- Metal fires (requires special Class D powder)
Advantages
- Multi-purpose
- Highly effective for rapid flame knockdown
- Works on gas and liquid fires
Disadvantages
- Leaves large amounts of residue
- Not suitable for sensitive equipment
- Can reduce visibility
Color Code
Blue
Wet Chemical Fire Extinguishers
Wet chemical extinguishers are specially designed for kitchen fires involving cooking oils and fats.
How Wet Chemical Extinguishers Work
The extinguishing agent reacts with hot oils to create a thick foam (saponification) that cools and seals the surface.
Suitable For
- Class K/F kitchen fires
- Deep fryers
- Commercial kitchens
Not Suitable For
- Electrical fires
- Metal fires
- Gas fires
Advantages
- Most effective for kitchen oil fires
- Prevents re-ignition
- Provides rapid cooling
Disadvantages
- Limited to kitchen fires
- Not suitable for general use
Color Code
Yellow
Clean Agent Fire Extinguishers
Clean agent extinguishers use chemicals like HFC-227ea, FM-200, and NOVEC 1230.
How Clean Agents Work
They interrupt the chain reaction and absorb heat without leaving residue.
Suitable For
- Electrical fires
- Class B fires
- Server rooms
- Labs and medical facilities
Not Suitable For
- Deep-seated Class A fires
- Kitchen oil fires
Advantages
- No cleanup required
- Safe for electronics
- Quick extinguishing
Disadvantages
- Expensive
- Must be refilled by professionals
Color Code
Green
Class D Metal Fire Extinguishers
Metal fires require special powders like:
- Sodium chloride powder
- Graphite powder
- Copper powder
Suitable For
- Magnesium
- Aluminum
- Sodium
- Titanium
Not Suitable For
- Any other classes of fire
These extinguishers are used in laboratories, metal factories, and machining shops.
Comparison Table of Fire Extinguishers
| Extinguisher Type | Classes of Fire | Color Code | Suitable For |
|---|---|---|---|
| Water | A | Red | Paper, wood, cloth |
| Foam (AFFF) | A, B | Cream | Petrol, diesel, solids |
| CO₂ | B, Electrical | Black | Server rooms, panels |
| DCP | A, B, C, Electrical | Blue | Industry, gas leaks |
| Wet Chemical | K/F | Yellow | Kitchens, fryers |
| Clean Agent | B, Electrical | Green | Labs, IT rooms |
Selection of the Right Fire Extinguisher
Selecting the correct extinguisher requires following steps:
Identify the Class of Fire
Different fuels require different agents.
Analyze the Environment
- Electronics → CO₂ or clean agent
- Kitchens → Wet chemical
- Fuel storage → Foam or DCP
- Offices → Water or DCP
Consider People and Hazards
Crowded areas require extinguishers with easy operation and minimal residue.
Follow Standards
Refer to NFPA, OSHA, IS, and local fire codes.
How to Use a Fire Extinguisher (PASS Method)
The correct firefighting technique is PASS:
- Pull the pin
- Aim at the base
- Squeeze the handle
- Sweep side to side
Training must be provided to all staff.
Inspection and Maintenance of Fire Extinguishers
Fire extinguishers must be maintained regularly to ensure functionality.
Monthly Inspections
- Check pressure gauge
- Check weight
- Inspect hose and nozzle
- Check safety pin and tamper seal
- Ensure visibility and accessibility
Annual Maintenance
Performed by certified technicians.
Hydrostatic Testing
Required every few years depending on extinguisher type.
Common Mistakes to Avoid
- Using water on oil or electrical fires
- Failing to aim at the base of the fire
- Standing too close to burning liquids
- Ignoring the pressure gauge
- Mishandling CO₂ horn with bare hands
Proper training eliminates these errors.
Frequently Asked Questions
Which extinguisher is the best for electrical fires?
CO₂ or clean agent extinguishers.
Can one extinguisher fight all fires?
No. Each extinguisher has specific applications.
How often should extinguishers be inspected?
Monthly inspections and annual maintenance are required.
Conclusion
Fire extinguishers are essential safety tools that can prevent small fires from turning into major disasters. Understanding their types, working mechanisms, applications, limitations, color codes, and selection criteria is essential for every fire safety student and professional. Proper training, maintenance, and knowledge ensure that extinguishers are used effectively and safely during emergencies.
Electrical Fire Safety: Causes, Controls, and Prevention Measures
Water Extinguisher: Uses and Limitations
Foam Fire Extinguishers and AFFF Explained: Working, Types, Uses, and Limitations
CO₂ Fire Extinguisher: Working Principle, Uses, Limitations, and Industrial Applications
Dry Chemical Powder DCP Fire Extinguisher: Full Guide on Types, Working, Uses, and Limitations
According to OSHA portable fire extinguisher standards, workplaces must select and maintain extinguishers based on fire class and hazard type.
