5 Main Fire Extinguisher Classes And How To Choose The Best

Fire extinguishers are lifesaving tools in the hands of prepared individuals. However, not all extinguishers are created equal — using the wrong type can worsen a fire or cause serious injury. Understanding fire extinguisher classes and their colour codes is crucial to protecting people, property, and the environment.

As a certified Fire Safety Consultant with over 10 years of industry experience, I have seen firsthand how confusion about extinguishers can lead to avoidable disasters. This article is crafted to demystify the classifications, explain colour codes, and help you make informed decisions about fire protection in your home, workplace, or industrial setting.

Why Understanding Fire Extinguisher Classes Matters

Each type of fire requires a different method of suppression. Fire extinguishers are classified according to the kind of fires they are designed to fight. Using the wrong extinguisher can be ineffective — or even explosive.

For example, using a water-based extinguisher on an electrical fire can result in electrocution. Similarly, CO₂ extinguishers are useless against combustible solids like wood or paper.

Understanding extinguisher classes and colour codes means:

• Faster emergency response

• Reduced property damage

• Increased workplace safety

• Compliance with safety regulations (e.g., OSHA, NFPA, BS EN 3)

Overview of Fire Classes

Different materials combust in different ways. Fire classes categorize fires based on the fuel source. Here’s a breakdown:

Types of Fire Extinguishers and Their Classes

Let’s explore each extinguisher type, its associated fire class, colour code, and real-life usage.

1. Water Fire Extinguishers – Class A Fires

Colour Code: Red
Label: “Water”
Suitable for: Class A fires (solid materials)

How It Works:
Water extinguishers cool the burning material, reducing heat and suppressing flames.

Common Use Cases:

• Offices

• Schools

• Public buildings

• Retail shops

Limitations:

• NEVER use on flammable liquids, gas fires, or electrical fires

• Risk of electrical shock if used on live equipment

Real-Life Scenario:
In 2022, a fire broke out in a UK classroom due to an overheated paper shredder. A staff member quickly used a red water extinguisher to suppress the fire before the fire brigade arrived, limiting damage to one corner of the room.

Reference: UK Home Office Fire Safety Guidance

2. Foam Fire Extinguishers – Class A and B Fires

Colour Code: Cream
Label: “Foam”
Suitable for: Class A and B fires

How It Works:
Foam forms a blanket over flammable liquids, cutting off oxygen, while also cooling solids.

Common Use Cases:

• Fuel stations

• Garages

• Warehouses storing paint/solvents

• Residential areas with flammable liquids

Limitations:

• Not ideal for electrical fires (unless tested dielectric-safe)

• Ineffective for Class D or F fires

Real-Life Scenario:
In a petrol station spill, a foam extinguisher was used to douse the flames from spilled diesel, preventing a catastrophic explosion.

3. CO₂ Fire Extinguishers – Electrical and Class B Fires

Colour Code: Black
Label: “Carbon Dioxide”
Suitable for: Electrical and Class B fires

How It Works:
Displaces oxygen and smothers fire without leaving residue. Also prevents thermal runaway in electrical devices.

Common Use Cases:

• Server rooms

• Offices with heavy electronics

• Commercial kitchens (for electrical panels)

• Laboratories

Limitations:

• Not effective on Class A fires

• Risk of suffocation in enclosed areas

• Metal horn can freeze skin on contact

Real-Life Scenario:
A CO₂ extinguisher prevented a data center fire from spreading in under 45 seconds when a monitor caught fire due to a power surge.

Safety Tip: Always direct the horn at the base of the flames. Use in well-ventilated areas.

4. Powder Fire Extinguishers – Multi-Purpose (Class A, B, C)

Colour Code: Blue
Label: “Dry Powder”
Suitable for: Class A, B, C fires (and electrical)

How It Works:
Powder interrupts the chemical reaction in the fire triangle (fuel, oxygen, heat).

Common Use Cases:

• Industrial plants

• Vehicles

• Workshops

• Fuel transport systems

Limitations:

• Leaves harmful residue

• Not safe in enclosed areas (risk of inhalation)

• Ineffective for Class F or metal fires

Real-Life Scenario:
In a Nigerian mechanical workshop, a powder extinguisher saved a car when gasoline spilled and caught fire during engine repair.

Note: Some variants (e.g., L2, M28) are specially made for Class D fires.

5. Wet Chemical Fire Extinguishers – Class F Fires

Colour Code: Yellow
Label: “Wet Chemical”
Suitable for: Class F fires (cooking oils and fats), Class A (limited)

How It Works:
The saponification process turns hot oils into non-combustible soap-like substances while cooling the burning fat.

Common Use Cases:

• Commercial kitchens

• Restaurants

• Food factories

Limitations:

• Not effective for electrical fires

• Must be used with a specific nozzle angle and coverage technique

Real-Life Scenario:
A chef at a London restaurant stopped a deep fryer fire with a wet chemical extinguisher, protecting kitchen staff and patrons from harm.

Regulatory Reference: BS 5306-8:2012

Fire Extinguisher Colour Code Chart (Quick Reference)

Best Practices for Fire Extinguisher Placement and Maintenance

Fire safety isn’t just about having extinguishers — it’s about strategic planning and regular upkeep.

Fire Extinguisher Placement Guidelines

• Install near exits, not directly over hazard points

• Mount at a visible, accessible height (1m from the floor for <4kg, 1.5m for >4kg)

• Place in every high-risk area (e.g., kitchens, electrical rooms, flammable storage)

• Use appropriate signage per ISO 7010 and NFPA 10

Maintenance and Inspection Tips

• Monthly visual checks: Signs of damage, tampering, pressure levels

• Annual servicing by certified professionals

• Replace or refill after any use, even partial

• Hydrostatically test every 5–10 years, depending on type

Source: NFPA 10 – Standard for Portable Fire Extinguishers

Fire Extinguisher Training: A Legal and Life-Saving Requirement

Training your staff on how to use extinguishers is not optional — it’s a legal mandate in many countries.

Key Training Elements:

• The PASS technique (Pull, Aim, Squeeze, Sweep)

• Fire classification basics

• Evacuation plans

• Role-based responsibilities during fire incidents

In the UK, the Regulatory Reform (Fire Safety) Order 2005 requires employers to provide adequate fire safety training.

Choosing the Right Fire Extinguisher for Your Environment

Here’s a simple guide based on the environment:

Always consult a certified Fire Risk Assessor to tailor your fire extinguisher setup.

Final Thoughts from a Fire Safety Consultant

Understanding fire extinguisher classes and their colour codes is not just about compliance — it’s about saving lives.

When selecting extinguishers:

• Know your fire risks

• Learn the colour codes

• Train your team

• Maintain and inspect regularly

Remember: Preparedness today can prevent a tragedy tomorrow.

For a safer workplace or home, consult a qualified fire safety professional. If you need assistance with fire extinguisher selection, installation, or training, contact your local fire protection service provider.

Related Posts

How a CO2 Fire Extinguisher Works and Its Limitations

6 Major Types Of Fire Extinguishers And Their Purposes

The Best Kitchen Fire Extinguisher For Your Kitchen

7 Best Places to Keep a Fire Extinguisher in Homes and Workplaces

How Can I Identify My Fire Extinguisher Expiry Date

How to Choose the Right Fire Extinguisher Sizes