Understanding the Different Classes of Fires

By Kayce Duvall
Posted July 30, 2025

Fires don’t all behave the same. For homeowners and business owners, understanding the five classes of fire is essential to choosing the right response.

What Are Fire Classes? 

The National Fire Protection Association (NFPA) classifies fires based on fuel type and severity. Following NFPA standards ensures you use the correct extinguisher for each fire type. Visit NFPA.org for official guidelines.

Overview of Fire Classes

Class A

Fires fueled by ordinary combustibles like wood, paper, cloth, rubber, and certain plastics. Use water-based or Class A-rated extinguishers. Common in home or office settings.

Class B

Sources include flammable liquids or gases like gasoline, oil, solvents, and paint thinners. Use dry chemical, foam, or CO₂ extinguishers.

Class C

Electrical fires involving energized equipment or wiring. De-energize first, then use non-conductive extinguishing agents like dry chemical or CO₂. Never use water.

Class D

Fires fueled by combustible metals such as magnesium, titanium, and sodium. Use specialized dry powder extinguishers.

Class K

Fires involving cooking oils and fats, which are frequent in kitchens. Use wet chemical extinguishers specifically designed for Class K. Never use water.

Why Proper Identification Matters

Using the wrong extinguisher can escalate the fire:

• Water on grease fires causes violent flare-ups.
• Water on electrical fires risks electrocution.
• Incorrect agents on metal fires may worsen combustion.

Choosing the right extinguisher minimizes fire damage and improves safety.

The Hidden Damage: Smoke & Soot

Visible flames are just the beginning. Smoke and soot can infiltrate walls, HVAC systems, fabrics, and electronics, causing staining, odor, corrosion, and health hazards.

• Wet smoke is sticky and clings to surfaces.
• Dry smoke spreads easily and contaminates ventilation systems.
• Smoke residue can damage electronics and metal fixtures over time.

How Kustom US Helps: Expert Fire Restoration Services

Kustom US offers a full range of fire restoration services:

• Emergency board‑up, fire & water mitigation
• Smoke & soot cleanup
• Deodorization and odor control
• Structural drying and reconstruction
• Insurance coordination

Conclusion

Understanding Class A, B, C, D, and K fires empowers you to act wisely and quickly. When damage occurs, prompt action and professional help from Kustom US ensures safety, efficiency, and recovery.

FAQs

What extinguisher should I use for a grease fire in the kitchen?

A Class K wet chemical extinguisher. Never use water, as it may cause the fire to spread.

Can smoke damage linger even after a fire is out?

Yes. Soot and smoke can continue to damage materials and create health risks. Immediate restoration is essential.

Is fire and soot damage covered by insurance?

In most cases, yes. Contact your insurance provider immediately. Restoration services like Kustom US often assist with claims.

How fast should I call for fire restoration?

As soon as the area is safe. Delaying can worsen odor, corrosion, and structural issues.

Can soot damage electronics or HVAC systems?

Yes. Soot can cause corrosion in electronics and contaminate HVAC systems, spreading toxins throughout the building.