Here at FTR Renovation & Build, the fastest way to keep a family safe is to give them explicit, practical knowledge they can use in an emergency.
Understanding the five classes of fire is essential because the wrong response can make a small incident much worse.
Our team has guided many Southern California homeowners through fire-safe design, repairs, and complete rebuilds, including the real-world lessons we share in this Pacific Palisades post-fire remodeling story. (See how thoughtful design can rebuild a life.)
Why does this knowledge matter so much? In 2023, U.S. fire departments responded to an estimated 344,600 residential building fires, with cooking as the leading cause, responsible for 48.7% of incidents.
Having the right equipment and plan changes outcomes: the death rate in reported home fires is about 60% lower when working smoke alarms are present. These two facts alone show why it pays to know what you are facing and how to act.
This guide breaks down each fire class—A, B, C, D, and K—in plain language, then shows which extinguisher to use, how to respond safely, and how to prevent a repeat. If you are planning a smarter rebuild or adding flexible living space as part of a resilience plan, explore our ADU Builder services to see how a well-designed conversion can improve safety, comfort, and long-term value.
For ongoing answers to common homeowner questions—from prevention checklists to permitting and construction insights—visit the FTR Resource Center. We publish step-by-step guides drawn from field experience so you can make confident decisions before, during, and after a project. Our goal is simple: to be your trusted partner for fire-smart remodeling and rebuilding in Southern California.
Introduction to Fire Classes: Understanding the Basics of Fire Safety
Not all fires behave the same—and using the wrong tactic can make a bad situation worse. Fire professionals group home fires into five classes (A, B, C, D, and K) based on the fuel that’s burning. Knowing the difference helps you choose the right extinguisher and the right first move. It’s not just academic: cooking remains the leading cause of home fires and injuries in the U.S., and Thanksgiving is the single peak day for home cooking fires, with incidents more than tripling vs. a typical day.
Pro Tip (from a builder’s lens): When you plan upgrades—or an ADU that brings in rental guests—bake safety into the design (dedicated kitchen circuits, non-combustible finishes near heat sources, protected storage for flammables). If you’re considering an ADU, see how we design with safety in mind on our ADU Builder page.
Class A Fires: Combustible Materials and Their Hazards
What they are: Fires in “ordinary combustibles” like wood framing, trim, furniture, paper, cloth, and many plastics. NFPA
How they start at home: Space heaters too close to furnishings, fireplace embers, construction debris near a pilot flame, or careless disposal of ashes.
How to put them out:
- Use water, water mist, or a multi-purpose ABC dry chemical extinguisher.
- Drench and stir embers; Class A materials can smolder and re-ignite.
Pro Tip (FTR): When we remodel or rebuild, we like to specify Class A-rated interior finishes in key areas and add spark-arresting fireplace screens. Small design choices create layers of safety.
Class B Fires: Flammable Liquids and Gases Explained
What they are: Fires in flammable liquids and gases—think gasoline, solvents, oil-based paints, and propane. (In the U.S. system, gases are grouped under Class B).
Home hot spots: Garages, workshops, outdoor cooking areas, storage sheds.
Prevention & handling of flammables:
- Store gasoline, oils, and paints away from living spaces—ideally in a detached shed—and only in approved, labeled containers.
- Fill portable gas cans outdoors, on the ground (not in a vehicle), in a well-ventilated area.
How to put them out:
Pro Tip (FTR): During garage conversions and ADU builds, we plan for safe storage zones and spark-safe electrical near lawn equipment and paints—small layout choices that lower risk and can help with insurance conversations later.
Class C Fires: Electrical Fires and Precautions for Homeowners
What they are: Fires involving energized electrical equipment—appliances, outlets, wiring, panels, power strips, chargers.
Prevention essentials:
- Plug major appliances directly into wall outlets (no extension cords).
- Don’t overload circuits or power strips; replace damaged cords; match bulb wattage to the fixture.
How to put them out:
- Use a C-rated (non-conductive) or ABC extinguisher; never water while the equipment is energized.
- If safe, de-energize (unplug or trip the breaker). Once power is off, the fire behaves like Class A/B.
Why it matters: Electrical distribution and lighting equipment cause tens of thousands of U.S. home fires annually, resulting in hundreds of deaths and over a thousand injuries in a typical year, proactive maintenance and correct outlet use are critical.
Pro Tip (FTR): In remodels, we often add arc-fault and ground-fault protection, label panels clearly, and dedicate circuits for high-draw appliances—upgrades that reduce nuisance trips and absolute risk.
Class D Fires: Combustible Metals and the Specialized Techniques Needed
What they are: Rare in most homes, combustible metal fires (magnesium, titanium, sodium, lithium, potassium, etc.) burn extremely hot and can react violently with water. They’re more common in shops that machine metals or store certain powders.
How to put them out:
- Only with Class D dry powders (e.g., sodium chloride or copper-based agents) applied gently to smother the metal. Do not use water or ABC extinguishers.
Pro Tip (FTR): If your hobby or home business involves reactive metals, tell us early—we can plan non-combustible work zones, grounded surfaces, and proper Class D agent storage in a detached outbuilding.
Class K Fires: The Unique Challenges of Cooking Oils and Fats
What they are: High-temperature cooking oils/fats in deep fryers or commercial-style appliances. Class K agents saponify the hot oil (make a soapy layer) and cool it below auto-ignition.
Home reality: Residential kitchens mostly rely on lids/baking sheets and B or ABC extinguishers for minor stovetop flare-ups, while Class K extinguishers are standard in commercial kitchens. Regardless, never use water on a grease fire—cover the pan, turn off the heat, and call 911 if it doesn’t go out immediately.
Pro Tip (FTR): In serious-cook kitchens (or rental ADUs), we can spec commercial-style hoods and clearances, fire-resistant backsplashes, and safe extinguisher placement just outside the immediate cooking zone.
The Importance of Fire Extinguishers at Home: Choosing the Right Type
What to buy (quick guide):
- Multipurpose ABC (most homes): Covers A, B, and C hazards. Look for UL-listed and a rating you can handle—2-A:10-B:C is a common household choice.
- CO₂ (B/C): Clean agent for electrical and flammable liquid fires (no residue).
- Class K: Consider for commercial-grade cooking setups.
- Class D: Only if you work with combustible metals.
Where to keep them (access > everything):
- One on every level, plus the kitchen and garage/workshop, in visible, reachable locations near an exit—not hidden in a closet or right beside the hazard. Mount per label and keep the path clear.
How to use them (PASS):
- Pull the pin → Aim at the base → Squeeze → Sweep. If you don’t have a clear escape route or the fire is growing, get out and call 911.
Maintenance matters:
- Check gauges and accessibility monthly; ensure no damage or corrosion.
- Follow the label for shaking/pressure testing intervals; recharge/replace after any use.
Smart Design = Safer Homes (and ADUs)
A safer layout is the best “extinguisher” you’ll never need. If you’re planning an addition or a garage conversion/ADU, we can integrate:
- Dedicated kitchen circuits and protected outlets (fewer overloads).
- Non-combustible surfaces near heat and cook zones.
- Ventilation and safe storage for flammables away from living areas.
See how thoughtful design supports recovery in our Pacific Palisades post-fire remodeling story, and explore more homeowner guides in our Resource Center.
Ready to make your home (or ADU) fire-smart?
If you’re updating your kitchen, converting a garage, or building an ADU for multi-gen living or rental income, FTR Renovation & Build can help you design in fire safety from day one—without sacrificing style. Let’s talk about your space, your goals, and a safety-forward plan that protects what matters.
Helpful links:
- ADU Builder (design with safety in mind)
- Resource Center (how-tos and remodeling insights)
- Pacific Palisades post-fire remodeling (a real-world recovery story)