How to Use a Fire Extinguisher: The PASS Method

This article is for educational purposes only. Fire safety requirements vary by jurisdiction, and your state or local fire code may impose additional or more stringent requirements than those described here. Always verify requirements with your local authority having jurisdiction (AHJ).

The PASS method is the standard technique taught by NFPA, fire departments, and all major fire protection training programs. PASS stands for Pull, Aim, Squeeze, Sweep. It works for ABC, BC, K-Class, and most portable extinguisher types. The technique takes 15 to 30 seconds of actual discharge to be effective. And it's printed on every fire extinguisher label—it's universal.

But knowing the technique and knowing when to use an extinguisher are two different things. Using one when you shouldn't—when the fire is too big or your exit is blocked—is a faster path to danger than evacuating. Understanding PASS is important. Understanding when NOT to use an extinguisher is more important.

Before You Use a Fire Extinguisher: The Immediate Safety Check

Only use an extinguisher if the fire is small and contained. A trash can fire. A small appliance fire. A small grease fire. You need a clear exit path behind you. Never let the fire block your way out. The fire is not spreading rapidly. You've called 911 or someone else has. You feel confident and trained.

Never use an extinguisher if the fire is already large and spreading. If the room is filling with smoke. If you don't know what's burning. If your exit is blocked. If the extinguisher is damaged or you're unsure it works. When in doubt, evacuate and call 911. Fighting a fire is secondary to getting people out safely. Fire department has proper equipment and training. A small fire can become a life-threatening fire in seconds.

Step 1: PULL the Pin

The pin is on top of the extinguisher handle, usually below a tamper seal or cap. Grip the extinguisher body firmly with one hand. Use your other hand to pull the pin straight out. The pin will release the seal on the trigger. Many units have a plastic pull-ring you grasp to make this easier.

When you pull the pin, you'll notice it comes out cleanly with slight resistance. The trigger handle is now free to press. The tamper seal is broken—confirming the unit was locked before use. Don't pull too early. Pull the pin only when you're ready to use the extinguisher. Pulling activates the seal but doesn't discharge. You have to squeeze the trigger to actually discharge.

Step 2: AIM at the Base of the Fire

Aim the nozzle or hose at the base of the flames, not the top. The base is where the fuel is burning. Discharging at the flames wastes agent and is less effective. Stand six to eight feet away from the fire—typical effective range. If you're closer, you may get too much heat. If you're farther, the discharge agent loses effectiveness. Adjust distance based on fire size and your comfort level.

Keep the extinguisher upright. Don't invert it unless it's a CO2 unit. Keep the nozzle pointing toward the base. Never stand directly in the smoke or flame. Keep your back to a clear exit. For different fire types: trash can or small fire, aim directly at the base of flames. Grease fire, aim at the base of the fuel source, not the flames themselves. Electrical fire, aim at the base; keep distance to avoid electrical shock. Large appliance, aim at the opening where flames are visible.

Step 3: SQUEEZE the Handle/Trigger

Squeezing opens the discharge valve. Pressurized agent flows out through the nozzle or hose. Discharge continues as long as you squeeze. Most units build up pressure before discharge begins—one to two seconds. You may hear a hiss or see discharge beginning. The pressure gauge will drop as agent is used.

Hold the trigger continuously while sweeping at the base. Use short pulses if you want to conserve agent and observe effect. Long continuous discharge uses agent faster but covers a larger area. If discharge doesn't start: verify the pin was fully removed. Check that the extinguisher is upright. Ensure no internal obstruction. If it still doesn't discharge, stop and evacuate. The unit may be defective.

Step 4: SWEEP from Side to Side

While squeezing the trigger, move the nozzle or hose back and forth. Cover the width of the fire base in a side-to-side motion. Don't just aim at one spot—distribute the agent across the fire. Repeat sweeping motions until flames are out. Continue for a few seconds after flames disappear—to ensure they don't reignite.

Watch the flames diminish. If flames are growing or spreading, stop and evacuate. If progress is visible, continue the sweep. The pressure gauge will show remaining agent. Your goal: cover the entire base of the fire with extinguishing agent. Repeat sweeping until flames are completely gone.

Understanding What Happens When You Discharge

ABC powder works by interrupting the combustion process. Water-based agents cool the fuel and smother oxygen. Wet chemical agents for kitchen fires saponify oil and prevent re-ignition. CO2 displaces oxygen in electrical and clean areas. Why the base matters: flames are visible but burning is happening at the fuel surface. Applying agent at the base smothers combustion. Applying at flames cools them but doesn't stop the underlying fire.

Why sweep matters: distributing agent across the base ensures coverage. Concentrated discharge in one spot may miss the edges. Sweeping creates a uniform blanket of extinguishing agent.

When the Fire Is Out—What to Do Next

After flames are completely extinguished, continue holding the trigger for two to three more seconds to cool the area. Stop squeezing when discharge is no longer needed. Watch the area for re-ignition. Keep the nozzle aimed at the extinguished area. If the fire re-ignites: resume PASS if extinguisher still has agent. If extinguisher is empty or fire is growing, evacuate immediately. Call 911 from outside the building.

After successful extinguishing: don't assume it's completely out. Embers or hot spots may remain. Watch the area for several minutes. Open windows or doors for ventilation if safe. Allow cleanup of powder residue—ABC powder is messy but non-toxic. Notify building management or facility team immediately. Report the extinguisher use. Note what was burning and how long it took. The used extinguisher must be recharged before returning to service. Document the incident.

Fire Extinguisher Classes and When to Use Them

Class A: ordinary combustibles (wood, paper, cloth, plastics). Uses water, ABC powder, water-based agents. Find ABC extinguishers in hallways, offices, warehouses.

Class B: flammable liquids and gases. Uses BC powder, ABC powder, CO2. Common in mechanical rooms, storage areas.

Class C: electrical equipment. Uses CO2, powder, clean agents. Never water alone. Find near electrical panels, server rooms, labs.

Class D: combustible metals. Uses specialized powder. Only in facilities with metal handling—uncommon.

Class K: cooking oils and fats. Uses wet chemical agents (potassium acetate or sodium potassium). Find in commercial kitchens only.

What Happens If You Use the Wrong Extinguisher Type

ABC powder on Class B flammable liquid: works fine. ABC covers multiple classes.

Water on Class B fire: spreads the fire. Water causes oil to splash and spread flames. Never use water on grease fires.

Wrong agent in kitchen: ABC or CO2 on cooking oil fire doesn't prevent re-ignition. Wet chemical extinguishers are designed to cool oil and form a crust. Only K-Class or specialized units work properly.

General rule: if the extinguisher is labeled ABC, it covers A, B, and C classes. If it's labeled BC, it covers B and C only. If it's K-Class, it's only for cooking oils in kitchens. When in doubt, evacuate rather than guess.

Limitations of Portable Fire Extinguishers

What they're designed to handle: small, contained fires (trash cans, small appliance, small grease fires). Fires that haven't spread to other materials. Fires in rooms with adequate ventilation.

What they can't handle: large fires (more than one to two feet in size). Fires with heavy smoke production. Fires near electrical equipment without appropriate agent. Fires that have spread to multiple areas. Uncontained fires spreading across ceiling, walls, or floor.

Agent depletion: most portable extinguishers discharge completely in 15 to 30 seconds. After that, you have no suppression capability. If fire is still burning after discharge, you must evacuate.

Training and Hands-On Practice

Most organizations require fire extinguisher training. OSHA requires employee training on portable extinguishers (29 CFR 1910.157). Training should cover PASS method and when to use versus evacuate. Refresher training recommended annually.

Hands-on practice: some fire departments and vendors offer burn demonstrations. Actually using an extinguisher—even on a small test fire—builds confidence. Video training and classroom instruction aren't substitutes for this.

Finding training: local fire departments often provide training. Fire protection companies offer commercial training. Some communities have fire safety education events.

Common Mistakes That Reduce Effectiveness

Aiming at flames instead of base: cools visible fire but doesn't stop burning at fuel. Wastes agent without effect.

Not sweeping side to side: concentrates discharge in one spot. Misses fire edges. Allows reignition at edges.

Using wrong extinguisher type: water on electrical fire equals electrocution risk. ABC powder on cooking oil equals insufficient suppression and re-ignition. Wrong agent doesn't work effectively.

Standing too close: too much heat exposure. Risk of agent splashing back. Reduced depth of field to observe fire.

Hesitating or being indecisive: turning back and forth between fire and exit. Freezing when flames don't immediately go out. Not evacuating when fire is too large.

Continuing when fire is growing: portable extinguishers aren't designed for large fires. Delay in evacuation increases danger. Fire department needs to handle anything larger than small contained fire.

After the Fire: What Happens to the Extinguisher

The used extinguisher must be recharged before use again. Even partial discharge requires recharge. Discharged unit is not compliant for safety. Call your fire protection vendor for immediate recharge.

Vendor will check the unit's condition while refilling. Report any damage from fire or discharge. Verify the extinguisher can return to service. Cost: recharge ($15 to $50 depending on unit type) is much less than replacement. Worth immediately recharging so the unit returns to service quickly.

Closing

The PASS method is straightforward and standardized: Pull the pin, Aim at the base, Squeeze the trigger, Sweep side to side. It works for the vast majority of portable fire extinguishers. But remember—the purpose of knowing PASS is to handle small fires only. For anything larger or spreading, the right answer is evacuation and calling 911. Fire protection professionals have the equipment and training for big fires. Your job is to get out safely.

CodeReadySafety.com provides fire safety education and compliance guidance. Requirements vary by jurisdiction — always verify with your local authority having jurisdiction. This content is not a substitute for professional fire protection consultation.