Fire Extinguisher Types Toolbox Talk

A ready-to-deliver toolbox talk for foremen and supervisors. 8-10 minute spoken script plus briefing register for operative sign-in.

8-10 minutes·Download PDF

Every site has fire extinguishers. Half the team can't tell you which one to grab if a stick welder sets a bag of rags off. Using the wrong one isn't just useless. Water on a chip pan or CO2 on a deep-fat fryer can make the fire worse and put the person holding the extinguisher in hospital. This talk walks the team through the five UK extinguisher types, what each one's for, and the one minute of technique they need to actually use one.

Why it matters

The Regulatory Reform (Fire Safety) Order 2005 puts the responsibility for fire safety on the responsible person on site (usually the PC). That includes making sure operatives know which extinguisher is for which fire. Construction sites are above-average risk: hot works, fuel cans, gas cylinders, timber stacks, polythene, expanding foam. Fire is the most common cause of total site loss in UK construction.

PPE for this task

Hard hat
Hi-vis vest
Safety boots
Safety glasses (for hot works, near any ignition source)
Welding gauntlets / heat-resistant gloves for hot works

Classes of fire

Fires are classified by what's burning. The class decides the extinguisher.

Class	Type	Examples on a UK construction site
A	Solids	Wood, paper, cardboard, timber off-cuts, polythene
B	Flammable liquids	Petrol, diesel, paint, thinners, white spirit
C	Flammable gases	Propane, butane, LPG cylinders
D	Metals	Magnesium, lithium (rare on site)
F	Cooking oils	Canteen deep-fat fryer, chip pan
E	Electrical	Live circuits, plant electrical faults (not a numbered class but treated separately)

What to say

Spoken script for the supervisor. Read or paraphrase, in order.

The classes of fire: what's actually burning

Fires are classified by what's burning, and that decides which extinguisher you grab. Class A is solids: wood, paper, cardboard, timber off-cuts, polythene. Class B is flammable liquids: petrol, diesel, paint, thinners, white spirit. Class C is flammable gases: propane, butane, the gas bottles for the kettle. Class D is metals: magnesium, lithium. Class F is cooking oils, mostly canteen fryers. And electrical isn't a class on its own but it's its own problem. Never put water on something live.

Water: red label

Class A only. Wood, paper, polythene, timber off-cuts. Cheap, plentiful, the default on construction sites. Never put water on electrical, never on a flammable liquid, never on hot cooking oil. Water on a live circuit makes you part of the circuit. Water on chip-pan oil throws burning oil three metres in every direction.

Foam: cream label on red

Class A and Class B. Solids and flammable liquids: diesel spills, paint fires, fuel container fires. The most common extinguisher on a UK construction site because it covers the two most likely fires. Some foam extinguishers are dielectrically tested to 35kV, which means they can be used on electrical if you're a metre back. Check the label. Don't assume.

Dry powder ABC: blue label

Class A, B and C, and it'll work on electrical. The most flexible option, and what you'll see by the gas cabinet or the welding bay. Downside: the powder is a respiratory irritant, makes a mess of everything for fifty metres, and damages electronics permanently. Don't grab it for a paper bin if a water one is closer. Outdoors first choice for fuel and gas fires; indoors, last resort because of the visibility loss.

CO2: black label

Electrical and Class B. The one you grab if the site cabin board is on fire or a piece of plant has an electrical fault. Clean. No residue, no mess, doesn't damage circuits. Two things to know: the discharge horn gets extremely cold, never grip it directly or you'll freeze your hand to it; and in a confined space CO2 displaces oxygen, so get out fast once you've used it.

Wet chemical: yellow label

Class F cooking oil fires. Site canteens, welfare units with a deep-fat fryer. Specialist. Most operatives will never touch one. But know where it lives and that it's the only one you use on a chip pan. Water on chip-pan fire is what every fire-service video shows you not to do.

PASS: the one minute of technique

Pull. Aim. Squeeze. Sweep. Pull the pin out, the tamper seal breaks first time. Aim at the base of the fire, not the flames. Squeeze the handle. Sweep from side to side across the base. Most extinguishers give you 10 to 30 seconds of discharge. You've got one go. If the first one doesn't put it out, the fire's beaten you and it's time to leave.

When NOT to fight it

Bin-sized fire, exit at your back, right extinguisher to hand, you've used one before. Fine. Anything bigger than that, evacuate, raise the alarm, call 999. Specifically: never fight a fire if you can't see the seat of it, if it's between you and the way out, if it's in a gas bottle or fuel container (move away, those can BLEVE), or if it's spreading faster than you can knock it down. The building can be rebuilt. You can't.

UK fire extinguishers: colour band and use

Every UK extinguisher has a coloured band identifying its contents. Check the band before you pull the pin.

Water
Use on: Wood, paper, polythene, timber off-cuts (Class A)
Avoid: Electrical, flammable liquids, cooking oil
Foam
Use on: Solids and flammable liquids (Class A and B). Most common on construction sites.
Avoid: Class F cooking oil. Electrical unless the label says dielectrically tested.
Dry Powder ABC
Use on: Solids, liquids, gases and electrical (A, B, C and electrical)
Avoid: Enclosed spaces. Visibility goes to zero. Damages electronics permanently.
CO₂
Use on: Electrical and flammable liquids (Class B). Site cabin board, plant electrical faults.
Avoid: Class A deep-seated fires (it'll reignite). Confined spaces (oxygen displacement).
Wet Chemical
Use on: Cooking oil fires (Class F). Site canteen / welfare deep-fat fryer.
Avoid: Most other fires. This is the chip-pan specialist.

Common mistakes to call out

Reaching for the nearest extinguisher without checking the label colour first
Aiming at the flames instead of the base of the fire
Standing too close (back off until the spray actually reaches the seat)
Using water on diesel or a generator (water spreads burning fuel, electrocutes you on a live circuit)
Gripping the CO2 horn while discharging (frostbite to the hand in seconds)
Putting a discharged extinguisher back on the bracket instead of flagging it for refill (next person grabs an empty one)
Fighting a fire with your only exit behind it
Forgetting to raise the alarm because you're "sorting it" (by the time it's clear you can't, everyone's still inside)
Storing extinguishers behind material stacks where no-one can reach them in 30 seconds
Annual service overdue (yellow tag on the body should be in date, check it)

Watch on site this week

What the supervisor should be actively spotting on walk-arounds.

Extinguishers obstructed by pallets, sheet material or scaffold components
Bracket fixings missing (the extinguisher sitting on the floor next to where it's meant to be)
Tamper seals broken or pins missing on extinguishers you're not currently using
Service tag overdue (annual check by a competent person)
Fire extinguisher signage missing or covered by polythene sheeting
Hot works happening without the dedicated extinguisher (fire watch) within arm's reach
Empty or partly-discharged extinguishers still on the bracket as if they're in service
Wrong extinguisher in the wrong location (water by the gas cabinet, CO2 by the timber stack)
Operatives smoking or vaping inside the welfare unit or near fuel storage

Confirm the team understood

Ask one or two of these at the end. Confirms attention more than a silent nod.

What does PASS stand for? (Pull, Aim, Squeeze, Sweep. And you aim at the base, not the flames.)
What's the only extinguisher you use on a chip-pan fire? (Wet chemical, yellow label.)
If you see a fire bigger than a wheelie bin, what do you do first? (Raise the alarm and get out. Fight it only if it's small, contained, and your exit is behind you.)
Where's the nearest extinguisher to where you'll be working today, and which class is it?

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