Get your fire extinguishers wrong and a fire officer can hand you an enforcement notice, or in the worst cases a prohibition notice that closes your premises until you put it right. Fire extinguisher requirements for a UK business are not optional extras: they sit inside the Regulatory Reform (Fire Safety) Order 2005, and getting them wrong is one of the quickest ways to fail an inspection or give your insurer a reason to reject a claim after a fire. Office fire extinguisher rules trip up more small firms than almost any other part of fire safety, usually because someone bought a multipack online and hung them on a nail by the back door.
The good news is this is one of the cheaper and more fixable areas of compliance. BS 5306 is the British Standard that tells you which types to fit, how many, where to put them, and how to keep them serviced. Get those four things right and you have covered most of what an inspector, an insurer, or a landlord will ask to see.
What the law actually requires
The RRO 2005 does not list a shopping order of extinguishers. It puts a duty on the "responsible person" (usually the employer, occupier, or building owner) to provide firefighting equipment that is appropriate to the risks in the building. Your small business fire risk assessment sets those legal obligations and should say, in writing, what extinguishers you need and why.
BS 5306 is the "how". It is not a law in itself, but courts and fire officers treat it as the benchmark for what "appropriate" looks like. If your provision matches BS 5306-8 for selection and installation, and BS 5306-3 for servicing, you can show you took reasonable steps. If it does not, you are the one explaining the gap. Note that the RRO 2005 covers England and Wales; Scotland works under the Fire (Scotland) Act 2005 and its own regulations, though the extinguisher standards and British Standards used in practice are the same.
Fire extinguisher requirements for a UK business: types and fire classes
Every extinguisher is matched to one or more fire classes. Fit the wrong type and it can do nothing, or make the fire worse. UK extinguishers have a red body with a coloured label band that tells you what is inside.
Water (red label)
Covers Class A only: ordinary solids such as wood, paper, textiles, and most office furniture. This is your workhorse for a typical office or shop floor. Never use it on electrical equipment or burning liquids.
Foam (cream label)
Covers Class A and Class B (flammable liquids such as petrol, paint, and solvents). Foam is a sensible all-rounder for premises that store small amounts of flammable liquid. It is not designed for live electrical fires.
CO2 (black label)
For electrical fires and Class B liquids. This is the one you want near computers, servers, photocopiers, and consumer units, because it leaves no residue and will not wreck the kit it saves. It does not cool solids well, so it is a poor choice as your only extinguisher on an office floor. Use it in ventilated spaces, not tiny cupboards.
Dry powder (blue label)
Covers Class A, B, and C (flammable gases), plus electrical. Powder is versatile, which is why the cheap online multipacks are usually powder. The problem is that indoors it creates a choking cloud that destroys visibility and can make escape harder, and it coats everything in fine residue. Keep powder for outdoor and vehicle risks, not the middle of a busy office. A special version handles Class D metal fires in workshops.
Wet chemical (yellow label)
The only correct choice for Class F fires: cooking oils and fats. Any premises with a commercial fryer or a serious kitchen needs one within easy reach of the appliances. A standard office kitchenette with a toaster and kettle does not, though a fire blanket is worth having.
Office fire extinguisher rules: how many and where
BS 5306-8 sets a sensible minimum. For a normal office, provide at least two Class A extinguishers (water or foam) per floor, with a combined fire rating of at least 26A. Add specific types for specific risks: CO2 near electrical equipment, wet chemical near cooking, foam or CO2 near stored flammable liquids.
The rule that catches people out is travel distance. No one should have to walk more than 30 metres to reach a Class A extinguisher. For higher risks the distances tighten: a CO2 unit should sit within about 10 metres of the electrical risk it protects, and in kitchens the wet chemical unit should be within roughly 2 metres of the cooking appliance, because a chip pan fire spreads in seconds.
Placement matters as much as the count. Fix extinguishers on the mounting bracket supplied, or on a proper floor stand, at the recommended height (heavier units with the handle around 1 metre from the floor, lighter ones a little higher). Site them on escape routes, next to exits and stairwells, so people grab one on the way out rather than walking deeper into the building. Every extinguisher needs a photoluminescent identification sign mounted above it, so it is visible in smoke and easy to find in a hurry.
Servicing: the two checks you cannot skip
An extinguisher is only firefighting equipment if it works on the day. BS 5306-3 sets out two routines, and you are responsible for both.
The monthly visual check is yours to do, or delegate to a competent member of staff. No engineer needed. Walk the building once a month and confirm each unit is in its correct place, unobstructed, undamaged, still sealed with its safety pin and tamper tag intact, and (where a gauge is fitted) showing a needle in the green. Log it. That log is exactly what a fire officer asks to see, and a landlord or insurer will want it too.
The annual basic service must be carried out by a competent engineer, ideally one registered to BAFE scheme SP101, at least once every 12 months. On top of that, most water, foam, and powder extinguishers need an extended service (a discharge test and refill) around every 5 years, and CO2 units need a pressure test or overhaul at about 10 years. A cheap contractor who skips the extended service leaves you with units that look serviced but may fail when triggered.
The mistakes that fail inspections
Two errors show up again and again, and both are avoidable.
The first is the wrong type near electrics. A water or foam extinguisher parked next to a bank of computers or a fuse board is a genuine hazard, because using it on a live electrical fire can conduct current back to the person holding it. Electrical risks want CO2, full stop. Walk your building and ask, at every extinguisher, "what would actually be on fire here, and is this the right unit for it?"
The second is treating extinguishers as door props. Wedging a fire door open with an extinguisher fails twice over: it takes the extinguisher off its station so no one can find it in an emergency, and it defeats the fire door that is meant to hold back smoke and flame. Propping fire doors is a serious finding in its own right and undermines the compartmentation your building relies on. If a door is inconvenient to keep shut, fit a compliant hold-open device, not a red cylinder.
Other common failings: powder units stationed indoors where they will blind everyone if used, extinguishers dumped on the floor instead of mounted, missing or hidden signage, blocked access, and service tags that expired a year ago. None of these cost much to fix, and all of them are the sort of thing that decides whether you pass. If you want the wider picture of who carries these duties, our guide to the responsible person under UK fire safety law sets out who is on the hook.
Next steps
Extinguishers do not sit in isolation. They are one output of a proper fire risk assessment that also looks at alarms, escape routes, signage, and staff training. Work through your office fire risk assessment step by step and the extinguisher provision falls out of it naturally, matched to the actual risks in your building rather than guessed at.
If you would rather be walked through it, FRASafe's small business fire risk assessment covers every area the RRO 2005 requires, completed online in 30 to 45 minutes for £45, giving you a PDF you can show your insurer, landlord, or council. Do the monthly visual checks yourself, book the annual service with a BAFE registered engineer, and keep both logs where you can find them. That combination is what turns a shelf of red cylinders into compliance you can prove.