How Many Fire Extinguishers Does My Workplace Need? (UK Guide)

The Legal Basis: What Does UK Law Require?

The Regulatory Reform (Fire Safety) Order 2005 (RRO 2005) is the primary legislation governing fire safety in non-domestic premises across England and Wales. It does not prescribe a specific number of extinguishers. Instead, it places a duty on the responsible person — usually the employer or building owner — to carry out a suitable and sufficient fire risk assessment and to ensure that appropriate firefighting equipment is provided, maintained, and accessible.

What counts as "adequate" provision is defined through guidance standards rather than statute. The most widely adopted is BS 5306-8, which covers the selection and positioning of portable fire extinguishers in non-domestic premises. Following BS 5306-8 is not a legal obligation in itself, but it represents recognised best practice and will typically be expected by fire safety inspectors and insurers alike.

What BS 5306-8 Recommends

For Class A fire risks — fires involving ordinary solid combustibles such as wood, paper, textiles, and plastics — BS 5306-8 sets out the following minimum guidance for standard-risk premises:

• A minimum of two Class A extinguishers per storey
• At least one extinguisher per 200m² of floor area
• A maximum 30-metre travel distance to the nearest extinguisher from any point on that floor

These are minimums for a standard-risk environment. Where the fire risk assessment identifies elevated hazards — significant quantities of flammable liquids, cooking equipment, high-value electrical assets, or large amounts of combustible storage — the provision must be increased accordingly.

Understanding Fire Classes and Choosing the Right Extinguisher

Using the wrong extinguisher type can be ineffective at best and dangerous at worst. UK fire classification divides fires into the following classes:

• Class A — Solid combustibles: wood, paper, textiles, plastics
• Class B — Flammable liquids: petrol, paint, solvents, spirits
• Class C — Flammable gases: propane, butane, methane
• Class F — Cooking oils and fats, such as those used in deep-fat fryers
• Electrical hazards — Not a separate fire class, but electrical equipment requires a non-conductive extinguishing agent

Matching the extinguisher type to the hazard is a fundamental part of any fire risk assessment:

• Water or water mist — Suitable for Class A; water mist also covers B, C, and electrical hazards
• Foam (AFFF) — Class A and B; good for premises with both general combustibles and flammable liquids
• CO2 — Electrical equipment and Class B; leaves no residue and is safe around live equipment
• Dry powder — Class A, B and C; broad coverage, but deposits residue and reduces visibility, so not ideal for enclosed spaces
• Wet chemical — Class F only; the correct choice for commercial kitchens with deep-fat fryers

Typical Workplace Scenarios

Office Buildings

An office is predominantly a Class A environment. For a two-storey office with 300m² per floor, the minimum provision would be two Class A extinguishers per floor — four in total. Water or foam extinguishers cover the general office risk. Where server rooms, comms cupboards, or UPS systems are present, a CO2 extinguisher should be added nearby.

Commercial Kitchens

A kitchen containing deep-fat fryers is a Class F environment. Water, foam, CO2, and dry powder extinguishers are all potentially hazardous on a burning cooking oil fire — water in particular can cause a violent steam explosion. A wet chemical extinguisher is essential wherever deep-fat frying takes place, and the unit must be rated to cover the maximum oil volume in the fryer. A fire blanket should also be mounted within easy reach of cooking stations.

Server Rooms and Data Centres

The primary hazard is electrical. CO2 extinguishers are the standard choice: they suppress fire without leaving residue and are safe around live equipment. Avoid dry powder in server environments — it causes extensive secondary damage and is very difficult to clean up.

Vehicle Workshops and Garages

Workshops typically present Class A (combustibles), Class B (fuels, lubricants, solvents), and electrical risks. Foam extinguishers handle fuel spills effectively; CO2 covers electrical hazards. Dry powder offers broad Class A/B/C coverage and is suited to open or outdoor areas, though its limitations in enclosed spaces should be factored into the risk assessment.

Multi-Storey Buildings and High-Risk Areas

In multi-storey buildings, each floor is assessed independently. Extinguishers should be positioned on every level — mounted on a fire extinguisher stand where possible for visibility and quick access — ideally near stairwells or exit routes, and at consistent locations on each floor so staff can locate them quickly in an emergency without having to search.

Where multiple hazard types co-exist within the same premises — a workshop with flammable liquid storage, welding equipment, and an office mezzanine, for example — each hazard zone should be addressed individually within the fire risk assessment, rather than relying solely on the standard per-floor calculation.

High-risk areas such as spray booths, chemical stores, plant rooms, and boiler rooms each require dedicated extinguisher provision that reflects the specific hazard present, regardless of what is provided in adjacent areas.

Annual Maintenance Is a Legal Requirement

Providing extinguishers is only part of the obligation. The RRO 2005 requires that firefighting equipment is maintained in efficient working order at all times. BS 5306-3 is the British Standard covering the maintenance of portable fire extinguishers, and it specifies that all units must receive an annual service carried out by a competent person — typically a BAFE-registered engineer.

In addition to the annual service, a designated person on site should carry out monthly visual checks covering:

• Pressure gauge reading in the green (charged) zone
• Safety pin and tamper seal intact and undisturbed
• No visible damage, corrosion, or signs of discharge
• Correct positioning — not obstructed, moved, or removed from its designated location

An unmaintained extinguisher is a liability, not an asset. Beyond the legal consequences of non-compliance, a unit that fails to operate when needed can have serious outcomes.

Start With Your Fire Risk Assessment

The number and type of extinguishers your workplace needs cannot be determined by formula alone — it must flow from a proper fire risk assessment. If yours is out of date, or you do not yet have one, reviewing it should be the first priority. For most standard premises, an annual service visit from a BAFE-registered engineer will include a review of extinguisher provision. For complex or high-risk sites, a qualified fire risk assessor should be engaged separately.

Browse Cocus's range of portable fire extinguishers — including water, foam, CO2, wet chemical, and powder types — at our fire extinguishers collection. All units supplied meet the relevant British and European standards and are suitable for annual servicing under BS 5306-3.