Fire Extinguisher

A fire extinguisher is a portable device used to control or put out small fires in an emergency. It works by discharging an agent such as water, foam, powder, CO2, or wet chemical that removes one of the three elements a fire needs to burn: heat, fuel, or oxygen. They’re intended for tackling fires in their early stages, not for fighting large or spreading blazes.

There are five main types, each colour-coded and suited to different fire classes. These are water (red label, for Class A materials like paper, wood, and textiles), foam (cream, for Class A and B flammable liquids), CO2 (black, for electrical fires and flammable liquids), dry powder (blue, a multi-purpose option for A, B, C and electrical), and wet chemical (yellow, for Class F cooking oils and fats). Most workplaces need a combination rather than a single type.

Each extinguisher attacks the “fire triangle” of heat, fuel, and oxygen. Water and foam cool the fire and cut off oxygen, CO2 displaces oxygen and smothers flames, dry powder interrupts the chemical reaction, and wet chemical reacts with burning fat to form a soapy layer that seals the surface. Operation generally follows the PASS method: Pull the pin, Aim at the base of the fire, Squeeze the handle, and Sweep side to side.

Yes. Under the Regulatory Reform (Fire Safety) Order 2005, the “responsible person” for a workplace must provide appropriate firefighting equipment and ensure it’s suitable, accessible, and properly maintained. Failure to comply can lead to enforcement notices, fines, or in serious cases prosecution. A fire risk assessment determines exactly what’s needed for your premises.

This depends on the size, layout, and risk profile of the premises, but general guidance recommends a minimum of two Class A extinguishers per floor, with a maximum travel distance of around 30 metres to reach one. Higher-risk areas need additional or specialist units. A fire risk assessment will set the precise number and mix for your site.

Extinguishers should be visually checked monthly by a responsible person, given an annual “basic” service by a competent engineer (in line with BS 5306-3), and undergo an extended service or test discharge at longer intervals. This is typically every five years for most types and ten years for CO2 units. Records of inspections and servicing should be kept.

Start with a fire risk assessment to identify the likely fire types in each area, then match extinguishers to those hazards. For instance, water or foam suits offices, CO2 suits server rooms, and wet chemical suits kitchens. Consider the size and weight that staff can safely handle, ensure adequate coverage across all areas, and have the selection reviewed by a competent fire safety provider.