About fire extinguishers: which type of extinguisher to choose?
About fire extinguishers: which type of extinguisher to choose?
Choosing a fire extinguisher is not only about the fire class. It is also important to understand what extinguishing agent the extinguisher contains, how it works and in what kind of environment it will be used.
Our fire safety advisor has highlighted the main types of fire extinguishers: water extinguishers, foam extinguishers, powder extinguishers, carbon dioxide extinguishers and wet chemical extinguishers.
Water extinguisher
A water extinguisher contains water or a Class A foam solution as the extinguishing agent. Its main effect is cooling.
A water extinguisher is suitable for locations where the fire risk is mainly related to solid materials. Examples include offices, hospitals, sports halls, childcare facilities, cinemas, theatres and waiting areas.
The advantage of a water extinguisher is its good cooling effect and lower clean-up burden compared with a powder extinguisher. However, it is important to note that it is not suitable for extinguishing flammable liquids or fat fires, and a standard water extinguisher must be protected from freezing.
Foam extinguisher
A foam extinguisher contains a mixture of water and foam agent. In Class A fires, it helps cool the burning material. In Class B fires, it forms a layer on the surface of the flammable liquid, helping to separate the fuel from the flame.
A foam extinguisher is suitable for locations where there may be a risk of both solid material fires and flammable liquid fires. Examples include homes, shops, garages, workshops and fuel stations.
The advantage of a foam extinguisher is that it suits many common environments and usually causes fewer clean-up issues than powder. At the same time, foam may damage water-sensitive items, and a standard foam extinguisher must be protected from freezing.
Powder extinguisher
A powder extinguisher is common because an ABC powder extinguisher is suitable for many different types of combustible materials.
A powder extinguisher is suitable for locations where fire may spread quickly or where low temperatures make the use of water or foam extinguishers unsuitable. Examples include vehicles, garages, workshops, unheated warehouses, outdoor areas at fuel stations, loading areas and harbour quays.
The advantage of a powder extinguisher is its wide range of use and good extinguishing capacity. It can be stored and used in different weather conditions.
However, powder extinguishers have an important drawback: powder dust contaminates the room. It may damage electronics and sensitive equipment, reduce visibility, irritate mucous membranes and lead to significant clean-up costs.
CO₂ extinguisher, or carbon dioxide extinguisher
A CO₂ extinguisher contains carbon dioxide as the extinguishing agent. Its effect is mainly based on displacing oxygen from the fire area and partly on cooling.
A CO₂ extinguisher is suitable for places where water, foam or powder may cause additional damage. Examples include electrical and electronic equipment rooms, laboratories, high-tech production areas and rooms with sensitive equipment.
The advantage of a CO₂ extinguisher is cleanliness: it does not leave powder or foam residue in the room. However, it is important to consider that a CO₂ extinguisher is not suitable for deep-seated smouldering fires, has little post-extinguishing effect and may pose suffocation and frostbite risks to people.
Wet chemical extinguisher
A wet chemical extinguisher is intended for extinguishing cooking oils and fats. Its extinguishing agent cools the fire and forms a layer on the surface of the fat, helping to prevent re-ignition.
A wet chemical extinguisher is especially suitable for commercial kitchens, restaurants, cafés and places where hot food is prepared.
Water must not be used on a fat fire. In hot fat, water can vaporise rapidly and spread the burning fat.
If you are not sure which type of extinguisher to choose, it is worth asking for advice before making a purchase.