Fire Risk Classes
Fire risks are categorised into classes. Fire extinguishers are rated in their ability to fight these different classes (letter), as well as their strength to fight this class (number).
Fire classes:
- Class A – fires involving solid combustibles, such as wood, paper or textiles.
- Class B – fires involving flammable liquids, such as petrol, diesel or oils.
- Class C – fires involving flammable gases, such as LPG and natural gas.
- Class D – fires involving flammable metals, such as magnesium swarf.
- Class ‘Electric Spark’ – fires involving live electrical apparatus.
- Class F – fires involving cooking fats, such as in deep fat fryers oils.
Extinguisher Types:
There are six types of extinguisher:
- Foam – Used for Class A and B
- Water – Used for Class A
- Wet Chemical – Used for Class A, B and F
- CO2 – Used for Class B and electrical equipment
- Dry Powder – Used for Class A, B and C and electrical equipment
- L2 & M28 Powder – Used for Class D
‘Dry’ water mist extinguishers can be used on Class A, B, C and F fires are very easy to use. They are typically installed in buildings, where extinguisher training for all of a building’s occupants is not feasible.
BS 5306-3 recommends that extinguishers are commissioned on site by a competent person.
It is recommended that extinguishers are serviced annually, but that a visual inspection is carried out monthly.
