Which fire extinguisher fits which fire class?
The right fire extinguisher depends on the fire class of the material likely to burn. This guide explains fire classes A, B, C, D and F, the matching extinguishing agent for each, and how to calculate the number of extinguishing units (LE) needed per floor area.
View fire extinguishersWhat do fire classes A, B, C, D and F mean?
Fire classes to EN 2 group fires by the type of burning material. Every extinguisher carries pictograms of the classes it may fight. Always choose the extinguisher by the substance that can burn at the workplace - the wrong agent can make a fire worse.
- Class A: solid, ember-forming materials such as wood, paper, textiles, coal and many plastics.
- Class B: liquid or liquefiable substances such as petrol, oil, paints, resins and waxes.
- Class C: gases such as propane, butane, methane, hydrogen and natural gas.
- Class D: combustible metals such as magnesium, aluminium, lithium, sodium and their alloys.
- Class F: cooking fats and oils in deep fryers and kitchen appliances.
Which extinguishing agent suits which class?
Not every agent works for every fire class. Powder covers a broad range but causes heavy contamination; fat-fire extinguishers are mandatory in kitchens. The table below shows the typical mapping.
How do you calculate the required extinguishing units?
The required basic provision follows the technical rule ASR A2.2. Rather than counting devices, it counts the sum of extinguishing units (LE). Every extinguisher shows an LE rating on its label, derived from its rating (for example 21A or 113B).
The basis is the floor area of the premises. A table in ASR A2.2 gives the minimum LE: 50 m² require 6 LE, 100 m² 9 LE, 200 m² 12 LE, and the value rises stepwise from there. Increased fire risk adds surcharges.
- Read the LE from the label, not the fill quantity in kg or l.
- Add up the LE of all devices in the area until the table value is reached.
- Add extra LE for increased fire risk based on the risk assessment.
- Keep the travel distance to the nearest extinguisher below 20 m.
Frequently asked questions
Which extinguisher is required for the kitchen?
For cooking fats and oils (class F) a fat-fire extinguisher is mandatory. It forms a sealing layer on the hot fat. Water or ordinary powder extinguishers are life-threatening on fat fires because the fat can flash over explosively.
Can an ABC powder extinguisher be used everywhere?
ABC powder covers classes A, B and C and is very versatile, but the fine powder causes heavy contamination. In electronics, laboratory and server rooms CO₂ is better because it leaves no residue.
How many extinguishing units do I need for 300 m²?
Under ASR A2.2 the value is roughly 15 to 18 LE, depending on the exact area and fire risk. The maximum travel distance of 20 m to the nearest device also shapes the distribution across the site.
How often must a fire extinguisher be inspected?
Under DIN 14406‑4 every two years by a competent person. Additional internal visual checks are advisable to monitor the gauge, seal and location regularly.
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