Fire extinguisher calculator: extinguishing units and number under ASR A2.2
Enter the floor area and choose the extinguisher size – the calculator shows the extinguishing units for the basic equipment under the German technical rule ASR A2.2 and how many fire extinguishers you need.
As of October 2026
With several floors, the sum of all floor areas.
Printed on the extinguisher, for example 21A or 43A.
Basic equipment under ASR A2.2
18LE
3devices
Other extinguisher sizes
- 27A (9 LE): 2 devices
- 34A (10 LE): 2 devices
- 43A (12 LE): 2 devices
- 55A (15 LE): 2 devices
Distribute the extinguishers so that no point is more than 20 metres walking distance from the nearest one – depending on the layout, this requires more devices.
From 400 m², wall hydrants may count under certain conditions (ASR A2.2).
Have fire extinguishers inspected by a competent person at least every two years.
The calculator shows minimum values under the regulations and rules listed. It does not replace the risk assessment and is not legal advice – the requirements of your accident insurance institution are decisive.
How the calculator works
- 1
Determine the floor area
What counts is the floor area of the workplace – with several floors, the sum of all floor areas.
- 2
Read off the extinguishing units
ASR A2.2 assigns extinguishing units (Löschmitteleinheiten, LE) to the floor area: up to 50 m² 6 LE, up to 100 m² 9 LE, then up to 1,000 m² another 3 LE per further 100 m² – so 36 LE at 1,000 m² – and above that 6 LE per further 250 m².
- 3
Choose fire extinguishers
Depending on its fire rating, each extinguisher provides a certain number of LE, for example 21A = 6 LE or 43A = 12 LE. Only extinguishers with at least 6 LE count towards the basic equipment. The required LE apply per relevant fire class.
- 4
Distribute and inspect
Fire extinguishers are distributed so that no point is more than 20 metres walking distance from the nearest one – which may require more devices than the calculation alone. With increased fire risk, further measures are needed.
Frequently asked questions
How many fire extinguishers are needed per m²?
ASR A2.2 does not count devices but extinguishing units: up to 50 m² 6 LE, up to 100 m² 9 LE, up to 1,000 m² 36 LE and 6 LE per further 250 m². How many extinguishers this means depends on their size.
Does the area count per floor or in total?
For the extinguishing units, the floor area of the workplace counts – with several floors, the sum. The extinguishers are distributed so that on every floor no point is more than 20 metres walking distance from the nearest one.
What applies with increased fire risk?
The basic equipment is then not enough. Additional fire extinguishers, suitable extinguishing agents at particular hazards or further measures follow from the risk assessment.
Do wall hydrants count?
Under certain conditions, wall hydrants may count towards the basic equipment from a floor area of 400 m². The conditions are set out in ASR A2.2.
How often must fire extinguishers be inspected?
At least every two years by a competent person, and immediately after every use or damage.
