The extinguisher rating of a fire extinguisher indicates per fire class how "capable" the fire extinguisher is to extinguish such fires. The higher the extinguishing rating, the more suitable the fire extinguisher is for that fire class (es). So always choose fire extinguishers with a high extinguishing rating!
What does the A extinguishing rating stand for?
For solids fires (fire class A), a fire test was developed in the form of a rectangular stack of wood. The pile of wood is stacked in a regular pattern with equal spacing so that there is an open space between the beams. The height and width of the wood pile are standard measurements: height is 0.5 M. and width is 0.56 M. The length of the pile ultimately determines the fire rating. After the pile burns for about 8 minutes, extinguishing is started.
- 13A: the wood pile has a length of 1.3 m.
- 27A: the pile of wood has a length of 2.7m
- 43A: the wood pile has a length of 4.3m
The extinguishment rating is only awarded when the test stand has been successfully extinguished. In addition, no re-ignition may occur within twenty minutes of the extinguishment.
What does the B extinguishing rating stand for?
For burning liquids (fire class B), a fire test was developed in the form of a round container filled 2/3 with heptane and 1/3 with water. The diameter of the container varies depending on the content. When the heptane is ignited, extinguishing should not begin until 1 minute has elapsed.
- 55B: a container filled with 55 liters of liquid
- 144B: a container filled with 144 liters of liquid
- 233B: a container filled with 233 liters of liquid
The extinguishment rating is only awarded when the test stand has been successfully extinguished. In addition, no re-ignition may occur within twenty minutes of the extinguishment.
What does the C extinguishing rating stand for?
Fire class C represents fires based on gases. Since gases are volatile, no rating can be assigned for this class. The designation "C" is therefore always without a number and simply indicates that the extinguisher is also suitable for extinguishing gas-based fires.
What does the F extinguishing rating stand for?
For grease fires (fire class F), a fire test was developed using a deep fryer. The frying fat is heated to above 350˚C so that the fat has reached its ignition temperature. When this has been burning for several minutes, extinguishing is started.
- 40F stands for a fryer with a capacity of 40 liters of frying fat.
- 75F stands for a fryer with a capacity of 75 liters of frying fat.
The extinguisher rating is not assigned until the test fixture has been successfully extinguished. In addition, no re-ignition may occur within twenty minutes of the extinguishment.
Need more information?
Be sure to check out the article "What fire classes are there?" and " How many and which fire extinguishers do I need? " in our advice center.