A Guide to Water (H2O) Fire Extinguishers
Water and water additive fire extinguishers
can be used on
- Class A: Ordinary combustibles (wood, paper, cloth, rubber and plastics)
Water fire extinguishers are most suitable for shops and offices that use normal combustibles (cloth, paper and furnishings).
How they work
When activated, a water extinguisher works by simply cooling down the fire. This also reduces the risk of re-ignition.
How to recognise them
Water fire extinguishers can be identified by their white label and red writing.
Water additive fire extinguishers conversely use white text on a red label.
They’re the most cost-efficient extinguisher
Water (H2O) fire extinguishers are the most affordable ones to buy and cheapest to refill.
Whatever your business, it’s always a great idea to have a water extinguisher on site – if a class A fire occurs, you won’t have to discharge a more expensive extinguisher.
Water vs. water additive fire extinguishers
As the name implies, water additive fire extinguishers use water with an additive as their extinguishing agent.
Water additive fire extinguishers are more expensive, but may be more cost-efficient. This is because the water additive makes them better at fighting fires.
This means that a smaller water additive extinguisher can fight the same size fire as a larger ordinary water extinguisher. As you’ve probably noticed, larger extinguishers are more expensive.
On top of this, smaller fire extinguishers are easier to handle.
When purchasing a water fire extinguisher, look out for a class A fire rating ( for more information on fire extinguisher fire ratings click here
Remember, a water additive extinguisher will have a higher fire rating than its water equivalent.
Unlike some other extinguishers, water fire extinguishers don’t discharge cloudy substances. This means that they don’t obscure people’s vision, and won’t restrict people’s view of emergency exits during a site evacuation.
Also, since water is the extinguishing agent, there’s no risk of exposure to harmful substances (other than those emitted from a fire!).
Keep away from electrical fires
Of course, water conducts electricity, so make sure that you never use a water or water additive fire extinguisher on electrical equipment.
Keep away from cooking fires
Again, we all know that water and oil do not mix. If you use water on an oil, grease or cooking fat fire, the oil will float (and potentially spread), making the fire become more out of control.
It is also dangerous when used on class B (flammable liquid) fires.