Water fire extinguishers are the most basic form of fire extinguishers on the market. They are a must for any business featuring onsite flammable solids. Sometimes simply referred to as a Class A fire extinguisher, water fire extinguishers can only be used on fires fueled by combustible materials such as wood, fabrics, paper, and other solid items.
Many fire types are off-limits for water fire extinguishers, including electrical fires and fires involving flammable liquids. Despite the tool’s limitations, water fire extinguishers can still play a vital role in any business’s fire prevention measures.
Find the Right Water Extinguisher
- For use with class A fires
- Comes with a wall bracket
- Kitemarked to BS EN3 & CE Certified
How Do Water Fire Extinguishers Work?
Water fire extinguishers attack the ‘heat’ side of the fire triangle by using water to cool and eventually extinguish the flames.
Water is sprayed onto the fire, which extinguishes some of the flames, wets the fuel, and brings the overall temperature of the fire down significantly.
In terms of how the mechanisms work, pressured gas compresses the water contained in the tank downward and then through a tube. This tube leads to the spout of the hose, and the compressed water sprays out with enough pressure to extinguish flames. The water often comes out with a mist effect, allowing the water to cover a wide area.
What do water fire extinguishers contain?
Water fire extinguishers only contain water and come in either 3, 6, or 9-litre sizes. Inside a water fire extinguisher, you’ll also find a small canister containing high-pressure gas.
This canister is punctured when the lever of the fire extinguisher is first squeezed. This releases the gas that pressurises the water.
Water fire extinguishers are the most cost-effective and low-maintenance extinguisher type. Unlike foam fire extinguishers, water extinguishers don’t leave residual stains, which makes cleaning up easy. On top of this, water fire extinguishers are the most environmentally-friendly fire extinguisher available.
What is a Water Fire Extinguisher Used For?
Water fire extinguishers are recommended for environments that store large amounts of combustible materials, such as paper mills, warehouses, and storage facilities.
However, anywhere that features such solid materials as paper and wood should consider getting a water fire extinguisher. This includes any type of office, school, shop, or residential property.
Small, 3-litre water fire extinguishers are sometimes stored under car seats for vehicle fire protection.
It is a requirement for every business premises to have at least two Class A fire extinguishers on each floor of their business property. Some businesses opt for water fire extinguishers to fulfil this requirement, while others instead invest in foam fire extinguishers.
Foam fire extinguishers are more versatile and can be used on both Class A as well as Class B fires. This means they can extinguish fires caused by a flammable liquid.
Having the right equipment to combat the fire risks present in your premises is vital.
What Type Of Fire Is A Water Extinguisher Used For?
Water fire extinguishers are only suitable for use on one type of fire: Class A fires.
It is possible to get a water fire extinguisher that has been di-electrically tested. That means they could be used on electrical fires if there is no CO2 fire extinguisher available.
Still, even if di-electrically tested, water fire extinguishers should only really be used on Class A fires.
Class A fires
A Class A fire is any fire that is fueled by organic, solid materials, including paper, wood, textiles, and a few types of light plastics.
A lot of the materials that cause class A fires are natural and contain some level of carbon. Class A fires are the most common type of fire. Therefore they need to be adequately safeguarded against with a water extinguisher.
Before using a water fire extinguisher on a fire, you need to make sure that it definitely is a Class A fire. Using a water-based extinguisher on the likes of a cooking fire can add to the fire by spreading the flammable cooking oils further.
Generally, a Class A fire will leave a pile of ash – so look out for this before using a water fire extinguisher.
What Not To Use Water Extinguishers For
To put it simply, water fire extinguishers cannot be used on anything that is not a Class A fire.
This makes them relatively limited compared to other extinguisher types, given how many combustible materials there are in the world.
Specifically, you cannot use a water fire extinguisher on the following:
Class B fires
Class B fires include any fire fueled by flammable liquids such as kerosene, gasoline, grease, oil, alcohol, and diesel.
Water fire extinguishers cannot smother these types of flames the same way foam fire extinguishers can. Instead, they would spread the flammable liquids around further, potentially leading to the fire becoming uncontrollable.
Electrical fires
You cannot use a water extinguisher on a fire involving electrical equipment as water conducts fire.
Not only would this put you at risk of receiving a dangerous electric shock, but these electric shocks caused could spread the fire further. Electrical equipment includes fuse boxes and heaters; these fires are best extinguished using a CO2 extinguisher.
Class C fires
Class C fires are caused by combustible, flammable gases such as methane, butane, hydrogen, and propane.
Basically, any form of combustible gas could lead to a Class C fire in the event of a gas leak. Not only is water ineffective at putting out gas fires, but gas flames will boil any water it comes into contact with, putting you at risk of sustaining steam burns.
Class D fires
Any combustible metal, including magnesium, titanium, potassium, and aluminium, could potentially cause a Class D fire.
Like many fire types, you should never use water as it will cause the flames to spread rather than extinguish. You should only use dry powder extinguishers on fires involving combustible metal.
Class F fires
Sometimes referred to as cooking fires, Class F are fires involving flammable liquids commonly used in cooking, such as oil and grease.
For Class F fires, only a wet fire extinguisher can be used – a standard water fire extinguisher will only spread the burning oil or grease around further, strengthening the flames.
What Colour Is A Water Fire Extinguisher?
On the side of the red fire extinguisher, you should be able to see the outline of a white box with ‘WATER’ written inside in white capital letters.
There should also be an ID sign near this label that reads ‘Water Extinguisher’.
See Also: UK Fire Extinguisher Colours guide – how to identify extinguishers via the label colour coding system.
How To Use A Water Extinguisher
Water fire extinguishers are amongst the most straightforward extinguishers to use and can easily be picked up by anyone, but they still need to be used responsibly.
Mainly, this extinguisher type should only be used on fires that are small and clearly identifiable as Class A. They should not be used on fires that are out of control; instead, you should focus on evacuating the building as quickly as possible and contacting the fire and rescue services.
If you determine that the fire is safe and contained enough to be extinguished using a water extinguisher, follow these steps:
Step 1: Make sure its a Class A fire
Before even attempting to use the water fire extinguisher, make sure that the only fuel is solid combustibles. Also, ensure that there’s no electrical equipment within proximity of the flames.
Step 2: Remove the safety pin
Once you’re confident that it’s a controllable Class A fire, stand around 3 metres away from the flames and remove the pin. Removing the pin will break the tamper seal, leaving the extinguisher ready for use.
Step 3: Aim at the base of the fire
Whether the fire is spreading horizontally or vertically, you should always aim for the base of the fire initially. The base is wherever the fuel lies. Once you’ve taken care of the fuel source, the fire has little chance of maintaining itself.
Step 4: Squeeze the lever
Once squeezed, the extinguisher should immediately start discharging mist-like water over your targeted area. Once you’ve sufficiently wet the base of the fire, slowly move the hose upwards or across (depending on whether the fire is spreading vertically or horizontally).
Step 5: Make sure the fire is extinguished
As the fire reduces in size, you can safely move closer to it. Continue to spray the fire and specifically target hot spot areas or any signs of reignition.
Final Thoughts
Water fire extinguishers work well at curbing small, Class A fires. Water is the most effective substance for stopping fires involving flammable solids.
For this reason, water is the most common fire extinguisher type. They are routinely used as office fire extinguishers, as well as in storage facilities, and warehouses.
However, they cannot be used on any other fire type, including Class B, C, D, F, and electrical fires. Therefore, water fire extinguishers are still a vital tool for fire control but should be purchased alongside other fire extinguisher types, like foam extinguishers and wet chemical extinguishers.
Further Reading
- UK fire extinguisher regulations – more on legal requirements for fire safety equipment in the workplace.
