What Is A Wet Chemical Fire Extinguisher?

Understanding different fire extinguishers and the suppressants that they use can be crucial in tackling small fires, preventing them from spreading and causing more damage.

Wet chemical fire extinguishers are one of the lesser-known extinguisher types, as they have a more specific and precise purpose. They are commonly identified with a yellow label and feature a nozzle with which to spray the wet chemical solution.

A wet chemical fire extinguisher uses potassium, spraying a fine mist to both cool the solution that is on fire without splashing it, but to also create a soap-like layer on the top in a process known as saponification. Both help to extinguish flames by cutting off oxygen and reducing the overall temperature of the fuel involved, which also minimises the risk of re-ignition.

What should wet chemical fire extinguishers be used for?

Wet chemical fire extinguishers are class F extinguishers, which means they should only be used for fires that involve cooking oils and fats. This includes materials such as animal fats, lard, vegetable oil, olive oil and butter.

They are ideal for these situations because they use chemicals that react with the above materials at high temperatures, creating a sealant layer via a fine mist spray. Using any other type of extinguisher is likely to splash the hot cooking oils and fats around, creating further hazards and risking spreading the fire.

Some wet chemical extinguishers can be cleared for use on other fire types, including class A or class B fires, but you should always check with your provider if you require this.

What should wet chemical fire extinguishers not be used for?

While useful against oils and fats in kitchens, wet chemical fire extinguishers should never be used on class B fires, involving paints and liquid fuels such as petrol and diesel, unless they have been specifically cleared to cover these additional substances. They should also not be used for class C fires that involve flammable gases, as this will not be effective. 

Instead, you will require either a foam or dry powder fire extinguisher for class B fires, while class C fires require a dry powder unit only. These requirements are dependent on the specific materials at risk of catching fire within your premises, so you should always tailor your extinguisher choice to this.

How often do wet chemical fire extinguishers need to be maintained?

While all fire extinguishers should be checked visually once a month, wet chemical fire extinguishers should be maintained by a professional every five years. This extended servicing will help ensure your extinguishers are safe and reliable to use when needed in an emergency.

Should wet chemical fire extinguishers be thrown away after use?

Since it’s recommended that you use the full contents of a wet chemical extinguisher on a fire, you might be wondering if the unit should be thrown away after use. The answer here is that you should never throw a fire extinguisher away in general waste, as they can either be recharged if still in good condition, or recycled by a professional fire extinguisher engineer.

Never empty the contents of a wet fire extinguisher into a drain or sink, as this presents a hazard. Instead, seek professional assistance if you wish to dispose of your units.

Which sectors are wet chemical fire extinguishers required for?

Since wet chemical fire extinguishers are ideal for cooking fires, they’re often found in a variety of sectors where there is any type of kitchen involved. This can include the following sectors, since they are likely to feature a commercial kitchen:

• Educational facilities (schools, colleges, universities)
• Hospitality (restaurants, hotels, cafés)
• Shared kitchens (offices, student accommodation)
• Mobile catering facilities (burger vans)

It is especially important to have a wet chemical fire extinguisher if your premises feature a deep fat fryer, as this is one of the most common areas where fires can occur due to the high temperatures of cooking liquids.

Wet chemical fire extinguishers from Fire Safety Equipment

Here at Fire Safety Equipment, we supply 3ltr and 6ltr wet chemical fire extinguishers, ensuring you have the high-quality equipment you need for your commercial kitchen in order to save lives.

Order online today and get free, fast delivery in the UK, or browse our full range of fire extinguishers to find the right units to meet the risks in your building.