Fire Extinguishers: The Complete Guide

Fire extinguishers are a critically important piece of Fire Safety Equipment and are a common sight in all workplaces, schools and public buildings. They can mean the difference between a small fire being put out straight away or the fire service being called. That is why it is important to know about the different types of fire extinguishers and their uses.

Index: 

• What are the different types of Fire Extinguishers?
• How long do Fire Extinguishers last?
• When should a Fire Extinguisher be replaced?
• How should Fire Extinguishers be Stored?
• What are ABC Fire Extinguishers
• What are Fire Blankets?
• What type of Fire Extinguishers should I use for Lithium Battery fires?
• What Signage is used with Fire Extinguishers?

What are the different types of Fire Extinguishers?

Before using a Fire Extinguisher, it's important to make sure it's suitable for the type of fire being tackled otherwise you could just make things worse.

An essential point to know is what fire class the extinguisher is able to put out. Fires are split into classes depending on the type of material and/or fuel used in combustion.

• Fire Class A are fires involving solid materials such as wood, paper or textiles.
• Fire Class B are fires involving flammable liquids such as petrol, diesel or oils
• Fire Class C are fires involving gases.

Powder Fire Extinguishers (Class A, B, C)

There are many types of fire extinguishers, for example, Powder Fire Extinguishers. These are one of the most effective types of Fire Extinguisher available as their compact size and high performance makes them perfect for high-risk areas where space is limited. When pointed in the direction of a fire, compressed nitrogen propels the powder extinguishing agent over, and starves the fire of oxygen which prevents it from burning or reigniting. Powder fire extinguishers are suitable for class A,B,C and electrical fires. They can be recognised by their blue label stating: 'Powder'.

Automatic Powder Fire Extinguishers (Class A, B, C)

Another type of fire extinguisher is Automatic ABC Powder Fire Extinguishers. Like powder fire extinguishers, they are suitable for use on class A, B, and C fires. As the name states, these are automatic and therefore provide round the clock protection as they spray dry extinguishing powder automatically as soon as a fire is detected.

This is thanks to a red glass bulb that is filled with heat-sensitive liquid. When the liquid heats up, it expands and once it reaches 68°C the bulb breaks and the extinguishing powder is sprayed onto the surrounding area. This swift, automatic fire suppression means that the risk of a large fire, with the possibility of injury or fatalities is avoided, and valuable stock, equipment and machinery is protected.

Water Fire Extinguishers (Class A)

Water Fire extinguishers are suitable for use on class A fires. This is because the pressurised water that is released from the extinguisher is able to permeate into the core of the burning material to cool them, therefore stopping the fire whilst also putting out any flames. The low toxicity of Water Fire extinguishers means they are more environmentally friendly, economical and suitable for use near children or vulnerable people.

Some types of water fire extinguishers have additives that makes water lose its surface tension, which allows it to be immersed better into burning materials and therefore making the extinguisher more size effective. They can be identified by their white label stating 'Water'.

Foam Fire Extinguishers (Class A, B)

An additional type of fire extinguisher is Foam Fire Extinguishers. These are suitable for both Class A and Class B fires. Some foam extinguishers have passed the 35kV conductivity test, which means they are safe for accidental use on electrical equipment. They can be identified by their cream label stating 'Foam'.

They work in a similar way to water fire extinguishers in the sense that they are water-based and therefore cool down the temperature, but they also have an addition of AFFF which stands for 'Aqueous Film Forming Foam'. This foam envelops the fire and creates a seal for flammable vapours which stops the surface of flammable vapours reacting with the flames. Foam fire extinguishers are non-toxic and non-damaging to materials which makes them perfect for use in multi-hazard spaces such as offices, warehouses and commercial spaces.

CO2 Fire Extinguishers (Class B)

Another type of non-damaging fire extinguishers are CO2 fire extinguishers. They are perfect for use in areas with delicate machinery and/or equipment as they leave behind no residue. This is because pure carbon dioxide is used to put out fires. The canister contains liquid CO2 and when it is ejected, it displaces the oxygen which the fire needs to burn and therefore puts out the fire. This type of extinguisher is suitable for use on Class B and electrical fires. It can be identified by its black label stating ‘CO₂’.

Lithium Battery Fire Extinguishers

A new type of fire extinguisher is known as Lithium Battery Fire Extinguishers. They are designed to be used on small fires that are caused by lithium batteries found in mobile phones, tablets and other similar devices.

These types of fires are caused when a lithium-ion cell overheats and are hard to put out with water or other fire-extinguishers as they are able to reignite even after the original fire is extinguished. They work by dispersing AVD (Aqueous Vermiculite Dispersion) compound in a fine water mist. This stops the fire because it halts the dangerous reaction that is occurring in the cells whilst the cold-water mist acts as a cooling agent.

This type fire extinguisher allows lithium battery fires to be put under control quickly as they are very dangerous and can reach temperatures of 800ºC. It is also environmentally friendly as AVD is made from vermiculite, a naturally occurring mineral which allows this extinguisher to be used in a variety of places such as battery recycling facilities, public services and in goods distribution. 

How long do Fire Extinguishers last?

Fire Extinguishers usually last between 5 years and 15 years, depending on the manufacturer, extinguishing agent and level of maintenance.

Fire Extinguishers don’t last forever. Over time, the canisters can become corroded by their contents, and the high pressure needed can eventually weaken body seams, among other common problems which occur with old extinguishers. So how long can you expect your extinguisher to last?

Most manufacturers and retailers of Fire Extinguishers will offer a guaranteed lifespan of 5 years, although they can remain safe and effective for longer with proper maintenance and storage.

It is recommended by UK fire extinguisher regulations that fire extinguishers be replaced every 5 years, or if not replaced then given an extended service. This applies to all types of extinguishers, excluding CO2, which are recommended to be replaced every 10 years.

20 years old is the maximum age any extinguisher should be.

Don't Know How Old Your Fire Extinguisher Is?

Where to start then? You may not know exactly how old your extinguisher is. If this is the case, the pressure gauge can be inspected; if the needle points within the green area, your extinguisher should be in working order. If the needle on the pressure gauge points anywhere else but to green, the unit will need to be serviced or replaced.

In the unlikely event that there is no gauge, the extinguisher should be taken to a professional for testing and if possible, recharged.

When Should a Fire Extinguisher Be Replaced?

If you notice any of the following, the extinguisher must be serviced or replaced straight away:

• The hose or nozzle is cracked, ripped, or blocked with debris.
• The locking pin on the handle is missing or unsealed.
• The handle is wobbly or broken.
• The inspection sticker or hang tag, with a record of check-ups and maintenance, is missing.

Continue to check the gauge at monthly intervals to ensure enduring safety, as well as inspecting them for any of the issues listed above.

Extinguishers should also be examined annually by a professional who will make sure everything is in order. They will record the inspection on the fire extinguisher’s tag when they are finished.

If there are significant problems with the unit, it can often be more economical to simply replace the extinguisher. This also ensured your life-saving equipment is fully functional, can be relied upon, and conform to the necessary standards.

How should Fire Extinguishers be Stored?

You’ve checked the pressure gauge; it’s green. You’ve checked monthly for any signs of damage, and everything is in working order.

The extinguisher should be stored in an easily accessible location in the event of a fire. Most modern extinguishers can perform effectively within a wide temperature range. However, if stored at too low a temperature, cracked valves or hoses can occur, so avoid your extinguishers freezing!

Although modern extinguishers can be stored on their side and this will not cause damage best practice is to store them with their supplied brackets to ensure accessibility. 

It is undoubtedly best to err on the side of caution when it comes to fire-fighting equipment; if there is any doubt as to your extinguisher’s safety or effectiveness, it should be inspected or replaced immediately. 

What are ABC Fire Extinguishers

ABC Fire extinguishers use a dry chemical called monoammonium phosphate which smothers flames to put out many different types of fire.

Identified on the canister by their blue label stating ‘Powder’, the pale-yellow extinguishing agent in ABC powder extinguishers is suitable for use on three classes of fire:

• Class A: Solid combustibles such as wood, paper and textiles
• Class B: Flammable liquids and gases such as petroleum, propane and solvents
• Class C: Energized electrical sources

So How Do ABC Fire Extinguishers Work?

The extinguisher is filled with monoammonium phosphate and nitrogen, which is used to pressurise the canister. When the extinguisher is activated (either manually or automatically), the extinguishing agent sprays out of the canister and creates an inert blanket over the fuel.

This separates the fuel from the oxygen in the air, stopping combustion, and the powder also interrupts the chemical reaction of the fire. This makes ABC powder extinguishers extremely effective.

Where Are ABC Fire Extinguishers Used? 

Due to their ability to tackle a wide range of fires, ABC extinguishers are particularly suitable for environments with multiple risks. It is for this reason that residential, commercial and industrial areas all benefit from their installation. The particular usage depends on their size.

Smaller 1kg and 2kg units are ideal for small or mobile kitchens, cars, caravans and boats, whereas 6kg and 9kg units are well suited to larger spaces, such as HGVs, offices, warehouses and factories

The bigger the capacity, the higher the fire rating, meaning a single extinguisher can cover a larger area of fire.

However, high capacity units are heavier than their smaller counterparts, making the 1kg and 2kg options a fantastic choice when being lightweight and portable is of paramount importance.

Although many ABC powder extinguishers on the market are manually operated, fully automatic ABC fire extinguishers are also available. These are available in a variety of sizes from 1kg (covering up to 3m2) through to 12kg (covers up to 18 m2).

They give additional protection to areas that are periodically or permanently unmanned, or in enclosed spaces that need a near-instant fire-fighting response. Often, they are employed in engine rooms, switch rooms and storage areas. 

How do Automatic ABC Extinguishers Work Differently?

A small glass bulb is filled with heat-sensitive liquid, which expands as it heats up. At a temperature of 68°C, the bulb breaks. This triggers the release of dry powder which is dispersed by the spray head on the underside of the extinguisher. This covers the fuel and flames in a powder ‘blanket’, and works to extinguish the fire in exactly the same manner as manual ABC extinguishers. 

As you can see, ABC fire extinguishers are an excellent fire safety option for a huge range of spaces due to their versatility and effectiveness, with your choice of manual or automatic activation available in an array of sizes to suit your needs.  

What are Fire Blankets?

Fire blankets are a common sight that you may see in all different types of workplaces. Most of the time they are overlooked, but in an emergency, fire blankets play a very important role.

Although they may seem simple in comparison to other fire extinguishing methods, fire blankets are highly effective when it comes to fighting small fires in the workplace, or at home.

A fire blanket is a piece of flexible material that can be used to help put out fires in various emergency situations. The fire blanket is thrown over or wrapped around the source of the fire to smother it. This deprives the fire of oxygen and stops it from getting any bigger, causing it to eventually die out.

Fire blankets are manufactured from two layers of woven glass fibre fabric with an inner layer of fire-retardant film. These work together to cut off any oxygen from getting to the fire and create an effective fire-extinguishing solution.

What type of fires can fire blankets be used on?

Generally, a fire blanket can be used on Class A, B and D fires. These are fuelled by ordinary combustibles such as wood or paper, by flammable liquids like oil or gas, or by combustible metals including magnesium and titanium.

That is why it is so important that all fire blankets are checked for safety and have a visible ID tag so users can clearly see what type of fires they are suitable for use on.

Fire blankets at home and in the workplace

Due to their compact size and flexibility, fire blankets can be used by anyone, anywhere. That is why it is recommended that there is a fire blanket on hand in an abundance of settings including your kitchen, your office, and even in your car.

At home: You never know when a small accident at home can turn into a fire. It is important to keep a fire blanket on hand in case you leave your electric fire on for too long, forget to switch off your straighteners, or accidentally overheat your pan whilst cooking.

In the workplace: It is an employer’s responsibility to ensure there is a fire blanket on hand and that everyone knows where it is kept. Because fire blankets can be used effectively on oil and grease fires as well as electric ones, they are ideal for use in garages and workshops too.

A fire blanket can also be used to extinguish burning clothes and hair. In the event that you encounter this situation, wrap a fire blanket around the affected area to quickly put it out.

How to use a fire blanket

1. Ensure all gas and electricity to the building, or at least all nearby plug sockets or gas points are switched off.
2. Pull the fire blanket out of its container and stretch it out fully, making sure that it covers the size of the fire.
3. Take the blanket by the upper corners and hold it with your palms facing the fire, then keeping the blanket at arm’s length, approach the fire.
4. Carefully cover the flames with the fire blanket making sure that you cover the whole area so that you can effectively cut off the airflow, effectively sealing the edges.
5. Leave for at least 60 minutes (1 hour) before attempting to uncover the source of the fire, and never attempt to transport a contained fire.

Fire blankets are suitable for use on small fires only. If you find that the fire is spreading quickly and getting out of control, evacuate immediately and call 999 as soon as possible.

British Standards on fire blankets

British Standard EN 1869:1997 is the current standard for fire blankets. It covers a wide range of sizes from 1.0m x 1.0m to 1.8m x 1.8m.

When purchasing a fire blanket, it is very important to make sure it adheres to the above British Standard. This is because it means that type of fire blanket has been rigorously tested against tacking a standard* fire.

*A standard fire refers to three litres of cooking oil at self-ignition temperature (around 350˚C – 370˚C).

Which Fire Extinguisher should I use for Lithium Battery fires?

Lithium-ion batteries are becoming more and more common and, in fact, millions of them are being produced every year to keep up with the increasing demand.

These types of batteries are rechargeable and although they are mostly used in electronic devices such as mobiles and tablets, more recently they have become popular for electric vehicles and aerospace applications.

However, the misuse of lithium-ion batteries can quickly become very dangerous if they are stored improperly, charged too quickly or sustain any structural damage.

Why are Lithium Batteries a Fire Risk?

If lithium batteries are stored, charged and used correctly they are relatively safe for daily use. However, they carry many risks when handled incorrectly – including starting fires which can quickly exceed temperatures of 800ºC. This happens when a process known as ‘thermal runway’ occurs.

Simply put, thermal runaway happens because lithium battery systems have a high energy density, so any small intrusion of a metal particle could have devastating consequences. These include heat-related battery failures, a chain reaction between cells, and battery destruction: all these can ultimately lead to flames.

Lithium batteries also pose a risk of fire if they are charged beyond their voltage limits. If you exceed the recommended charging voltage you are risking the explosion of the reactive components in the cell which, again, ultimately leads to a fire.

How do lithium battery fire extinguishers help to put out these fires?

If you find yourself in a position where a lithium battery is on fire, it is essential to use a fire extinguisher that has been specially designed for this type of emergency.

Lithium battery fire extinguishers work by spraying AVD (Aqueous Vermiculite Dispersion) compound in a fine water mist. AVD quickly extinguishes the fire and stops the hazardous reaction processes within the cells, while the water acts as a cooling agent. When AVD dries, it forms a thin thermally insulating film that stops the fire from re-igniting.

What are the different types of lithium battery fire extinguishers and how do I know which one is best for me?

All lithium battery fire extinguishers are similar in the sense that they are all compact, lightweight, easy to store, non-toxic and environmentally friendly. The main difference between the different types is size.

For example, 500ml Lithium Battery Fire Extinguisher is one of the smaller options available, which makes it useful for keeping in compact spaces such as at home, in a small office or in your vehicle. This size can be used to extinguish lithium-based battery fires from personal electronic devices such as mobile phones and tablets.

Larger models such as this 9 Litre Lithium Battery Fire Extinguisher are much more suited to industrial and commercial environments such as goods distribution, battery collection bin centres and battery recycling locations.

What Signage is used with Fire Extinguishers?

Fire safety signs give information, instruction or warning about fire-related hazards and emergencies. There are several different types and so here is an overview of the differences and what situations each should be used for. 

1) Fire Equipment signage 

These signs indicate where emergency response equipment is kept and can include directions to fire blankets, extinguishers or alarm points. These very important signs should be prominent in places where it is perhaps not clear where the nearest equipment or alarm point is.

This kind of sign has a highly recognisable and clearly visible white background with red graphics and/or text. 

2) Prohibition signage 

These signs are typically used to instruct and warn people, prohibiting unsafe behaviours and activities. They include the commonly seen ‘No Smoking’ sign, as well as signs like ‘In the event of fire do not use lift’. It is a legal requirement to have some of these signs present and obvious in businesses and commercial vehicles. This kind of sign takes the form of a red circle with diagonal line over a white background and black graphics and/or text. 

3) Mandatory signage 

Contrasting with prohibition signage, this kind of sign informs employees and visitors of behaviours and actions that should be undertaken. These can include signs like ‘Fire Door Keep Shut’ and ‘Automatic Fire Door Keep Clear’. These signs are a solid blue circle with white text and/or graphics and a white background. 

4) Warning signage 

This kind of signage highlights potential hazards. It includes signs indicating the presence of flammable materials, physical hazards and increased risk of fire. These signs are usually a black triangle with a yellow background and black graphics and/or text. 

5) Safe condition signage 

This kind of sign is used to inform and direct, marking out escape routes, directing to emergency exits, showing the location of first aid equipment, and operation instructions such as ‘Push Bar to Open’. These signs are usually square or rectangular with a solid green background and white text and/or graphics. 

Any business, public area and even commercial transport like taxis, buses and trains should have a combination of these signs. This is not only common sense and good health and safety practice, but a legal requirement under The Regulatory Reform (Fire Safety) Order of 2005 and The Health and Safety (Safety Signs and Signals) Regulations of 1996.  

Signs are designed with internationally recognisable graphics, ensuring that they can be understood regardless of the reader's native language. The vast majority of fire safety signage is also available in a photo-luminescent version, ensuring that in low-light areas (or in the event of a power cut) the signs are still visible and eye-catching. 

Make sure that your staff, customers, visitors and members of the public are protected in the event of a fire, and ensure that you are correctly adhering to the relevant laws, by using fire safety signs as the cornerstone of your fire safety planning.

References

 - UK Fire Regulations (www.gov.uk)

 - UK Fire Blanket Standards BS EN 1869:1997 (bsigroup.com)

 - The Regulatory Reform (Fire Safety) Order 2005 (legislation.gov.uk)