guide to the classes of fire

A Guide to the Classes

by with One Comment Classes of Fire

Introduction

This is a guide into all the different classes of fire that our extinguishers aim to combat. This guide is designed to help you make the correct decision with fire safety. When it comes to choosing the correct type of fire extinguishers for your specific needs, we are here to help.

This guide of the classes will show what the differences between the classes are and what makes each class of fire unique. We will also tell you what extinguishers are able to combat each class of fire.

Class A Fires

Class B Fires

Class C Fires

Class D Fires

Electrical Fires

Class F Fires

Class A Fires

Class A fires are generally caused by a naked flame or items of high temperatures coming into contact with combustible materials. Class A fires are fires involving solids such as paper or cardboard, any carbonaceous item fires are defined as Class A fires. This is the most common type of fire as these items are the most combustible and are the most common type of fuel.

Almost all premises are at risk of Class A fires due to the common use of such materials. There are many types of fire extinguisher that can be used on Class A fires. These are: Water, Foam, MultiCHEM, Powder, Wet Chemical and Water Mist.

Class B Fires

Class B fires are fires involving flammable liquids, these can be any of the likes of:  Cleaning fluids, Solvents, Fuels, Inks, Adhesives and Paints. Class B fires only make up for 2% of all fires but make up a massive 21% of all fire deaths. This Class of fires are extremely dangerous, this is why many different types of extinguisher aim to tackle them to try to protect the users. The main key to staying safe from Class B fires is prevention, this is why up to date COSHH assessments are key. For the initial stages of Class B fires, a fire bucket could be used, link to our blog post on fire buckets here.

Many settings may have a risk of a potential Class B fire. This is why most locations must have a fire extinguisher that is fit to fight such a fire. Fire extinguishers suitable for Class B fires are: MultiCHEM, Foam, Powder and CO2.

Class C Fires

Class C fires are fires involving flammable gases. This could be natural gas, LPG or any other gases forming a flammable or explosive atmosphere. Class C fires can be tackled with fire extinguishers. Although, the best method of stopping these types of fires is shutting off the supply of the gas.

Manufacturing and industrial warehouses, chemical plants or anywhere that stores large quantities of flammable gases are at particular risk of Class C fires. Class C fires must be tackled using a Powder fire extinguisher.

Class D Fires

Class D fires are niche so therefore are not covered by the conventional types of fire extinguishers. Class D fires are fires involving combustible metals such as potassium, lithium and magnesium. This type of fire is uncommon but is more prevalent in laboratories, warehouses and metal fabricators.

Only specialised fire extinguishers are suitable for use on Class D fires. These are: L2 and M28 fire extinguishers.

Electrical Fires

Electrical fires aren’t their own class of fire because they are seen as more a form of ignition than a fuel. Electrical fires are a risk to all premises that use electricity. They occur when live electrical equipment is involved in a fire. They must not be tackled by a liquid-based fire extinguisher. This is because water is a conductor and will spread the current across a greater area if used. This could potentially endangering the user of the fire extinguisher.

As a result, only Powder (for electrical currents under 1000v) and CO2 fire extinguishers are suitable here, as they do not rely on a liquid agent.

Class F Fires

Class F fires are fires involving deep fat frying and spillages of flammable oils near heat sources. This type of fire poses the highest risk to restaurants and kitchens. These types of fires can be made significantly worse by using a liquid-based agent to extinguish it.

As a result, specialised MultiCHEM, Water Mist and Wet Chemical fire extinguishers are essential. These extinguishers are used in settings that use cooking fats or oils.

water vs water plus vs water mist fire extinguishers

Water vs Water Plus vs Water Mist Fire Extinguishers

by with No Comment Types of Fire Extinguisher

What are the differences of Water vs Water Plus vs Water Mist fire extinguishers? Which is best and what is the best for certain situations?

Water fire extinguishers are the most accessible fire extinguisher, this is likely due to their low price point and their ability to fight the most common type of fire. The Water extinguishers are given an A fire rating, meaning they are capable and suited for extinguishing Class A type fires.

Water Plus extinguishers are an easy upgrade on the regular water extinguishers. They feature a wetting agent which allows them to achieve a greater fire rating. This helps to meet regulations on minimum fire ratings per floor or room of a building. This extinguisher still only features an A fire rating, meaning it can only extinguish Class A fires.

Water Mist extinguishers are another option as an upgrade from the regular water extinguisher. This is due to it having an AF fire rating. This means they are capable of extinguishing Class A and Class F fires. Class F fires are fires involving deep fat frying and spillages of flammable oils near heat sources. These are often found in kitchen environments. The Water Mist extinguisher doesn’t offer an increased A fire rating from the Water extinguisher but instead offers an F fire rating. This is useful if there is a risk of a Class F fire but if not it is a wasted feature.

The Water Plus extinguishers’ boosted A fire rating is great when the fire risk is higher. This is because the boosted fire rating allows the location meet regulations. The increased price point of this extinguisher is justified if the extra A fire rating. This makes it useful when the fire rating is needed to meet regulations of what fire rating is required.

Water extinguishers are the basic option with the lowest price. These are still a great option when the paired with another extinguisher. If the only main fire risks in the area fall into the Class A fire group. When the premise is small, this standard water extinguisher is the perfect choice.

In summary each of these types of extinguisher meet the basic need for a Class A fire extinguisher. The Water Plus and the Water Mist are both upgrades from the standard Water extinguisher in their own ways. The Water Plus offers an increased A fire rating and the Water Mist offers an AF fire rating over the basic A fire rating of the other two extinguishers. So, in the Water vs Water Plus vs Water Mist fire extinguishers debate. There is no ‘best one’ of the three, it is just a case of what is need or a certain scenario.

how do you deal with lithium-ion battery fires

Lithium-ion Battery Fires 5 – How do you deal with lithium-ion battery fires?

by with No Comment Lithium-ion Battery Fires

We know how a Lithium-Ion (Li-Ion) battery fire may occur. But how do you deal with lithium-ion battery fires? Li-Ion battery fires you may think would be classed in class D of fire and so therefore would be able to be extinguished by a Dry Powder extinguisher. But no, they are not classed as a class D fire even though lithium is a metal, the nature of the fire means that they cannot be extinguished like a usual class D fire.

Products

The new products that are being developed and produced of late are AVD Vermiculite extinguishers and EV fire blankets. The EV fire blanket is specifically designed for electric vehicles and is placed directly over the electric car to maintain the fire. These fires are much harder to put out as the fires themselves are around 700℃ to 1,000℃ and can burn for up to 24 hours. But with the EV fire blanket it can drastically reduce this time by depriving the fire with oxygen. 

The AVD Vermiculite extinguishers are products aimed to try to target all types of Li-Ion battery fires. They are a water based extinguishing system with vermiculite particles suspended in the water to act as a smothering tool to stop the fire from receiving oxygen. These extinguishers are designed to deprive the fire from heat, oxygen and also act as an electrical barrier.

British Standard

Currently there is no British standard for these types of extinguishers and technology, and also there is no Kitemark that is able to be displayed on the extinguisher itself. This is because there is no current actual fire rating for this type of extinguisher so it is unable to to kitemarked. The industry has been particularly slow in trying to get these extinguishers to a certain standard and also finding a fire rating for them. This therefore isn’t allowing the widespread of this technology as it is seen as not as much of a know entity.

Check out our last iteration of Lithium-ion battery fires here.

how do you deal with lithium-ion battery fires

damage and penetration

Lithium-ion Battery Fires 4 – Damage and Penetration

by with One Comment Lithium-ion Battery Fires

Spreading knowledge and knowing about the dangers of Lithium-ion (Li-ion) batteries is important as they are a growing danger in the modern home and in modern life in general. Whether the battery has damage or penetration is important to think about as this creates a large amount danger. They are seen as a horrible danger with a spontaneous nature, e-bikes and e-scooters have been banned from all London transport systems after a number of fires on the network caused by these vehicles.

Damage and Penetration to Li-ion Batteries

Li-ion battery fires can sometimes occur after disposal of the batteries themselves. These are due to when the battery is penetrated or crushed. These scenarios are a danger when disposing of and maybe even still at the end of the life of one of these batteries. This comes from when potent electrolytes leak through the hole in the battery, this then often creates a chemical reaction that releases heat. This then in-turn heats the other cells in the battery and can lead to thermal runaway. Thermal runaway is when a cell of the Li-ion battery enters a self heating uncontrollable stage which leads to the explosion and then fire.

Disposal of Li-ion Batteries

This is a huge danger when disposing these batteries, on a domestic scale officials recommend placing and leaving the batteries into salt water for at least two weeks then disposing them as hazardous waste. If one of these batteries were to get to landfill and get damaged this could lead to thermal runaway and then could cause an absolutely huge fire damaging the whole site by engulfing it into flames. So when disposing and dealing with damaged Li-ion batteries please take great care.

Check out our last iteration of Lithium-ion battery fires here.

damage and penetration

damage and penetration

Li-ion battery fire 3 resized

Lithium-ion Battery Fires 3 – Overheating

by with No Comment Lithium-ion Battery Fires

Lithium-ion (Li-ion) battery fires usually have a cause, even if what the user has done has been done loads of times before. Li-ion battery fires are still uncommon but they do have factors that can increase the likelihood of one starting. We touched upon overcharging in the last iteration but another factor is whether the battery is overheating.

Overheating

Overheating can be caused by many different things such as blocked ventilation or over exposure to direct heat such as the sun. In most overheating due to being in the direct sun for too long comes in the form of li-ion battery fires in electric cars. These fires are usually very dangerous as obviously there are many things that are flammable inside of cars and when a li-ion fire occurs in an electric car they quickly ball up in flames as the battery itself is spread along the whole of the bottom of the car. Some cases for this have been involved with Teslas that have gone up in flames and some have been caused by this overheating but some coming from other sources that we will touch upon in a later iteration.

Another common reason for fires caused by overheating is leaving products such as phones charging under things like pillows or blankets where ventilation is poor. These fires are dangerous as they are likely in or under a carbonaceous item that is very flammable and would allow the fire to spread with ease.

Check out our last iteration of Lithium-ion battery fires here.

lithium-ion batteries overcharging

Lithium-ion Battery Fires 2 – Overcharging

by with No Comment Lithium-ion Battery Fires

Lithium-ion batteries are everywhere as shown by the last iteration of Lithium-ion battery fires. But what makes them so dangerous and what causes them to start fires? Most lithium-ion batteries are safe and will never start a fire with safe and sensible usage, but sometimes they are used with not enough care for what a danger they could be. When the batteries are consistently left overcharging, the risk starts to rise.

Overcharging

One of the causes of lithium-ion battery fires is when people are overcharging the batteries. This is when the battery is constantly being charged all the time for extensive periods of time. The biggest culprit for this is people such as phone users who leave their phone charging overnight, every night so eventually overtime the battery is worn and worn until just one time it could explode and burst into flames. This is also a growing problem with e-bikes and e-scooters as they are another common item that is left to charge for extended periods of time.

How to stay safe

Lithium-ion batteries’ optimal window of charge is 30-70% and maybe 20-80% for some other products. If a battery is kept in this window at all times, the wear on the battery will stay minimal for a long time, therefore leading to longer lives of batteries and less chance of starting a fire.

Check out our last iteration of Lithium-ion battery fires here.

Lithium-ion batteries overcharging is one of the greatest risks.

lithium-ion battery

Lithium-ion Battery Fires 1

by with No Comment Lithium-ion Battery Fires

The first Lithium-ion battery was invented in 1982, and are different from the standard lithium battery. Lithium batteries are the standard non-rechargeable batteries and are very safe however, lithium-ion batteries are rechargeable and this leads to their problems. As they are rechargeable they store lots of energy relative to their size. And this is another of their problems, as they are so small, they are very accessible and useful for all different rechargeable products of all different shapes and sizes.

Development of the Lithium-ion Battery

As the technology has developed the lithium-ion battery has been able to hold more and more energy relative to their size, and this is what has made them more dangerous over the last few years. In the modern household, they can be seen everywhere from our phones, our watches, our earphones and even more recently popular e-bikes and e-scooters which have shown to be the most dangerous in the latest statistics.

Check out our next iteration of Lithium-ion battery fires here. Where we touch upon the dangers of overcharging lithium-ion batteries and what can YOU DO to help stay safe.

To learn more about extinguishing lithium-ion battery fires click here to look into AVD extinguishers.