Fire is a powerful force that can cause immense destruction. It is crucial to understand the different types of fires and how to effectively combat them in order to protect lives and property.
In this comprehensive guide, you can find a detailed overview of the various types of fire alongside the appropriate firefighting techniques for each.
Understanding the Six Classes of Fires
Fires are classified into six distinct classes, each representing different types of fuel sources. It is essential to know these classes in order to select the appropriate firefighting methods and equipment.
- Class A Fires: Combustible materials
- Class B Fires: Flammable liquids
- Class C Fires: Flammable gases
- Class D Fires: Combustible metals
- Electrical Fires
- Class F Fires: Kitchen fires
Class A Fires: Combustible Materials
Class A fires involve ordinary combustible materials such as wood, paper, cloth, and plastics.
Where might you find a Class A fire?
These fires typically occur in common areas such as homes, offices, schools, and other everyday environments where these materials are present.
What is the appropriate fire extinguisher to use?
Water extinguishers are the most common and simplest type of fire extinguisher for Class A fires. They work by cooling the burning material and removing the heat needed for the fire to continue.
Water extintuishers are also suitable for fires involving ordinary combustible materials like wood, paper, and cloth.
Foam extinguishers are another option for Class A fires. They contain a mixture of water and foam concentrate, which creates a foam blanket over the fire, smothering it and preventing re-ignition.
How to fight a Class A fire?
These extinguishing agents work by cooling the fire and preventing re-ignition. Aim the extinguisher at the base of the fire, sweeping from side to side until the flames are extinguished.
After the fire is extinguished, continue to monitor the area for any signs of re-ignition. If the fire re-ignites, use the extinguisher again or evacuate if it becomes unsafe.
Case history of a Class A Fire
Booth’s factory fire 1941
On 31 October 1941, in the town of Huddersfield, West Yorkshire, inside the H Booth & Son factory, a fire was started by a . The fire was caused by a worker’s lit pipe left inside a jacket pocket during a shift. It destroyed the building and killed 49 people, ainlywomen and young girls. Many were left trapped in the upper floors of the five storey building as it did not have a fire escape. This tragedy led to radical improvements in fire safety.
Class B Fires: Flammable Liquids
Class B fires involve flammable liquids such as petrol, turpentine or paint.
These fires are very dangerous as they can spread rapidly and are often reignited if not properly extinguished.
Where might you find a Class B fire?
Class B fires can occur in any area where flammable liquids are stored or used such as garages, construction sites, warehouses, hospitals, and laboratories.
What is the appropriate fire extinguisher to use for a Class B fire?
The most common method is to use a CO2 fire extinguisher. These smother the fires by removing oxygen.
Dry powder extinguishers which work by inhibiting the chemical reaction causing the fire.
Foam fire extinguishers which remove oxygen from the surrounding air.
Fire blankets are also an effective method of extinguishing a small Class B fire, as they work by removing oxygen from the surrounding area.
How to fight a Class B fire?
By using carbon dioxide or dry chemical extinguishers, the fire’s oxygen supply is cut off, suffocating the flames. Aim at the base of the fire and sweep from side to side until the fire is completely smothered.
Remember to aim at the base of the fire and sweep back and forth until the flames are completely extinguished.
Never use water to extinguish a Class B fire: the water will vaporise and the fire may spit hot oil causing further harm to anyone in range.
Case history of a Class B Fire
Olympic Varnish Company, Portsmouth
Date: July 10, 2015.
A worker was injured following a machinery fire at the company’s facility. The fire resulted from the use of a highly flammable liquid to clean rollers on a coating machine. The employee suffered burn injuries due to the fire.The Health & Safety Executive investigation revealed that the company had not adequately eliminated or reduced risks associated with the use of highly flammable liquids across various areas of their activity. The company was fined £16,000 and ordered to pay costs of £4,505.40.
Class C Fires: Flammable gases
Class C fire are caused by flammable gases such as propane, butane, methane, natural gas, hydrogen, etc. Dueto their high volatility, even a minor or isolated leak of one of these gases can rapidly ignite in the presence of an open flame or ignition source and cause a fire or explosion.
Where might you find a Class C fire?
Class C fires occur most commonly in environments which store and use large quantities of flammable gases, such as chemical plants and industrial warehouses. However, as they are also used in heating systems, they are also a risk in other locations, including hospitals and schools.
What is the appropriate fire extinguisher to use?
Class C fires must be tackled by dry powder fire extinguishers or clean agent fire extinguishers.
How to fight a Class C fire?
The first thing to do is to turn off the gas supply. Once the gas is cut off, use a dry powder extinguisher.
Case history of a Class C Fire
King Street, Southall
Two people died after a gas explosion is a phone shop in Ealing. The fire caused extensive damage to the shop and to the flats above.
At least 21 people were evacuated from the surrounding area. Firefighters used a ladder to rescue five people at the back of the collapsed building, one of whom was injured as a result of the blast.
Class D Fires: Combustible Metals
Class D fires involve combustible metals such as magnesium, titanium, potassium, and sodium which can ignite when exposed to air or water, making them particularly challenging to extinguish.
These fires are relatively rare but they are also extremely hazardous and require specialized firefighting techniques and extinguishing agents.
Where might you find a Class D fire?
These typically occur in industrial settings, metal fabricators, warehouses or laboratories where there is a presence of combustible metals such as magnesium, titanium, potassium, sodium, and lithium.
What is the appropriate fire extinguisher to use?
A dry powder extinguisher. These work by smothering the fire and preventing the combustion process.
How to fight a Class D fire?
The best way to extinguish a Class D fire is to use a dry powder fire extinguisher. This covers the burning metal with a powder barrier, cutting off the fire’s supply of oxygen.
The powder also absorbs heat from the fire. By reducing the temperature, it helps prevent the metal from reigniting.
Powder fire extinguishers will also stop the burning metal or powder from spreading, reducing the spread and resulting devastation of the fire. This is particularly useful in environments containing metal dust or shavings.
Electrical Fires
Electrical or (rarely used) Class E fires are caused by electrical equipment or live electrical wires. Overloaded circuits, faulty wiring, and electrical malfunctions can all contribute to these fires.
These fires pose a unique danger as water-based extinguishers should not be used due to the risk of electrical shock.
Where might you find an electrical fire?
Offices, retail stores, and other commercial establishments often have electrical equipment and wiring throughout the premises, making them susceptible to electrical fires.
Industrial facilities typically contain a wide range of electrical machinery and equipment. Fires can occur due to electrical faults, short circuits, or equipment malfunctioning, especially in areas with heavy machinery or high voltage systems.
What is the appropriate fire extinguisher to use?
There are only two types of fire extinguisher that can safely suffocate the flames of an electrical fire: CO2 fire extinguishers and dry powder fire extinguishers (only suitable for outdoor applications and where electrical equipment is below 1000v)
The most important thing to remember is that an electrical fire cannot be fought with water.
How to fight an electrical fire?
First, if it is safe to do so, disconnect the item from its power source. An electrical fire becomes “just a fire” once you’ve disconnected the electricity.
Next, remove the oxygen source. When it’s a small fire, a fire blanket is an effective, clean and safe way of tackling the flames.
If you need to use an extinguisher, you should only use one with extinguishants such as powder or CO2.
If the fire becomes too large or spreads quickly, it’s crucial that the area is fully evacuated immediately and left to trained firefighters.
Case history of an electrical fire
Grenfell Tower
The Grenfell Tower fire broke out on 14 June 2017 at the 24-storey Grenfell Tower block of flats. It caused at least 72 deaths. Police and fire services believe the fire was started by an electrical fault in a refrigerator. The rapid growth of the fire is thought to have been accelerated by the building’s exterior cladding, which at the time was of a type in widespread use.
Class F Fires: Kitchen Fires
Class F fires occur in commercial kitchens and involve cooking oils, greases, and fats.
These fires can quickly escalate if not promptly and properly extinguished.
Where would you find a Class F fire?
These types of fire typically occur in commercial kitchens or areas where cooking appliances are present. For instance, in restaurants, cafeterias, hotels and hospitals.
What is the appropriate fire extinguisher to use?
To tackle Class F fires, wet chemical extinguishers are recommended. These extinguishers are specifically designed to cool and suppress fires fueled by cooking oils and fats.
Fires from cooking oils and fats can be made significantly worse by using a liquid-based agent to extinguish it. For instance, using water fire extinguishers might cause an explosion, spreading the burning oil and exacerbating the fire.
Similarly, CO2 and powder fire extinguishers may cause more harm than benefit to the fire, the property, and the person operating the extinguisher.
How to fight a Class F fire?
To extinguish a Class F fire, one must eliminate one of its three elements: fuel, oxygen, or heat. To do so effectively, especially with fat fires, the temperature of the burning substance must be lowered below its flash point, a challenging task due to the high temperatures involved.
When it’s a small fire, a fire blanket is an effective, clean and safe way of tackling the flames.
Case history of a Class F fire
The Frying Pan Restaurant, Southend on Sea
On March 17, 2022, a fire broke out at The Frying Pan restaurant in , Southend. The origin ofthe fire is thought to be a pan of hot cooking fat. According to Essex Fire and Rescue, the building was “almost completely alight” when firefighters arrived, and the fire had quickly spread to neighbouring properties. Fortunately, no one was injured in the blaze.
Special Considerations
There are other types of fires that require special considerations when it comes to firefighting. These include fires involving flammable gases and fires in confined spaces
When dealing with fires involving flammable gases, it is crucial to first shut off the gas supply if possible. Carbon dioxide or dry chemical extinguishers are often used to extinguish these fires.
Fighting fires in confined spaces presents unique challenges due to limited access and ventilation. It is important to follow proper procedures and use self-contained breathing apparatus (SCBA) when entering confined spaces.
Fire Suppression Systems
Fire suppression systems are specialised systems typically installed in commercial and industrial settings, designed to control or extinguish fires.
These systems work by detecting fires early and deploying various agents to suppress or extinguish the flames before they can cause extensive damage.
Each type of fire suppression system has its advantages and is suited for specific environments and fire risks.
- Sprinkler Systems These extensively-used systems use water to extinguish fire. They are commonly found in commercial and residential buildings. When a fire is detected, sprinklers release water to extinguish or control the flames.
- CO2 systems are commonly used in industrial settings, such as machine rooms, electrical equipment rooms, and paint booths. When activated, these systems discharge CO2 gas, which displaces oxygen, suffocating the fire.
- Kitchen Fire Suppression Systems are designed to protect commercial kitchens from fires involving cooking oils and grease. They use a wet chemical agent that reacts with the grease to form a blanket-like foam, extinguishing the fire and preventing reignition.
- Foam Systems are often used to combat fires involving flammable liquids for ie in a fuel storage area, chemical plant or aircraft hangar.
They discharge a foam blanket over the fire, smothering it and preventing reignition. - Dry Chemical Systems are often used in industrial settings and vehicle engine compartments. They release dry chemical powder to suppress fires involving flammable liquids and electrical equipment.
Fire Safety Precautions and Prevention Measures
While knowing how to combat fires is crucial, prevention is always the best approach. Here are some fire safety precautions and prevention measures to keep in mind:
- Install smoke detectors and fire alarms throughout your workplace. Test them regularly to ensure they are functioning properly.
- Develop and practice a fire escape plan. Ensure that everyone knows the exits and designated meeting points in case of a fire.
- Keep flammable materials away from heat sources and open flames. Store them in designated areas and follow proper storage guidelines.
- Regularly inspect and maintain electrical equipment. Faulty wiring and malfunctioning appliances can increase the risk of electrical fires.
- Educate yourself and others on fire safety.
- Avoid smoking indoors, especially in bed or when drowsy. Carelessly discarded cigarettes are a common cause of fires.
- Keep fire extinguishers readily accessible and ensure they are regularly inspected and maintained.
Conclusion
Understanding the different types of fires and the appropriate firefighting techniques is essential for effective fire safety. By familiarising yourself with the five classes of fires and the corresponding extinguishing agents, you can be better prepared to protect yourself and others in case of an emergency. Remember to always prioritise safety and prevention measures to minimise the risk of fires.
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