In our modern world, where the risk of fire is a constant concern, it’s crucial to be informed about the types of fire extinguishers and the classes of fire they’re designed to combat. While there are several types of fire extinguishers, our discussion will primarily focus on the five main types, with additional insights into specialized extinguishers for specific needs.
Portable fire extinguishers can be lifesaving tools. They effectively protect people and property when used correctly by someone trained and skilled. Understanding how to use these extinguishers in different fires aka classes is essential for safety.
Different Classes of Fire and Their Characteristics
Not all fires are created equal. The classification of different types of fires is based on the kind of material that initially ignites them. Fires are categorized into six classes, each defined by the type of fuel they consume. Understanding these classes is crucial for selecting the appropriate fire extinguisher.
- Class A Fires:
- These fires involve common combustibles such as paper, fabric, wood, and coal. They can burn unchecked if not properly extinguished.
- Class B Fires:
- This class includes fires caused by combustible liquids like gasoline, paint, fuel, and turpentine. These liquids pose unique risks and require specific extinguishing methods.
- Class C Fires:
- These are fires ignited by combustible gases such as propane, hydrogen, methane, or butane. The volatility of these gases demands careful extinguishing techniques.
- Class D Fires:
- Involving combustible metals like titanium, potassium, aluminum, or magnesium, Class D fires are extremely hazardous. They require specialized fire extinguishers designed for metal fires.
- Class F/K Fires:
- This class comprises fires fueled by cooking substances, including oils and fats. These fires are common in kitchen settings and need extinguishers suitable for cooking-related fires.
- Electrical Fires:
- While not a separate class, fires involving live electrical equipment are notable. Depending on the combustible materials affected by the electrical current, they fit into one of the above categories. Look for the electric spark emblem on fire extinguishers to identify those suitable for extinguishing fires involving live electrical equipment.
Fire Extinguishers and Their Uses
It’s essential to understand that no single type of fire extinguisher is capable of handling all kinds of fires. Different types of fires require specific extinguishing agents to be controlled effectively. The most commonly used fire extinguishers are:
- Water Fire Extinguishers
- Foam Fire Extinguishers
- Dry Powder Fire Extinguishers
- Carbon Dioxide (CO2) Fire Extinguishers
- Wet Chemical Fire Extinguishers
Being familiar with these different types of fire extinguishers is crucial. Each type is designed for specific fire classes, and using the wrong extinguisher can be ineffective or even dangerous.
For further guidance, see our review of the best fire extinguishers, which can assist in the quick and correct identification of the fire type and the appropriate extinguisher, significantly impacting safety and damage control during a fire emergency.
1. Water Fire Extinguisher
The primary agent in these extinguishers is water, often mixed with other additives. This type of fire extinguisher is considered traditional and is effective for Class A fires involving flammable solids like wood, paper, and textiles. It is available in 3, 6, and 9-liter sizes.
Effectiveness of the Extinguisher
- It is equipped with a spray nozzle that covers a greater surface area, allowing the fire to be extinguished more easily and rapidly.
- Water’s cooling nature slows the burning process until the flames are eventually extinguished.
Color Label
The water fire extinguisher is typically labeled in bright red stating water.
Usage of the Extinguisher
Water fire extinguishers are ideal for areas constructed of wood and places where organic materials are commonly found, such as:
- Offices
- Schools
- Hospitals
- Residential properties
- Warehouses
Disadvantages
- It is not suitable for use in cold weather, as the water inside can freeze. However, some models contain an antifreeze agent, making them usable in cold conditions.
- It is ineffective on flammable liquids, cooking fats, etc.
- Using water fire extinguishers on electrical fires can lead to electrocution.
2. Foam Fire Extinguishers
As the name suggests, foam extinguishers use foam to extinguish fires involving volatile liquids, such as paint and gasoline, rather than using liquid or powder. AFFF (aqueous film-forming foam) is utilized primarily for Class B fires like gasoline, paint, fuel, and turpentine, although it can also be used for Class A fires.
These extinguishers are available in 2, 3, 6, and 9-liter sizes, with the 6-liter size being the most common.
Effectiveness of the Extinguisher
- The water-based nature of the foam helps lower the fire’s temperature.
- The aqueous film foam formed on the fire smothers it, preventing dispersion and reignition.
- When used on Class B fires with considerable depth, the extinguisher can float on the liquid’s surface, preventing reignition.
Color Label
Foam extinguishers are labeled in a cream color stating it as “Foam extinguisher”.
Usage of the Extinguisher
Foam extinguishers are suitable for places with multiple fire risks, such as:
- Hostels
- Offices
- Garages
- Schools
- Hospitals
- Factories
Disadvantages
- They are not suitable for cold weather, as the foam can freeze at low temperatures.
- They cannot be used on cooking fires, also known as Class F fires.
- They are ineffective on fires involving flammable gases, which belong to Class C fires.
3. CO2 Fire Extinguisher
Carbon dioxide fire extinguishers are predominantly used for electrical fires. The reason for using them is that the agent does not leave any residue behind after usage. It is stored in the form of liquid and converts to gas when released from the nozzle.
They are also used on Class B fires, like those involving flammable liquids such as paint and petrol, and Class C fires involving combustible gases such as propane, hydrogen, methane, or butane.
They come in 2 and 5-kg sizes.
Effectiveness of the Extinguisher
- Due to its residue-free nature, the extinguisher is used for delicate and costly equipment and areas.
- Its non-conductive nature allows it to be used on electrical fires without leaving any harmful residue.
- It doesn’t cool the fire; instead, it replaces oxygen with CO2, which results in removing the fuel source.
Color Label
It is identified by a black color label indicating ‘CO2’ and has a distinctive black nozzle.
Usage of the Extinguisher
CO2 fire extinguishers are primarily used in areas where special precaution is necessary, such as:
- Electronic equipment areas
- Food preparation areas
- Laboratories
- Printing or duplication areas
Disadvantages
- It is not recommended for outdoor use because of its short range of 3ft to 8ft, which is mostly 1 to 2.4m in length.
- Due to its cloud-like nature, it is not effective in areas that are subjected to strong air currents.
- Its gaseous nature makes it unsuitable for fires involving oil and grease which may occur mostly in grills and frying pans (Class F fires), as they may be spread.
4. Dry Powder Fire Extinguishers
This type of extinguisher uses chemical powder composed of very small particles. Due to its chemical nature, it is also known as dry chemical fire extinguishers. The main component includes sodium bicarbonate base and potassium bicarbonate base.
It is a multi-purpose fire extinguisher that works on classes A, B, and C. That’s why it is also known as ABC fire extinguisher. It can also extinguish electrical fires but not more than 1000V. It is available in 1, 2, 3, 6, and 9 kg sizes.
Effectiveness of the Extinguisher
- Makes a barrier between the source of fire and the oxygen, hence suppressing the fire quickly.
- Due to its broad nature, it is suitable indoors and outdoors.
- Can extinguish class A, B, C, and electric fires.
Color Label
It is labelled in blue stating ‘powder’ over it.
Usage of the Extinguisher
As the name suggests, ABC extinguishers are used in various fires and areas such as:
- Offices
- Schools
- Homes
- Industrial areas
- Large workshops
- Flammable liquid storage areas
- Hospitals.
Disadvantages
- Not recommended for use in small areas as there is a great risk of inhalation.
- Difficult to clean the residue after usage as it sticks to the material used on.
- Can suppress the fire but can’t cool the fire, so there is a possibility of reignition.
- Not suitable for cooking oil fires.
- Works only on electrical fires under 1000V.
5. Wet Chemical Fire Extinguishers
The primary agents in these extinguishers are water, potassium acetate, and other potassium salts. They are uniquely suited for Class F fires, commonly known as cooking oil fires. Besides being used for Class F fires, they are also usable on Class A fires.
The water component provides a cooling effect, lowering the temperature of hot oils and fats, which reduces the risk of hot grease splashing. This makes them an essential tool in kitchens and fast-food restaurants. Available sizes include 2, 3, and 6 liters.
Effectiveness of the Extinguisher
- Features a longer nozzle than standard extinguishers, allowing use from a safe distance.
- Creates a film over the fire to suffocate it, preventing the spread of flames.
- Easier cleanup process due to the visible nature of the chemicals.
- Acts as a coolant for Class A fires and forms a protective blanket on Class F fires to prevent re-ignition.
Color Label
These extinguishers are coded in yellow and labeled as “wet chemical.”
Usage of the Extinguisher
Their versatility makes them ideal for use in various settings, including:
- Cafés
- Restaurants
- Kitchens
- Homes
- Schools
- Textile industries
- Warehouses
Disadvantages
- Ineffective on combustible gas fires, such as those involving methane or butane, classified as Class C fires.
- Not suitable for electrical fires due to their conductive nature.
- They can produce toxic fumes, so caution is advised when using them in enclosed or congested areas.
Other Types of Fire Extinguishers
Below are the other types of fire extinguishers that are specifically used for:
Water Mist Fire Extinguisher:
This type is primarily used for Class A, B, C, and F fires, which include ordinary combustibles, flammable liquids, electrical equipment, and cooking oil fires. The fine mist provides a cooling effect and is safe for use on electrical fires up to a certain voltage.
Dry Powder L2/M28 Fire Extinguisher:
Specifically designed for Class D fires involving combustible metals such as magnesium, aluminum, and sodium. These extinguishers smother and cool the burning metal, preventing re-ignition.
Lith-Ex Fire Extinguisher:
Exclusively used for fires involving lithium batteries. These extinguishers are specialized in cooling the high temperatures of lithium battery fires and preventing re-ignition, essential in tech-heavy environments and industries dealing with lithium batteries.
Frequently Asked Questions
Can we use expired fire extinguisher?
Generally, it is advised against using an expired fire extinguisher. As fire extinguishers age, their effectiveness can significantly decrease due to potential degradation of the chemical agent and loss of pressure, which is crucial for proper discharge. Additionally, the mechanical parts such as valves and hoses might deteriorate over time.
What is K Type Fire Extinguisher?
A “K type” fire extinguisher, also known as a Wet Chemical extinguisher, is mainly used for Class K fires in the United States, similar to Class F fires in other countries. These extinguishers are specifically designed for fires involving cooking oils and fats, which are typical in kitchen environments.
Conclusion
There are many types of fire extinguishers, and each one is made for different kinds of fires. It’s really important to pick the right one to put out a fire effectively. Whether it’s a water extinguisher for regular fires or a special Lith-Ex for battery fires, knowing which one to use is crucial. Keeping these extinguishers well-maintained and using them correctly is essential. This helps make sure they work right when you really need them, helping to keep people and places safe.
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