Fires can occur in any workplace, posing a serious risk to employees, equipment, and property. Understanding the different types of fires and knowing how to use the correct fire extinguisher is essential for ensuring safety. The ability to recognize fire classifications and respond appropriately can prevent injuries, limit damage, and even save lives.
Types of Fires
Fires are categorized based on the materials that fuel them. Each type requires a specific firefighting approach to prevent the fire from spreading or reigniting.
Class A – Ordinary Combustibles
Class A fires involve common combustible materials such as wood, paper, cloth, rubber, and plastic. These fires are most frequently found in offices, warehouses, and homes. Water is often used to extinguish them, as it cools the burning material and removes heat from the fire.
Class B – Flammable Liquids and Gases
Class B fires involve flammable liquids like gasoline, oil, grease, alcohol, and propane. Water should not be used to extinguish these fires because it can spread the burning liquid. Instead, foam, dry chemical, or carbon dioxide extinguishers are recommended, as they work by smothering the flames and cutting off the oxygen supply.
Class C – Electrical Fires
Class C fires are caused by electrical equipment such as wiring, circuit breakers, transformers, and appliances. Water is dangerous in these situations because it conducts electricity and can lead to electric shocks. Fire extinguishers that use carbon dioxide or dry chemical agents are best for these fires, as they do not conduct electricity.
Class D – Metal Fires
Class D fires involve combustible metals such as magnesium, titanium, aluminum, and potassium. These types of fires are common in laboratories and industrial settings. Special dry powder extinguishers are used for Class D fires, as they prevent reactions with burning metals. Water and foam are ineffective and can cause violent reactions.
Class K – Cooking Fires
Class K fires are fueled by cooking oils, greases, and fats, often occurring in commercial kitchens. These fires require special wet chemical extinguishers, which create a soap-like barrier that cools the fire and prevents re-ignition. Water and other common extinguishers are ineffective, as they can cause splattering and spread the flames.
Types of Fire Extinguishers
Different fire extinguishers are designed to handle specific types of fires. Understanding their classifications and proper usage is critical for workplace fire safety.
Water Fire Extinguishers
Water extinguishers are used for Class A fires involving ordinary combustibles. They work by cooling the flames and soaking the burning material. However, they should never be used on Class B (flammable liquids) or Class C (electrical) fires, as they can spread the flames or cause electric shocks.
Foam Fire Extinguishers
Foam extinguishers are effective on Class A and Class B fires. They create a blanket over burning liquids, cutting off the oxygen supply and cooling the flames. These extinguishers are commonly used in workplaces that handle flammable liquids, such as garages and factories.
Carbon Dioxide (CO₂) Fire Extinguishers
CO₂ extinguishers are ideal for Class B and Class C fires. They work by displacing oxygen and cooling the fire, making them useful for electrical fires. Since CO₂ does not leave a residue, it is safe for use around sensitive electronic equipment. However, they are not effective on Class A fires, as they do not cool burning materials enough to prevent re-ignition.
Dry Chemical Fire Extinguishers
Dry chemical extinguishers are among the most versatile, capable of handling Class A, B, and C fires. They release a fine powder that interrupts the chemical reaction of the fire, effectively smothering the flames. These extinguishers are widely used in offices, factories, and homes due to their broad application.
Wet Chemical Fire Extinguishers
Wet chemical extinguishers are specifically designed for Class K fires in kitchens. They release a cooling mist that reacts with cooking oils and fats to form a protective barrier, preventing re-ignition. These extinguishers are essential in restaurants and commercial kitchens where grease fires are a risk.
Class D Fire Extinguishers
For combustible metal fires, Class D extinguishers use dry powder to smother flames without reacting with the burning metal. These are specialized extinguishers used in industries where metalworking is common.
How to Use a Fire Extinguisher (PASS Method)
Proper fire extinguisher use follows the PASS method:
- Pull the pin to unlock the extinguisher.
- Aim the nozzle at the base of the fire.
- Squeeze the handle to release the extinguishing agent.
- Sweep the nozzle from side to side to cover the flames completely.
This technique ensures that the fire is extinguished effectively at its source rather than just temporarily suppressing flames.
Fire Prevention and Safety Tips
While knowing how to use a fire extinguisher is essential, preventing fires is even more important. Simple workplace fire safety measures include:
- Keeping flammable materials stored properly and away from ignition sources
- Ensuring that electrical wiring and equipment are maintained and inspected regularly
- Training employees in fire response procedures, including evacuation plans and extinguisher use
- Keeping fire extinguishers accessible, regularly inspected, and fully charged
Conclusion
Fires can be devastating, but understanding their types and knowing how to use the correct fire extinguisher can significantly reduce risks. Workplaces must prioritize fire safety through proper training, equipment maintenance, and emergency preparedness. By taking the right precautions, employees can help protect themselves, their coworkers, and their workplace from fire-related hazards.
