Classes of Fire and Fire Extinguisher Placement Requirements

• Different types of fire, including fires involving electrical equipment, require specific extinguishers to ensure safe and effective handling.
• Fires involving flammable liquids can be managed with foam, CO2, or ABC powder extinguishers.
• Fire extinguisher training is crucial for understanding how to respond to different fire hazards, whether it's electrical or cooking fires.
• Proper placement of fire extinguishers ensures that the right type is available for specific hazards
• Knowing fire classifications helps users quickly identify the appropriate extinguishers, such as wet chemical extinguishers for kitchen hazards.

 

Fire classifications are a way to categorize different types of fire based on the source of fuel and how the fire behaves. This system helps firefighters, emergency responders, and building occupants understand the specific risks associated with each type of fire. The classifications of fire guide individuals and professionals to use the correct response measures, minimizing damage, reducing hazards, and ensuring faster fire control.

Fire safety standards and regulations are designed to ensure proper fire prevention, response, and protection across different environments, including residential, commercial, and industrial settings. Below are some of the key standards and regulations governing fire safety:

• NFPA 10: Provides guidelines on the selection, installation, and maintenance of portable fire extinguishers based on fire classifications.
• NFPA 101: Outlines safety requirements for building design, including fire prevention strategies and fire protection systems like alarms and sprinklers.
• OSHA 29 CFR 1910 Subpart L: Mandates fire protection measures in workplaces, including fire extinguishers, alarms, emergency evacuation plans, and employee training.
• International Building Code (IBC): Sets fire safety requirements for new construction, focusing on fire-resistant materials and fire protection systems.
• International Fire Code (IFC): Provides comprehensive guidelines on fire prevention, including hazardous material storage and maintenance of fire safety systems.
• NFPA 13: Establishes standards for the installation and maintenance of fire sprinkler systems in various types of facilities.

 

There are generally five main types of fire extinguishers based on the material they use to extinguish fires. These are:

• Water fire extinguisher cools the flames and reduces the fire’s heat; ideal for fires involving solid materials like wood, paper, and textiles.
• Foam fire extinguisher smothers the fire, cutting off the oxygen supply, and creating a barrier to prevent re-ignition; ideal for flammable liquid fires.
• ABC powder fire extinguisher releases a dry chemical powder that coats the fire and interrupts the chemical reaction necessary for combustion; ideal for mixed fire hazards but leaves residue
• Carbon dioxide fire extinguisher displaces the oxygen around the fire which suffocates and stops the combustion process; ideal for mixed fire hazards and does not leave residue
• Wet chemical fire extinguisher forms a soapy layer over burning oil to cool it and prevent reignition

Fire extinguishers are also rated based on their effectiveness in combating specific fire classes. These ratings are expressed as a combination of numbers and letters, indicating both the type of fire it can extinguish and the size of the fire it can handle.

• Class A Ratings: The number before the "A" (e.g., 2-A or 4-A) refers to the water equivalency in gallons that the extinguisher holds. The higher the number, the larger the fire it can extinguish.
• Class B Ratings: The number before the "B" (e.g., 10-B or 20-B) refers to the approximate square footage of a flammable liquid fire the extinguisher can effectively combat.
• Class C Ratings: These extinguishers do not have numerical ratings, but they are rated for non-conductivity, meaning they are safe to use on electrical fires.
• Class D and K Ratings: These extinguishers are tested specifically for their ability to handle metal and cooking oil fires, respectively, without a numerical rating system.

 

In general, there are five recognized fire classes: Class A, Class B, Class C, Class D, and Class K. These classifications are based on the materials or substances that can cause a fire. Fire extinguishers also have ratings that are based on these classifications, and it’s important to use the right type of fire extinguisher for the corresponding class of fire.

In addition, the Occupational Safety and Health Administration also has requirements on how fire extinguishers should be distributed in a workplace for employee use, as stated in OSHA 29 CFR 1910.157.

Class A fires involve combustible solid materials like wood, paper, fabric, plastics, and other common organic materials. These fires typically occur in homes, offices, and industrial settings where these materials are abundant. According to NFPA 10, fire extinguishers for Class A fires must be placed no more than 75 feet away from potential fire hazards. They should be easily accessible in areas with combustible materials, such as storage rooms, offices, or warehouses.

Fire Extinguisher Symbol: Green triangle with the letter A.

Class B fires are caused by flammable liquids such as gasoline, oil, grease, alcohol, and paints. These fires are often encountered in garages, workshops, chemical plants, or fueling stations. For Class B fires, NFPA 10 requires extinguishers to be located within 50 feet of high-risk areas where flammable liquids are stored or used and strategically placed in areas like fuel storage rooms, kitchens, and vehicle maintenance areas.

Fire Extinguisher Symbol: Red square with the letter B

Class C fires involve electrical equipment such as wiring, circuit breakers, appliances, and transformers. They are commonly seen in server rooms, electrical panels, or locations where electrical devices are heavily used. Class C fire extinguishers must be placed within easy reach of areas where electrical hazards are present, such as electrical rooms or near circuit breaker panels. There are no specific distance requirements, but accessibility is key for safety.

Fire Extinguisher Symbol: Blue circle with the letter C

Class D fires are caused by combustible metals such as magnesium, titanium, aluminum, and lithium. These fires are most commonly found in laboratories, manufacturing plants, or workshops where metalworking occurs. NFPA 10 recommends that Class D fire extinguishers be readily available within 75 feet of areas where combustible metals are stored or used. These extinguishers should be present in metalworking or fabrication facilities.

Fire Extinguisher Symbol: Yellow star with the letter D

Class K fires involve cooking oils and fats, which are typically found in commercial kitchens or food preparation areas. These fires are usually caused by overheated oil or grease. Class K fire extinguishers must be located no more than 30 feet from cooking appliances, as required by NFPA 10. This proximity ensures quick access in case of a grease fire in commercial kitchens.

Fire Extinguisher Symbol: Black hexagon with the letter K

One important thing to remember about fire extinguisher location requirements is that extinguishers should be spaced in such a way that they completely cover their protected area. Thus, calculating the distance between two extinguishers isn’t always simple or straightforward.

For example, a Class A fire extinguisher has a maximum travel area of 75 feet. This does not automatically mean that two Class A extinguishers can be 150 feet apart. A distribution like this can leave blind spots and may end up making employees take longer to respond to fires.

It’s also important to remember that while these extinguishers have a recommended maximum travel area, you should also take these two things into account:

• The time it would take for a person to get to an extinguisher and back to a fire
• The actual distance a person would have to travel to get to an extinguisher and back to a fire

For example, a Class A fire extinguisher has been placed at its maximum distance of 75 feet from a hazard. If a fire breaks out, an employee will have to travel the entire 75 feet toward the fire extinguisher, and the entire 75 feet once again to get back to the fire. Thus, the employee will actually have to travel 150 feet, not 75. Fires can grow and a lot can happen in the short time it takes for a person to run 150 feet.

With careful consideration of fire classes and fire extinguisher distribution, you’ll be able to ensure that your employees will be able to respond to fires in the most efficient manner possible. This can help prevent damage to property, injuries, and loss of life.

Fire extinguisher training is critical for ensuring that individuals know how to respond effectively during a fire emergency. This training helps prevent panic and confusion, ensures that the correct extinguisher is used for each fire type, and can significantly reduce potential damage. OSHA regulations also require employers to provide fire extinguisher training as part of their overall fire safety strategy.

Key components of a comprehensive fire extinguisher training program include:

Identifying Fire and Extinguisher Types: Proper training includes recognizing the different fire classifications (A, B, C, D, K) and knowing which extinguishers are suitable for each type. Multi-purpose ABC fire extinguishers are common in many environments as they can tackle Class A, B, and C fires, but specific workplaces may require Class D or K extinguishers.

PASS Method: The PASS acronym is a simple and effective technique taught in fire extinguisher training. It breaks down the steps of using a fire extinguisher as follows:

• Pull the pin: This releases the locking mechanism.
• Aim the nozzle or hose at the base of the fire: Targeting the flames won't be effective; the base of the fire is where the fuel source is located.
• Squeeze the handle: This releases the extinguishing agent.
• Sweep from side to side: Move the extinguisher nozzle in a sweeping motion to cover the entire fire and ensure it is fully extinguished.

Hands-on Practice: Individuals need to familiarize themselves with the weight and feel of an extinguisher, understand how to operate it, and experience the recoil when discharging the extinguishing agent. Fire safety drills often include simulated fire situations where participants practice using extinguishers in a controlled environment.

Maintaining Fire Extinguishers: Training should also cover the importance of regular fire extinguisher maintenance. An improperly maintained extinguisher may not work when needed. Perform fire extinguisher inspections monthly for issues such as low pressure, corrosion, or damage.

Evacuation Procedures and Emergency Protocols: Fire extinguisher training is often combined with evacuation procedures and emergency protocols. In addition to knowing how to use an extinguisher, individuals must be familiar with the building’s emergency exits, alarm systems, and assembly points. In some cases, using a fire extinguisher may not be enough, and individuals will need to evacuate the premises. It is important to place both fire extinguisher signs and emergency exit signs that are highly visible even with thick smoke.

• Install and Maintain Smoke Detectors: Place smoke and fire detector systems on every floor, test them monthly, and replace batteries yearly to ensure they are functional.
• Have a Fire Evacuation Plan: Develop a fire evacuation plan, ensure everyone knows the exits, and conduct regular fire drills for safety.
• Keep Fire Extinguishers Accessible: Place fire extinguishers in high-risk areas, such as kitchens and workshops, ensuring they are easily accessible and visible.
• Properly Store Flammable Materials: Store flammable materials away from heat sources in well-ventilated, labeled containers to reduce fire risk.
• Avoid Overloading Electrical Circuits: Prevent electrical fires by avoiding overloaded outlets, unplugging unused appliances, and using surge protectors.
• Practice Good Housekeeping: Maintain clutter-free spaces, ensure emergency exits are clear, and keep firefighting equipment unblocked to prevent fire spread.
• Use Appliances Safely: Turn off stoves, ovens, and heaters when not in use, and never leave cooking unattended, especially when using oils.
• Educate and Train Employees: Provide regular fire safety training and drills so employees can respond correctly and use fire extinguishers effectively during emergencies.

Understanding the different classes of fires—whether it's fires involving electrical equipment, flammable liquids, cooking oils, or even metal fires—is crucial for selecting the right extinguisher. For example, wet chemical extinguishers are essential for tackling cooking fires in commercial kitchens, while powder extinguishers are versatile for handling fires involving gases and other hazards. By knowing which extinguisher to use for each type of fire, you can effectively manage emergencies and prevent them from escalating.

There are five classes of fire: Class A, Class B, Class C, Class D, and Class K. Each class represents a different type of fire hazard, ranging from solid combustibles to flammable liquids and electrical fires.

For flammable liquids (Class B fires), use a Class B fire extinguisher, such as foam, ABC powder, or carbon dioxide extinguishers.

Carbon dioxide (CO2) fire extinguishers are designed for Class B (flammable liquids) and Class C (electrical) fires.

There are five classes of fire extinguishers, each corresponding to a specific fire type: Class A, Class B, Class C, Class D, and Class K.

There are five different classes of fire, each labeled with a specific symbol to indicate the type of fire the extinguisher is designed to combat. Class A fires are labeled with a green triangle, Class B fires with a red square, Class C fires with a blue circle, Class D fires with a yellow star, and Class K fires with a black hexagon. These labels help users quickly identify the appropriate extinguisher for each fire type.