Fire extinguishers are essential fire safety equipment that can help prevent the spread of fire and protect people and property from harm. However, not all fire extinguishers are the same, and different types of fire extinguishers are suitable for different types of fires. Therefore, it is important to know how many fire extinguishers are required in a business premises, and what kind of fire extinguishers are appropriate for the fire risks present.
Key Takeaways
- The number and type of fire extinguishers required in a business premises depend on the size, layout, occupancy, and fire hazards of the premises.
- The Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA) provide general guidelines and standards for fire extinguisher placement, distribution, and maintenance.
- The NFPA classifies fires into five classes: A, B, C, D, and K. Each class of fire requires a specific type of fire extinguisher that is rated for that class.
- Fire extinguishers are also rated by their size and capacity. The higher the number before the letter, the more effective the extinguisher is at putting out that class of fire.
- Fire extinguishers should be mounted, located, and identified so that they are readily accessible to employees without subjecting them to possible injury.
- Fire extinguishers should be inspected, maintained, and tested regularly to ensure they are in good working condition.
Fire Extinguisher Regulations and Guidelines
The OSHA standard for fire extinguishers (29 CFR 1910.157) requires employers to provide portable fire extinguishers and to train employees on how to use them. The standard also specifies the following requirements for fire extinguisher placement, distribution, and maintenance:
- Fire extinguishers should be provided for every 3,000 square feet of the protected building area or a major fraction thereof.
- Travel distance from any point of the protected area to the nearest fire extinguisher should not exceed 100 feet.
- Fire extinguishers should be mounted at a height between 3.5 feet and 5 feet above the floor.
- Fire extinguishers should be conspicuously located where they will be readily accessible and immediately available in the event of fire.
- Fire extinguishers should be inspected monthly and maintained annually by a qualified person.
- Fire extinguishers should be hydrostatically tested at the intervals specified by the manufacturer or NFPA 10.
The NFPA standard for portable fire extinguishers (NFPA 10) provides more detailed guidance on how to select, install, inspect, maintain, and test fire extinguishers. The standard also defines the maximum travel distance and floor area per unit of A rating for different classes of fires and occupancies. The following table summarizes some of the key provisions of NFPA 10:
| Class of Fire | Occupancy | Maximum Travel Distance | Maximum Floor Area per Unit of A |
|---|---|---|---|
| A | Light | 75 ft | 3,000 ft2 |
| A | Ordinary | 75 ft | 1,500 ft2 |
| A | Extra | 75 ft | 1,000 ft2 |
| B | Low | 30 ft | N/A |
| B | Moderate | 50 ft | N/A |
| B | High | 30 ft | N/A |
| C | N/A | Same as Class A or B | N/A |
| D | N/A | 75 ft | N/A |
| K | N/A | 30 ft | N/A |
Note: The maximum floor area per unit of A is calculated by multiplying the maximum floor area per unit of A by the numerical A rating of the extinguisher. For example, a 4-A rated extinguisher can cover up to 6,000 ft2 in a light hazard occupancy.
Fire Extinguisher Types and Ratings
The NFPA classifies fires into five classes based on the type of fuel involved:
- Class A fires involve ordinary combustible materials such as wood, paper, cloth, rubber, and plastic.
- Class B fires involve flammable or combustible liquids such as gasoline, oil, paint, solvents, and grease.
- Class C fires involve energized electrical equipment such as appliances, wiring, circuit breakers, and outlets.
- Class D fires involve combustible metals such as magnesium, titanium, sodium, potassium, and lithium.
- Class K fires involve cooking oils and fats such as vegetable oil, animal fat, and grease.
Each class of fire requires a specific type of fire extinguisher that is rated for that class. Fire extinguishers are also rated by their size and capacity, which indicate how much extinguishing agent they contain and how effective they are at putting out a given class of fire. The rating is usually expressed as a number followed by a letter, such as 2-A, 10-B:C, or 40-B:C. The higher the number before the letter, the more effective the extinguisher is at putting out that class of fire. The following table lists some of the common types of fire extinguishers and their ratings:
| Type of Fire Extinguisher | Extinguishing Agent | Class of Fire | Typical Rating |
|---|---|---|---|
| Water | Water or water with additives | A | 2-A, 3-A, 4-A |
| Water Mist | Distilled water in fine spray | A, C | 2-A:C |
| Foam | Aqueous film-forming foam (AFFF) or film-forming fluoroprotein (FFFP) | A, B | 2-A:10-B, 3-A:20-B, 4-A:40-B |
| Carbon Dioxide (CO2) | Carbon dioxide gas | B, C | 5-B:C, 10-B:C |
| Dry Chemical | Sodium bicarbonate, potassium bicarbonate, or ammonium phosphate powder | A, B, C | 1-A:10-B:C, 2-A:20-B:C, 3-A:40-B:C |
| Wet Chemical | Potassium acetate or potassium citrate solution | K | 2-K, 6-K |
| Dry Powder | Sodium chloride or graphite powder | D | D |
Note: Some fire extinguishers are multipurpose and can be used on more than one class of fire. For example, a fire extinguisher labeled as ABC can be used on Class A, B, and C fires.
How to Choose the Right Fire Extinguishers for Your Business Premises
To choose the right fire extinguishers for your business premises, you need to consider the following factors:
- The size, layout, occupancy, and fire hazards of your premises. You need to assess the potential sources of ignition and fuel in your premises, and determine the class and severity of fires that may occur. You also need to consider the number of people who work or visit your premises, and the ease of access and evacuation in case of fire.
- The type and rating of fire extinguishers that are suitable for your fire risks. You need to select fire extinguishers that are rated for the class of fire that you may encounter in your premises. You also need to ensure that the fire extinguishers have enough capacity and effectiveness to control or extinguish the fire. You should avoid using fire extinguishers that are not compatible with the type of fuel involved, as this may cause more harm than good.
- The location and distribution of fire extinguishers in your premises. You need to install fire extinguishers in conspicuous and accessible locations where they can be easily reached and used in case of fire. You also need to distribute fire extinguishers according to the guidelines and standards provided by OSHA and NFPA. You should avoid placing fire extinguishers near potential sources of heat or ignition, or where they may be obstructed or damaged.
The following table provides some examples of how to choose the right fire extinguishers for different types of business premises:
| Type of Business Premises | Fire Risks | Fire Extinguisher Types and Ratings |
|---|---|---|
| Office | Paper, furniture, electrical equipment | Water (2-A), CO2 (5-B:C), Dry Chemical (2-A:10-B:C) |
| Restaurant | Cooking oil, grease, electrical equipment | Wet Chemical (6-K), CO2 (10-B:C), Dry Chemical (3-A:40-B:C) |
| Warehouse | Wood, cardboard, flammable liquids, electrical equipment | Water (4-A), Foam (4-A:40-B), Dry Chemical (3-A:40-B:C) |
| Factory | Flammable liquids, combustible metals, electrical equipment | Foam (4-A:40-B), CO2 (10-B:C), Dry Powder (D) |
Conclusion
Fire extinguishers are vital fire safety devices that can help save lives and property in case of fire. However, not all fire extinguishers are the same, and different types of fire extinguishers are suitable for different types of fires. Therefore, it is important to know how many fire extinguishers are required in a business premises, and what kind of fire extinguishers are appropriate for the fire risks present.
To choose the right fire extinguishers for your business premises, you need to follow the regulations and guidelines.
