Fire extinguishers are essential safety devices that can help you stop small fires before they become uncontrollable. However, not all fire extinguishers are the same. Different types of fires require different types of extinguishers, and using the wrong one can be dangerous or ineffective. That’s why fire extinguishers have ratings that indicate what kind of fires they can put out and how powerful they are. In this article, we will explain how fire extinguisher ratings work and how to choose the right one for your needs.
Key Takeaways
- Fire extinguisher ratings consist of a letter and a number that indicate the class and size of fire they can extinguish.
- The letter corresponds to the type of fire: A for ordinary combustibles, B for flammable liquids, C for energized electrical equipment, D for combustible metals, and K for cooking oils.
- The number indicates the extinguishing potential or the amount of fire that the extinguisher can put out under test conditions. The higher the number, the larger the fire it can extinguish.
- You should choose a fire extinguisher that matches the type of fire you are likely to encounter and has a sufficient number rating to cover the area you want to protect.
- You should also consider other factors such as the size, weight, and maintenance of the extinguisher, as well as the local codes and regulations.
Fire Extinguisher Ratings: What Do They Mean?
Fire extinguisher ratings are based on the standards set by the Underwriters Laboratory (UL), an independent organization that tests and certifies fire safety products. The ratings consist of a letter and a number that indicate the class and size of fire that the extinguisher can put out.
Fire Class
The letter in the fire extinguisher rating corresponds to the type of fire that the extinguisher is designed to fight. There are five classes of fires, each involving different kinds of fuel:
| Fire Class | Fuel Type | Examples |
|---|---|---|
| A | Ordinary combustibles | Wood, paper, cloth, rubber, plastic |
| B | Flammable liquids | Gasoline, oil, paint, alcohol, propane |
| C | Energized electrical equipment | Appliances, wiring, circuit breakers |
| D | Combustible metals | Magnesium, sodium, potassium, lithium |
| K | Cooking oils | Vegetable oil, animal fat |
Some fire extinguishers can handle more than one class of fire. For example, an ABC fire extinguisher can put out fires involving ordinary combustibles, flammable liquids, and energized electrical equipment. However, some classes of fire require special types of extinguishers that are not suitable for other classes. For example, a D fire extinguisher can only be used on combustible metal fires and should not be used on any other type of fire.
Fire Size
The number in the fire extinguisher rating indicates the extinguishing potential or the amount of fire that the extinguisher can put out under test conditions. The higher the number, the larger the fire it can extinguish.
The number rating is different for each class of fire. For class A fires, the number represents the equivalent amount of water in gallons that the extinguisher contains. For example, a 2A fire extinguisher contains 2.5 gallons (2 x 1.25) of water or its equivalent in chemical agent. For class B fires, the number represents the approximate square footage of flammable liquid that the extinguisher can cover. For example, a 10B fire extinguisher can cover 10 square feet of burning liquid. Class C fires do not have a number rating because they involve energized electrical equipment that must be de-energized before using an extinguisher. Class D and K fires also do not have a number rating because they require specific types of agents that are not measured by water or square footage.
To give you an idea of what these numbers mean in practice, here are some examples of common fire sizes and their corresponding ratings:
| Fire Size | Description | Rating |
|---|---|---|
| Small | Trash can or wastebasket | 1A or 5B |
| Medium | Sofa or mattress | 2A or 10B |
| Large | Kitchen or garage | 3A or 20B |
How to Choose the Right Fire Extinguisher
Choosing the right fire extinguisher depends on several factors, such as:
- The type of fire you are likely to encounter
- The size of the area you want to protect
- The size and weight of the extinguisher
- The maintenance and inspection requirements
- The local codes and regulations
Type of Fire
The first factor to consider is the type of fire you are likely to encounter in your home or workplace. You should choose a fire extinguisher that matches the class of fire that you expect to face. For example, if you have a kitchen, you should have a class K fire extinguisher that can handle cooking oil fires. If you have a workshop, you should have a class B fire extinguisher that can handle flammable liquid fires. If you have electrical equipment, you should have a class C fire extinguisher that can handle energized electrical fires.
Some fire extinguishers can handle more than one class of fire, which can be convenient and cost-effective. For example, an ABC fire extinguisher can handle most common types of fires in a home or office. However, some classes of fire require special types of extinguishers that are not suitable for other classes. For example, a D fire extinguisher can only be used on combustible metal fires and should not be used on any other type of fire.
Size of Area
The second factor to consider is the size of the area you want to protect with your fire extinguisher. You should choose a fire extinguisher that has a sufficient number rating to cover the area you want to protect. For example, if you want to protect a 10 x 10 foot room, you should have a fire extinguisher with at least a 10B rating. If you want to protect a 20 x 20 foot garage, you should have a fire extinguisher with at least a 20B rating.
The number rating is not an exact measure of the fire size that the extinguisher can put out, but rather an indication of its performance under test conditions. The actual performance of the extinguisher may vary depending on factors such as the type and amount of fuel, the wind and ventilation, and the skill and experience of the user. Therefore, it is always better to have a higher number rating than a lower one, as long as the extinguisher is not too heavy or bulky to use effectively.
Size and Weight
The third factor to consider is the size and weight of the fire extinguisher. You should choose a fire extinguisher that is easy to carry and operate in an emergency. A larger and heavier fire extinguisher may have more extinguishing power, but it may also be more difficult to handle and maneuver. A smaller and lighter fire extinguisher may be more convenient and portable, but it may also run out of agents faster and be less effective.
The size and weight of the fire extinguisher depend on the type and amount of agent it contains, as well as the design and material of the cylinder. Fire extinguishers come in various sizes and weights, ranging from 2.5 pounds to 30 pounds or more. The most common sizes for residential and commercial use are 5 pounds (2A:10B:C), 10 pounds (4A:60B:C), and 20 pounds (10A:120B:C).
You should choose a fire extinguisher that is comfortable for you to lift and use. You should also consider where you will store and mount your fire extinguisher, as some locations may have limited space or accessibility. You should follow the manufacturer’s instructions on how to install and use your fire extinguisher safely.
Maintenance and Inspection
The fourth factor to consider is the maintenance and inspection requirements of your fire extinguisher. You should choose a fire extinguisher that is easy to maintain and inspect regularly. A well-maintained and inspected fire extinguisher can ensure its reliability and effectiveness in case of a fire.
Fire extinguishers require periodic maintenance and inspection by qualified professionals to ensure their proper functioning and compliance with safety standards. The frequency and type of maintenance and inspection depend on the type and model of the fire extinguisher, as well as the local codes and regulations. Generally, fire extinguishers require:
- A monthly visual inspection by the owner or occupant to check for any signs of damage, corrosion, leakage, or tampering.
- An annual maintenance service by a certified technician to check for any defects, repairs, or replacements.
- A hydrostatic test every 5 or 12 years (depending on the type of cylinder) by a licensed facility to check for any cracks or leaks in the cylinder.
You should follow the manufacturer’s instructions on how to maintain and inspect your fire extinguisher properly. You should also keep records of all maintenance and inspection activities for future reference.
Local Codes and Regulations
The fifth factor to consider is the local codes and regulations that apply to your location. You should choose a fire extinguisher that meets or exceeds the minimum requirements set by your local authorities. Different jurisdictions may have different rules and standards for fire safety, such as:
- The number and type of fire extinguishers required for each occupancy or building.
- The location and placement of fire extinguishers within each occupancy or building.
- The signage and labeling of fire extinguishers for easy identification.
- The training and education of the occupants or users on how to use fire extinguishers correctly.
You should follow the local codes and regulations that apply to your location and consult with your local fire department or fire safety authority for more guidance.
Conclusion
Fire extinguisher ratings are important indicators of the type and size of fire that a fire extinguisher can put out. You should choose a fire extinguisher that matches the class of fire you are likely to encounter and has a sufficient number rating to cover the area you want to protect. You should also consider other factors such as the size, weight, and maintenance of the extinguisher, as well as the local codes and regulations. By choosing the right fire extinguisher, you can enhance your fire safety and be prepared for any emergency.
