Fire extinguishers are devices that can help put out small fires or contain them until professional help arrives. But do you know if fire extinguishers are flammable themselves? In this article, we will answer some common questions about fire extinguishers, such as:
- Are fire extinguishers flammable?
- What are the different types of fire extinguishers and their flammability?
- How can you prevent fire extinguishers from becoming a fire hazard?
Key Takeaways
| Question | Answer |
|---|---|
| Are fire extinguishers flammable? | Fire extinguishers are not flammable in general, but some types of fire extinguishers may contain flammable or combustible materials that can pose a risk of fire or explosion under certain conditions. |
| What are the different types of fire extinguishers and their flammability? | There are five main types of fire extinguishers: water, foam, dry powder, carbon dioxide (CO2), and wet chemical. Water and foam fire extinguishers are not flammable, but dry powder, CO2, and wet chemical fire extinguishers may contain flammable or combustible materials. |
| How can you prevent fire extinguishers from becoming a fire hazard? | You can prevent fire extinguishers from becoming a fire hazard by storing them properly, inspecting them regularly, and using them correctly. |
Are Fire Extinguishers Flammable?
The answer to this question depends on the type and model of the fire extinguisher. Fire extinguishers are not flammable in general, but some types of fire extinguishers may contain flammable or combustible materials that can pose a risk of fire or explosion under certain conditions.
For example, dry powder fire extinguishers contain pressurized nitrogen gas and a powder-based agent inside the cylinder. The powder may be flammable or combustible depending on its composition, such as sodium bicarbonate, potassium bicarbonate, ammonium phosphate, or other powders⁶. If the cylinder is damaged or exposed to high temperatures, the gas or the powder may leak or ignite.
Another example is CO2 fire extinguishers, which contain pressurized liquid carbon dioxide inside the cylinder. The liquid carbon dioxide expands into a gas when discharged and cools down dramatically. The gas can reach temperatures as low as -78°C (-109°F), which can cause frostbite if it comes into contact with skin⁵. The gas also displaces oxygen and smothers the fire. However, if the cylinder is overfilled or exposed to high temperatures, the pressure inside may increase and cause the cylinder to rupture or explode.
A third example is wet chemical fire extinguishers, which contain pressurized nitrogen gas and a liquid-based agent inside the cylinder. The liquid may be flammable or combustible depending on its composition, such as potassium acetate, potassium citrate, or potassium carbonate⁷. These agents react with the heat and oil of the fire and create a layer of foam that seals and cools the surface. However, if the cylinder is damaged or exposed to high temperatures, the gas or the liquid may leak or ignite.
What Are the Different Types of Fire Extinguishers and Their Flammability?
There are five main types of fire extinguishers: water, foam, dry powder, carbon dioxide (CO2), and wet chemicals. Each type of fire extinguisher is designed to put out different kinds of fires based on their class⁷.
The following table summarizes the main types of fire extinguishers and their flammability.
| Type of Fire Extinguisher | Extinguishing Agent | Flammability | Class of Fire |
|---|---|---|---|
| Water | Water or water with additives | Not flammable | Class A fires (fires in ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics) |
| Foam | Class A, B and C fires (fires that involve energized electrical equipment) and Class D fires (fires in combustible metals) | Not flammable | Class A and B fires (fires in flammable liquids, combustible liquids, petroleum greases, tars, oils, oil-based paints, solvents, lacquers, alcohols, and flammable gases) |
| Dry Powder | Sodium bicarbonate, potassium bicarbonate, ammonium phosphate, or other powders | Flammable or combustible depending on composition | Class A, B, and C fires (fires that involve energized electrical equipment) and Class D fires (fires in combustible metals) |
| Carbon Dioxide (CO2) | Carbon dioxide gas | Not flammable but can cause frostbite | Class B and C fires |
| Wet Chemical | Potassium acetate, potassium citrate, or potassium carbonate | Flammable or combustible depending on composition | Class K fires (fires in cooking appliances that involve combustible cooking media) |
There are also multipurpose fire extinguishers that can be used on more than one class of fire, such as A-B-C or A-B-C-D fire extinguishers. These fire extinguishers may contain a combination of different agents, such as dry powder and wet chemicals.
How Can You Prevent Fire Extinguishers from Becoming a Fire Hazard?
You can prevent fire extinguishers from becoming a fire hazard by storing them properly, inspecting them regularly, and using them correctly. Here are some tips to follow:
- Store fire extinguishers in a visible and accessible location, away from potential fire sources and hazards. Use the appropriate mounting brackets to secure the fire extinguisher to the wall or the floor. Avoid storing fire extinguishers in direct sunlight, near heat sources, or in extreme temperatures.
- Inspect fire extinguishers at least once a month. Check the pressure gauge, the inspection tag, the external condition, and the age of the fire extinguisher. Replace or recharge the fire extinguisher if it is low on pressure, damaged, missing a tag, or more than 10 years old.
- Use fire extinguishers only for their intended purpose and class of fire. Do not use water or foam fire extinguishers on electrical or metal fires. Do not use dry powder or CO2 fire extinguishers on cooking oil fires. Do not use wet chemical fire extinguishers on any other type of fire except cooking oil fires.
- Follow the PASS technique when using a fire extinguisher: Pull the pin, Aim the nozzle at the base of the fire, Squeeze the handle, and Sweep from side to side until the fire is out.
- Call 911 or your local emergency number before or after using a fire extinguisher. Do not attempt to fight a large or spreading fire by yourself. Evacuate the area and wait for professional help to arrive.
Fire extinguishers are essential safety devices that can help prevent the spread of fire and save lives. But they also have limitations and risks. Therefore, it is important to know how to store, inspect, and use them properly and safely. Remember, the #1 priority in case of a fire is to get out safely and stay out.
