Are Fire Extinguishers Cold

Fire extinguishers are devices that can help put out small fires or contain them until professional help arrives. But do you know why some fire extinguishers feel cold when you use them? In this article, we will answer some common questions about fire extinguishers, such as:

  • Are fire extinguishers cold?
  • What causes fire extinguishers to be cold?
  • How does temperature affect fire extinguishers?

Key Takeaways

QuestionAnswer
Are fire extinguishers cold?Some fire extinguishers are cold, especially those that use carbon dioxide (CO2) or dry chemical as the extinguishing agent. Others, such as water or foam fire extinguishers, are not cold.
What causes fire extinguishers to be cold?Fire extinguishers are cold because of the rapid expansion of gas or the endothermic reaction of chemicals when they are discharged. This lowers the temperature and pressure of the extinguishing agent and the surrounding air.
How does temperature affect fire extinguishers?Temperature can affect the performance and safety of fire extinguishers. Extreme heat or cold can cause the pressure inside the cylinder to change, which may affect the discharge rate and range. Fire extinguishers should be stored and used within the recommended temperature range specified by the manufacturer.

Are Fire Extinguishers Cold?

The answer to this question depends on the type and model of the fire extinguisher. Some fire extinguishers are cold, especially those that use carbon dioxide (CO2) or dry chemicals as the extinguishing agent. Others, such as water or foam fire extinguishers, are not cold.

The following table summarizes the main types of fire extinguishers and whether they are cold or not.

Type of Fire ExtinguisherExtinguishing AgentCold or Not
WaterWater or water with additivesNot cold
FoamAqueous film-forming foam (AFFF) or film-forming fluoroprotein (FFFP)Not cold
Dry PowderSodium bicarbonate, potassium bicarbonate, ammonium phosphate, or other powdersCold
Carbon Dioxide (CO2)Carbon dioxide gasCold
Wet ChemicalPotassium acetate, potassium citrate, or potassium carbonateNot cold

What Causes Fire Extinguishers to Be Cold?

Fire extinguishers are cold because of the rapid expansion of gas or the endothermic reaction of chemicals when they are discharged. This lowers the temperature and pressure of the extinguishing agent and the surrounding air.

For example, CO2 fire extinguishers contain pressurized liquid carbon dioxide inside the cylinder. When the valve is opened, the liquid carbon dioxide expands into a gas 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.

Dry powder fire extinguishers contain pressurized nitrogen gas and a powder-based agent inside the cylinder. When the valve is opened, the nitrogen gas propels the powder out of the nozzle and creates a cloud that covers the fire. The powder also reacts with the heat and oxygen of the fire and absorbs energy from it. This causes a drop in temperature and pressure in the powder and the air⁶. The powder also interrupts the chemical reaction of combustion and smothers the fire.

How Does Temperature Affect Fire Extinguishers?

Temperature can affect the performance and safety of fire extinguishers. Extreme heat or cold can cause the pressure inside the cylinder to change, which may affect the discharge rate and range. Fire extinguishers should be stored and used within the recommended temperature range specified by the manufacturer.

The following table shows some examples of temperature ranges for different types of fire extinguishers⁷.

Type of Fire ExtinguisherTemperature Range
Water0°C to 60°C (32°F to 140°F)
Foam5°C to 60°C (40°F to 140°F)
Dry Powder-20°C to 60°C (-4°F to 140°F)
Carbon Dioxide (CO2)-40°C to 60°C (-40°F to 140°F)
Wet Chemical0°C to 60°C (32°F to 140°F)

If a fire extinguisher is exposed to temperatures outside its range, it may not work properly or even explode. Therefore, it is important to check the pressure gauge regularly and inspect the cylinder for any signs of damage or corrosion. If a fire extinguisher is damaged or defective, it should be replaced or repaired by a qualified professional.

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 use them properly and when to call for professional help. Remember, the #1 priority in case of a fire is to get out safely and stay out.

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