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26/01/2024 • by
A dry powder fire extinguisher is one of the most versatile and useful fire extinguishers currently available. You may have heard a powder extinguisher described as an ABC fire extinguisher. This is because they can be used on Class A, B, and C fires.
In this guide, we explain how dry powder fire extinguishers function, what makes them so useful, the kinds of places where they’re most suited, the types of dry powder available, and how you can identify a dry powder extinguisher.
A dry powder fire extinguisher contains, as the name suggests, a dry powder that is expelled to fight fires. Typically, the powder inside an extinguisher is primarily made from mono-ammonium phosphate mixed with other powders to add bulk or improve the flow. The powder is propelled out of the extinguisher using a compressed, non-flammable gas like nitrogen.
The powder then forms a ‘blanket’ over the fire, starving it of oxygen. A fire requires a source of ignition, a fuel, and oxygen in order to burn and spread. A dry powder extinguisher cuts it off from the oxygen it needs, smothering the fire and preventing it from reigniting.
One of the best things about dry powder fire extinguishers is just how versatile they are. The sheer variety of different fires that they can be used on makes them an essential addition to any fire safety plan.
Of course, it’s still vital to ensure that any fire extinguisher is used on the correct fire classification. Here are the types of fires that a dry powder fire extinguisher is suitable for:
Class A fires are caused by combustible, solid materials. Usually, they result from a flame or high temperature object coming into contact with combustible materials like wood or paper. Class A fires are common in all kinds of environments including schools, offices, hospitals, and warehouses. Dry powder fire extinguishers are particularly effective against Class A fires.
Class B fires are caused by a source of ignition coming into contact with a flammable liquid like petrol and spirits. These kinds of fires are typically common in settings like bars, restaurants, workshops, and laboratories. Thanks to the lack of water in ABC fire extinguishers, they won’t simply help the fire spread and are effective at starving the fire of the oxygen it needs.
A Class C fire is caused by the burning of flammable gases such as butane and propane. These gases are commonly found in gas canisters. This makes a dry powder fire extinguisher essential for any setting that stores large quantities of these gases such as industrial warehouses and chemical plants. A dry powder fire extinguisher is essential if your building is at risk for Class C fires. Any other type of extinguisher will just spread the fuel and flames. The dry powder cools the flames, bringing down the heat until the fire can no longer burn.
Electrical fires, otherwise known as Class E fires, are a risk for any building that uses electricity. This makes them one of the more common types of fire that will come up in your risk assessment. Dry powder extinguishers can be used as electrical fire extinguishers thanks to their low level of conductivity. However, dry powder fire extinguishers should only ever be used on fires caused by electrical currents under 1000v. For electrical equipment above 1000v, the best choice for an electrical fire extinguisher is a CO2 fire extinguisher.
Dry powder fire extinguishers are very useful and versatile. However, there are still some types of fire where they’re not suitable.
For instance, dry powder fire extinguishers should never be used on Class F fires. Class F fires result from cooking oils and fats. This is because these fires typical burn at very high temperatures that dry powders are unable to extinguish. Likewise, a water-based agent will just spread the fire and make it worse. In the case of Class F fires, you should have a wet chemical fire extinguisher on hand.
You should also exercise caution when using ABC fire extinguishers on equipment like computers and scientific instruments as the powder can be corrosive to sensitive electrical equipment. Likewise, using dry powder fire extinguishers in enclosed spaces can be hazardous as inhalation of the powder can cause potential health issues.
The most common form of dry powder fire extinguishers is commonly known as an ABC fire extinguisher. This is because of their ability to fight Class A, B, and C fires. These extinguishers contain a mix of ammonium sulphate and mono ammonium phosphate. You may see some ABC fire extinguishers labelled with the term “MAP 50.” This means that they have a 50% concentration of mono ammonium phosphate, maximising their firefighting power.
You may also see dry powder fire extinguishers labelled as BC fire extinguishers. These extinguishers contain a sodium bicarbonate agent. As the name suggests, these extinguishers are used for fighting Class B and C fires. These smaller extinguishers are commonly used in cars, taxis, caravans, and small boats.
B+ dry powder fire extinguishers are particularly useful when fighting liquid fires resulting from petrol and diesel. If you are in a setting that is at high risk for Class B fires, like petrol stations and petrochemical plants, a B+ fire extinguisher is a great option.
You can identify dry powder fire extinguishers by the blue coloured label on the front of the extinguisher that reads “POWDER.” Make sure that, wherever you require fire extinguishers, that their labels are clearly on display and they can be easily accessed.
Dry powder fire extinguishers are one of the most useful and valuable extinguishers that you can use in a wide variety of settings. If you think that a dry powder fire extinguisher is right for your needs, or you think your existing dry powder extinguishers need servicing, the best thing that you can do is to reach out to the experts.
To discuss your firefighting needs, you can call Fire Protection Shop on 0330 058 0631 or click here to get in touch online.