Dry Powder Fire Extinguishers

What Is A Dry Powder Fire Extinguisher Used For?

A dry powder extinguisher is used for Class A, Class B, and Class C fires.

These classifications cover combustibles such as wood, paper, and textile (Class A), flammable liquids like petrol (Class B), and gas fires (Class C). These are also effective for electrical fires, but a powdery mess ensues. Dry powder is most appropriate for garages, workshops, and industrial buildings.

• In 2023/24, there were approximately 7,000 workplace fires recorded, marking a significant decline of 25% over the past decade.

Learn more about Fire Extinguisher Classifications and Types

How Does a Dry Powder Fire Extinguisher Work?

A dry powder fire extinguisher smothers flames by cutting off oxygen and disrupting the chemical reaction of the fire.

• Powder is usually composed of monoammonium phosphate or sodium bicarbonate.

• It envelops the object on fire and prevents it from spreading.

• Dry powder is efficient for Class A, B, and C fires, so it is multi-purpose.

• The residue can damage electrical equipment.

Once released, it creates a barrier over the fire, cutting off its oxygen supply. Without oxygen, the fire can’t burn or reignite, stopping it in its tracks.

When NOT To Use A Dry Powder Fire Extinguisher

Avoid using a dry powder extinguisher in small, enclosed spaces. The powder can reduce visibility and make breathing difficult. Don’t use dry powder on chip pan fires (Class F) or reactive metal fires unless it’s a specialist type. Lastly, powder can damage electrical equipment, so it’s not ideal for offices or server rooms.

What Is MAP 50 Dry Powder?

MAP 50 is an acronym for Monoammonium Phosphate 50%, a high-performance extinguishing powder

It is used in ABC dry powder fire extinguishers and is very effective in fighting Class A (solids), Class B (liquids), and Class C (gases) fires. 50% is its purity level and is consequently more effective when compared with other lower grades of powder. It blankets and coats surfaces, depriving oxygen and inhibiting re-ignition.

What is MAP 90 Dry Powder?

MAP 90 is an abbreviation for Monoammonium Phosphate 90%, a premium-grade extinguishing powder. At 90% purity, it is superior in effectiveness when compared with lower grades. As with the MAP 50, it blankets and envelops surfaces, and suffocates fires so no re-ignition occurs. Preferably used in high-risk locations.

What Is A B+ Powder?

B+ Powder is a dry chemical fire extinguisher powder designed for Class B and C fires. B+ is so potent, that it contains the force of an 8kg fire extinguisher in only a 2kg cylinder.

• B+ Powder works by smothering the fire and interrupting the chemical reaction.

• This specialist powder is more effective than standard powders for Class B fire types.

• It’s commonly used in industrial and commercial settings.

How To Identify A Dry Powder Fire Extinguisher

In the UK, a dry powder fire extinguisher, according to BS EN 3, is red with a distinctive French blue label.

The label will also list the fire classes it covers and include clear instructions on use. The pressure gauge is visible, showing if it's fully charged.

Fire Statistics For 2024

• ​In the year ending September 2024, England's fire and rescue services attended 598,504 incidents.

• These incidents included 133,072 fires.

• False alarms increased by 2.9%, reaching 254,041 in 2024.