Types of Fire Extinguishers

A fire extinguisher is a portable container used to control small fires by directing a substance onto the flames that cools them, deprives them of oxygen, or interferes with the chemical reactions required for combustion. They are typically rated according to a system described in the ANSI standard, NFPA 10, Portable Fire Extinguishers. They are available in a wide variety of sizes and types to match different needs, and they must be maintained and serviced regularly. Fire extinguishers are typically located near potential hazards in a building or vehicle, and people using them should follow the four-step PASS procedure.

The earliest handheld fire extinguishers were essentially nozzles that directed water or other substances at a fire. The earliest models were invented by Ctesibius of Alexandria in 200 bce, with improvements occurring throughout the Middle Ages and into the early 1700s, when English inventor George Manby developed a device that used soda acid (potassium carbonate). In 1817, French chemist Ambrose Godfrey introduced a battery-powered device that dispensed a gaseous solution of ammonium chloride to put out a fire.

In 1928, DuGas produced a dry chemical fire extinguisher that was much smaller than previous models and was the first readily available agent for fighting Class A fires. It was a copper cylinder with an internal cartridge of sodium bicarbonate that you would puncture by turning a wheel valve on top. When you were ready to use it, you would simply squeeze the lever on the hose to discharge the chemical.

These extinguishers are commonly found in offices, retail premises, schools, hotels and warehouses. They have a spray or jet nozzle and contain pressurised Carbon Dioxide, which works by replacing the oxygen in a fire and also has a cooling effect on the material. They are suitable for Class A, Class B and Class C fires and are particularly useful on electrical fires as they do not damage or disrupt electrical equipment.

These are easy to maintain and usually the least expensive type of fire extinguisher. They are filled with water and may have detergents added to create a foam that smothers a fire by absorbing the heat, cooling it and removing the oxygen. They are designed for Class A, Class B and Class C burns and are particularly useful on kitchen fires or electrical appliances. These are the only fire extinguisher types to be fitted with a pressure gauge so you can check that the seal is intact and the pressure is at the recommended level. These are often used in vehicles and on fires at work. They are often private label versions of major brands and are a collectable.