The History of Fire Extinguishers

The original firefighting agent that still is in use today is water, which, is not surprising as the stuff works pretty well. The problem was application. Buckets required you to get pretty close to the fire and volume was limited to a throw. Early in the last century, water was combined with another popular agent, sodium bicarbonate, in a fire extinguisher called the soda acid. Most people are familiar with the inverting style extinguishers shown in early black and white movies. Flipping the extinguisher upside down allowed a bottle of sulfuric acid to spill into the soda & water mix. The resulting chemical reaction propelled the water out of the extinguisher onto the fire. Eventually, safety issues (read explosions) caused the demise of this design, which was replaced by the pressurized water extinguisher. This unit, along with CO2 or compressed carbon dioxide units and baking soda fire extinguishers, were the major players up through the late 60’s. Each of these extinguisher types, however, only handled one type of fire.

The first true multipurpose agent was monoamonium phosphate, better known as “ABC dry chemical”, noting its effectiveness on class A, B and C fires. Followed soon after by Halon, which was a clean, multipurpose agent that was safe to use on electronics. These two new agents took the lion’s share of the market for the next 25 years. The 80’s and 90’s brought additional new agents including several new clean agents after Halon was phased out in 1994, Halotron, Cleanguard and FM36 to name a few. Water mist and “K” Class liquid agents were breakthroughs in a category stagnant for decades. “K” Class agents were created primarily for hot kitchen (‘K’ for kitchen) grease fires because it not only extinguished the fire, but also cooled the grease to prevent flare ups after the fire had been extinguished. This is especially important in today’s fast food establishments who use new oils designed to withstand even higher temperatures to keep their deep fryers hot, which tend to cool too much from heavy use during lunch rushes.

Using the wrong agent on certain fire can cause life-threatening injury. One powerful example illustrating what I mean is a 30 second video from the British Fire Brigade you can find by clicking this link Be sure to have your speakers on when watching to hear the narrator.