Fire fighting grenade not so hot
There is nothing new under the sun – or rather in the case of Japan the rising sun. This past week there has been a flurry of announcements and videos on YouTube concerning the “invention” by the Japanese of a grenade type fire extinguisher that can be thrown into a fire to extinguish the flames. The idea is far from new as students of fire safety history will no doubt recall the glass CTC fire grenade introduced in the early 1900’s. They were eventually withdrawn in the 1950’s because a by product of CTC was phosgene gas the poisonous nerve gas used in the trenches of World War 1.

The difference appears to be in the fire suppressant used which is quoted as Potassium Carbonate in a water (aqueous) solution. Potassium carbonate is also used to make soaps and glass amongst other applications but when exposed to the heat of a fire produces carbon dioxide gas that in theory will replace the oxygen thereby removing one of the three essential elements required to support combustion – oxygen, heat and combustible fuel.

I would personally question the safety and reliability of such devices as so much depends on the type of fire you are tackling and then by definition the knowledge of the individual doing the throwing. Potassium salts or “wet chemical” suppressants are most commonly used for type BC fires involving flammable liquids , gases and some cooking oils. How effective would it be on other types of fires?

Also a small grenade with less than a litre of suppressant could only be used on a small fire and the user would also have to have an accurate throwing arm to hit the heart of the fire. The more out of control the fire is the more grenades you would need. All the video demonstrations of the device also show the grenades controlling a fire in a small enclosed space. In open spaces I can see problems particularly in the great outdoors where air flow is so variable. To rely solely on a hand held fire grenade to my mind is to court disaster and may give a false sense of security.

For me the safest solution would be to conduct a proper fire risk assessment and install fire extinguishers of a size and type appropriate to the risk. A table showing the different types of fire extinguisher, including wet chemical, carbon dioxide and special ABF multipurpose extinguishers can be found in our advice centre.