Foam fire extinguishers are widely used because they are handy, easy to use and above all they are easily available: here is how they work and their price. They are among the most appreciated and bought because they combine quality with convenience, and also the most widely available types of fire extinguishers. Used to extinguish class A and B fires, they have a very ancient history: here are their characteristics, how they work and what their market price is.

Foam Fire Extinguishers: history, composition and types

The first fire extinguisher dates back to 1723 and was made by Ambrose Godfrey, but the first "modern" fire extinguisher dates back to 1818 and was made by William Manby: there has been a lot of progress thanks to new technological discoveries. The history of foam fire extinguishers dates back to the early 1900s when, in Russia, Aleksandr Loran built the first chemical foam extinguisher based on the previous invention of fire-fighting foam. The device was composed of a main tank with water solution of sodium carbonate and an internal tank with aluminium sulphate: by mixing together these two substances, foam and carbon dioxide were generated in a gaseous state able to cause the substance leakage. Loran's first experiment was the switching off of a naphtha tank, a mixture of hydrocarbons, classified today as liquid fuel: the foam, in fact, had a greater resistance so the result became a success. 

Today this type of fire extinguisher is regulated by a tank, a valve to regulate the flow of the extinguisher, a hose (or flexible tube) to direct the extinguishing agent, the extinguishing agent and finally the propellant material. It is red like all fire extinguishers, complies with EN 3 regulations and has a label which shows the type of fire it is capable of extinguishing, the type of extinguishing agent contained and the achievable classes through pictograms. Moreover, this type of fire extinguisher is divided into two large classes: chemical foam extinguishers, based on the base-acid reaction, which are used by giving a shot to the ground with the extinguisher turned upside down so that the two elements are mixed together and the foam comes out; mechanical foam extinguishers, which contain carbon dioxide in order to expel the foaming liquid.

Foam Fire Extinguishers: how they work and their price

This fire extinguisher is used to put out class A and B fires, therefore solid fuels that cause embers like paper, coal, wood or liquid and solid liquefied fuels such as diesel oil, petrol and lubricating oils. Its action occurs in three different ways: smothering, dilution and cooling, steams’ interruption. The extinguishing agent’s characteristics of the foam fire extinguisher are mainly three:

• expansion: the foaming liquid at low and medium expansion has a superficial action; at high expansion instead, it has a volumetric action and then a greater saturation power of the whole space;
• fluidity: that is the ability of the foam to overflow and then flow well on liquid or solid surfaces, very important to penetrate and reach all the sections not directly accessible by the jet;
• stability to drainage, heat, pollutants and mechanical breakdown of the cover.

But what are the prices of foam fire extinguishers? The 6-l model has a cost that varies between 55 and 75 €, and the 9-l one costs about 150/170 €. Handiness, ease of use and convenience: these products are chosen by many people to ensure the safety and tranquillity of every environment.