Fire Extinguisher

A fire extinguisher is an apparatus designed to direct an extinguishing agent onto a fire source. The discharge from the apparatus is achieved by internal pressure, which can result either from the prior compression of the extinguishing agent or from the release of a propellant gas at the moment of activation. 

Fires are categorized into 6 classes, thereby enabling the determination of the fire type based on the nature of the combustible material. The purpose of these classes is to optimize the effectiveness of the fire-fighting method and to prevent any danger during use. 

Class A fires are the most commonly encountered (at home or in professional environments). They are defined by the combustion of common solid materials (paper, wood, fabrics, plastics...). 

For a Class A fire, the use of a water-based extinguisher of type A or AB (sprayed, with or without additive, and in foam form) will be preferred. An ABC powder extinguisher can also be used on this type of fire. 

Class B fires, i.e., fires involving liquids (gasoline, alcohol, oil) and liquefiable solids (paraffin, greases...) that produce only flames, will require the use of powder extinguishers (BC and ABC). For this type of fire, a water-based extinguisher with additive or a CO2 extinguisher will also be effective. 

However, caution must be exercised not to use a CO2 extinguisher over too large an inflamed area. Indeed, the reduction in air oxygen content caused by CO2 extinguishing could pose a risk of asphyxiation for the user. It should be noted that Class B fires can generate gaseous or explosive mixtures, produce toxic fumes, and trigger unpredictable chemical reactions. 

Furthermore, they can cause violent reactions in the presence of water. 

Class C fires, i.e., gas fires (acetylene, town gas, propane...), can be encountered at various levels (in industrial companies or in residential buildings). When gas mixes with air, it creates optimal combustion conditions. Thermal radiation can then be particularly strong, as can the risk of explosion. Intoxication can also be a significant danger during gas fires. 

Before tackling this type of fire, it is essential to shut off the gas supply. Carbon dioxide (CO2) extinguishers can then be used. 

Mainly observed in the industrial or chemical sectors, Class D fires involve metals (aluminum, magnesium, potassium, sodium...). They can generate extremely high temperatures. The primary danger lies in using water for extinguishing, as at high temperatures, sprayed water instantly transforms into hydrogen, thus causing an explosive release of gas (H2).  

To control these fires, it is imperative to use a special powder extinguisher. The type of powder will be adapted according to the metal involved. Therefore, it is crucial to anticipate and provide suitable extinguishers in risk areas. 

Particularly reactive upon contact with water, it is strictly forbidden to use a water extinguisher on Class F fires. We recommend using a powder or CO2 extinguisher. 

Covering the flame with a dampened and wrung-out cloth or a fire blanket can also be effective. 

Electrical fires result from the combustion of cables, transformers, and other electrical equipment. Before the fire breaks out, the danger is related to electric shock or even electrocution. 

Therefore, cutting off the electricity supply is the first reflex to have. For this type of fire, the use of CO2 or powder extinguishers is recommended. 

CNPP tests extinguishing agents in its laboratories, and our CNPP Cert. department issues the joint APSAD & NF Service certification for the installation of mobile fire extinguishers.