Fires pose a serious risk to people, the environment and property. It is therefore crucial to fight them with suitable extinguishing agents. The choice of the right agent depends on the type of combustible material - the so-called fire class.
In this article, we provide a comprehensive overview of the common extinguishing agents and explain their specific areas of application in fire extinguishers and extinguishing systems.
The fire classes as a basis for selection
The fire classes are the basis of all firefighting. Fires involving solid materials such as wood, paper or textiles belong to fire class A, while fire class B includes liquid or liquefying materials such as petrol or alcohol.
Gas fires are assigned to fire class C, while fire class D refers to metal fires. Finally, there is fire class F for grease and oil fires in kitchens. The various extinguishing agents are each suitable for one or more of these fire classes.
Extinguishing agents in fire extinguishers
Small helpers with a big impact
Fire extinguishers are indispensable tools for fighting fires in their early stages.
Water as an extinguishing agent
Water is the simplest and most effective extinguishing agent for class A fires. It cools the burning material and thus prevents the fire from spreading further. Water extinguishers are often found in offices, schools and public buildings, as these mainly contain solid materials such as paper or textiles.
However, water is unsuitable for class B, C, D and F fires, as it can cause dangerous explosions in grease fires, for example.
Foam as an extinguishing agent
Foam is often used for class A and B fires. This extinguishing agent smothers the fire by cutting off the oxygen supply and at the same time provides a cooling effect.
Foam is the preferred choice, particularly in industry, at filling stations and in vehicles, where liquid fuels are often involved. Foam also provides valuable services in large warehouses with mixed goods, as it is versatile.
Powder as an extinguishing agent
Powder is one of the most universal extinguishing agents and is suitable for fire classes A, B and C, and in some cases also for class D metal fires. It works by interrupting the chemical reaction of the fire.
Powder extinguishers are widely used, for example in households, workshops or vehicles, as they are versatile and comparatively inexpensive. In metal processing, where magnesium or aluminum can burn, special powders are also used that are suitable for such demanding fires.
The disadvantage of powder, however, is that it leaves behind residues that can damage sensitive electronics or machinery.
CO2 as an extinguishing agent
Carbon dioxide is a residue-free extinguishing agent that is used particularly in the electronics and IT industries. It is suitable for fire classes B and C and extinguishes by displacing the oxygen required by the fire.
In data centers, museums or laboratories where sensitive equipment and valuable objects need to be protected, CO2 is the preferred choice as an extinguishing agent.
Another special extinguishing agent is the grease fire extinguisher, which was developed for fire class F. These extinguishers contain a special liquid that forms a soapy layer on contact with burning oils or fats, which smothers the fire.
They are indispensable in commercial kitchens, restaurants and food processing plants, where grease fires are one of the most common causes of fire.
Extinguishing agents in extinguishing systems
Extinguishing systems are designed to fight larger fires and minimize damage. The following extinguishing agents are used:
Water
One of the best-known technologies is the water extinguishing system, which efficiently extinguishes class A fires. Sprinkler systems spray water specifically onto the source of the fire, reducing the temperature until the fire is extinguished. These systems are widely used in office buildings, shopping centers and warehouses where large quantities of flammable materials need to be safely protected.
Foam
Foam extinguishing systems are often used for class A and B fires. The foam smothers the flames and cools the affected areas to prevent them from flaring up again. Such systems are particularly invaluable in chemical warehouses, refineries and filling stations where highly flammable liquids are present. Foam extinguishing systems are also frequently used in aircraft hangars and airports to quickly bring fuel fires under control.
Gas
Gas extinguishing systems rely on extinguishing gases such as carbon dioxide, inert gases such as argon and nitrogen or chemical extinguishing gases such as FM-200 and Novec 1230. These gases are residue-free and interrupt the fire reaction without damaging the surroundings. Such systems are particularly popular in data centers, archives and museums where sensitive electronics or valuable works of art need to be protected.
Powder
Powder extinguishing systems offer a fast and effective solution for class A, B and C fires, and in some cases also for class D fires. They are particularly suitable for industrial plants where mixed fires can occur or for refineries where chemical reactions can quickly get out of control. For metal processing plants where magnesium or aluminum is processed, special powder extinguishing systems are used to safely fight metal fires.
Ansul
Grease fires, which can occur in commercial kitchens or in industrial food production, are a special case. Special extinguishing systems are used here, which use fat-dissolving substances to smother the fire safely and without leaving any residue.
The range of extinguishing agents is just as diverse as the fire hazards themselves. Whether water, foam, powder, CO2 or special solutions for grease fires - each extinguishing agent has its strengths and specific areas of application. While fire extinguishers are indispensable for initial firefighting, extinguishing systems offer large-scale and often automated protection in particularly high-risk areas.
Choosing the right extinguishing agent is not only a technical decision, but also an economic and safety-related one. Investing in suitable extinguishing systems not only protects assets, but also saves lives in an emergency.