The Types of extinguishers Can be classified according to their origin - class A, B, C, D and K - and according to the extinguishing agent that uses.
Fire is one of the most chaotic and dangerous natural elements, especially because of how fast it is spread and how difficult it is to control. It was precisely for this reason that fire extinguishers were born, portable devices designed to put out fires by means of a jet of water or a chemical mixture.
Fire extinguishers allow extinguishing the fire in a brief manner. However, because there are different kinds of fire, there are also different types of fire extinguishers. This means that the same appliance can not be used in different areas of an office or home, for example. This is because different elements may be involved in the fire.
Classification of extinguishers
According to its origin
The first classification of fire extinguishers is the one that is made depending on the type of fuel that produces the fire. It is divided into the following groups.
- A class
Class A fire extinguishers are reserved for all fires caused by solid organic materials such as wood, paperboard, paper, cloth, among others. The devices designed for this type of fire have an international symbolism represented by a green triangle bearing the letter"A"inside.
- Class B
This type of fire extinguisher is designed to put out fires that have been fueled by flammable liquids and easily burnable materials such as oil, gasoline, diesel, bunker, paraffin, wax, paint, plastics, among others. In this case the international symbolism is represented by a red box bearing a letter"B"inside.
- Class C
Extinguishers belonging to class C are those intended to extinguish fires that have been caused by energized electrical equipment. Among them are computers, servers, power tools, appliances, fuse boxes and switches. Class C extinguishers are identified with a blue circle and the letter"C".
- Class D
These types of fire extinguishers are those used to extinguish fires that have been caused by metals. This type of combustion is rare and the metals that can burn are magnesium, sodium, potassium or aluminum powder.
That is, basically alkaline and alkaline earth metals. It is important to keep in mind that this type of fuel reacts violently when having contact with the water. As for its international symbology, it is a yellow five-pointed star, which carries the letter"D"inside.
- Class K (kitchen = Kitchen)
This is a type of extra fire extinguisher designed for fires in kitchens. In this case the fire is caused by cooking oil (vegetable oil, animal, fat, etc.), specifically in fryers
This new category arose because cooking oil is very difficult to extinguish and also reacts violently to contact with water. Devices designed for this kind of fire carry as a symbol a hexagon with a letter"K"inside it.
According to the extinguishing agent used
- Water-based
These extinguishers contain water, which acts as a physical agent of cooling but also of suffocation. Because this liquid absorbs heat and can also evaporate at high combustion temperatures, it can expand its volume by about 1671 times. This makes it easy to put out fires.
Water-based fire extinguishers are suitable for Class A fires. Under no circumstances should they be implemented to extinguish Class C fires because water conducts electricity.
- Water-based spray
This class differs from the previous one because it has distilled water and a special discharge nozzle. Thanks to this, the discharge of the water is produced in very fine drops and produces an effect like that of the fog.
They are much more effective than common water because the heat is better absorbed and the suffocation is greater. They are suitable for Class A and Class C fires because this discharge does not conduct electricity.
- The foam base
This type of extinguisher generates a layer of aqueous material that is responsible for moving the air, cool and prevent steam from escaping. In this way, the foam manages to stop or prevent combustion. Foam-based fire extinguishers work because they suffocate the flame and cool the fuel. They are designed to combat type A and B.
- Carbon dioxide based
The discharge of this type of extinguishers is known as 'dry ice'. This is because the carbon dioxide upon release expands abruptly and causes the fuel temperature to drop drastically to -79 ° C. When this fog comes into contact with the fuel, it cools it in such a way that it turns it into dry ice. It is used to extinguish fires of class B and class C.
- The base of chemical powders
These fire extinguishers are designed to interrupt the chain reaction and to quench the fire. They do this because the monoammonium phosphate they contain melts with heat. This forms a sticky substance that acts as a barrier that adheres to the surface of the solids. They are used to fight class A, B and C fires.
- Based on special dust for class D fires
There is no extinguishing agent capable of extinguishing fires fed by all types of metals. And because some metals can react violently if a wrong extinguishing agent is used, this type of fire extinguishers have been created.
They are created depending on the type of metal you want to fight. All act by suffocation by creating a crust between the air and the burning material. Although there are some that also act by cooling.
- A base of halogenated compounds
This type of extinguisher acts in the same way as the one that is based on chemical powders, that is to say, chemically interrupting the chain reaction. However, the advantage of these is that they are clean agents that leave no residue. And because they are not conductors of electricity, they can be used in fires of class A, B and C.
- A base of potassium acetate
These fire extinguishers are suitable for extinguishing type K (cooking) fires. In this case the potassium acetate is discharged as a fine mist. Upon contact with the combustion agent, a saponification effect occurs. That is, a soapy foam is formed which is responsible for sealing the surface away from the air.
References
- Classification of Types of Fire and Types of Fire Extinguishers / José Iván Morales Ramírez Retrieved January 13, 2017.
- Type and classification of extinguishers / My Extinguishers Consulted January 13, 2017.
- Definition, Classification and Types of Fire Extinguishers / Profesor Group Consulted January 13, 2017.