Fire is the combination of elements with oxygen that is accompanied by heat and light.
Four aspects of fire:
Until 1960, fire experts believed that fire occurs with the presence of three elements, oxygen, temperature and combustible material, and defined the fire triangle.
After the production and manufacture of halon, the fourth aspect was identified because halon gas was only effective on chain reactions and extinguished the fire.
Types of fire:
Not all fires are the same. Combustion may be classified into one or more of the following fire classes.
Fire experts select the appropriate size and fire extinguishing agent to eliminate the hazard.
Class A fire is common combustion such as wood, paper, cloth, rubber and many plastics.
Class B fire is a fire in flammable liquids such as gasoline, petroleum grease, bitumen, oil, oil paints, solvents, alcohols.
A Class B fire also involves flammable gases such as propane and butane.
Class B fire does not include cooking oil and grease fires.
Class C fires are fires involving energized electrical equipment such as computers, servers, motors, transformers, and appliances.
Turn off the power and the Class C fire will become another class of fire.
Class D fire is a fire in combustible metals such as magnesium, titanium, zirconium, sodium, lithium and potassium.
A class K fire is a fire in cooking oils and fats such as animal and vegetable fats.
Some types of fire extinguishing agents can be used in more than one class of fire.
But some other fire extinguishers can be dangerous for the operator to use in several classes.
The principles of combustion and the basis of fire extinguishing
General fire fighting methods
1- Cooling method
By using water, you can cool the flame and the combustible material. The smaller the water particles, the higher the heat absorption power.
2- Method of suffocation
Distance between fire and oxygen with the help of a blanket.
Diluting and reducing the ratio of oxygen in the environment using CO2 and other inert gases.
3- Combustible material separation method
Closing the fuel supply valve, blowing into the candle flame and removing gases and vapors and finally cutting off the combustible material.
4- Disorder in chain reactions
Use of extinguishing gases such as halogenated compounds and disruption of fire oxidation.