We all are aware of the increasing rate of fire disasters because of which millions of people lost their lives and assets. So, it is very crucial to have some basic firefighting equipment for safety from fire. Every kind of building must have a fire extinguisher for fire safety because it is a very effective firefighting device. Fire extinguishers act as a blanket over the fire. It is basically an apparatus that consists of a pressure agent that can extinguish the fire. Extinguishers are of different types:
But having a fire extinguisher is not enough, it is also essential that people should be trained in its use and should know some technical points about it. For effective and efficient results of the extinguisher, we must know different types of fire and types of extinguishers that can work on these classes of fire. Because choosing the wrong type of extinguisher can have life-threatening consequences.
Now the question is what are different types of fire?
Here is the answer to this question.
There are following types of fires.
Class A fire is the most common class of fire and we all are familiar with this class of fire. This class of fire contains many ordinary combustibles like wood, fabric, paper, plastic, rubber, and trash. Class A fire occurs when the ordinary combustible materials reached their ignition temperature and burning starts at that stage. The flames continue burning as long as there is an excess of oxygen because the supply of oxygen is the major cause of ignition. We can easily smother the fire. We can extinguish class A fire with water fire extinguishers, DCP Fire Extinguisher, and Foam Extinguisher. A can of water that can spray water on the flames can be used for smothering it.
Class A fires are commonly put out with water or mono ammonium phosphate. We can also extinguish it with the help of a fire blanket or other materials or products.
Class B fire includes flammable liquids like gasoline, acetone, kerosene, grease, paint, and alcohols. Flammable liquids catch on the fire and start burning easily at normal working temperature. Once the class B fire starts it is very difficult to control the fire and prevent its spreading. This class of fire involves nonmetal burning in a liquid state. It is also a common hazard in industries that are dealing with lubricants and paints. We can knock out this class of fire by simply cut off the supply of oxygen. We can extinguish class B fire by using Carbon dioxide extinguishers because when we fill CO2 gas in a cylinder at very high pressure it becomes cold and creates a barrier between the flame and oxygen cutting down the supply of oxygen to the fire and smother it in a very effective way.
The Source of class C fire involves burning gases. Most commonly used flammable gases include methane, butane, and propane that have the potential to cause an explosion. It is one of the most dangerous classes of fire and is very difficult to control. Gases add the fuel to the fire and fuel is one of the components of the fire triangle. So the locations that store burning gases must adopt some precautionary measures to avoid the fire hazards. Additionally, as flammable gases are heavier than air, they can travel a significant distance to an ignition source, which means the fire can spread rapidly. Flammable gases can also cause an explosion and lead to severe impact.
It is very difficult to extinguish class C fire. Before smothering the fire one should make sure that the supply of gas is first isolated because most of the fire extinguisher is ineffective to smother this class of fire. We can also extinguish Class C fire by using DCP.
Combustible metals can cause significant fire hazards because they are good conductors and transfer heat very rapidly. Certain metals like potassium, sodium, and aluminum can also cause severe damage. These metals burn when they come in contact with the fire and air. These metals even in the powdered form can cause a fire. We need great care to cools down Class D fire because water, foam, and another agent can excite the metals and cause massive burning.
Electrical Fire can originate from energized electrical equipment. It also starts ignition in wires, cables, circuit breakers, and other electrical components. An electrical fire can start because of overloading on the circuits when the supply of electricity is inadequate. Electrical fires are often fueled by motors, appliances, and electronic transformers.
Because it is very tricky to put off Class E fire. Firstly, we need to cut off the supply of electricity, and then we need to choose the ABC dry chemical fire extinguisher for spraying the powder over the fire. This powder will prevent the supply of oxygen to the flames and smother the fire efficiently.
Class F contains cooking oil and fats as a source of this class of fire. Cooking fires are fueled by a wide range of liquid cooking materials. Greases, cooking oils, vegetable fat, and animal fat are all fuel sources. It is very difficult to extinguish oil fire because it involves high temperatures. Using water to extinguish a cooking fire can worse the flame intensity and can cause huge fire damage to the building.
This is why we use a special extinguisher to smother the cooking fire. Wet chemical extinguishers also contain a formula that cools the fire and prevents re-ignition.
Once we understand the fire classes and extinguishers used for each class of fire the next question is How to use Fire Extinguisher? Using methodology is different for different types of fire extinguishers. So, that is why I am going to mention the methodology for every single type.
There are different techniques of using the DCP extinguisher for different types of fire.
If the fire occurs from different combustible material like wood or solid, then aim the fire extinguisher at the base of the fire and then sweep the cylinder across the flames in a steady motion.
If the fire occurs due to liquid, the powder jet should be directed at the nearest edge of the fire, and a sweeping motion used to work backward from there.
For the fire involving electrical equipment, we must disconnect the power supply, and then use the fire extinguisher to smother the flames. When the fire appears to be out, allow the area to clear and check for any areas of remaining flame and use the extinguisher again.
A powder extinguisher cannot work on all types of fire, because the powder can penetrate some appliances and there is a danger that fire can start again.
Direct the horn at the base of the fire and move across in a sweeping motion. When the fire appears to be out, check for a while afterwards for any areas of remaining fire and use the extinguisher again if necessary.
We cannot use a CO2 fire extinguisher for smothering oil fires because the jet will spread the burning oil everywhere. So, it cannot work efficiently on the cooking fires. CO2 gas can be harmful to human health if not used in prescribed quantity, so we must use CO2 extinguisher with great care. It is necessary to ensure that the area is ventilated after we use it.
We use a foam extinguisher for a fire involving flammable liquid. When the burning liquid is inside a container, direct the jet of foam at the inside edge of the container and this will break the jet and allows the foam to flow gently over the surface of the liquid, extinguishing the flames. Another alternative is that direct the jet of foam from a distance in a sweeping motion so that it drops down onto the surface of the fire without breaking it up.
But we cannot use foam fire extinguishers to smother fat/oil fire. On burning, liquids do not aim the foam directly into the liquid as this will send it into the liquid and make it ineffective. It could also cause splashing and therefore spread the fire around.
For using the water extinguisher, we have to direct the jet of water at the firebase and sweep it back and forth across the fire. If the fire is spreading vertically, start at the lowest point, and work upwards. After using it we must ensure that all the area is free from fire and if you see any single flame, then put it off completely.
For using the wet chemical fire extinguisher, use the jet to spray the chemical in a steady circular motion. This type is crucial because this is the only type of fire extinguisher that we can use to smother fat fires.
The ball needs to place close to the hotspot area. When the fire breaks out the user needs to pick up the fire blanket from the bag with the help of two hanging tails. Then the user has to cover the object which catches the fire with a blanket. It works by reducing off the oxygen delivered to the fire. A fire breaks out when all the three-element of the fire triangle (heat, fuel, and oxygen) are present. When the blanket cuts off the oxygen from these three elements the fire will be knocked out. Users can also use this method when the body catches the fire, a user just has to wrap the body with the blanket and smother the fire.