Fire plays an important role in various aspects of human life. The importance of fire in the development of human civilization and today in human survival doesnít need to be overemphasized. It is both the creator and destroyer of life. Nowadays, fire has become a topic of headache to the people and government of our country. Fire related accidents are increasing in the country. Every year, more than 1,500 fire-related incidents are occurring in the nation and itís claiming an average of 43 lives and property worth at least Rs 350 million. Our country is ill-equipped to cope with fire. Even the Kathmandu metropolitan city does not have proper equipment to fight fire. As per the international standards, there must be at least a fire truck for 28,000 people but we have only five fire trucks for more than 2.4 million people in the Kathmandu valley. In this deficient environment it will be unwise for the people to believe that government authorities will control the fire if it outbreaks in their home or locality. Every individual needs to prepare for probable cases of fire at their home and locality.
How does fire work?
Many people may not know that oxygen, fuel and heat are required to start a fire. In absence of any one of these three components fire canít be active. Fire is the result of chemical reaction that burns the fuel in oxygen and produces heat. Fire extinguishers are designed in such a way that they remove at least one of these components to stop fire.
Types of fire
Experts have classified fire into four categories namely class A, B, C and D. The fire that start in wood, paper or clothes fall into Class A fire while Class B fire is that which starts in flammable liquid, oil or gas. The fire incident because of electrical short circuit, overload and other electrical equipment falls under Class C and fires in combustible metals are classified as Class D fires.
Types of fire extinguishers
Different types of fire extinguishers are designed for the purpose of stopping fire on the basis of above classification. However, there are four most commonly used extinguishers namely all purpose water extinguisher, carbon dioxide extinguisher, multipurpose dry chemical type extinguisher and dry powder type extinguisher.
Water is a universal solvent. Water is the building block of life of every flora and fauna available on the earth. This pious molecule is the first and most commonly available material to cope with fire. Water is used to stop fire in most fire incidents in our country. But, engineering and fire experts suggest that water can control only A type fire such as fire on wood, paper, trash or cloth. If fire is of other classes like B, C or D, water alone will not easily control the fire. In the water type extinguisher, water is kept in compression inside it. With the help of pressure gauge water from the device comes out in a high pressure when the handle of the extinguisher is squeezed. This pressurized water removes the heat (component needed for fire) so that the fire extinguishes.
In Class B and Class C fires, carbon dioxide (co2) extinguisher should be used. The extinguisher device contains carbon dioxide gas. The CO2 severs as a subtracting factor to the equation of fire as it displaces oxygen to produce excess carbon monoxide. As fire canít start without any of oxygen, fuel or heat the fire comes under control. This type of extinguisher does not have a pressure gauge because CO2 gas isnít pressurized. It has a hard plastic nozzle to disseminate CO2 gas over the fire.
Multi-purpose dry chemical type of fire extinguisher is effective to control all of the Class A, B, C and D type of fires. This type of extinguisher consists of fine powder under pressure. When the handle is squeezed, the pressure gauge comes into action and it releases the pressurized chemical powder projected towards the fire. This chemical reacts with oxygen, removing oxygen so that fire canít burn further in its absence. Some of the chemicals react with fuel so that these fuels turn into anti-flammable compounds.
Dry powder type of fire extinguisher is effective to control every type of fire. The powder is applied to fire which displaces oxygen by reacting with it to form various by-products, and hence, the fire is controlled.
How to use a fire extinguisher?
Fire extinguishers are operated manually with our hands. So, it must be properly handled. Otherwise the chemicals may harm our health and even endanger our lives. The most effective method accepted by everyone is PASS method, i.e. 1) Pull the pin, 2) Aim at the base of fire, 3) Squeeze the handle and 4) Sweep side to side.
Every extinguisher contains a pin that locks the handle when not in use. It acts like a safety valve. At first this pin should be pulled to operate the extinguisher. This pin will allow the user to squeeze the handle in order to discharge the extinguisher.
The user needs to aim the discharge nozzle at the base of the fire. Aiming in the middle will do no good to stop the fire. If the extinguisher is water type, discharging water at the centre of fire means the water is evaporated to vapour because of heat. Thus, it contributes 0 per cent to control the fire. Every individual needs to know about this, be it a small fire at their home or bigger one at their locality.
The next step in using extinguisher is to squeeze the handle which will release the pressurized extinguishing agents like water or chemicals to the target. The user needs to sweep the nozzle from side to side in order to target a large area effectively. The user needs to keep an eye on the controlled area for possible relighting also.
One shouldnít fight against fire when they donít have an extinguisher, enough water or equipment. If fire has spread beyond the area of its origin it will be in vain to try to stop it with only an extinguisher. One should fight with fire if it is only in the incipient stage. If one feels the fire has spread beyond control, s/he should leave the site as soon as possible.
One should call the nearest fire control station as soon as possible. The location should be evacuated as soon as possible. For this, the provision of fire alarm needs to be installed in buildings.
All the electric equipment should be switched off after their use. One shouldnít keep inflammable objects, petroleum products and lubricants in their room. Candles and lamps should be placed at places where one can keep an eye continuously. Above all, I recommend everyone to keep one fire extinguisher at their home.