Fires are the real scourge of mankind. Since ancient times, fire has been both an ally of man, giving warmth and protection, and a terrible enemy, destroying entire cities. And even now, with the development of fire fighting technologies, with modern security systems and low-combustible materials, from which houses and other premises are built, such disasters are still extremely dangerous. This article will discuss the stages of fire development and their brief description.
History of the development and creation of special equipment
The most used fire extinguishing agent at all times was water. However, with the development of technology and chemistry, it was found that some chemical compounds dissolved in water can cope with fire much more efficiently. Such substances, for example, include alum - double metal salts. Their aqueous solution has much higher fire extinguishing than just water.
The first mention of such solutions can be found in the fourth century AD, and later they became very popular throughout Europe. In the 17th century, fire extinguishing cartridges began to be used in Sweden, which when they were thrown into a burning building, alum exploded and sprayed. Similar experiments were carried out in Russia under Peter the Great, but the results were not particularly inspiring and the technology did not receive strong development in those days.
Modern fire fighting equipment and technologies
The fire extinguisher, roughly as we know it now, was invented in 1813 by an English captain named George Manby. As today, it was a vessel containing potassium carbonate under pressure. In view of its great efficiency and the possibility of use without preparation, it very quickly gained popularity all over the world and came to our times as a manual extinguishing agent, especially effective at the initial stage of a fire development.
Of course, since then, the design of the device has undergone some changes, now many fire extinguishers are not powder, but foam or carbon dioxide, however, this contribution to the history and saving of human lives cannot be underestimated. According to safety rules, in every building or public place there must be working fire extinguishers, which will allow to cope with a small fire and prevent a tragedy.
Stages of development of a fire in a building: first phase
Currently, it is customary to divide the fire stages into three phases. The first phase begins when the source of ignition appears. Ignition goes into fire when the fire begins to spread predominantly linearly through the combustible substance.
Depending on the parameters of the fire, such as the rate of combustion of the substance and gas exchange with the environment, this stage of the development of the fire takes from five to ten minutes. During this time, there is an extremely strong growth of the combustion zone and abundant smoke emission. It is at this moment that it is necessary to evacuate from a burning building, immediately at the first sign of smoke.
It must be remembered that very little time passes from the first signs of ignition and light smoke to a gigantic disaster. Therefore, when signs of smoke are detected, every second is important.
Second phase: features
The second stage of fire development takes 30-40 minutes. This phase is considered the main. During its time, an extremely stormy process of the spread of fire takes place. At its beginning, the temperature in the room rises to three hundred degrees, and the fire begins to spread through the air. Due to such high temperatures, the glazing of the building is destroyed, and the influx of fresh air enhances the fire and its spread rate. It can cover the entire building. The temperature in the room rises from 500 to 900 degrees. Fire covers even low combustible materials.
After this, the last stage begins - the stabilization of the fire, which lasts another 20-30 minutes or much longer.
Last phase: description
The last stage in the development of a fire is its burning out. The temperature is unevenly distributed throughout the room and can be hundreds of degrees higher near sources of ignition, and the smoke is most concentrated near the ceiling. At the same time, the volumes of exhaust gases become sharply less than the volumes of air and combustion products.
Because of this, the entire room is smoky, and visibility drops sharply to almost zero values. Afterburning time depends on the type of room and the combustible substances in it and can last a very long time before the fire finally extinguishes. Some rooms can burn for whole days, even despite the efforts of the services.
Conclusion
Knowing the stages of fire development and their characteristics, you can plan your actions in case of fire. Self-extinguishing is only possible with a small source of ignition. If the fire is already moving from the first phase to the second, it is urgent to evacuate yourself and take people out. It is necessary to move carefully, breathing through a wet rag and pressing against the ground, as toxic carbon monoxide accumulates mainly from above. Compliance with simple rules will save the life of yourself and your loved ones.
In no case should you use elevators. A similar technique may be de-energized. If the elevator gets stuck, it will be almost impossible to get out in a fire. It is always necessary to remember the safety rules, not to violate regulations, to control the free passage through the exits. Cluttered or idle exits can cause major tragedies that could have been avoided.