The main damaging factors of the fire. Primary and secondary fire damage factors

In the modern world, the security of each person is one of the most priority conditions of existence. Nevertheless, it is precisely now that various catastrophes and natural disasters carry a significant number of human lives. One of the most terrible situations is fires. In the material presented below, both the causes of their occurrence and the destructive factors damaging to all living things will be examined in detail.

What is a fire?

To begin with, let's look at the definition itself. Such a term implies an uncontrolled combustion process, as a result of which material damage is caused both to individuals and to the interests of the entire state. It is also possible to cause harm to health and even a threat to the lives of citizens.

Classification of the place of ignition

Current practice distinguishes the following categories:

1. Underground fires.

2. Forest.

3. Field.

4. Technogenic.

5. Fires on vehicles.

6. Combustion in buildings.

It should be noted that the latter, in turn, are divided into external, internal and domestic. Each of the categories presented reveals some features and distinctive features.

Separation into classes

Such a systematization is based on the allocation of groups with similar properties of materials subject to combustion. Data for classes and subclasses for ease of mastering are summarized in the table below.

Causes

After studying the classification of fires, in addition to the need to separately consider the factors that may cause a fire. One of the most common causes for which a fire occurs is the careless handling of fire. Unextinguished cigarette, children's prank or burning garbage - each of these actions can lead to uncontrolled burning, namely fire. The second factor of the appearance of the source of ignition is considered widespread at all kinds of production facilities. This is a failure to comply with the rules and regulations for the operation of equipment and various electrical installations. As a consequence, short circuits and other phenomena that contribute to the appearance of a spark discharge are possible. And he, in turn, is likely to grow into a fire. By the way, since the topic of discharges was touched upon, it is necessary to mention the following reason for the origin of the ignition. Of course, these are atmospheric phenomena, for example, thunderstorms. A lightning strike in a building containing combustible substances, with a sufficiently high probability, can lead to a fire. However, lightning discharges are quite rare phenomena in order to prepare themselves for their appearance in advance.

Nevertheless, mother nature can also throw another trick. Everybody knows the laws of the reflection of light from the surface, because they are still studying in high school. But the practical application of the above laws can have a harmful effect on the technogenic environment of modern megacities. For example, because of the architecture of buildings, a so-called optical system may arise that will collect scattered sunlight into a concentrated beam. The temperature on the surface on which such a ray will fall will gradually begin to rise. And at some point it will reach the point of melting or spontaneous combustion of the material. And as a result, a fire may occur. It should also be noted that spontaneous ignition of materials and substances belongs to a separate group of causes of life-threatening and human health situations.

Arson

In addition to all the above reasons, fires can occur as a result of deliberate incineration. In such cases, there is always an initiative of one or several people. Of course, every modern inhabitant of a metropolis knows that such actions are pursued by the current legislation. However, some people do not stop this circumstance.

Explosive processes

A special category that can cause a fire also includes various emergency situations. As a result of a small error, an explosion of a combustible substance may occur.

The main fire damage factors

In the event of an emergency, an ignition can form, which, in turn, has some characteristic features. They are called "damaging factors of fire." These are the conditions under which material damage can be caused, as well as causing harm to both health and life of citizens. At present, the following fire damage factors are distinguished: primary and secondary. As the name suggests, the first group includes those conditions under which the burning process actively develops. Thus, the damaging factors of fire include flame, sparks, high ambient temperature. To the secondary, in turn, belong phenomena and processes that arise as a result of the action of the conditions of the first group. Typically, such damaging fire factors include smoke, reduced oxygen content, the formation of toxic combustion products and other negative consequences. Let's consider each of the previously presented factors in more detail.

Flame and heat flow

As mentioned earlier, sparks and fire are among the damaging factors of the fire, which can rightly be considered the primary cause of the outbreak. The flame in the form of open uncontrolled fire can pose a significant threat to both the health and life of people in close proximity. In addition, such damaging factors contribute to the spread of the latter. Thermal radiation, as part of the previously described conditions, allows the environment to gradually warm up, which in turn gives the languages of the flame the opportunity to significantly increase the range of the affected area.

Products of reaction

The combustion process, like other chemical reactions, allows obtaining some substances. However, it must be remembered that as a result, all kinds of connections are formed. In the opinion of a large number of experts, these highly toxic substances, which are considered dangerous for normal human activity, are also the damaging factors of the fire. Among such compounds, obtained during chemical reactions, traditionally include carbon dioxide and carbon monoxide, as well as hydrogen chloride. It is important to know that abroad, a substance called cyanhydrogen is also listed among the above combustion products. Remember that these damaging factors of fire are extremely toxic, therefore even their insignificant contact with the human body can cause considerable damage.

Reducing visibility

As they say, "there is no smoke without fire." And if there is a lot of fire? In this case, it is necessary to remember about such damaging factors of a fire, as smoke "veils", consisting of suspended in air particles of solid and liquid substances. It is necessary to know that this category can cause both significant deterioration of visibility and a reduction to the minimum of the percentage of oxygen in the environment. Because of the above factors, light penetrates much worse through the formed obstacle. And people caught in a flame-swept building can hardly find a safe way out. Thus, it can be concluded that smoke and the subsequent deterioration of visibility are not so much dangerous damaging factors of fires and explosions, as a psychological barrier. After all, it is he who prevents prompt and safe evacuation from the dangerous building. Most people who find a highly smoke-filled room on the way out, are likely to turn back and try to hide in the previous room.

A significant increase in temperature

Everyone knows that, in addition to the formed chemical compounds, during the course of the combustion reaction heat energy is released. And in significant quantities. If in the very beginning of the fire the air temperature is about 200-300 degrees, then during its most destructive phase the flame heats the environment up to 900 ^о С! Damage caused to a person in such a case can be calculated by studying the main fire damage factors of this category. As a rule, it is humidity, air exchange conditions, airborne suspended particles and much more.