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

In the modern world, the security of every person is one of the highest priority conditions of existence. Nevertheless, it is at this time that various catastrophes and natural disasters claim a significant number of human lives. One of the worst situations is fires. The material presented below will examine in detail both the causes of their occurrence and the damaging factors that are harmful to all living things.

What is a fire?

First, let's deal with the definition itself. Such a term implies an uncontrolled combustion process, as a result of which material damage is caused to both individuals and the interests of the entire state. At the same time, harm to health and even a threat to the life of citizens is also possible.

Fire classification

Modern practice distinguishes the following categories:

1. Underground fires.

2. Forest.

3. Field.

4. Technogenic.

5. Fires on vehicles.

6. Fire in buildings.

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

Classification

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

Causes of occurrence

After studying the classification of fires, in addition to it, it is necessary to separately consider factors that may result in a fire source. One of the most common causes of fire is the careless handling of fire. An uncoupled cigarette, childish prank or burning garbage - each of these actions can lead to uncontrolled burning, namely a fire. The second factor in the appearance of a fire source 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 result, short circuits and other phenomena that contribute to the appearance of a spark discharge are possible. And he, in turn, is likely to grow to a fire. By the way, since the topic of discharges was raised, it is necessary to mention the next reason for the occurrence of the source of ignition. Of course, these are atmospheric phenomena, for example, thunderstorms. A lightning strike into a building in which flammable substances are located is likely to cause a fire. However, lightning discharges are rare enough to prepare in advance for their appearance.

Nevertheless, Mother Nature can throw another trick. Everyone knows the laws of reflection of the light flux from the surface, because they are already studying them in high school. But the practical application of the above laws can adversely affect the technogenic environment of modern megacities. For example, due to the architecture of buildings, a so-called optical system may arise that collects diffused sunlight into a concentrated beam. The temperature on the surface onto which such a beam will fall will gradually begin to rise. And at a certain point it will reach the melting point or spontaneous combustion of the material. And as a result, a fire can occur. It should also be noted that spontaneous ignition of materials and substances belongs to a separate group of causes of situations that are dangerous to human life and health.

Arson

In addition to all of the above reasons, fires can occur as a result of deliberate arsonization. In such cases, the initiative of one or more people always takes place. Of course, every modern resident of the metropolis knows that such actions are prosecuted by applicable law. However, sometimes this circumstance does not stop some.

Explosive processes

Various emergency situations also belong to a special category that can cause a fire. As a result of a small error, an explosion of some combustible substance may occur.

The main damaging factors of the fire

In the event of an emergency, a fire may form, which, in turn, has some characteristic features. They are called "damaging factors of the fire." These are the conditions under which material damage is possible, as well as harm to both the health and life of citizens. Currently, the following damaging fire factors are distinguished: primary and secondary. As the name implies, the first group includes those conditions under which the active development of the combustion process occurs. Thus, fire, sparks, and high ambient temperature are among the damaging factors of a fire. Secondary, in turn, belong phenomena and processes that arise as a result of the action of the conditions of the first group. As a rule, such damaging fire factors include smoke, low oxygen content, the formation of toxic combustion products and other negative consequences. Consider each of the previously presented factors in more detail.

Flame and heat flux

As mentioned earlier, the damaging factors of fire include sparks and fire, which can rightly be considered the root cause of the fire. Flames in the form of open uncontrolled fire can pose a significant threat to both the health and life of people in the immediate vicinity. In addition, such damaging fire factors contribute to the spread of the latter. Thermal radiation, as part of the previously described conditions, allows the environment to gradually heat up, which, in turn, provides flame languages ​​with the ability to significantly increase the range of the affected area.

Reaction products

The combustion process, like other chemical reactions, allows you to get some substances. However, it must be remembered that all kinds of compounds are formed as a result. According to a large number of experts, these highly toxic substances, which are considered dangerous for the normal functioning of people, are also striking factors of the fire. Such compounds obtained in the course of chemical reactions traditionally include carbon dioxide and carbon monoxide, as well as hydrogen chloride. It is important to know that abroad, a substance called hydrogen cyanide is also ranked among the above combustion products. Remember that these damaging fire factors are extremely toxic, therefore even their slight contact with the human body can cause significant damage.

Reduced visibility

As the saying goes, "there is no smoke without fire." And if there is a lot of flame? In this case, it is necessary to recall such damaging factors of the fire as smoke "curtains", consisting of particles of solid and liquid substances suspended in the air . You need to know that this category can cause both a significant deterioration in visibility and a decrease in the percentage of oxygen in the environment to a minimum. Due to the above factors, light penetrates the formed obstacle much worse. And people who find themselves in a building in flames can hardly find a safe exit. Thus, we can conclude that smoke and subsequent deterioration in visibility are not so much the dangerous damaging factors of fires and explosions as a psychological barrier. After all, it is he who impedes the prompt and safe evacuation of a building that is dangerous. Most people who find a very smoky room on their way out are very likely to turn back and try to hide in the previous room.

Significant temperature increase

Everyone knows that, in addition to the formed chemical compounds, thermal energy is released during the course of the combustion reaction. Moreover, in significant quantities. If at the very beginning of the fire the air temperature will be about 200-300 degrees, then during its most destructive phase the flame heats the environment to 900 ° C! The harm caused to a person in such a case can be calculated by studying the main damaging factors of a fire in this category. As a rule, these are humidity, air exchange conditions, suspended particles contained in air, and much more.