Definition of a fire. Natural fires (forest, peat): definition

Fires present a great danger to life, health and property of people. Fire in nature occurs usually in conditions of prolonged and severe drought and windy weather. The flame that rages in the forest is a terrible enemy of the environment. After all, it brings enormous losses and sometimes leads to human casualties. Peat fires cause irreparable damage to nature, the elimination of the consequences of which will take dozens of years. The article will define the term "fire", the concept of this phenomenon in nature, in particular in the forest, is disclosed.

Definition of fires

A fire is a burning process that can not be controlled, occurs outside a special focus, causes material damage and poses a danger to human life and health. This is not necessarily an open flame, at times only incandescence and decay occur. The definition of the concept of "fire" assumes that such a combustion process is capable of self-propagating beyond the places that are intended for breeding and maintaining fire.

The characteristics that necessarily accompany this phenomenon are as follows:

• combustion;
• Gas exchange;
• heat exchange.

Depending on the place of burning, the classification of fires assumes the following types:

• Industrial;
• Household;
• Natural.

The obligatory condition of occurrence of ignition is presence of such components:

• Source of ignition;
• oxidizer;
• Combustible materials or substances.

Fire zones

The definition of fire assumes that such a phenomenon, regardless of its type, occurs on a certain space. This area can be conditionally divided into three zones:

• Zone of active burning;
• Zone of thermal impact;
• Smoke zone.

The zone of active burning is a part of the space in which there is directly a flame, smoldering or incandescent materials. In the case of a fiery (homogeneous) ignition, the boundary of this section is considered to be the surface of a flaming material and a thin layer of fire that glows. If the combustion is flameless (heterogeneous), then this zone is determined by the glowing surface of the glowing substance.

The zone of thermal impact is the space around the active combustion zone, where heat exchange takes place between the fire surface and the materials and structures nearby. The temperature here reaches values that are dangerous for people and surrounding objects. A person can not stay in this zone without special thermal protection.

The smoke zone is a space that adjoins the site of heat exposure, and where people can not be without special protection of the organs of vision and breathing. In such a site, the actions of firefighters are hampered by a lack of visibility.

A definition of the fire that occurs in the natural environment will be given below.

Definition of natural fires

Natural (landscape) fire is a burning process that can not be controlled, arises spontaneously and spreads in the environment. Occasionally such a phenomenon arises from a lightning stroke, a meteorite fall or a volcanic eruption, but the main reason is human actions. Because of deliberate arson or careless handling of fire and natural fires occur. The definition of this phenomenon distinguishes such types of fires:

• Forest fires;
• Fires of steppe massifs;
• Peat fires and fires of organic fossils.

Among the listed species there is one, which is the most widespread and brings huge losses. These are forest fires.

Definition of forest fires

Forest fires are the burning of vegetation, which can not be controlled and spreads spontaneously through the territory of the massif.

The main reasons for this phenomenon are two:

• Natural factors. This can be a lightning strike or spontaneous combustion of dry vegetation or peat.
• Anthropogenic factors. These include planned cleansing arson, targeted or accidental fires, or trivial non-compliance with safety rules when dealing with fire.

At the moment, the probability that such a forest fire will occur due to any natural factors, is approximately 20%. The main cause of forest fires is human activity.

The definition of a fire that unfolds in a forest massif assumes a classification depending on the speed of propagation and on the nature of the ignition.

Classification by speed of distribution

An important characteristic of forest fires is the speed of their propagation. According to this indicator, such fires are classified as follows:

• Weak;
• Average;
• strong.

For a weak forest fire, the propagation velocity is characteristic, which does not exceed 3 meters per minute. For average ignition, the value of this indicator varies from 3 to 100 meters per minute. And strong forest fires are characterized by a propagation speed of more than 100 meters per minute.

Classification by nature of ignition

Forest fires, depending on the nature of the ignition, are classified as follows:

• Grassroots;
• Riding;
• Underground (peat).

A grassland fire is a fire spreading through the lower layers of trees and shrubs, litter, leaves and branches that have fallen. The bulk of the inflammation begins with this type. Further, when creating certain conditions, a forest fire from the grassland is transformed into a mountain fire or a subterranean fire.

Horse fire - ignition, which covers the forest canopy. Fire in this case spreads over the crowns of trees. This type of ignition is characteristic of mountain forests. The emergence of high fires promotes strong wind.

An exact definition of the fire that occurs in the soil under forestlands will be given in the article below.

Peat fires: definition

A peat fire is the ignition of a natural or drained peat bog due to overheating of its surface by sunlight or when the person turns to the fire with careless handling.

Also, the causes of underground ignition may be lightning strikes or high and low fires. Their flame penetrates into the depth of the peat layer near the roots of trees and shrubs.

Peat fire can occur in the form of simple smoldering when there is no ignition, or in the form of burning with the incoming masses of carbon dioxide. Such phenomena are complex for detection. Often smoldering peat gives itself out only a small amount of smoke from the soil. The prolonged process of an underground fire can cause repeated ignition of fires.

Peat fires are classified according to the number of foci and the depth of burning.

Classification of peat fires

Depending on the number of outbreaks, peat fires are divided into the following types:

• Single-point;
• Multifocal.

Single-focal underground fires occur in the event of a lightning strike or careless handling of a person with fire in a particular place. Multi-focus is formed from several points of burning of underground organic substances.

The classification of peat fires according to the depth of burning is as follows:

• weak;
• average;
• strong.

A weak peat fire is characterized by a burn-in depth of not more than 25 centimeters. The average underground ignition has a value of this indicator from 25 to 50 centimeters. For a strong peat fire, the burning depth is more than 50 centimeters.

Conclusion

Fires, depending on the place of origin, are divided into industrial, domestic and natural. The space on which the ignition occurs is divided into three zones: active combustion, heat exposure and smoke. In turn, natural fires are additionally classified into forest and peat fires . The main reason for their occurrence is human activity. The definition of a fire occurring in a forest massif assumes an additional classification by the speed of propagation. Depending on the nature of the fire, this phenomenon can be grass-roots, upland and underground. Peat fires are subdivided into types depending on the number of foci and the depth of burning.