Fire and causes of fire ignition

Fire is, an uncontrolled burning out of the special area thatbrings moral and material losses and sometimes people victims.

The causes of fire:

- violation of fire prevention rules;

- careless behavior with fire;

- electrical equipment malfunction;,

- failure, catastrophe;

- natural phenomena.

Process of burning is possible when the following is present:

- combustible;

- ignition source;

- oxidizer.

Combustible is a solid, liquid or gaseous substance capable to oxidize with heat and light radiation.

Oxidizer is oxygen, chlorine, fluorine, sulfur and other substances capable under heating or impact to decompose extracting oxygen.

Ignition source is influence on combustible and oxidizer that can induce inflaming. Ignition sources are divided into open and hidden.

When any of three factors is missing burning doesn't appear.

Fire risk materials are materials and substances which by their properties enable origin or development of fire.

Ignition is burning appearing under influence of ignition source.

Flash is fast burning of combustible mixture that is not followed by formation of compressed gases.

Self-ignition is phenomenon of sharp magnification of velocity of exothermal reaction that results in substance burning appearing.

Combustion is ignition followed by flame appearing.

Self-combustion is self-ignition that is followed by flame.

Explosion is a fast substance transformation that is followed by extracting of energy and formation of front of compressed gases.

Combustion temperature is the lowest temperature of the substance under which the stable flame burning appears

All the materials and substances are divided into three combustibility groups:

1. incombustible is substance unable to burn in the air;

2. hard-combustible is substance able to ignite on the air from the source of fire, but unable to keep burning after the fire source is taken off;

3. combustible is substance able to self-ignite and also ignite from the source of fire and continue burning without fire source.

Fire-resistance of building constructions is the characteristic to keep bearing and protection function on fire (measured in hours). Fire-resistance of structures is determined by ultimate fire-resistance of main building structures. Combustible parts of buildings have no ultimate fire-resistance.

By fire-explosive risk work areas are divided into 5 categories:

А, Б - fire-explosive risk area ;

В - fire-risk

Г - area where heated incombustible solid, liquid or gaseous substances burned on salvaging as fuel are used.

Д - area having incombustible substance in cold state.

Building area or its part where the explosive mixtures can appear or combustible materials are, is named as fire-explosive risk zone.

The explosive risk zones are divided into 6 classes: ВІ, ВІа, ВIб, ВІг, ВІІ, ВІІа; fire risk - into 4 classes: П-І, П-ІІ, П-ІІа, П-ІІІ.