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Conflagration is an uncontrolled burning that threatens human life, health, property or ecology. A conflagration can be accidental or intentionally created (arson). Arson can be accomplished for the purpose of sabotage, diversion, and also they can be the consequence of pyromania. During conflagration the property is destroyed by fire. Sometimes the conflagration produces the firestorm, in which the central column of rising heated air induces strong inward winds, which supply oxygen to the fire.
Definitions
The causes and types of conflagration [5]The most common causes of conflagration are: careless handling of fire, the nonobservance of the operating instructions of production equipment, spontaneous combustion of substances and materials, the discharges of static electricity, the lightning, arson. Depending on an occurrence place we can distinguish: vehicles conflagration; steppe and field conflagrations; underground conflagrations in mines and mines; peat and forest conflagrations; conflagrations in buildings and constructions. The space covered by conflagration, is usually divided into 3 zones - the active fire zone, the heat zone and the smoke zone. External signs of a zone of the active fire are the presence of flame and the smouldering or hot materials. The main characteristic of the ravages of fire temperature is developed during combustion. For residential houses and public buildings indoor temperature reaches 800-900 °C. Typically, the highest temperature occur during outdoor fires and the average for combustible gases 1200-1350 °C, for liquids 1100-1300 °C, for solids 1000-1250 °C. When burning thermite, elektron, magnesium the maximal temperature reaches 2000-3000 °C. The space around the burning zone, where temperatures reached as a result of heat transfer values, causing destructive impact on the surrounding objects and dangerous for humans, called the zone of heat. Adopted take that into a zone of heat, burning the surrounding area, includes land, the temperature at which the mixture of air and gaseous products of combustion of not less than 60-80 °C. During a conflagration a significant movement of air and combustion products occurs. Hot gaseous products of combustion move upward, causing the influx of more dense cold air to the combustion zone. Inside the building the intensity of gas exchange depends on the size and location of openings in walls and floors, the height of the premises, and the number and burning properties of materials. The direction of traffic hot product and usually determines the probable spread of the fire path, as well as powerful back heat flows can move sparks, burning coals and lead to considerable distance, creating new hotbeds of burning. Products of a fire combustion (smoke) form a smoke zone. The composition of smoke usually consists of nitrogen, oxygen, carbon monoxide, carbon dioxide, water vapor as well as ash and other substances. Many products of incomplete and complete combustion, which are parts of the smoke, have high toxicity, the products generated during combustion of polymers are especially toxic. In some cases, products of incomplete combustion, such as carbon monoxide, may form with oxygen combustible and explosive mixtures. The most famous conflagrations
Ostankino conflagration (August 2000)
References
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