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Fire - Uncontrolled fire

Fire - Uncontrolled fire: Encyclopedia II - Fire - Uncontrolled fire

Fire: Encyclopedia II - Fire - Uncontrolled fire

Fire - Uncontrolled fire

The self-sustaining nature of fire makes it extremely dangerous if uncontrolled. Fire can consume structures and forests and can severely injure or kill living things through burns or smoke inhalation. Structure fires can be started by cooking accidents, electrical faults, fuel leaks, children playing with lighters and/or matches, and accidents involving candles and cigarettes. Fire can propagate rapidly to other structures, especially where proper building standards are not met. Purposefully starting destructive fires constitutes arson and is a criminal offense in most jurisdictions. The destructive capacity of fire has led most municipalities to offer fire fighting services to quickly extinguish fires. Trained firefighters use fire trucks, fire hydrants, and an array of other equipment to combat the spread of fires. Municipal buildings such as schools and government buildings often conduct fire drills to inform and prepare citizens on how to react to a building fire. Outside of urban settings, wildfires can consume large areas of forest and brush and often damage nearby settlements.

There are many different classification systems used for uncontrolled fires; in Europe and Australasia six groups are used:

Class A: Fires that involve flammable solids such as wood, cloth, rubber, paper, and some types of plastics.
Class B: Fires that involve flammable liquids or liquefiable solids such as petrol/gasoline, oil, paint, some waxes & plastics, but not cooking fats or oils.
Class C: Fires that involve flammable gases, such as natural gas, hydrogen, propane, butane.
Class D: Fires that involve combustible metals, such as sodium, magnesium, and potassium.
Shock Risk (formerly known as Class E): Fires that involve any of the materials found in Class A and B fires, but with the introduction of an electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire, with a resultant electrical shock risk if a conductive agent is used to control the fire.
Class F: Fires involving cooking fats and oils. The high temperature of the oils when on fire far exceeds that of other flammable liquids making normal extinguishing agents ineffective.

In the U.S., fires are generally classified into four groups: A, B, C, and D.

Class A: Fires that involve wood, cloth, rubber, paper, and some types of plastics.
Class B: Fires that involve gasoline, oil, paint, natural and propane gases, and flammable liquids, gases, and greases.
Class C: Fires that involve any of the materials found in Class A and B fires, but with the introduction of an electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire.
Class D: Fires that involve combustible metals, such as sodium, magnesium, and potassium.

A fifth group, Class K, is sometimes added. It refers to fires involving large amounts of grease or oil. Although, by definition, Class K is a subclass of Class B, the special characteristics of these types of fires are considered important enough to recognize.