2-3-1 Flammability and Source of Ignition

Flammability and Sources of Ignition
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Fire Triangle & Definitions
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The The Fire Fire Triangle Triangle
Fire prevention consists of making sure that the three sides of the fire triangle never meet
FUEL
OXIDIZER
IGNITION
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Fire Fire Propagation Propagation
ƒ Recent studies indicate that the spread or propagation of a fire is also dependent on a fourth factor – the chemical chain reactions that can occur as a result of heat produced by the fire.
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Fire Fire Propagation Propagation
The fire tetrahedron or fire pyramid adds a fourth component— chemical chain reaction—as a necessity in the prevention and control of fires.
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Flammable Flammable Liquid Liquid
ƒ ƒ ƒ A flammable liquid in its liquid state will not burn. It only will ignite when it vaporizes into a gaseous state. All flammable liquids give off vapors that can ignite and burn when an ignition source i.e., lighted cigarette or spark. A flammable liquid is one having a flash point below 100oF (37.8oC). A combustible liquid is one with a flash point of 100oF (37.8oC) or above.
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Spontaneous Spontaneous (Auto) (Auto) Ignition Ignition Temperature Temperature
ƒ The lowest temperature to which a liquid or gas requires to be raised to cause self-sustained spontaneous combustion without ignition by a spark or flame . When a flammable liquid is in its liquid state, it will not ignite. It will only burn when in its gaseous state.
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Auto Auto Ignition Ignition Temperature: Temperature:
ƒ Ignition temperature is the minimum temperature at which a material will burn or explode. ƒ Auto ignition temperature is the temperature at which a mixture of flammable vapor and air would ignite without a spark or flame. ƒ External source of ignition include sparks and flames and , less obviously, hot compressor discharges that can bring combustibles above their auto ignition temperature without a spark or flame.
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Flammable Flammable Conditions Conditions
ƒ A fire will not always start when the THREE sides of the fire triangle meet, unless all three elements are present in the required amounts
ƒ For example, vapors from a flammable liquid must be mixed with a certain amount of air in order to ignite and propagate a flame.
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Lower Lower Flammable Flammable Limit Limit
ƒ The lowest concentration at which a fuel/air mixture will burn. Below this there is too little fuel (the mixture is too lean). Also, known as “Lower Explosive Limit or LEL.”
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