Fire and Explosions.

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Presentation transcript:

Fire and Explosions

Combustion Reactions A combustion reaction is an exothermic oxidation-reduction chemical reaction. Both fires and explosions are this type of reaction. The burning of methane is a good example: CH4 + 2O2 → 2H2O + CO2 Oxygen is the oxidizing agent, fires and explosions need either oxygen or another oxidizing agent.

A good way to look at the requirements For either a fire or an explosion is by using the fire triangle.

Fires and Explosions Fires Explosions “slow reactions” starts with a heat source does not involve shock waves release heat and energy Redox reaction Fire can cause explosion and explosion can cause fire Explosions quick reactions starts with a detonation involve shock waves release heat and energy Redox reactionFire can cause explosion and explosion can cause fire

Accelerants Accelerants are catalysts which alter a chemical bond and speed up a chemical process. Accelerants are often used to commit arson. When a fire is accelerated, it can produce more heat, consume the reactants more quickly, burn at a higher temperature, and increase the spread of the fire.

Boosters An explosive booster acts as a bridge between a low energy explosive and a low sensitivity (but typically high energy) explosive. Typical fuse does not deliver sufficient shock to detonate charges like TNT and other high energy explosives. Therefore, some form of "booster" is required to upgrade the energy released by the detonator so that the main charge will detonate.

Arson A fire set intentionally to cause damage or to cover up another crime. Arson is the leading cause of fire in the United States. According to arson statistics of the Federal Bureau of Investigation, an estimated 16,163 individuals were arrested for arson in 2006 - 84.4% were male and 50.8% were under the age of 18, an alarming 31.2% of which were under the age of 15