ExplosionsGROUP NO 05

Presented By : Sayyed Ali Hassan

Reg# 12 CET 05GCT Rasul Mandi Bahauddin pakistan

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Definition of Explosions• An explosion is a rapid increase in volume and release

of energy in an extreme manner, usually with the generation of high temperatures and the release of gases.

•  Supersonic explosions created by high explosives are known as detonations and travel via supersonic shock waves. 

• Subsonic explosions are created by low explosives through a slower burning process known as deflagration or firework.

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Types of Explosions

There are 4 general types of explosions;1. Mechanical2. Chemical, 3. Nuclear 4. Electrical. 

Types of Explosions•1. Mechanical

In which a high pressure gas produces a physical reaction, vessel failure or rupture of the container.

• Nature of the Fuel does not change• a. Damage to the vessel ( BLEVE, Boiler Failure)

• 2. Chemical• The generation of high pressure gas is the result of an exothermic reaction

resulting from the initiation of chemical explosives or fuel gases. The rate of reaction will vary, and when explosives are present, an outside oxidizer is not required.

• a. Combustion Flammable Gases• Vapors of Flammable and Combustible Liquids Dusts or Fines• Backdraft (Smoke) Carbon Monoxide and Carbon

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Types of Explosions………….cont3. Electrical Explosions High energy electrical arcs may generate sufficient heat to cause an explosion. A common example is found in residential occupancies (and others) is that the cover of the electrical panel box has been violently dislodged from the remaining box. Often this has been caused by a lightning strike or other high energy arc. This reaction may or may not result in subsequent fire.

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4. Nuclear Explosions .

Caused by a man-made device such as an exploding rocket • High quantities of heat

and gas are produced as a result of the fusion or fission process.

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Properties of explosions• Force• Velocity• Evolution of heat

The generation of heat in large quantities accompanies most explosive chemical reactions.

• Initiation of reaction• Fragmentation

Fragmentation is the accumulation and projection of particles as the result of a high explosives detonation.

• High velocity, low angle fragments can travel hundreds or thousands of feet with enough energy to initiate other surrounding high explosive items, injure or kill personnel and damage vehicles or structures. 7

Causes of ExplosionsNaturalExplosions can occur in nature. o  Volcanic processes of various sorts.

Explosive volcanic eruptions occur when magma rising from below has much dissolved gas in it;

o  Bushfires  in Eucalyptus forests where the volatile oils in the tree tops suddenly combust.

o Animal bodies some animals hold a large amount of flammable material such as animal fat. (This, in rare cases)

o Explosion due to hurricane sandy 8

Causes of Explosions……………… Astronomical• Supernovae

which result when a star explodes from the sudden starting or stopping of nuclear fusion, and gamma ray bursts.. Solar flares  an example of explosion common on the Sun, and presumably on most other stars as well.

• Asteroids  (e.g. planet asteroid)

Chemical• The most common artificial explosives are chemical explosives, usually involving a rapid

and violent oxidation reaction that produces large amounts of hot gas.•  Gunpowder was the first explosive to be discovered and put to use

Gunpowder is a mixture of potassium nitrate, carbon, and sulfur. Mixtures of these chemicals (in the correct ratios) can produce a chemical explosion.

• The potassium nitrate is reduced and the carbon and sulfur are oxidized.9

Causes of Explosions…………Electrical and magnetico A high current electrical fault

can create an 'electrical explosion' by forming a high energy electrical arc which rapidly vaporizes metal and insulation material.

o Explosion due to weldingMechanical and vaporo Mechanical explosion that can occur when a vessel containing a pressurized liquid is

ruptured, causing a rapid increase in volume as the liquid evaporates

Nuclearo Nuclear explosions, a man-made nuclear weapon is a type of explosive weapon that

derives its destructive force from nuclear fission or from a combination of fission and fusion.

o A nuclear weapon with a small yield is significantly more powerful than the largest conventional explosives available

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Causes of Explosions……………..

• Other common causes for plant explosions include:• Boilers that are not properly cared for;• Careless cigarette smoking while on premises;• Malfunctioning and dangerous equipment;• Improper maintenance of machinery• Unseen corrosion• The use of impure or dirty chemicals• Failing to properly train all employees.•  In other cases, a natural disaster such as an earthquake or lightning storm can be the cause.• poor labeling, • unsafe procedures, • even violations of OSHA safety regulations.

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EFFECTS OF EXPLOSIONS

• More fires• Increased stress on endangered species • Loss of livestock and crops• Disease• Loss of habitat• Houses, buildings, and other structures destroyed

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EFFECTS OF EXPLOSIONS……..• Tsunamis• Toxic gases released into the atmosphere.• Loss of power• Contaminated water supply and other

services• Property damage• Floods 13

EFFECTS OF EXPLOSIONS……..EFFECTS OF EXPLOSIONS ON HUMANS1. Direct ( Primary Effects) o The main direct, primary effect to humans is the sudden increase in pressure

that occurs as a blast wave passes.

o Injury to pressure sensitive human organso Lethality Due to Lung Injuryo Ear Damageo Thermal burns.

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EFFECTS OF EXPLOSIONS ON HUMANS…………..

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2. SECONDARY EFFECTS

o Collapse of Buildings

o TERTIARY EFFECTS thrown away

THANK YOU

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