Explosions and types

1. Explosions
GROUP NO 05
Presented By : Sayyed Ali Hassan
Reg# 12 CET 05
GCT Rasul Mandi Bahauddin pakistan
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2. 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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3. Types of Explosions
There are 4 general types of explosions;
1. Mechanical
2. Chemical,
3. Nuclear
4. Electrical.

4. 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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5. Types of Explosions………….cont
3. 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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6. 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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7. 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.
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8. Causes of Explosions
Natural
Explosions 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
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9. 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.
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10. Causes of Explosions…………
Electrical and magnetic
o 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 welding
Mechanical and vapor
o Mechanical explosion that can occur when a vessel containing a pressurized liquid is ruptured, causing a
rapid increase in volume as the liquid evaporates
Nuclear
o 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 10

11. 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. 11

12. 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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13. EFFECTS OF EXPLOSIONS……..
• Tsunamis
• Toxic gases released into the atmosphere.
• Loss of power
• Contaminated water supply and other services
• Property damage
• Floods
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14. EFFECTS OF EXPLOSIONS……..
EFFECTS OF EXPLOSIONS ON HUMANS
1. 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 organs
o Lethality Due to Lung Injury
o Ear Damage
o Thermal burns.
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15. EFFECTS OF EXPLOSIONS ON HUMANS…………..
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2. SECONDARY EFFECTS
o Collapse of Buildings
o TERTIARY EFFECTS
thrown away

16. THANK YOU
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