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Dynamic pressure of the air (velocity head air) P is a dynamic load created
d
by the flow of air. In the same way as the excess pressure, velocity head is
measured in Pascal (Pa).
The duration of the shock wave t — is measured by seconds. This value
depends on the power of the explosion. With the increase in the power of the
explosion, the duration of compression increases and the stronger its striking
power.
The shock wave causes damage as a result of the overpressure, dynamic
pressure of the air, it instantly covers the person from all sides.
The collision of the shock wave front with a person or animal acts on the
body a lot of pressure and it felt like a blow. This impact creates a compression
wave that is distributed in tissues and organs with great speed to 1500 m/sec.
Tissues and organs can react (change shape, shrink or grow), so some of them, the
pressure that much more than they can handle and, of course, happen organ
damage. The degree of damage to tissues and organs depends on the pressure of
the shock wave velocity. Particularly severely injured bodies filled with gases
(lungs, intestines), blood (liver, spleen, large vessels) and those that have cavities
filled with fluids (gallbladder, stomach and bladder). When exposed to a blast
wave passes a strong grip and then a very rapid expansion of air that is in the
organs that leads to the rupture of a significant amount of tissue.
Depending on overpressure and dynamic pressure of the air there are various
damage in humans and animals that the complexity of the lesions are divided into
light, medium and very heavy.
2
Minor injuries occur at a pressure of 20-40 kPa (0.2-0.4 kgf/cm ) and are
characterized by the dislocation, temporary hearing damage, a concussion.
Secondary injuries occur when excessive pressure 40-60 kPa (0.4-0.6
2
kg/cm ) and end up in concussion, hearing damage, dislocations of the extremities,
bleeding from the nose and ears, breaks eardrums.
2
Serious injuries occur when excessive pressure 60-100 kPa (0.6-1 kg/cm )
and are characterized by severe contusions, broken limbs, often public, a strong
bleeding from a nose and ears.
Very severe injuries occur when excessive pressure more than 100 kPa (1
2
kgf/cm ). They are characterized by bone fractures, ruptures of internal organs
(liver, spleen, kidneys, lungs and others), open fractures of the limbs, concussions,
fractures of the spine.
Territory, where under the influence of damaging factors of nuclear
explosion occurred the destruction of buildings, fires, radioactive contamination
and destruction of people and animals, is called the hearth of nuclear destruction.
To determine the nature of the destruction and the establishment of rescue
and other emergency operations, depending on the excess pressure in the shock
wave front, the center of nuclear destruction is conventionally divided into four
zones.
The zone of complete destruction is characterized by an overpressure of 50
kPa and the destruction or severe deformation of all structural and construction

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