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elements, the formation of solid debris. Underground (basement) of the buildings
much less destroyed. Completely destroyed residential and industrial buildings,
fallout shelters, a sealed vault near the center of the explosion. Up to 75 % sealed
storage, and up to 90 % of the underground utility and energy networks is
preserved.
The zone of strong damage is overpressure from 50 kPa up to thirty. A
fracture caused when excess pressure: high-rise buildings – 25-30 kPa, low-rise
buildings — 25-35 kPa, structures of industrial type, 30 to 50 kPa. A large part of
the deformed bearing structures. Can stay partly the walls and ceilings of the lower
floors. Formed blockages.
In a zone of medium destruction most of the supporting structures remains
and is only partially deformed. Remains the walls with possible cracks in external
walls and gaps in some places, but it is minor and part of the load-bearing
structures can be completely destroyed. Sealed vault and part of the fallout shelter
are not damaged. Average damage will suffer a multistory structure at a pressure of
10-20 kPa, low-rise building of 15-25 kPa, facility — 20-30 kPa. Utility-energy
network to deform and collapse the individual supports of overhead power lines,
damaged process pipelines.
In the zone of low damage destroyed windows, doors, light partitions, cracks
mainly in the walls of the upper floors. Basements and lower floors remain. Minor
destruction and damage to communal energy networks.
Weak destruction of buildings of all types occur at a pressure of 7-20 kPa.
Damages are characterized by failure of the weakest elements of buildings:
cornices, partitions, doors, windows, etc. Damage to buildings of all types occur at
a pressure of 3-5 kPa.
One of the features of the shock wave is a relatively long duration of action,

which can reach several seconds. The shock wave can penetrate into buildings
through windows, vents, chimneys, crevices and other openings. When you receive
a shock wave inside the premises, it is possible sharp increase in pressure, which
leads to various destructions.
The dilution that occurs as result of high pressure, much weaker shock wave,
but increases the impact of a direct blow, and this should be considered during the
rescue, emergency and restoration works.
The main reason for the destruction of the hard structures (stone and wooden
buildings) will kick off at the moment of wave reflection from the building, that is,
the pressure of the reflection of the shock wave. Approaching the obstacle, the
shock wave is reflected, creating a pressure shock wave reflection. The inhibition
of air masses that moves, and the pressure increases. Through this obstacle applies
a blow of great strength, which increased as result of pressure reflection.
During a nuclear explosion under water also produces a shock wave.
Pressure front of the shock wave in underwater explosion is ten times greater than
the overpressure in an air blast (at equal distances). The duration of elevated
pressure, on the contrary, several times less than during the air blast and the

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