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Antiterrorism
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| Ways of blast mitigation
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Within the past two-three decades of the XX century terrorism has become a disappointing reality of world life. Explosions are a very attractive method for terrorists because they cause great destruction and allow criminals to escape far away from the site of the crime by the moment of the blast.
Various technical devices is used to decrease the effect of Explosive Device (ED). Every device has its own specific features, its area of application, its advantages and disadvantages ...
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Bomb blanket
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Special equipment, known as "Bomb Blanket", has been designed to reduce a blast way energy and fragmentation area. Made of aramid fabrics such as Twaron, Kevlar or Ballistic Nylon it is placed over the suspicion object and its efficiency depends on a number of ballistic fabric layers, ways of stitching and other factors.
Disadvantages: Protects only against blast energy from small amount of explosives, retains fragments of limited size and velocity, cannot prevent fire, two people are required for installing it .
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Bomb bins
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Bomb bins are designed for keeping and transporting explosives inside them. Made of ballistic materials. Mainly there are two types known: closed and semi-open. Closed type bins are dedicated to complete localization of brisance, blast and fragmentation effects resulted from 10g to 5 kg TNT. They are widely used in aviation, for example, when suspicious object found on board a plane. According to I ATA requirements , each plane must be equipped with bomb bins enough to suppress blast energy from 450 g TNT. An example of such a bin is a 122 kg device designed by Royal Ordnance ( Great Britain).
Disadvantages: Placed in a bomb bin a suspicious object is not seen and cannot be properly evaluated. Some bins don't guarantee complete retain of blast gaseous products. In semi-open type bins a blast way is moving upwards and can cause secondary damages. All of such devices are pretty heavy and expensive. One of the lightest bins dedicated to suppressing blast energy from 850g TNT weighs 170 kg. It can be placed over an object not bigger then a radius of its load input inner diameter ( for example a bomb bin designed against 400 g TNT explosion has 163mm load input inner diameter).
Apart from it , such devices have two very serious disadvantages:
First. If a bomb bin is used against a charge bigger than that it was designed for , the bin can become a source of additional fragmentation.
Second. A suspicious object has to be removed and placed into a bin, which is very dangerous. Remote control systems and robots developed for this are very expensive and have a limited area of application.
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Liquid inhibitors
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Mass production of this type of blast localization devices started at the beginning of 90-th [patent USA N 4836079]. Liquid Inhibitors (LI) are very efficient and comfortable for extensive use . LI is dedicated to reduce a risk of injuries and destruction until an arrival of professionals. It is recommended for administrative buildings, banks, airports and other public places where a possibility of terrorist acts are very high.
LI combines such advantages as efficiency, comfort and ease at usage, low price. You don't have to touch or replace a suspicious object, cover it with an LI and that is all. Whatever a weight of a charge is, there is no risk of additional dangerous fragmentation from the devise!
LI is a container divided into several elastic shell compartments. The compartments are filled with a liquid ( usually with a solution of ethylene glycol). LI shape provides fully isolation of a suspicious object. A right installed LI significantly reduces a blast pressure, restricts fragmentation area and localizes heat.
LI can be taken off a suspicious object manually or with some special devices and the object can be observed and studied by a professional.
LI can be easily x-rayed and the object can be detonated inside of it. LI designed to protect against max. 2-5 kg charge are used in actual practice.
Disadvantages: LI significantly reduces but doesn't completely inhibit a blast effect. A suspicious object can be observed through LI only in x-ray spectrum.
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Special Materials Ltd. has developed a line of LI " Fountain" ( patent N 125232, publ. 20.01.99, N 2150669 and 2150670, publ. 10.06.00).
Our "Fountain" is equipped with additional antifragmentation screen made of ballistic fabric. 11-55 kg LI are designed for protection against hand grenades or 0.4 - 1 kg TNT explosion.
"Fountain" LIs have been tested and certified . Testing demonstrated their high efficiency.
Thus, "Fountain" LI is an efficient and reliable liquid blast inhibitor reducing blast energy and fragmentation. It can be favorably compared with devises known in this field. "Fountain" has great potential and Special Materials Research Lab are being working on enhancing its efficiency.
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commerce@npo-sm.ru
Special Materials Ltd.
B.Sampsonievski, 28A,
St.Petersburg,
194044,Russia
Phone: +7(812)248-85-68 Fax: +7(812)274-59-44
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