Explosion protection
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Explosion protection is used to protect all sorts of buildings and civil engineering infrastructure against internal and external
explosion An explosion is a rapid expansion in volume associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Supersonic explosions created by high explosives are known ...
s or
deflagration Deflagration (Lat: ''de + flagrare'', "to burn down") is subsonic combustion in which a pre-mixed flame propagates through a mixture of fuel and oxidizer. Deflagrations can only occur in pre-mixed fuels. Most fires found in daily life are diffu ...
s. It was widely believed until recently that a building subject to an explosive attack had a chance to remain standing only if it possessed some extraordinary resistive capacity. This belief rested on the assumption that the specific impulse or the
time integral In mathematics, an integral assigns numbers to functions in a way that describes displacement, area, volume, and other concepts that arise by combining infinitesimal data. The process of finding integrals is called integration. Along with d ...
of pressure, which is a dominant characteristic of the blast load, is fully beyond control.


Techniques


Avoidance

Avoidance makes it impossible for an explosion or deflagration to occur, for instance by means of suppressing the heat and the pressure needed for an explosion using an aluminum mesh structure such as eXess, by means of consistent displacement of the O2 necessary for an explosion or deflagration to take place, by means of
padding Padding is thin cushioned material sometimes added to clothes. Padding may also be referred to as batting when used as a layer in lining quilts or as a packaging or stuffing material. When padding is used in clothes, it is often done in an attempt ...
gas (f. i. CO2 or N2), or, by means of keeping the concentration of flammable content of an atmosphere consistently below or above the
explosive limit Mixtures of dispersed combustible materials (such as gaseous or vaporised fuels, and some dusts) and oxygen in the air will burn only if the fuel concentration lies within well-defined lower and upper bounds determined experimentally, referred to a ...
, or by means of consistent elimination of ignition sources.


Constructional

Constructional explosion protection aims at pre-defined, limited or zero damage that results from applied protective techniques in combination with reinforcement of the equipment or structures that must be expected to become subject to internal explosion pressure and flying debris or external violent impact.


Method selection

The technology of protection can range in price dramatically but where the type of device is rational to use, is typically from the least to the most expensive solution: explosion doors and vents (dependent on quantities and common denominators); inerting: explosion suppression; isolation – or combinations of same. To focus on the most cost effective, doors typically have lower release pressure capabilities; are not susceptible to
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
failures or subject to changing release pressures with changes in temperature, as "rupture membrane" types are; capable of leak tight service; service temperatures of up to 2,000 °F; and can be more cost effective in small quantities.
Rupture Rupture may refer to: General * Rupture (engineering), a failure of tough ductile materials loaded in tension Anatomy and medicine * Abdominal hernia, formerly referred to as "a rupture" * Achilles tendon rupture * Rupture of membranes, a "wate ...
membrane type vents can provide a leak tight seal more readily in most cases; have a relatively broad tolerance on their release pressure and are more readily incorporated into systems with discharge ducts. There are several fundamental considerations in the review of a system handling potentially explosive dusts, gases or a mixture of the two. Dependent upon the design basis being used, often National Fire Protection Association Guideline 68, the definition of these may vary somewhat. To facilitate providing the reader with an appreciation of the issues rather than a design primer, the following have been limited to the major ones only.


Database combustion and explosion characteristics of dusts

The database GESTIS-DUST-EX comprises important combustion and explosion characteristics of more than 7,000 dust samples from nearly all sectors of industry. It serves as a basis for the safe handling of combustible dusts and for the planning of preventive and protective measures against dust explosions in dust-generating and processing plants. The GESTIS-DUST-EX database is produced and maintained by the
Institute for Occupational Safety and Health of the German Social Accident Insurance The Institute for Occupational Safety and Health of the German Social Accident Insurance (German: ''Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung'', ''IFA'') is a German institute located in Sankt Augustin near Bonn and ...
. It was elaborated in co-operation with other institutions and companies. The database is available free of charge to be used for
occupational safety and health Occupational safety and health (OSH), also commonly referred to as occupational health and safety (OHS), occupational health, or occupational safety, is a multidisciplinary field concerned with the safety, health, and welfare of people at wor ...
purposes.Institute for Occupational Safety and Health of the German Social Accident Insurance: GESTIS-DUST-EX
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See also

* Explosion pressure * Explosion prevention standards for electrical equipment *
Explosion vent An explosion vent or rupture panel is a safety device to protect equipment or buildings against excessive internal, explosion-incurred pressures, by means of pressure relief. An explosion vent will relieve pressure from the instant its opening ( ...
*
Explosives safety Explosives safety originated as a formal program in the United States in the aftermath of World War I when several ammunition storage areas were destroyed in a series of mishaps. The most serious occurred at Picatinny Arsenal Ammunition Storage ...
*
Inert gas An inert gas is a gas that does not readily undergo chemical reactions with other chemical substances and therefore does not readily form chemical compounds. The noble gases often do not react with many substances and were historically referred to ...
*
Pressure relief valve A relief valve or pressure relief valve (PRV) is a type of safety valve used to control or limit the pressure in a system; pressure might otherwise build up and create a process upset, instrument or equipment failure, or fire. The pressure is re ...
*
Prestressed structure In structural engineering, a prestressed structure is a load-bearing structure whose overall integrity, stability and security depend, primarily, on ''prestressing'': the intentional creation of permanent stresses in the structure for the purpo ...


References

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