Explosions defined

A kit for detecting explosives on suspects hands or clothing — Explosives Handling Detection Kit — was developed by Newhouser and Dougherty in 1972 [96]. It was designed to detect three types of explosives, defined by the authors as TNT-based explosives, RDX-based explosives, and NG-... 

Theory. If p is pressure, v - specific volume, e - specific internal energy, D detonation velocity, u - particle velocity, C - sound velocity, y - adiabatic exponent and q -specific.detonation energy, the velocity of propagation and particle velocity immediately behind any plane detonation wave in an explosive, defined by initial conditions, pD, v0, eQ, and uQ, are given by the first two Rankine-Hugoniot relations ... 

Deflagration constant An e q)erimental value for e losion characterization which is indicative of the maximum rate of pressure increase during an explosion. Defined by Equation (3.50). 

The hazard posed can be limited by maintaining a zone free of people and property around a storage area of explosive material. The minimum radius of the zone depends on the type and quantity of explosive, the extent and type of barrica ding, and the magnitude of loss that would be encountered if an explosive incident occurred. The maximum distance to which hazardous explosive effects propagate depends on the blast overpressure created, which as a first approximation is a function of the cube root of the explosive weight, W. This is termed the quantity distance and is defined as... 

The literature of chemistry and associated fields has iacreased enormously siace 1980. Kstahlishment of subspecialties and newly defined disciplines as well as iacreased research output have led to an explosion of journals, books, and on-line databases, all of which attempt to capture, record, and disseminate this plethora of knowledge (1). Tertiary reference tools ia chemistry and technology (eg, KJrk-Othmer, 4th ed.) help track the primary Hterature. Excellent references that discuss basic chemical information tools are The Titerature Matrix of Chemistry (1), Chemical Information Sources (2), and Mow to Find Chemical Information (3). 

The covalent compounds of graphite differ markedly from the crystal compounds. They are white or lightly colored electrical insulators, have Hi-defined formulas and occur in but one form, unlike the series typical of the crystal compounds. In the covalent compounds, the carbon network is deformed and the carbon atoms rearrange tetrahedraHy as in diamond. Often they are formed with explosive violence. 

Explosion-proof enclosures are characterized by strong metal enclosures with special close-fitting access covers and breathers that contain an ignition to the inside of the enclosure. Field wiring in the hazardous environment is enclosed in a metal conduit of the mineral-insulated-cable type. All conduit and cable connections or cable terminations are threaded and explosion-proof. Conduit seals are put into the conduit or cable system at locations defined by the National Electric Code (Article 501) to prevent gas and vapor leakage and to prevent flames from passing from one part of the conduit system to the other. 

The propagation of a shock wave from a detonating explosive or the shock wave induced upon impact of a flyer plate accelerated, via explosives or with a gun, result in nearly steady waves in materials. For steady waves a shock velocity U with respect to the laboratory frame can be defined. Conservation of mass, momentum, and energy across a shock front can then be expressed as... 

The combinations of failures and non-failed conditions define the state of the pJani at the right branches. The damage associated with these plant damage states are calculated using thermal-hydraulic analyses to determine temperature profiles that are related to critical chemical reactions, explosions and high pressure. These end-states serve as initiators fot breaking confinement that leads to release in the plant and aquatic and atmospheric release outside ol the plant,... 

Highly Hazardous Chemical - Toxic, reactive, flammable, or explosive substances, as defined in Appendix A of 29 CFR 1910.119, "Process Safety Management of Highly Hazardous Chemicals."... 

Among common areas where explosion can occur are coal mines, petrochemical plants, chemical plants, paint shops, grain handling industry, etc. Explosive limits for gases and vapors are expressed as percentages (% ), and may be defined as minimum and maximum concentrations of a flammable gas or vapor between which ignition occur. Concentrations below the lower explosive limit (LEL) are too lean to burn, while those above the upper explosive limit (UEL) are too rich. Table 7.8 lists explosive limits for some common gases. 

Fumes are defined as solid airborne particulates that have been produced by a change of state. Many industrial operations produce fumes which affect both the indoor environment and the outdoor environment. For many operations, fumes are generated by a high-temperature process. The gas stream containing the fume is usually of high temperature and contains combustibles. The combustibles may form an explosive mixture, thus necessitating specialized design inputs for most fume control ventilation systems. The major elements of a fume control system are pictured in Fig. 13.28. 

Originally the classification of materials was derived from tests of proprietary explosion-proof (flameproof) enclosures. There were no published criteria. Equipment was approved relative to the lowest ignition temperature of any material in the group (Magison 1987). In about 1965 the U.S. Coast Guard asked the National Academy of Sciences (NAS) to form a panel to classify 200 materials of commerce. The Electrical Hazards Panel of the Committee on Hazardous Materials was formed by the NAS. The Panel studied many ways to estimate the hazard classification of materials. The Panel finally reported to die U.S. Coast Guard in 1970 that no workable, predicdve scheme could be defined, and it then proceeded to assign tentative classifications to the 200 materials. 

Flammable Limits The minimum and maximum concentration of fuel vapor or gas in a fuel vapor or gas/gaseous oxidant mixture (usually expressed in percent hy volume) defining the concentration range (flammable or explosive range) over which propagation of flame will occur on contact with an ignition source. See also Lower Flammable Limit and Upper Flammable Limit. 

A vapor cloud explosion may be simply defined as an explosion occurring outdoors, producing a damaging overpressure (Factory Mutual Research Corporation, 1990). 

Application of the Baker-Strehlow method for evaluating blast effects from a vapor cloud explosion involves defining the energy of the explosion, calculating the scaled distance (/ ), then graphically reading the dimensionless peak pressure (Ps) and dimensionless specific impulse (i ). Equations (4.41) and (4.42) provide the means to calculate incident pressure and impulse based on the dimensionless terms. 

The energy term E must be defined to calculate energy-scaled standoff R. The energy term represents the sensible heat that is released by that portion of the cloud contributing to the blast wave. Any of the accepted methods of calculating vapor cloud explosive energy are applicable to the Baker-Strehlow method. These methods include ... 

---