Explosions sources

In order to be 100% safe from a hydrogen explosion (sources passivation air, CO2), a hydrogen removal system is installed before the CO2 passivation air enters the stripper. 

A BLEVE can produce fragments that fly away rapidly from the explosion source. These primary fragments, which are part of the original vessel wall, are hazardous and may result in damage to structures and injuries to people. Primary missile effects are determined by the number, shape, velocity, and trajectory of fragments. 

Event Group Number Number of Events Explosion Source MateriaJ Shape Vessel Mass (kg) Number of Fragments... 

TNT equivalence The amount of TNT (trinitrotoluene) that would produce observed damage effects similar to those of the explosion under consideration. For non-dense phase explosions, the equivalence has meaning only at a considerable distance from the explosion source, where the nature of the blast wave arising is more or less comparable with that of TNT. 

Generally, explosions liave an identifiable accidental, natural, or intentional cause. Table 7.4.4 lists a nmiiber of explosion sources according to tliese tliree allegories. Extensive calculational details on a host of ex-plosion types is available in tlie literaulure. ... 

R = adjusted value of R, for NFPA Code-69 Rcxp = distance from center of explosion source to the point of interest, ft... 

Explosion consequences in terms of overpressure and other effects may be evaluated by appropriate methods such as those described in Reference 5 and Appendix A. In evaluating the consequences of potential explosions, all these methods account for the energy of the explosion, the location of the explosion source, and attenuation of explosion effects with distance from the explosion source. From such an evaluation, maximum blast parameters can be determined at all locations of interest. Evaluation results can be graphically expressed by plotting contours of equal blast overpressure on a site plan of the facility, as shown in Figure 4.4. 

Scaling of the properties of blast waves from explosive sources is a common practice, and anyone who has even a rudimentary knowledge of blast technology utilizes these laws to predict the properties of blast waves from large-scale explosions based on tests on a much smaller scale. Similarly, results of tests conducted at sea level ambient atmospheric conditions are routinely used to predict the properties of blast waves from explosions detonated under high altitude conditions. 

The Hopkinson-Cranz scaling law described earlier applies to scaling of reflected blast wave parameters just as well as it does to side-on waves. That is, all reflected blast data taken under the same atmospheric conditions for the same type of explosive source can be reduced to a common base for comparison and prediction. Sachs law for reflected waves fails close to high explosive blast sources but it does apply beyond about ten charge radii. 

For blast waves from relatively small explosion sources, the diffraction phase of the loading may dominate, and the drag phase may be relatively or entirely unimportant, because the diffraction times may be as long as or greater than drag pressure durations. 

The loads from external near-surface burst explosions are based on hemispherical surface burst relationships. Peak pressure (P psi) and scaled. impulse Ci/W psi/lb ) are plotted vs. scaled distance (R/W ft/lb ). Roof and sidewall elements, side-on to the shock wave, see side-on loads (P and i ). The front wall, perpendicular to the shock wave, sees the much higher reflected shock wave loads (P and i ). An approximate triangular pressure-time relationship is shown in Figure 5a. The duration, T, is determined from the peak pressure and impulse by assuming a triangular load. Complete load calculations include dynamic loads on side-on elements, the effect of clearing times on reflected pressure durations, and load variations on structural elements due to their size and varying distance from the explosive source. 

The side walls are defined relative to the explosion source as shown in Figure 3.6. These walls will experience less blast loading than the front wall, due to lack of overpressure reflection and to attenuation of the blast wave with distance from the explosion source. In certain cases, the actual side wall loading is combined with other blast induced forces (such as in-plane forces for exterior shear walls). The general form of side wall blast loading is shown in-Figure 3.8,... 

The high resistance and mass provided by reinforced concrete structures makes it particularly suited for buildings located in close proximity to explosion sources. Concrete also provides effective resistance to fire and projectile penetration which are important considerations in many explosion accidents. 

Refs 1) Ya.B. Zel dovich, ZhEksper i TeoretFiz 10, 542(1940) (On the theory of propagation of detonation in gaseous systems) la) J.G. Kirkwood S.R. Brinkley Jr, "Theory of Propagation of Shock Waves from Explosive Sources in Air and Water , OSRD 4814(1946) 2) G.N. Abramovich ... 

Balloons of the size needed to contain a 1-kton fuel-oxygen explosive source (FOE) are commercially available in today s market. (In fact, present large balloons, designed as warehouses, athletic stadiums, etc., are much too rugged for our purpose of one-time use, and yet they are cheap enough for the system.) ... 

A.W. Magnison, Measurements of Underwater Explosive Source Levels for Yields of 0.0012 to 126 Pounds , TR 73-02, Delco Electronics Div, General Motors Corp, Santa Barbara (1971) 103) R.K. McGrath, Dynamic Response of Concrete Arch Bunkers Event Dial Pack, Project LN 314A , AEWES-TR-N-71-8 (1971), Army Engineer Waterways Exptl Sta, Vicksburg... 

Several systems based on LIDAR (Section 2.3.) have been developed for explosives and explosive device detection. While not fitting the conventional LIDAR experiment definition, these systems apply LIDAR principles to the detection of explosive sources. 

It is same as the variable initiator test using an underwater explosion, but the distance of the sensor from the explosion source is 2 m. 

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