Blast Pressures

Absence of ignition peaks or reinforcing pressure waves Minimum gun smoke, flash, and blast pressure Detonation-free in event of malfunction... 

Pressure Development Overpressure in a UVCE results from turbulence that promotes a sudden release of energy. Tests in the open without obstacles or confining structures do not produce damaging overpressure. Nevertheless, combustion in a vapor cloud within a partially confined space or around turbulence-producing obstacles may generate damaging overpressure. Also, turbulence in a jet release, such as may occur with compressed natural gas discharged from a ruptured pipehne, may result in blast pressure. 

The blast pressure, P, at the surface of an exploding pressure vessel is estimated by Prugh (I tSS) with equation 9.1-26 where P, is the pressure at surface of vessel (bara), Pb is the burst... 

Ice and hail, snow, etc. can cause a loss of off-site power. The reactor building was designed to withstand blast pressure of 1,000 Ibs/ft can withstand tornado missile impact (Sharp, 1986). A tornado could damage the reactor by hitting the river water pump houses similar to the flooding scenario. 

These mechanisms may cause very high flame speeds and, as a result, strong blast pressures. The generation of high combustion rates is limited to the congested area, or the area affected by the turbulent release. As soon as the flame enters an area without turbulence, both the combustion rate and pressure will drop. 

Sad6e et al. (1976-1977) give a detailed description of structural damage due to the explosion and derived blast pressures from the damage outside the cloud... 

The fuel-air explosion produced, in a large area covered by the cloud, substantially higher blast pressures than would be expected from a 100,000-kg TNT surface blast. 

Baker et al. (1978a) developed a method which can predict blast pressures in the near field. This method is based on results of numerical simulations (see Section 6.3.1.1) and replaces Step 5 of the basic method (Figure 6.20). The refined method s procedure is shown in Figure 6.25. 

Wind-druck, m. (Metal.) blast pressure wind pressure, -dtise, /. blast nozzle, twyer, tuyere. 

Wind-kanal, m. air passage, air duct, -kastea, m. wind chest, air chamber Metal.) twyer box. -kessel, m. blast pressure tank, blast box air chamber, -leitung,/. Metal.) blast main, -leitungsrohr, n. Metal.) blast pipe, -messer, m. wind meter, anemometer blast gage, -miihle, /. windmill, -ofen, m. wind fiirnace, air furnace, -ppcken, f.pl, chicken pox. -pressung, /. Metal.) blast pressure, -lohr, n. Metal.) blast pipe, twT r pipe, -sammler, m. air reservoir, compressed-air tank. 

Damage Limits Avg Overpressure (PSI) Physiological Effects of Blast Pressures Peak Over-pressme (PSI)... 

Low absolute pressure calculations, 129 Low pressure system, 129 American Petroleum Institute, 399 American Society of Mechanical Engineers, 399 API Codes, 399 API oil field separators, 239 API, heat absorbed from fire, 451-453 Babcock steam formula, 103, 107, 108 Back pressure, 404 Effect of, 407, 408 Baffles, lank mixing, 311 Diagrams, 330 Bag filters/separators, 270 Bag materials, 274 Cleaning, 272, 273 Heavy dust loads, 271 Specifications, 271 Temperature range, 271 Bins, silos, hoppers venting, 516 Blast pressure, 496 Blowdown, 404... 

Explosion calculations, 499-504 Estimating destruction, 501 Overpressure, 502 Pressure piling, 501, 504 Relief sizing, 505 Scaled distance, 502, 503 Schock from velocity, 503 TNT equivalent, 499-504 Explosion characteristics of dusts, 515 Explosion suppression, 518 Explosion venting, gases/vapors, 504 Bleves, 504 Explosions, 482 Blast pressure. 496 Combustion, 482 Confined, 482 Damage, 498-501 Deflagration, 482 Detonation, 483... 

Mass and stiffness. These relate to the natural period of vibration or natural frequency of the components. The relationship between the dynamic characteristics of the structure (i.e., natural frequency) and the dynamic characteristics of the blast load (i.e., duration or impulse) affects the magnitude of the structural response to blast pressures. 

The reflected pressure wave amplitude and impulse for shock waves associated with detonations are well documented, as shown in Figure A. 3 (Ref. 7, Volume II). Less information is available on reflected overpressure and impulse resulting from deflagration pressure waves. Reference 67 documents approaches for evaluating reflected overpressure from weaker blast pressure waves. Forbes (Ref. 71) suggests the following approximate relation to model the more complex relations in Reference 64 ... 

This section has been primarily concerned with the response of structural elements to which the blast pressure loading has been directly applied. This is termed primary (local) response to blast loading, and it is commonly... 

Diffraction loading Forces on a stmcture resulting from the direct and reflected blast pressure wave. 

---