Blast structural damage

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... 

Brasie and Simpson (1968) use the Kingery and Pannill (1964) TNT blast data to represent blast parameter distributions, and the US Atomic Energy Commission s recommendations (Glasstone 1962) for the attendant structural damage. Brasie and Simpson (1968) base their recommendation for the TNT equivalency of vapor clouds on the damage observed in three chemical-plant explosion incidents. Analyzing the... 

Acquisition of practical knowledge in the field of explosion-indueed structural damage is still heavily dependent upon empirical data. Such data, however, usually give information only about those overpressure levels which relate to certain degrees of damage. Other parameters, such as duration, impulse, and shape of the blast wave are not taken into aecount. Tables containing such information are frequently published. The best known are contained in Glasstone (1966, 1977), a frequently cited reference. 

The earliest tables were compiled from data collected from nuclear weapon tests, in which very high yield devices produced sharp-peaked shock waves with long durations for the positive phase. However, these data are used for other types of blast waves as well. Caution should be exercised in application of these simple criteria to buildings or structures, especially for vapor cloud explosions, which can produce blast waves with totally different shapes. Application of criteria from nuclear tests can, in many cases, result in overestimation of structural damage. 

F. Blast effects from a nearby explosion (unconfined vapor cloud explosion, bursting vessel, etc.), such as blast overpressure, projectiles, structural damage... 

Explosion Sudden release of energy that causes a blast or shock wave may lead to personal injury or structural damage. 

Design of petrochemical facilities for accidental explosions is similar in many ways to design of facilities Tor high explosive detonations, nuclear weapons effects and nuclear power accidents for which design guides arc available. However, blast design for petrochemical plants is different in that more structural damage may be tolerated, in accordance with a company s blast protection philosophy. 

Hazard Division 1.1 Comprises items which have a mass explosion hazard. The major hazards of this division are blast, high velocity projections and flame the explosion results in severe structural damage, the severity and range being determined by the quantity of explosives involved. There may be a risk from heavy debris propelled from the structure in which the explosion occurs or from the crater. 

The explosive charges are placed at vantage points that will permit the blasts to inllict a maximum amount of structural damage. The... 

In designing for explosion/blast, attention should be given to second order effects, as the ultimate limit slate for stability due to excessive deflection or loss of stiffness due to structural damage may be grossly exceeded in the event of explosion/blast. 

Hazards resulting from blast over-pressure can be from direct and indirect sources. For example, indirect sources of fatal harm resulting from an explosion can be missiles, building collapse or severe structural damage (as occurred at Buncefieid). 

The primary input is the blast overpressure (defined as the peak side-on overpressure), although for structural damage analysis, an estimate of the duration is also necessary. Projectile damage analysis requires an estimate of the number, velocity, and spatial distributions of projectiles, and is more difficult than overpressure analysis. 

Response of Equipment The response of equipment to blast is usually a combination of two effects one is the displacement of the equipment as a single entity and the other is the faihire of the equipment itself. The displacement of the equipment is an important consideration for small, unsecured items—e.g., empty drums, gas cyhnders, empty containers. Most damage resmts from the faihire in part or totally of the equipment or containing structure itself. 

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. 

On January 16,1966, an explosion occurred after liquefied methane was discharged from a vent. The resulting cloud was ignited. The subsequent explosion resulted in minor structural blast damage. About 75 persons were injured, primarily from glass breakage, and 1 person was killed. 

Table 6.10 presents some damage effects. It may give the impression that damage is related only to a blast wave s peak overpressure, but this is not the case. For certain types of structures, impulse and dynamic pressure (wind force), rather than overpressure, determine the extent of damage. Table 6.10 was prepared for blast waves of nuclear explosions, and generally provides conservative predictions for other types of explosions. More information on the damage caused by blast waves can be found in Appendix B. 

In a few, special situations, a building may need to be evaluated for the combined effects of explosion and toxic release. For example, in the event of an explosion, a building may retain sufficient structural integrity to protect the building occupants from the blast, yet suffer damage to the point that it can no longer offer sufficient protection from a toxic release occurring in conjunction with the explosion. 

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