Explosions Damage

EMEC 1980. Process Control House and Other Structures Subject to External Explosion Damage. Eoss Prevention Data Sheet No. 7-45S. Eactory Mutual Engineering Corporation, Norwood, MA. 

TNT Equivalence. Explosion strength is often expressed as equivalent mass of TNT in order to permit estimates of possible explosion damage. For BLEVEs and pressure vessel bursts, using this equivalence is unnecessary because the methods mentioned above give explosion blast parameters which relate directly to the amount of possible damage potential. However, the concept of TNT equivalence is still useful because it appeals to those who seldom deal with blast parameters. For reasons explained in Section 4.3.1, BLEVEs or pressure vessel bursts catuiot readily be compared to explosions of TNT (or other high explosives). Only the main points are repeated here. 

Water supply - It is the most important of all extinguishing agents for most chemical plant fires. The water supply should be sufficient to fulfill the demand for automatic protection and hose streams for at least a four-hour period. Allowance should be made for explosion damage to the system and protection against freezing. 

Z, or Z-jxT = scaled distance for explosive blasts, ft/(lb) z = actual distance for explosion damage, feet... 

Explosion damage cover means damage resulting from a wide variety of trade-related explosions (e.g. dust, vapor or uncontrolled chemical reactions). The explosion or collapse of boilers and pressure plant, in which internal pressure is due to steam or other fluids, is covered by engineering (not fire) policies. 

Detonations. Pressure rise ratios of -15 1 for hydrogen-air or methane-air detonations and a ratio of -12 1 for a gasoline-air detonation are normally expected. The impulse created by explosion pressure profile should be taken into account in evaluating explosion damage and in the design of barricades or structures to mitigate explosion consequences. 

Explosion An explosion is a rapid expansion of gases resulting in a rapidly moving pressure or shock wave. The expansion can be mechanical (by means of a sudden rupture of a pressurized vessel), or it can be the result of a rapid chemical reaction. Explosion damage is caused by the pressure or shock wave. 

V. J. Clancey, Diagnostic Features of Explosion Damage, paper presented at the Sixth International Meeting of Forensic Sciences (Edinburgh, 1972). 

The explosions were felt 6 miles away. Twelve buildings were destroyed, and fire and explosion damage occurred throughout the polyethylene plant. The damage was estimated at over 15 million. 

Industry literature typically cites concern with open air explosions when 4,536 kgs (10,000 lbs.) or more of flammable gas is released, however, open air explosions at lower amounts of materials are not unheard of. When the release quantity is less than 4,536 kgs (10,000 lbs.), a flash fire is usually the result. The resulting fire or explosion damage can cripple a hydrocarbon processing facility. Extreme care must be taken to prevent the release of hydrocarbon from vessels resulting in vapor releases and resultant blast overpressure. Measures such as hydrotesting, weld inspections, pressure control valves, adequate pressure safety valves, etc., should all be prudently applied. 

A-2.11.1 Storage Vessel Failure. The release of GH2 or LH2 may result in ignition and combustion, causing fires and explosions. Damage may extend over considerably wider areas than the storage locations because of hydrogen cloud movement. Vessel failure may be started by material failure, excessive pressure caused by heat leak, or failure of the pressure-relief system. 

FACEDAP 1994, Facility and Component Explosive Damage Assessment Program (FACEDAP) - Theory Manual, version 1.2, Protective Design - Mandatory Center of Expertise Technical Report 92-2, Corps of Engineers, Omaha District, Omaha, NE,... 

Objects in the vicinity of an explosion can often serve as useful post-blast witnesses. Thus for large explosions damage to structural elements of buildings, street furniture, motor vehicles, and glazing can all prove informative. A number of authors have published studies that provide guidance on both damage assessment techniques and interpretation of the data [2-7]. 

McIntyre, D. Assessment of Fire and Explosion Damage to Chemical Plant Equip-ment/Analyzing Explosions and Pressure Vessel Ruptures. Materials Technology Institute of the Chemical Process Industries, Publication 30, National Association of Corrosion Engineers. 

Hagiya, H., Morishita, M., Ando, T, Tanaka, H., and Matsuo, H., Evaluation of Explosive Damage of Concrete Wall by Numerical Simulation, Science and Technology of Energetic Materials, Japan Ex-... 

Detonation (and Explosion), Damage Caused by. See Vol 3 of Encycl, p D3-L under Damage Effects of Organic High Explosives"... 

See also Blast Effect (Vol 2, p 180ff), Detonation (and Explosion, Damage Caused by (Vol 3, p D3-L), and previous item on Shock Effect... 

Shaped Charge (Brit Hollow Charge), also called Cavity Charge. An explosive charge with a shaped cavity to make possible the concentration of the explosive force in the desired direction. The localized explosive damage obtained by the shaped charge is known in US as Munroe Effect (Ref 23, pp 8-33 G4)... 

The destruction of scarce, critical, or one-of-a-kind equipment in or near a process unit could create many days of downtime, even with minimal fire or explosion damage. This potential for high losses due to business interruption might qualify such equipment as a pertinent process unit for evaluation. 

Of the 28 who perished, 18 were found in the control room. The blast of the vapor cloud explosion shattered the control room windows and caused the roof to collapse. The initial explosion damaged so much equipment that numerous fires started and some burned for days. Even after ten days, the fires were hindering rescue activities. [17]... 

A six-inch carbon steel elbow in a Los Angeles refinery ruptured releasing a hydrocar-bon/hydrogen mixture at 9 43 P.M. on October 8, 1992. The vapor cloud ignited within seconds. The explosion damaged nearby buildings and shattered windows several miles away and was recorded as a sonic boom at the California Institute of Technology about 20 miles away. [21]... 

Tetsuzo Kitagawa, "Analyses of Explosion Damages", Nikkan Kogyo Shinbun (1981)... 

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