Explosion propagation, probability

When a detonation wave passes through an explosive, the first effect is compression of the explosive to a high density. This is the shock wave itself. Then reaction occurs and the explosive is changed into gaseous products at high temperature. These reaction products act as a continuously generated piston which enables the shock wave to be propagated at a constant velocity. The probable structure of the detonation zone is illustrated in Fig. 2.3. 

Extremely insensitive articles which do not have a mass explosion hazard. The articles contain only extremely insensitive detonating substances and demonstrate a negligible probability of accidental initiation or propagation. 

In pure water local explosions occur, but without propagation due to the abstraction of heat. With the ammonia solns the inhibition is probably due both to cooling and to reaction with hydrogen iodide which lowers the heat liberated during the reaction... 

Manufacture of these explosives received great impetus in Germany and France during World War I, probably on account of the lack of nitrogen compounds. Composition The chief constituent, 60-80 per cent, is a chlorate or perchlorate of ammonium, sodium, or potassium. The other ingredients are combustible products such as charcoal, sulfur, aluminum powder, or mixtures of vegetahle meals uitro derivatives of benzene, toluene, naphthalene, phenol and as de-sensitizers solid hydrocarbons (paraffin) and castor oil may he added. The addition of the nitro compounds serves to improve the propagation. 

Incident The loss of containment of material or energy (e.g., a prmcture or fittings leak of ammonia on a railcar). Not all events propagate into incidents. Incident Outcome The physical manifestation of the incident for toxic materials, the incident outcome is a toxic release, while for flammable materials, the incident outcome could be a boihng liqtrid expanding vapor explosion (BLEVE), flash fire, vapor cloud explosion (VCE), etc. (e.g., for a leak of chlorine from a railcar, the incident outcome is a toxic release). Likelihood A measure of the expected probability or frequency of occurrence of an event (e.g., events/year). 

Division 1.6 Extremely insensitive articles which do not have a mass explosion hazard. This division comprises articles which contain only extremely insensitive detonating substances and which demonstrate a negligible probability of accidental initiation or propagation. UN 2.1.1.4(f) IMO Class 1, 1.5.2 ICAO 2-1.2 lATA 3.1.3.6... 

The approach used for the estimation of loss of life in floods shows considerable resemblance to the approach that is used in the Dutch major hazards policy. In both cases, the probability of a critical event (loss of containment or flood) is estimated using fault tree analysis, after which the physical effects associated with that critical event are considered (using e.g. dispersion or flood propagation models) and related to mortality estimates (using dose-response functions or flood mortality functions). But while the potential for evacuation is often limited when it comes to explosions or toxic releases, it could be significant when it comes to floods. 

The mixture probability, that is the probability of occurrence of an explosive atmosphere, depends on type, quantity, composition and consistency of the combustible substances, their safety characteristics and possible release and propagation in the surrounding air. 

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