Data on Explosive Materials

CHEMICAL DATA ON EXPLOSIVE MATERIALS Primary Explosives... 

Explosions involving organic dusts can usually be contained in equipment that can withstand about 7-10 times the initial pressure (Lees, 1980). Thus, if the system is originally at atmospheric pressure, the maximum pressure to be expected is about 100-150 psig. Data on explosion characteristics of the actual material to be processed are usually necessary to confirm the required design pressure. 

The purpose of this study is to generate peak pressure and impulse data on explosives, propellants, and other hazardous materials which are compared to similar parameters obtained from a hemispherical surface burst of TNT (Fig 3)> The results are reduced to a TNT equivalency value, which is defined as the weight ratio of TNT to test material for a given output condition. 

The worst hazard scenarios (excessive temperature and pressure rise accompanied by emission of toxic substances) must be worked out based upon calorimetric measurements (e.g. means to reduce hazards by using the inherent safety concept or Differential Scanning Calorimetry, DSC) and protection measures must be considered. If handling hazardous materials is considered too risky, procedures for generation of the hazardous reactants in situ in the reactor might be developed. Micro-reactor technology could also be an option. Completeness of the data on flammability, explosivity, (auto)ignition, static electricity, safe levels of exposure, environmental protection, transportation, etc. must be checked. Incompatibility of materials to be treated in a plant must be determined. 

All the data on health and fire/explosion hazards for compounds and (if possible) mixtures to be dealt with in a process should be collected in the form of an MSDS (Material Safety Data Sheet). It is common practice for users to require that suppliers attach an MSDS to all batches of materials delivered. 

All mathematical models require some assumed data on the source of release for a material. These assumptions form the input data which is then easily placed into a mathematical equation. The assumed data is usually the size or rate of mass released, wind direction, etc. They cannot possibly take into account all the variables that might exist at the time of the incident. Unfortunately most of the mathematical equations are also still based on empirical studies, laboratory results or in some cases TNT explosion equivalents. Therefore they still need considerable verification with tests simulations before they can be fully accepted as valid. 

The data to be listed on the Material Technical Sheet needs to be comprehensive enough for an accurate assessment of the fire and explosion characteristics, reactivity hazards, corrosion or erosion effects, and safety, health, and environmental hazards. 

In an alternative assessment of the effectiveness of these computer programs, it was concluded that explosive power was over-emphasised in relation to the more practically important aspect of sensitivity to initiation, and many compounds were being indicated as hazardous when they were not. There was also no provision for considering polymerisation as a hazardous possibility, and there was little quantitative data on this. The parameter best correlating with material sensitivity is the bond-dissociation energy. It was recommended that regulations specifying the... 

The end-of-run hydrolysate analyses provide more useful data on the presence of energetic species, because they are based on a larger homogeneous sample. The end-of-run hydrolysate analyses indicate that, in half of the cases, the level of energetic material had been reduced below the detection limit. The exceptions are listed in Table 2-4. None of these low levels of energetic material pose any explosion hazard, because even slurries with 10 to 30 percent of strong explosives... 

Table 9.3 shows the measured detonation velocities and densities of various types of energetic explosive materials based on the data in Refs. [9-11]. The detonation velocity at the CJ point is computed by means of Eq. (9.7). The detonation velocity increases with increasing density, as does the heat of explosion. Ammonium ni-trate(AN) is an oxidizer-rich material and its adiabatic flame temperature is low compared with that of other materials. Thus, the detonation velocity is low and hence the detonation pressure at the CJ point is low compared with that of other energetic materials. However, when AN particles are mixed with a fuel component, the detonation velocity increases. On the other hand, when HMX or RDX is mixed with a fuel component, the detonation velocity decreases because HMX and RDX are stoichiometrically balanced materials and the incorporation of fuel components decreases their adiabatic flame temperatures. 

A) C.A. Taylor W. H. Rinkenbach, "Explosives Their Materials, Constitution, and Analysis , USBurMinesBull 219(1923), 188 pp (contain Heat of Formation data on substances used in expls)... 

As discussed under explosives and propellants, a number of energetic binders GAP, NHTPB, poly(NiMMO), poly(GlyN), poly(BAMO), poly(AMMO) and BAMO-AMMO copolymers etc. have been reported in the recent past and are at various stages of development and introduction for bulk production of explosives and propellants for various applications. These polymeric binders are reasonably stable and are of established compatibility with a wide range of ingredients used for explosive and propellant formulations. The data on their explosive properties impact, friction and electric spark sensitivities, indicate that it is safe to handle these materials. However, there appears to be no report in the open literature on... 

A useful source of data on the safety record of the transportation of expls is the Office of Hazardous Materials News, Office of the Secretary, Department of Transportation, Washington, DC. A European collection of data on industry connected accidents is said to have been collected by Dr Karl Trautzl (Ref 44). The Department of Defense Explosives Safety Board has issued two series of publications (Ref 26). The first are the proceedings of the Annual Explosives Safety Seminars. The second publication series are the abstracts of expl accidents. These reports are submitted voluntarily by both government and industry and are complete with descriptions of causes, damage and casualties. Incidents related to the Fireworks industry are reported annually in the Fire Journal (Ref 64)... 

The heat of explosion of an explosive material, an explosive mixture, gunpowder or propellant is the heat liberated during its explosive decomposition. Its magnitude depends on the thermo-dynamic state of the decomposition products the data used in practical calculations usually have water (which is a product of the explosion) in the form of vapor as the reference compound. 

Fig.3.93 shows the data on the sensitivity of ammonium nitrate, which is an important explosive material. There is a difference in the sensitivity level between crystalline and prilled ammonium nitrate (AN (Prill)), which has many holes in the porous grains that make it more sensitive. The porous prills do not explode completely at a PETN equivalent 1.2g, but they do in the 50/60 steel tube test with an initial explosive booster of 50 g of RDX. 

The priming sensitivity of the explosive materials depends on the physical condition of the materials. Data from powdery materials is shown. 

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