Hazards of detonations

Tests made on explosives for "sensitivity by impact or friction, although in reality only ignition tests, should correlate well with the hazard of detonating the material. On the other hand, the same tests on a cohesive solid propellant would indicate only its ignitability under that particular stimulus and would not correlate prior experience in the explosives industry. 

Hazards of detonation and violent combustion of oxidizer mixtures are generally evaluated by tests of detonation—propagation, initiation sensitivity and explosion power. For oxidizer mixtures explosiveness is important To ensure the safety of operaters, it is necessary to investigate the mixing ignition, stability and super high—sensitivity with a small mass of sample before the practical test. In this field Treumann has done much of the work 1 1. ... 

S. Wachtel, "Prediction of Detonation Hazards in Sohd PropeUants," paper presented at the 145th National Meeting of the Division of Fuel Chemisty, New York, 1963. 

Materials which (in themselves) are readily capable of detonation or of explosive decomposition or explosive reaction at normal temperatures and pressures. Includes materials which are sensitive to mechanical or loceilized thermal shock. If a chemical with this hazard rating is in an advanced or massive fire, the area should be evacuated. 

Fire Hazards - Flash Point Data not available Flammable Limits in Air (%). Not pertinent Fire Extinguishing Agents Water, dry chemical, carbon dioxide, foam Fire Extinguishing Agents Not to be Used Not pertinent cial Hazards of Combustion Products Vapors are toxic Behavior in Fire Can detonate or explode when heated under confinement Ignition Temperature Data not available Electrical Hazard Not pertinent Burning Rate Not pertinent. 

Lee, J. H. S, Knystautas, R., and Goroshm, S. 1996. The Testing of Detonation Arresters. Proc. Inti. Symp. On Hazards Prevention and Mitigation of Industrial Explosions, pp. 7.27-7.40. Christian Michelsen Research AS, Bergen, Norway. 

Matsui, H., and J. H. S. Lee. 1979. On the measure of relative detonation hazards of gaseous fuel-oxygen and air mixtures. Seventeenth Symposium (International) on Combustion, pp. 1269-1280. Pittsburgh, PA The Combustion Institute. 

A special study [74] was commissioned by the American Petroleum Institute (API) entitled Mitigation of Explosion Hazards of Marine Vapor Control Systems. The report examines the effects of deflagradons and detonations in pipes in the region of detonation flame arrestors. The primary objective was to resolve potential... 

A new compn was developed consisting of RDX 35.9, NC (1-2.6% N) 24.5, NG 22.8, DNEtB 10.0, DBuPh 6.6 DPhA 0.2%. It was tough and thermally stable, relatively non-hygroscopic, and insensitive to friction, impact and rifle fire. It was also superior to TNT in rate of detonation and brisaiice. A relatively simple and non-hazardous procedure was developed for its manuf. Another formulation variation was TNT 35, Comp A-3 35, M-l proplnt powder 20, and DNEtB or TEGDN 10%. This was hard and tough at room temp, but softened at 65° (Refs 1 3)... 

See under Explosion Hazards of Organic Vapors, Reduction of, in Vol 6, E373-L Detonation (and Explosion), Hazards (Dangers) of, in Vol 4, D366-L to D367-R and D245-L... 

VIII. Explosive Characteristics. Picric Acid is generally considered to be a relatively insensi tive but brisant expl. On a qualitative sensitivity scale of comparing common expls, PA would be judged to be more sensitive than TNT but appreciably less sensitive than Tetryl. Its power and brisance are also similar to those of TNT (112% TNT in the Ballistic Mortar 101% of TNT in the Trauzl Block and 107% in the plate dent test (Ref 48). In this section we will consider the steady detonation parameters. initiation characteristics and potential hazards of PA... 

The particular hazard of firedamp ignition relates to the circumstance when a hole fired early in the round breaks the coal at another hole and exposes the explosive before it detonates. This is simulated by firing gallery tests similar to those described above, but with inverse initiation of a... 

For civilian aircraft the facility for rapid starting is not important and cartridge operation is not often employed, particularly because it involves storing and handling explosives, even though the hazards of these explosives are those of fire and not of detonation. For military purposes, however, particularly for fighter aircraft which are best scattered on an airfield, a rapid start is of considerable importance. Therefore cartridge operated starters are much used for these aeroplanes. In Britain, development has been essentially with propellants based on ballistite, namely double base propellants of the solventless type, whereas in the United States composite propellants based on ammonium nitrate have proved more popular. 

The preparation is hazardous because a highly explosive peroxidic polymer is formed as the major product. After extraction of the title product with pentane, the residue must be disposed of forthwith to avoid the possibility of detonation of the polymer as it dries, as happened on one occasion. 

Several of the combustion-related properties of hydrogen in air, such as its wide flammability limits (4-75 vol%), wide detonation range (20-65 vol%), very low spark ignition energy (0.02 mJ), high heat of combustion (121 kJ/g) and high flame temperature (2050°C) combine to emphasise the high fire-related hazards of the... 

The detonation capacity of mixtures of acetylene and liquid oxygen is increased by the presence of organic material (oils) in the oxygen. Hazards of accumulation of oil in air-liquefaction and -fractionation plants are emphasised. 

The first aim of a thermal stability screening test (e.g., DSC/DTA) is to obtain data on the potential for exothermic decomposition and on the enthalpy of decomposition (AHd). These data, together with the initial theoretical hazard evaluation, are used in reviewing the energetic properties of the substance (Box 4) and the detonation and deflagration hazards of the substance (Boxes 7 and 8). The screening tests also provide data on the thermal stability of the substance or mixture, on the runaway potential, on the oxidation properties, and to a lesser extent, on the kinetics of the reaction (Box 10). 

In all of the test methods, the observed burning rates or times are compared to the burning rates or times of reference substances under the same experimental conditions. Based on the comparison with several oxidizing substances having a known classification, the hazard of the sample substance is rated. It should be emphasized that some oxidizer/combustible mixtures will react vigorously. Some mixtures are able to detonate, depending on the specific composition (see Section 2.2.4.2). 

The results of a number of tests such as those described in Chapter 2 led to classifications for the peroxide group. These tests included the determination of the hazards of decomposition (deflagration and detonation), bum rate, fire hazard, and reactivity hazards. Five different classes were formulated, as listed in the NFPA 43B Hazard Class, from the test results. Emergency procedures have been established for these five classes. 

With the possible exception of delay fuses, any pyrotechnic mixture represents a hazard worthy of report. Although the cause of frequent accidents reviewed in [2], compositions intended to explode or deflagrate are generally outside the field of this work and few are listed. Numerous reviews and specialist texts exist and hundreds of patents appear yearly. The account [1] of the theory and practice of pyrotechnics contains much useful information on the performance and potential hazards of a great variety of oxidant-fuel combinations which burn very rapidly or explosively. Safety measures are found in [2], Other reviews written from a functional viewpoint are found in [3] and [4], Some hazardously incompatible pyrotechnic mixes are reported [5], Detonability of pyrotechnic compositions has... 

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