Permitted explosive design

From the days of Nobel to about 1950 the scientific basis of commercial explosives remained relatively unchanged, although continuous and numerous improvements in manufacturing methods occurred throughout the world. There were, however, many advances in military explosives, note of which will be made later. These advances were, of course, largely due to the two world wars, which occurred since the death of Alfred Nobel. There were also many advances in the development of permitted explosives designed for use in gassy coal mines. 

It was early recognised that an explosive is more hazardous in a coal mine if it is fired in a borehole from which the stemming is omitted or blown out early by the explosive than if it is fired in a properly stemmed hole and does adequate work in bringing down rock or coal. The tests which led to the original permitted explosives, now called P1 explosives, were therefore designed to test the product under these conditions. 

A new modern experimental gallery (modelled on the one at Buxton in Great Britain) was constructed in 1927 and the explosives which passed the gallery test with the charge of 400 g were designated Permitted Explosives (Kentei Bakuyaku). 

This test is designed to simulate the real circumstances of the possible industrial use of ion exchange (permitted) explosives. 

A great deal of experimental work has also been done to identify and quantify the ha2ards of explosive operations (30—40). The vulnerabiUty of stmctures and people to shock waves and fragment impact has been well estabUshed. This effort has also led to the design of protective stmctures superior to the conventional barricades which permit considerable reduction ia allowable safety distances. In addition, a variety of techniques have been developed to mitigate catastrophic detonations of explosives exposed to fire. 

Modem methods for the manuf and storage of expl materials, which include many exotic chemicals, fuels, and propints, allow less space for a given quantity of expl material than previously permitted. Such concns of expls increase the possibility of the propagation of accidental explosions (one accidental explosion causing the detonation of other expl materials). It was evident that a requirement for more accurate design techniques had become essential. Ref 3 describes a rational design method to provide the required structural protection. It presents methods of design for protective construction... 

The Sikarex safety calorimeter system and its application to determine the course of adiabatic self-heating processes, starting temperatures for self-heating reactions, time to explosion, kinetic data, and simulation of real processes, are discussed with examples [1], The Sedex (sensitive detection of exothermic processes) calorimeter uses a special oven to heat a variety of containers with sophisticated control and detection equipment, which permits several samples to be examined simultaneously [2]. The bench-scale heat-flow calorimeter is designed to provide data specifically oriented towards processing safety requirements, and a new computerised design... 

Homeland Security Act, Title XI, Subtide C contains the Safe Explosives Act [130]. The Act is designed to heighten security for explosive materials by requiring all persons desiring to obtain explosives, for any use, to possess a federal permit or hcense [131]. The Safe Explosives Act [132] addresses procedures and requirements in the following areas permits (Sect. 1122(a)—(e)) inspections (Sect. 1122(f)—(g)) background checks and clearances (Sect. 1122(h)) prohibitions on distribution and possession (Sect. 1123) required samples (Sect. 1124) reheffrom disabilities (Sect. 1126) theft report requirements (Sect. 1127) and authorization for appropriations (Sect. 1128). 

Enclosures, even partial enclosures, containing equipment handling flammable, combustible, ortoxic materials may permit the accumulation of hazardous concentrations of these materials within the enclosure, potentially resulting in fire, explosion, or personnel exposure. Where the possibility of a flammable spill or release within an enclosure exists, the enclosure design should include a relevant selection from the following features noncombustible construction, adequate ventilation, drainage, appropriate electrical classification, flammable vapor detection, isolation and alarm, and internal automatic sprinkler or water spray protection. 

In order to make the Encyclopedia ascompactas possible we used abbreviations, many of which are the same as used in Chemical Abstracts except that periods after abbreviations are omitted. A list of abbreviations symbols, code letters and special designations of items connected with explosives, propellants, pyrotechnics, ammunition and weapons is included in this work. This list is placed immediately before the Encyclopedia proper (see Abbreviations, pp Abbr 1-59) and also includes abbreviations and code letters for various Ordnance establishments, industrial installations and scientific institutions, both US and foreign. Some additional abbreviations are given in a supplementary list (see Abbreviations, pp Abbr 59-65). Wherever we have been able to do so and are permitted by security regulations, the meaning of code letters on ammunition, weapons and other military items is briefly explained... 

Valve, Explosive Calculations. In the past, explosively actuated valves have been designed on an empirical basis because the interactions and forces involved in a valve operation were not fully understood. However, this design approach was satisfactory in that the size and design of the valves permitted a more than adequate amount of expl to be used to ensure proper operation of the valves. That is, the driving force available from the extra expl pro-... 

Compex. One of the Brit "permitted mining expls which are designated as EqS (equivalent in safety to sheathed explosives). It is listed in Ref without giving the composition Ref Taylor Gay (1958), 96... 

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