Transmission of detonation

To examine this property of explosives, it is necessary to determine the maximum distance between two cartridges (weighing 100 g each, 30 mm dia.) at which detonation will propagate from the cartridge fitted with a No. 8 detonator to the second cartridge which has no detonator. This distance should not be less than 3 cm, and 

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Experiments on the detonability of nonhomogeneous mixtures are scarce. Two experiments reported in the literature may shed some light on this matter. Bull et al. (1981) investigated the transmission of detonation across an inert region in hydrocarbon-air mixtures under unconfined conditions. The transmission of a hydrocarbon-air detonation across an inert region in a tube was studied by Bjerketvedt and Sonju (1984) and Bjerketvedt, Sonju, and Moen (1986). 

Nitroglycerine can detonate in pipes of diameter down to approximately 5 mm. In nitroglycerine manufacture there is, therefore, an inherent danger of transmission of detonation from one manufacturing house to another in the series. Even a pipe which has been emptied of nitroglycerine can have on it a skin of the product sufficient to enable transmission of detonation from one end of the pipe to the other. To prevent the spread of an accident it is now usual to transfer nitroglycerine as a non-explosive emulsion in an excess of water. Such emulsion transfer is particularly convenient with the NAB process, as the emulsion transfer lines can also carry out the necessary process of washing and purification. 

Contact Transmission of Detonation. Accdg to definition given by Dunkle (Ref 3) "If is the transmission of the process, as a detonation, directly from one medium to another". 

Refs 1) S. Paterson, Contact Transmission of Detonation , 4thSympCombstn (1953),... 

Ability to Propagate Detonation Transmission of Detonation or Extent of Propagation of Explosion. See Vol 1, p VII... 

Transmission of Detonation (or Explosion) Through Air. Same as Detonation (or Explosion) by Influence... 

CA 61, 13118(1964) [Transmission of detonation for exchanged ions expls (EIE) is not as good under confinement as it is in open air, whereas classical safety expls transmit deton to a distance which is proportional to the degree of confinement. An EIE is relatively insensitive to a shock wave but very sensitive to impact of particles. This is attributed to the fact that these expls contain some nongelatinized NG Nitroglycol, the initiation of which occurs accdg to a thermal process]... 

M.A. Cook etal, TrFaradSoc 56, 1028-38(1960 Promotion of shock initiation of detonation by metallic surfaces) 36a) Andreev Belyaev (i960), 265-68 (Starting impulse and mechanism of initiation) 268-70 (Initiation by heat) 270-73 (Initiation by flame) 273-86 (Initiation by shock or friction) 287-89 (Initiation of expln in projectiles on hitting a target) 36b) J. Favier C. Fauquignon, MP 42, 65-81(1960) (Initiation of expls. and transmission of detonation) 37) D.B. Moore J.C. Rice, Detonation of Secondary Explosives by Lead Azide , SRI (Stanford Research Institute), Poulter Laboratories, Technical Report 004-60(1960) 37a) S.J. Jacobs, AmRocket-... 

Transmission of detonation is different for air gaps and dirt gaps. Transmission distances are much greater in v wet soil than in dry soil. In the open, distances (across air gaps) are shorter than in bore holes. In the open, the medium on which the cartridges are laid also... 

Modified Influence (Propagation) Test. Gawthrop (Ref 1) and others used a modified gap test to determine the relative ability of a shielded donor charge to transfer detonation over an air gap to an acceptor charge. Clark (Ref 2) also used this method for the determination of the gap in the transmission of detonation from a small charge (0.5 to 2g) of HE to a cartridge of 40% straight dynamite... 

Ability to Propagate Detonation or Transmission of Detonation. Se Vol 1 of Encyci,... 

Transmission de dytonatiqn k distance (Transmission of Detonation at a Distance), known as Aptitude k traosmettre la detonation a distance (Ability to Transmit the Detonation at a Distance). See Ref 24, E140-L. Same as Detonation by Influence, Sympathetic Detonation or Gap Test... 

Gap Transmission of Detonation Through Various Gases was discussed By T. Kikita K. Yoneda in KogyoKayakuKyokaishi (Journal of the Industrial Explosives Society of Japan) 21, 21-31(1960) CA 55, 9878(1961)... 

Recently Hino and Yokogawa [59] found that by adding less than 1% surface active agents, an improvement of transmission of detonation of ammonium nitrate explosives can be achieved. 

The production of sheaths has led, however, to some new and unexpected difficulties. Thus, the explosive core was sometimes not sufficiently well centered, or the substance filling the sheath moved to one end and formed a barrier to the transmission of detonation from one cartridge to another. 

Being an explosive, the sheath does not weaken the charge and does not inhibit the transmission of detonation from one cartridge to another. 

It should be pointed out that the transmission of detonation depends not only on the composition of the explosive and the previously mentioned factors but also on the diameter of the cartridges, their confinement and their density. 

An investigation of the probability of transmission of detonation as a function of the diameter of the cartridge was carried out by Hino [69]. This is depicted by the diagram in Fig. 143. 

Fig. 143. Probability of detonation (in %) as a function of cartridge diameter, according to Hino and Yokogawa [59]. Rt— diameter which does not give any transmission of detonation c— critical diameter (50% probability of transmission of detonation) —minimum diameter which gives 100% probability of transmission...

The transmission of detonation in a confined space (in a tube or shothole) is higher than in the open air. E.g. an ammonium nitrate explosive with 4% nitroglycerine which ordinarily has a transmission value of 10-15 cm, in a mortar gives the value 19-23 cm, according to T. Urbanski [70]. This author studied change of transmission as a function of density. The results for ammonium nitrate explosives are given in the diagram in Fig. 144. 

Fig. 144. Transmission of detonation as a function of density, according to T. Urban-...

Figure 145 suggests a very small reduction (n the power of dynamite and ammonium nitrate explosives on storage, measured in a ballistic mortar. Figure 146 indicates the change in the transmission of detonation during storage. The decline in trans-... 

Fig. 147. Change in the transmission of detonation of explosives with temperature [71] /-semi-plastic explosive, type S with 54% NG //—ammonium gelatine, type B with 35% NG ///—ammonium nitrate explosive, type II with 6% NG and 76%...

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