Cap sensitivity test

The methods described below are primarily intended for sensitivity testing of an explosive to the standard detonator, the blasting cap. The tests are also known as cap sensitivity tests. 

The cap sensitivity tests described here are based on the initiation of a high explosive charge by the standard detonator. The effects of the detonation of the explosive charge on a lead cylinder, steel plate, or steel tube are observed. On the basis of these effects, the conclusion about the completion of the detonation... 

Figure 2.20. Steel tube cap sensitivity test (Rq>rinted with permission from Fukuyama,...

Another cap sensitivity test was developed in Germany (cited in Kohler and Meyer, 1993). According to this test, a high explosive is filled into a 200 mm long cardboard tube having an inside diameter of 80 mm. The determination of completion of the detonation is accomplished on the basis of the clean hole cutting in the 1 mm thick steel witness plate. 

Booster-Gap Explosive Sensitivity Test of Cole Edwards, described in detail in USP 2832213(1958) (Ref 17). It was claimed to be more reliable and less ex. pensive than the card test (See after "card-gap test") and the three-legged table test, described here after "shock-pass-heat-filter test . The "booster-gap test serves for evaluating shock sensitivity of liquid explosives. It includes a set of snug-fitting telescopic cardboard tubes (ca 1 inch diam) and a cylindrical wooden block for holding the electric blasting cap, Tetryl booster pellet, circular spacer cards, and the cup with liquid explosive (to test) fit compactly in the cardboard tubes when... 

Detonation, Wax-Cap Test in. See Vol 1 of Encycl p VIII, under "Booster Sensitivity Test and also on p A 354, Footnote c, entitled Wax Gap Test ... 

Tetryl has been used as an expl since 1906. In the early part of this century it was frequently used as the base charge of blasting caps but is now replaced by PETN or RDX. During WWII it was used as a component of expl mixts (see Tetrytols in this Vol). Tetryl is still used in military boosters and leads (the expl component of a fuze between the detonator and booster), but even here it is being replaced by plastic-bonded or waxed RDX and HMX expls. A widely used shock sensitivity test employs Tetryl as the donor charge (see Shock Sensitivity of ... 

A similar test has been developed in the USA (according the deformation of a lead block, using commercial caps with 0.4-0.45 g PETN). It is advisable to classify according to test results and not, as was the custom in the USA, by the classification of NCN according to the explosive composition. As indicated above, ANFO s are not cap sensitive mixtures of finely ground ammonium nitrate containing only 2% instead of 6% of oil or wax can, however, be cap sensitive. 

Some substances make a loud sound upon exploding and others hardly make a sound in drop ball impact sensitivity tests. The simple contact mixture of potassium chlorate and red phosphorus is one of the substances which makes loud sound when exploding. About a lOOdB (A-fast) noise is measured at a distance of 3m. The frequency distribution is shown in Figure 3.19 J 21. However the mixture does not always make the same explosive sound sometimes it makes softer sound, and other times, no sound at all. Sporting paper caps and toy paper caps cause loud noises with narrow frequency... 

A cap-sensitive explosive material is one that will detonate with an IME No. 8 Test Detonator when the material is unconfined. Glossary of Commercial Explosives Industry Terms. 7. 

The insensitivity of nitromethane to detonation by shock under normal conditions of handling has been demonstrated by a number of fljH-scale tests. Sensitivity to shock increases with temperature at 60° C, nitromethane can be detonated by a No. 8 blasting cap. Nitroethane can be initiated only when heated near its boiling point under heavy confinement neither it or the nitropropanes can be detonated in unconfined conditions. 

Its d was 1.20—1.25g/cc Trauzl test value, 370-380cc sensitivity to initiation, required at least a No 3 cap for detonation Refs 1) Naoum, Expis (1927), 132—3 2) Stettbacher (1933), 316 3) Pepin-Lehal-... 

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