Minimum initiating charge

The minimum initiating charges for pentryl as compared with other explosives (according to Clark [78]) are listed in Table 14. 

Azide Ignition temperature °C Sensitiveness to impact (work in kgm/cm2) Minimum initial charge, g ... 

Primary explosive Minimum initiating charge necessary for explosion of 1.25 g of tetryl Sand crushed per g... 

Fig. 58. Minimum initiating charge of lead azide, lead styphnate and their mixtures for 1.25 g of tetryl, according to Grant and Tiffany [40].

I. Improved explosives for coal work (explosifs couche ameliorgs). They may be used with delay detonators provided that the delay between the first and the last shot is less than 5 sec. In particularly dangerous places short-delay detonators should be used. The minimum initial charge is 1500 g in coal and 2000 g in rock. 

Following are some props of silver acetyl-ide which was prepd from ammoniacal solns of silver nitrate deton vel 1880 m/sec at d (not given) power by Trauzl test 132 cm at d 1.67(Ref 6, pp 304-5) minimum initiating charge for 0.8g tetryl, 0.07g AgaCj compared co 0.02g for LA(Ref 2,p 4) heat of expln 400 cal/g... 

The minimum initiating charge was determined as follows. The amount of sand pulverized by a detonator loaded, say, with TNT and with fulminate insufficient to explode the TNT was determined. Another experiment with a slightly larger amount of fulminate was tried. If this showed substantially the same amount of sand pulverized, then the charge of fulminate was increased still further, and so on, until a sudden large increase... 

Impact tests indicate composition C4 is less sensitive than composition C3. The rifle bullet test results, with only 20 percent of the vials burning, also indicate less sensitivity. Composition C4 is unaffected in the pendulum friction test and has a five second explosion temperature of 263°C to 290°C. The minimum initiating charge required is 0.20 grams of lead azide or 0.10 grams of tetryl. 

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