BAM drop hammer

Testing the response of solid, liquid or pasty substances to impact, friction and thermal stimuli is required in various standards such as EEC, Official Journal of the European Communities as well as UN Recommendations on the Transport of Dangerous Goods, 13.4.2 Test 3(a)(ii) BAM drop hammer. 

Table 3-11 Test Variables for the BAM Drop Hammer Test...

Large drop hammer of BAM with protective box and ventilating equipment used for determining the sensitivity to impact of explosible substances... 

The materials requiring less than 3 mm of critical gap width in the small gap test cannot be measured in a BAM friction test. More sensitive materials can be measured in both tests and show a reasonable correlation. But the correlation between the results of the drop hammer test and the friction test is not always good for the mixtures of oxidizer and fuel. Examples of this are shown in Fig.3.121. In these examples the samples demonstrate high blow sensitivities but low friction sensitivities or low blow sensitivities but high friction sensitivities. The interpretation of the results seems to indicate four possibilities. 

Fig. 6.1 Drophammer in accordance with the BAM (a) and detailed sketch of the drop-hammer test with the two steel rollers, a hollow steel collar and a centring ring for fixation (b).

Table 9.1 Impact (drop-hammer machine, 2.5 kg hammer, 50 % probability) and friction sensitivity (BAM apparatus, 1 event in 10 trials) of powdered CP [6]...

In Table 1.2 impact sensitivity values of different azido compounds according to the BAM fall hammer procedure are listed and compared with the corresponding values of the well-known explosives trinitrotoluene (TNT) and nitroglycerine. For the BAM procedure it is necessary to have at least one positive event within a series of six trials (probability of at least 16.7%). In the case of the US drop hanuner tests (according to the Bruceton procedure) the required probabihty level is often 50% initiation within a series of at least 25 trials. 

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