Sensitivity of Explosives to Electric Spark

The electric spark sensitivity or electrostatic sensitivity test determines the minimum amount of energy of an electric spark discharge that will cause initiation of the tested sample. 

The test starts at the maximum energy level. It is then gradually decreased until the minimum ener level of electric spark that produces the initiation of the sample, is achieved. Initiation is considered to have occurred if either smoke, flame, flash, crackle, or characteristic smell of the reaction products is observed. 

The minimum energy level of electric spark that produces the initiation of the sample is considered to be measure of explosive sensitivity to the electric spark. 

Source After Safety and Performance Tests for Qualification of Explosives , NAVORD OD 44811, Naval Weapons Center, China Lake, CA, 1972. 

Since different types of testing apparatus are in use, it is necessary to standardise testing procedure, sample size, electrode to anode energy transfer, and the size of the electrodes. Despite differences in equipment, there seems to be a rather good correlation between different test data. 

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