Blast Training International

Creating the pit left by an explosion.

A credible evacuation scenario is one with a high likelihood that within 45 minutes of the evacuation being initiated there is no person in a building inside Protected Works Class B distance and no person in the open inside Protected Works Class A distance. (Note that 45 minutes is the worst case – the target evacuation timeframe is 30 minutes.) Whether evacuation is credible can only be assessed on a site-specific basis. Refer Appendix D.

Critical Density is defined for mechanically sensitised explosives.

This is the density above which detonation fails. The failure is due to insufficient gas bubble to create hot spots when impacted by a shock wave.

Critical diameter is the minimum physical size a charge of a specific explosive must be to sustain its own detonation wave.

To determin the critical diameter a series of charges of smaller and smaller diameters are fired until difficulty in detonation wave propagation is observed.

A charge with a critical diamter more than the physical diameter of the charge will fail to maintain detonation.

A machine system which has been assessed to present unacceptable consequences if the machine or its protective system should fail.
This includes all failures or malfunctions, which could lead to danger to life or significant harm to any person or to the environment.

When emulsion explosives age the Ammonium Nitrate solution crystallises out. This occurs when the AN salts solidify and the product feel becomes gritty.

Crystallisation reduces the sensitivity of emulsions.

A Dangerous Goods Officer (DGO) is appointed by the competent authority to administer and enforce the Dangerous Goods Legislation.

dBL or decibel linear peak is the maximum reading in decibels (dB) obtained using the "P" time – weighting characteristic as specified in AS 1259.1 – 1990 with all frequency weighted networks inoperative.

dBL is the scale used for measuring blasting overpressure.

dBA is weighted for human response (high frequencies and low frequencies beyond the range of hearing are not used) and is not used in the recording of blasting noise and overpressure. dBA is used to measure noise levels that affect hearing.

A dead blow hammer is a specialized mallet helpful in minimizing damage to the struck surface and in controlling striking force with minimal rebound from the striking surface. The head of these hammers are commonly hollow and filled with sand or lead shot, which both absorbs the impact of a strike and concentrates all of the energy of the blow in a focused point.

The operation of a pump when there is no flow due to the outlet or discharge line being closed or blocked.