Witness-Board Testing and Probabilistic Fragment Range for Explosive Fence Breaching: Assessment of Minimum Safety Distance
Abstract
This work reports the testing and evaluation of fragment hazards arising from an explosive fence-breaching charge. Four controlled detonations were conducted using witness boards, supported by a high-speed camera, to capture fragment distribution and fragment velocities. A Gurney-based estimate and an aeroballistic model (including gravity and drag) were applied to obtain range predictions. Fragment wounding effectiveness was assessed based on their kinetic energies and energy densities. Simulations were performed to determine the probability of fragment impacts on targets at various distances. The results indicate that distinct levels of fragment effectiveness occur over different distance ranges. A minimum safety distance for training applications was established based on fragment effectiveness calculations and simulations. However, for shorter fence charges, prescribed safety distances may not adequately protect against flying fragments. This study contributes to the understanding of the risks posed by nonstandard explosive threats represented by atypical fragment fields to non-participants in proximity. To refine safety distances, comprehensive fragment capture and classification procedures, along with trajectory angle analysis, are recommended.