Comparison of debris throw modelling with KG-ET software, SAFER and UK approach

Debris throw from reinforced concrete structures is an important explosion effect for scenarios with accidental detonations of stored ammunition. Models to quantify this effect are part of risk assessment software. Recently the ‘Klotz Group’, an international group of experts on explosive safety, has developed an engineering tool (KG-ET) for the prediction of debris throw. The tool is based on state of the art knowledge, and available debris pick-up data from a number of trials. With the help of this data, relations have been obtained for the initial distributions of debris mass, velocity and launch direction, as a function of the loading density. In combination with trajectory calculations and the source function theorem, the model is used as a prediction tool.
The SAFER methodology and code was developed by APT Research for the United States Department of Defense. It has a wider scope of applications than the KG-ET. SAFER provides methodologies for calculating the risk associated with explosives operations and storage. The three elements of the methodology are the probability of event, probability of fatality given an event, and exposed personnel. The prediction of the break-up of the structure and the debris throw are an essential part of the methodology to quantify the risks. The KG-ET and SAFER both are engineering approaches based on physics combined with assumptions and engineering judgment to schematize the problem and limit the computational effort. The UK on its turn follows a different approach to quantify break-up, debris formation and the debris launch conditions. First principle methods are used to determine the initial debris launch conditions. Recently, a first software version of the KG-ET method was handed over to the Klotz Group. In a workshop the SAFER, KG-ET and the UK approach were compared. The features of the models and the results of the model comparison are presented in this paper.