Assessing Hazards from Explosives as Part of Explosives Facility Safety Cases

In many hazardous industries within the United Kingdom, there is a requirement for operators to produce a Safety Case for each of their facilities in order to demonstrate that their activities are carried out safely and without ill effect to persons ’ health or the environment. A key aspect of the Safety Case is the risk assessment section, which identifies hazards and evaluates the control measures in place to determine the associated risks and demonstrate that these levels of risk are tolerable and kept as low as reasonably practicable. This paper presents a methodology for assessing condensed phase explosion hazards. The methodology has been developed in recognition of problems in risk assessment which are specific to processes and activities where explosive substances and articles are handled. A fundamental difficulty is in the application of numerical data to estimate credible probabilities of initiation under accident conditions. Furthermore, it is often the case that organisational and human factors are critical aspects of hazard control in any given explosives facility. None of these aspects are readily quantifiable. Hence, there is little benefit in carrying out detailed probabilistic analysis when such great uncertainties in data exist. The approach advocated here places a strong emphasis on understanding the hazards and their controls, which is then demonstrated through rigorous evaluation based on strong qualitative arguments