2016 – The Use of a Safety Case to Demonstrate ALARP

Shane McGrath, Stuart Richardson, Mark Arnold

Melbourne Water Corporation has recently completed a complex safety upgrade of Greenvale, an extreme consequence category dam. An assessment concluded that the residual risks were As Low as Reasonably Practicable (ALARP). However, given the uncertainty associated with the calculations the estimated residual societal risk was not comfortably below the limit of tolerability. Melbourne Water has experience with preparing hazardous industry safety cases for its water treatment chemical storages and decided to trial the methodology for Greenvale Dam. This paper describes the approach taken in hazardous industries to construct safety cases and how his was adapted to demonstrate that dam safety risks are ALARP.