Debris Throw Model for Accidental Explosions in a Complex Industrial Environment

Alongside the accidental release of potentially hazardous substances, incidents evolving around the physical aspects of explosions are the second most reported type of hazard in the processing industry (ZEMA, 2002). The sudden failure of a component processing combustible gases exhibits a considerable risk to the operational safety of the affected process unit, if not the entire plant, and therefore to the health of affected personnel and public. In addition to the potential hazard associated with the blast wave propagation and the potential structural loss itself, the debris throw originating from the housing structure poses a significant threat to structures and personnel in the surrounding working environment in distances which may exceed the hazard-range of the blast wave itself. Further to the impending personal damage, other processing components or building structures can be affected, potentially causing cascading hazards. Insight into the break-up process during structural failure and the ensuing debris throw thus aids in defining safety distances important for a safe operation of the plant. This contribution describes a fast and efficient engineering methodology to determine the decisive safety ranges. For this purpose, dynamic threshold values for the break-up of building components are derived and the debris throw originating from masonry structures subjected to shock loads caused by the accidental gas explosion is described analytically. The methodology is demonstrated by picking up the example by Breitung and Yanez (2016) for an accidental release of hydrogen in a turbine hall. The debris throw from an affected masonry wall as part of an enclosure is exemplarily calculated.