Assessment and Control of Fire and Explosion Hazards and Risks of Particulates

Abstract

Fires and explosions of particulates have caused, and continue to cause, substantial financial loss and loss of life. This Chapter provides knowledge and insight into preventing or at least mitigating particulate fire and explosion hazards and risks. To this end we distinguish between the concepts hazard and risk, first discussing in some detail the nature of fire and explosion hazards of particulates, the indexes expressing these hazards, the many factors that determine such hazards, and a widely used and internationally accepted system for ranking fire and explosion hazards of particulates. All of these topics relate to a given particulate; i.e., a particulate of a given chemical composition and given physical form (e.g., particle shape and size distribution). We next discuss fire and explosion risks of particulates. Risk is a much more extensive and complex topic than hazard, as risk involves factors extensive to the particulate itself, such as: amounts of particulate; where (region, country) it is made, transported, and stored; the (process) conditions under which it is made, transported, and stored; relevant legislation; and management. Rather than discuss the complex topic of particulate risk as such, we concentrate on a number of fundamental approaches to reduce risk, approaches which are increasingly applied in modern (chemical) engineering design. One general method to reduce risk is to negate the basic factors causing risk. This is the basic logic of Inherently Safer Design (ISD), which, essentially, aims at avoiding or at least greatly reducing hazard by clever design/choice of materials, process, and conditions. Inherently Safer Design forms the starting point of designing layers of defense against mishap. The analysis of the degree of risk reduction by the layers is called Layers of Protection Analysis (LOPA). LOPA recognizes that in practice Inherently Safe Design rarely can eliminate all hazards. Thus, starting from the ideal of Inherently Safer Design, LOPA applies ‘layers of protection’ around manufacturing the particulate. These ‘layers of protection’ are applied at various scales, starting from the process itself (e.g., safety devices, such as a device to suppress explosion) to the neighborhood in which the plant manufacturing the particulate is located (e.g., a disaster plan involving local government). The goal of LOPA is to reduce risk to an acceptable level. We discuss Inherently Safer Design and LOPA in some detail, including examples. Relevant legislation and management aspects are also absolutely essential topics in particulate safety. These are mentioned, but because this Chapter focuses more on scientific and technical aspects, these two important topics are discussed in less detail. The Chapter ends with a note on research and also provides an extensive literature list.