(156a) Inherent Safety and the Elements of PSM/RBPS Programs

Inherent safety is implicitly part of PSM/RBPS programs, that it not be included as a discrete element, but as part of the thought process for the design of these programs and how they are applied and implemented. The four IS strategies, i.e., Substitution, Minimization, Moderation, and Simplification have usually been applied in the context of the chemicals and the hazards/risks that they present, e.g., substituting one chemical with another that presents less of a process safety hazard, or minimizing the inventories of the chemicals that can create process safety hazards. Traditionally, IS has been regarded as an intrinsic part of the design of the process, i.e., part of the “hardware” aspect of the process or as part of the properties of the process with respect to the hazards presented by the hazardous materials used in the process. However, they can also be applied to the thought process of each element of a PSM/RBPS program when the elements are being conceived and planned, or later as they are revised and refined. That is, the same principles of inherent safety can be applied to aspects of the process that are largely programmatic, i.e., the design and execution of the PSM/RBPS program policies, practices, and procedures. This is a new application of inherent safety concepts.

For example, Minimization has traditionally been associated with reducing the inventory of hazardous materials, which is a physical aspect of the process. However, we can pose the question: Can/should shift schedules and their working times be minimized to avoid fatigue? This is a possible application of minimization to a non-physical or programmatic/procedural aspect of the process. Another example: Can a different type of non-destructive testing be substituted to increase the likelihood of detecting a particular type of corrosion. This is an example of how the inherent safety strategies can be used in the planning of a mechanical integrity program. Another possible use of the four inherent safety strategies is their use in guidewords, deviations, checklists, and other process safety analytical and assessment tools. In particular, the HIRA/PHA, MOC, and Incident Investigation elements are examples of such possible use.

For some PSM/RBPS elements the relationship with the IS strategies is direct and relatively strong, e.g., PHA, whereas for other elements the relationship is more indirect, e.g., Measurement and Metrics. While the use of the four main inherent safety strategies in this non-traditional manner represents a novel use of the terms, it is not intended to supplant their possible use in traditional, physical aspects of the process, but to supplement them.