Pyramid, process safety

Serious incidents may be predicated by a number of less-severe related incidents resulting in minor or even no loss. Such predicating events may be low-consequence incidents such as loss of containment into a diked area, near misses, or failures in which no injuries, damage, or loss occurred. This relationship between no- or low-impact events and actual process safety incidents is demonstrated in the process safety pyramid (see Figure 1.2). ... 

Use of the process safety pyramid in selecting metrics is discussed in Chapters 3 and 6. 

Figure 1.2 Process Safety Pyramid (CCPS, 2007b)...

The process safety pyramid described in Figure 1.2 provides a useful concept for categorizing metrics by severity. Lagging, leading, and near-miss metrics are associated with the different levels of the safety pyramid. Figure 3.1 illustrates how each of these four areas fit into that categorization. ... 

Regardless of whether one uses the process safety pyramid, the Swiss cheese model, or something else (for example, the anatomy of an incident model discussed in HEP 3), the concepts of... 

Dowell, A.M. 2002. "Getting from Policy to Practices The Pyramid Model (Or What Is this Standard Really Trying to Do )." Process Safety Progress 21(1). March. 

The assumption underpinning the incident pyramid is that the causes for all types of event are the same. In fact, this assumption is only partially correct because the root causes of minor events are different from those that lead to process safety events. Therefore, improving day-to-day safety will not necessarily reduce the number of serious incidents. Minor events are typically caused by occupational problems such as trips and falls, lack of proper PPE, and improper use of machinery. Major events, however, are more often caused by process safety problems such as incorrect instrument settings, corrosion, or mixing of incompatible chemicals. Hence a program that leads to improvements in occupational safety will not necessarily help reduce the frequency of process-related events. Indeed, improvements in the occupational safety record may induce a false sense of confidence regarding the potential for a major event. (It is probable, however, that a poor performance in occupational safety will correlate positively with a poor performance in process safety.)... 

Values and attitudes form the foundation of the pyramid in Figure 7.1. These obviously critical person factors need to support the safety process. Remember our discussion about risk compensation in Chapter 5, and Wilde s warning that it is more important to reduce risk tolerance than increase compliance with specific safety rules (Wilde, 1994) This happens when people believe in the safety process and help to make it work. Behavior helps to make the process work and, if involvement is volimtary and appropriately rewarded, it will lead to supportive attitudes and values to keep the process going. 

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