Sequentially Timed Events Plot

However, in the case of a root cause analysis system, a much more comprehensive evaluation of the structure of the accident is required. This is necessary to unravel the often complex chain of events and contributing causes that led to the accident occurring. A number of techniques are available to describe complex accidents. Some of these, such as STEP (Sequential Timed Event Plotting) involve the use of charting methods to track the ways in which process and human events combine to give rise to accidents. CCPS (1992d) describes many of these techniques. A case study involving a hydrocarbon leak is used to illustrate the STEP technique in Chapter 7 of this book. The STEP method and related techniques will be described in Section 6.8.3. 

Sequentially Timed Events Plotting Procedure (STEP)... 

The first case study describes the application of the sequentially timed event plotting (STEP) technique to the incident investigation of a hydrocarbon leak accident. Following the analysis of the event sequence using STEP, the critical event causes are then analyzed using the root cause tree. 

This case study concerns the events leading up to the hydrocarbon explosion which was the starting point for the Piper Alpha offshore disaster. It describes the investigation of the incident using the sequentially timed events plotting (STEP) technique. Based on the STEP work sheet developed, the critical events involved in the incident are identified and analyzed in order to identify their root causes. 

In order to accurately describe the actual sequence of events that make up the accident techniques such as STEP (sequential timed event plotting—see Chapter 6 and the case study in Chapter 7) can be used by the investigator. 

Sequentially Timed Events Plot (STEP)<4) is a name used for the multilinear events sequence-based matrix display. It evolved from the 1975 MES concepts, but only events are displayed because conditions or states... 

STEP is an acronym for sequentially timed events plotting. STEP is an events-analysis-based approach in which the events are plotted, sequentially — and in parallel, if appropriate — showing the cascading effect as each event impacts on others. It is built on the management system... 

The heart of the book is its presentation of Sequentially Timed Events Plotting (STEP). The accident investigation methodology presented relies on a new conceptual framework, building on system safety technology and the safety assurance systems of MORT (management oversight and risk tree). 

After having set the stage of the workshop, an overview of the case and the decision criteria for riser disconnection were presented. This was followed by a presentation of the STEP-analysis, i.e. Sequentially Timed Events Plotting (Hendrick and Beimer, 1987) as a method to analyse scenarios. STEP-analysis is an accident investigation method involving a detailed mapping out of a scenario (accident) by plotting the... 

The basic concept from which event and causal factors charts were developed can probably be traced back to Ludwig Benner and others at the National Transportation Safety Board. Benner developed a very similar technique called multilinear event sequencing (MES) and more recently sequentially timed events plotting (STEP). Event and causal factors charts were part of the overall MORT approach to system safety developed by W. G. Johnson for the Atomic Energy Commission in the early 1970s and further developed and taught by the Department of Energy s System Safety Development Center (SSDC). The use of the event and causal factors chart is sometimes referred to as causal factors analysis. 

The situation was analysed by the STEP investigation method (Sequentially Timed Events Plotting, see Hendrick Benner, 1987). The STEP diagram is shown in Figure 1. 

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