System Safety for the 21st Century, 2nd Edition

CHAPTER 14Energy Trace and Barrier Analysis

Energy trace and barrier analysis (ETBA) is a relatively new technique based on some of the principles found in the management oversight and risk tree (MORT) program, which defines an incident as an unwanted flow of energy. An accident is defined as occurring when this unwanted flow of energy, in the absence of adequate barriers, strikes targets in the energy path and injures people and/or damages property (Fig. 14‐1). So, an incident is an unwanted energy flow, and an accident is an unwanted energy flow or incident that results in adverse consequences.

The sides of the accident triangle that are discussed in the MORT program are the unwanted energy flow, barriers that are less than adequate to prevent or control the energy flow, and targets (persons or objects) in the energy path (Fig. 14‐1). This approach is the basis for ETBA, which systematically analyzes these three factors and their interrelations.

PURPOSE OF ETBA

This particular analytical technique can be used to aid in preparing preliminary hazard lists (PHLs), conducting preliminary hazard analyses (PHAs), subsystem hazard analyses (SSHAs), or system hazard analyses (SHAs). The ETBA may be helpful in performing operating hazard analyses (OHAs) and accident analyses and in other situations. The ETBA seems to be particularly well‐suited to facility system safety programs.

INPUT REQUIREMENTS

The primary input requirements for performing an ETBA are project plans and drawings ...