Barrier analysis ETBA

A typical system safety task for hazard identification would be the preparation of a preliminary hazard list (PHL). Hazard identification or discovery is accomplished by reviewing lessons learned, accident reports, and other historical data. A PHL may be prepared through an informal conference, the use of checklists, and occasionally other techniques such as energy trace and barrier analysis (ETBA). 

The methods used for preparation of a PHL include informal conferencing and the use of checklists and/or energy trace and barrier analysis (ETBA). 

The recommended techniques for preliminary hazard analysis are energy trace and barrier analysis (ETBA) and failure modes and effects analysis (FMEA). Recommended techniques for system and subsystem hazard analyses are FMEA, fault tree analysis (FTA), common cause analysis, sneak circuit analysis (for electrical, electronic, and some hydraulic or pneumatic circuits) and, of course, software hazard analysis for software. 

The energy flow and barrier analysis (ETBA) technique described in Chapter 13 evolved from this part of the MORT chart, and the mini-MORT chart was developed from this configuration. This version of the chart had a block (not shown) under the incident branch that indicated that in cases of multiple energy flows the analysis process should be repeated for each energy flow and barrier failure that led up to the accident (Fig. 18-9). 

Figure 18-8 Accident triangle. The incident , LTA barriers , and vulnerable target concept is the basis for Energy Trace and Barrier Analysis (ETBA) described in Chapter 13.

Figure 9.1 Sample energy trace and barrier analysis (ETBA) worksheet.

Fault (or Functional) Hazard Analysis (FHA) Management Oversight and Risk Tree (MORT) Energy Trace and Barrier Analysis (ETBA) Sneak Circuit Analysis (SCA)... 

The qualitative tool called energy trace barrier analysis (ETBA) was initially developed as part of MORT. Since the demise of MORT, ETBA has been used extensively in hazard analysis. The purpose of ETBA is to identify hazards by tracing energy flow into, through, and out of a system. A hazard is defined as an energy source that adversely affects an unprotected or vnlnerable target. 

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