Mini-MORT chart

In side-by-side comparisons with the MORT chart and the mini-MORT chart (see Chapter 18), PET has consistently been more favorably received than either of the others by persons with and without prior MORT experience or training. 

Color coding of the PET chart is recommended, using red for evaluation criteria determined to be less than adequate (LTA), green for items that are adequate, black for criteria or branches of the PET chart than do not apply to the particular project or item being evaluated, and blue to indicate areas with insufficient input data to make a decision. (This color-coding system is the same that is used for the MORT chart and the mini-MORT chart (see Chapter 18). 

The mini-MORT chart is basically the full-size MORT chart with the bottom tier removed to reduce the number of events to be evaluated from... 

The purposes of the mini-MORT chart are to aid in teaching MORT concepts and, for relatively minor accidents, to serve as a tool for performing MORT analysis on a reduced scale. 

Input requirements for MORT analysis, like those for any other detailed, comprehensive analysis, are extensive. Detailed information about the hardware and facilities, environment, procedures, and personnel directly involved is required for full evaluation of the specific control factors, and additional information about the management system is required to evaluate the policies, procedures, implementation plans, risk assessment program, and other upstream factors. Normally, a combination of interviews, physical inspections, and reviews of many procedures and project documents is required. The MORT chart and/or mini-MORT chart can serve as a planning and organizational tool for the collection of evidence and other relevant information. 

The MORT analysis effort begins as soon as the accident occurs and the accident board is notified. The MORT analysis is usually performed by the trained investigator on the board (or an advisor to the board). The MORT (or mini-MORT) chart is used as a working tool to aid in gathering information and storing information as it is gathered. 

Figure 18-4 Color coding. These colors are generally used on the MORT or Mini-MORT chart when performing MORT Analysis. They are also used for the PET chart.

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). 

Whether using the MORT chart or the mini-MORT chart to perform MORT analysis (or using the PET chart for PET analysis), the general approach is to use the chart as a working paper, begin as early as possible, add information as it is obtained until the chart is complete, and then use the com-... 

The following instructions are for performing MORT analysis using the mini-MORT chart. The mini-MORT chart was chosen because it is easier to use and to learn and is probably better suited to all except catastrophic accidents. 

System Safety 2000 is the only known source of instructions for using the mini-MORT chart. 

The event and causal factors chart is developed and expanded as new evidence and information become available. It should also be developed in conjunction with other analyses (change analysis and PET or MORT analysis), and information should be cross-checked (Fig. 19-2). Conditions that are causal factors on the event and causal factors chart should be identified as less than adequate areas on the PET, MORT, or mini-MORT chart. 

Figure 19-2 Relationships between PET or MORT and events and conditions. The event and causal factors chart and the PET, MORT, and/or mini-MORT chart are initiated as soon as the investigation begins and are developed together as evidence is collected.

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