Applications of Performance-Influencing Factors

Performance-influencing factors analysis is an important part of the human reliability aspects of risk assessment. It can be applied in two areas. The first of these is the qualitative prediction of possible errors that could have a major impact on plant or personnel safety. The second is the evaluation of the operational conditions under which tasks are performed. These conditions will have a major impact in determining the probability that a particular error will be committed, and hence need to be systematically assessed as part of the quantification process. This application of PIFs will be described in Chapters 4 and 5. 

The PIF concept is also useful during the process of design. Design guidelines to maximize the usability of plant and to minimize the potential for error can be based upon comprehensive descriptions of PIFs such as the factors which determine the most effective presentation of information in control rooms, or the characteristics of usable and clear operating instructions. 

For some applications, for example, human reliability analysis, a situation needs to be rated on a numerical scale. In these cases, values such as those shown in the left-hand column of Table 3.1 can be generated by comparing the situation being evaluated with the descriptions in the second, third, and subsequent columns which represent other PIFs relevant to the situation being assessed. These represent the worst, average, and best conditions that are likely to occur in chemical plants in general and correspond to ratings of 1,5, and 9 on the numerical scale in the left hand colunrm of Table 3.1. Obviously, 

PIF EVALUATION SCALE (QUALITATIVE AND QUANTITATIVE) PROCEDURES PHYSICAL WORK ENVIRONMENT 

WORST 1 No written procedures, or standard way of performing tasks Not integrated with training High levels of noise Poor lighting High or very low temperatures and high humidity or wind chill factors 

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