Human factors

A HUMAN FACTORS APPROACH TO THE OPTIMISATION OF STAFFING IN THE PROCESS INDUSTRY
Joanne Stokes,1 Karl Rich,2 and Tony Foord 3 Senior Human Factors Consultant, Human Engineering Limited, Shore House, 68 Westbury Hill, Westbury-on-Trym, Bristol BS9 3AA. 2 Associate Director, Human Engineering Limited, Shore House, 68 Westbury Hill, Westbury-on-Trym, Bristol BS9 3AA. 3 Principal Engineer, 4-sightConsulting, Southern Office, 51 Cowper Road, Harpenden, AL5 5NJ.
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SYNOPSIS
Staffing arrangements for process plant have been studied extensively in recent years taking account of the many interdependent variables influencing system performance (individual competence, equipment, teamwork and communications, procedures and organisation). This paper describes work to determine the optimumstaffing using human engineering tools such as task analysis, function allocation, workload analysis, and human reliability analysis.

INTRODUCTION
For several decades, staff rationalisation has been driven by a wide range of factors. Advances in technology, organisation, education and training have enabled significant increases in productivity. As a result of best practice, major incidents andregulatory pressure, facility operators have also strived to reduce exposure to major hazards. This has left the industry with highly automated plant and processes that in many instances have been “over-alarmed”, and a residual workforce obliged to multi-task and take ownership for secondary and tertiary activities. In some instances this has led to exposure to high workload, fragmented jobs and riskthat has been displaced rather than eliminated. Some companies are responding to this by adopting a user-centred, risk-based approach to staffing. This requires the participative rationalisation of processes and their associated alarms and procedures and a better allocation of function between operators and equipment. This can lead to an improvement in, and better prioritisation of, taskallocation. This can be achieved by developing a better understanding of the target audience and utilising this knowledge through task analysis and allocation of function. The baseline data can then be subjected to workload and human reliability analysis (to a level appropriate for the perceived risk). This allows the definition of roles, and appropriate and coherent job design. From this, training which istargeted, cost-effective and matches the requirement can be developed. The Health and Safety Executive Contract Research Report “Assessing the safety of staffing arrangements for process operations in the chemical and allied industries” [HSE CRR 348, 2001] and the “Best Practice Guide” [Energy Institute, 2004] provide techniques for checking whether a particular staffing is sufficient to meet therequirements for safety. The [HSE CRR 348, 2001] report states “It is not designed to calculate the minimum or optimum number of staff.” and also states about other human factors techniques for assessing staffing: “it is concluded that many of the techniques are research tools, requiring specialist skills to interpret even though they may be straightforward to apply. A method tailored toassessing staffing arrangements, and designed for general use, has not been produced.” This paper describes an approach that still requires the use of human factors specialists, but is suitable for general use to determine the optimum workload and the optimum staffing.

BACKGROUND
For several decades, improvements in technology, organisation, education and training have enabled significant increases inproductivity, often described as reductions in workload, staff rationalisation or reduction in staffing. For example, before 1995 a gas processing unit had 40 staff, mainly on shifts. Following a review this was reduced to 25 staff in 1996. Subsequent experience meant that the

numbers were increased by one or two, but the number of staff is still well below 30. Another unit had a large...