1996
PhD Thesis
Edinburgh University
Abstract
The desire for continuous improvement in safety performance has lead the process industry to a situation where the main contribution to accident causation is the actions of people rather than equipment failure. Models of human behaviour and accident causation, and risk assessment techniques aim to improve safety by reducing human error rates. These models require appropriate data and this thesis examines sources of information that could be used to provide accurate data for use in human factors studies.
Accident reporting systems are widely used by the process industry to record events resulting in loss. A survey of the systems used by companies has been carried out. This found that some of the information recorded in accident reports was relevant to human factors studies although it was generally limited to details of the behaviour of people “at the sharp end.” Little consideration had been given to the actions of people working away from the plant or of the factors that affect human performance.
Near miss reporting systems are now used by most companies in the process industry to increase the number of incidents from which they can learn about their safety performance. Most systems lack maturity and at present the provision of data for use in human factors studies is poor. This thesis describes studies carried out to determine the potential of near miss reporting systems to provide appropriate data. It was found that people find it difficult to determine what events and consequences might have happened because there is a lack of evidence. Simple risk assessment based on what people do, the hazards involved and overall unit objectives has been used to provide the required evidence. This has resulted in more effective human factors assessment. Near miss reporting has great potential to provide data for use in human factors studies but it should be considered as a living risk assessment exercise rather than an extension to accident reporting.
Investigation allows an in-depth analysis of incidents to be carried out. A review of the techniques developed to aid investigations has shown that most guide investigators to uncover and record root causes. A study of actual incident investigation reports has shown that human factors problems are considered in reasonable detail although formal techniques are rarely used. Only major accident inquiries, however, are able or willing to identify management and cultural failures so that changes can be made that will lead to wide-ranging improvement to overall safety performance.
Companies operating continuous process require people to work shifts. Log books and handover reports are used to pass on important information about past and future activities. A survey of log books and handover reports was carried out. The contents included; information about routine and non-routine tasks, descriptions of problems experienced, and records of human errors and unreported incidents. These could provide much data useful for use in human factors studies and may actually provide a mechanism for improved incident reporting.
Systems currently used in the process industry to report and record events have been examined. Although companies in the process industry rarely use these sources of information in assessing human factors these existing systems have all been shown to have the potential to provide the site specific data that is required but often missing in the assessment.