Human error is the cause of most major accidents. This was one of the central messages to come out of a presentation by Ian Hamilton, ERM’s Global Human Factors Lead Partner, who spoke recently at the Energy Institute Human Factors Application in Major Hazard Industries Conference in Leeds, UK. In his talk to an audience of oil and gas and other industry professionals, Ian highlighted a range of human factors which could contribute to human error and, in turn, to major accidents.
Ian’s focus on human error as part of what he termed “organizational integrity” – the marriage between human performance and an effective safety management system - was echoed by a number of speakers, including calls to improve the way we learn from accidents and analye what has actually gone wrong. These learnings, it was agreed, are important in understanding how people could be better supported in order to prevent future accidents.
According to Ian, human factors analysis is an important ingredient of effective bowtie analysis, a tool which is now widely applied in the oil and gas industry to analyse hazard risk scenarios. Bowtie diagrams can be used to examine high risk scenarios for the loss of control of hazards. The diagrams reveal the threat conditions that can lead to a loss of control and how this can develop into increasingly severe consequences. Using these diagrams it is possible to identify both existing and additional control measures that can prevent loss of control and mitigate consequences to reduce losses; these are known as barrier measures.
Bowties, Ian told one questioner, are not a substitute for technical studies such as HAZID, HAZOP and LOPA but a way of representing key findings in order to share understanding and implement the right safety measures.
Ian argued that human factors must be considered as part of safety analysis. He explained that human error can act as a threat by introducing possible failure modes. For instance, errors in tasks that manage containment, such as isolations, could lead to a loss of control of a hazardous material. Alternatively, human error can enter the system as failures on tasks that are necessary to ensure the reliability and availability of safety barriers. For instance, an error on a task intended to test, calibrate or maintain a barrier system, could mean that it fails to work when required. This can be represented in the bowtie diagram as an escalating factor that introduces risk to barriers or as performance standards for the barrier measure.
The need to consider human factors as an integral part of technical safety arises earlier and earlier in the lifecycle of an asset. ERM’s experience, said Ian, shows that human factors engineering is now an established part of the engineering design activities on capital projects. The benefits of this, he argued, are not just the improved, comprehensive assessment of risk factors, but also better design that avoids delays and re-engineering as the project approaches commissioning. ERM, he said, is increasingly being asked to perform human factors studies in the earliest stages of a project to help the selection of the most appropriate operating concept. Clients recognised that human factors analysis both helped to meet safety regulatory demands and also played its part in creating a more efficient operating solution.
For further information and a copy of Ian Hamilton’s paper contact [email protected]