This posting is a spin-off of information presented in the white paper from the UK’s Chartered Institute of Ergonomics and Human Factors. That paper focused on concerns with treating human factors in Bowtie’s analysis. I have modified their wording to make their valid points reflect all recognized PHA methodologies.
The paper mentions eight (8) concerns about human factors being viewed and managed in process hazard analyses.
- Human error is commonly modeled as a threat, and barriers are put in place that try to block the error from leading to an event. Indeed, human error is frequently the single most commonly identified threat in a barrier model. This focuses effort and attention in the wrong place. The effort is concentrated on trying to minimize the risk of human error rather than recognizing the real barriers and ensuring they are as robust against any degradation factors – of which human error is usually only one – as they can be.
- Equipment that is identified as performing a barrier function will typically have an equipment performance specification associated with it, specifying precisely what performance is required of the equipment for the barrier to be relied on. Although PHAs frequently identify a reliance on human performance to achieve barrier functions, they rarely (if ever) specify the level of human performance that needs to be achieved for the barrier to function.
- PHA scenarios frequently analyze the events that barrier systems seek to avoid by means of prevention barriers that are too close in time to the consequences (fatalities, losses, etc.) that those events can lead to. So while preventative barriers typically operate over a timescale that can be measured in weeks, days, and hours, mitigation barriers typically have to operate in a timescale of hours and minutes. This can create pressure for people to perform to extremely high standards in situations of both stress and time pressure.
- Too many barriers are identified, most of which are not able to meet the generally accepted criteria for robust barriers. While they have a role as “safeguards”, they should not be confused with the principal barriers that need to be capable of being relied on.
Important NOTES from this paper:
- The term “controls” means all of the measures expected to be in place to prevent incidents.
- Controls comprise barriers and safeguards.
- The term “barriers” means controls assessed as being sufficiently robust and reliable and relied on as primary control measures against incidents.
- The term ‘safeguards’ means controls that support and underpin the availability and performance of barriers. However, that cannot meet the standards of robustness or reliability to be relied on as a primary measure (i.e., as a barrier).
5. Barrier models rarely take a systems view of the human and organizational factors associated with the threats they try to control. They rarely recognize the influence that a wide range of organizational factors – such as leadership, culture, incentive schemes, commercial arrangements, or contractor management – can have on the performance of people on the front line.
6. There is often a lack of understanding of the nature or complexity of the tasks – and especially the cognitive elements of those tasks – that must be carried out for barriers to function as intended. Because of that, organizations frequently hold unrealistic expectations about what people will be able to do and how they will actually perform in the circumstances that exist when barriers need to function. Box 4 gives an example of such unrealistic expectations. Unrealistic expectations can be avoided by conducting task analysis to understand what operators will actually need to do for barriers to perform as intended.
7. There is often a lack of awareness of the difference between “work-as-imagined” and “work-as-done” (Hollnagel, 2014). “Work-as-imagined” reflects an idealized, office-based view of how tasks and processes are to be performed without recognizing the many situational factors – established work practices, practical difficulties, uncertainties, competing goals, and stresses – that exist in reality at the front line. “Work-as-done” captures how work is done, including the compromises and adaptations made when carrying out tasks under real-world constraints and pressures. The intentions and expectations of human performance that are implicit in the decision to rely on people as part of a barrier system are rarely made explicit. Therefore, they are not communicated to those who need to implement, perform, support, or maintain barriers.
8. Barrier models are often prepared, implemented, and distributed to the workforce in a manner that does not properly support their operational use. The individuals assigned to carry out tasks or whose performance is expected either to act as a barrier or to ensure a barrier is capable of functioning, are frequently unaware of the significance of the task or their assigned role. Similarly, they are unaware of the importance of reporting when they are unable to perform in the expected way or to the expected standard.
CLICK HERE for the full publication. Definitely worth your time