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A Practical View of the Contribution of Human Error and Safety Critical Task Analysis in the Prevention of Major Accident Events

20 June 2016

In order to address human failures in potential major accident hazard events, TOTAL E&P UK (TEPUK)  has developed a process to manage the risk of human error across its operational assets. This article, by Lead Human Factors Engineer George Petrie and Head of Safety Engineering Ann Rosbrook, explains the process and looks at progress in implementing it across the company.

Historically, the Oil and Gas industry has focused on the identification and prevention of technical failures as a cause of major accident hazard (MAH) events. Over the last 20 years or so, there has been an increase in emphasis of the role of human failures in incident causation, but less emphasis on the implementation and embedding of good human factors practice in everyday site-based activities. The benefits of engaging the workforce and educating them in human factors methodology and practices, has resulted in operations sites having significantly more robust work instructions that are genuinely understood by the people who work with them. People are more hazard aware, more confident in challenging activities which they are unsure of and quicker to identify potential anomalies.

TEPUK’s process to manage the risk of human error across its operational assets started in 2013, and by developing sound foundations, the company has identified significant benefits of managing human failures in the prevention of MAH scenarios. The progress that has been made is explained in the following steps;

• How are we implementing change?

• How far are we on the journey?

• Challenges along the way:

• TEPUK future plans, 2016 and beyond

How are we implementing change?

TEPUK decided that a move to focus on Human and Organisational factors (HOF) in process safety required a competent human factors engineer to be embedded in the Safety Engineering Department not an occupational safety department which is traditionally the case in many oil and gas industry companies.

The HOF methodology chosen was to follow the guidance produced by the HSE in their Roadmap for safety critical task analysis (SCTA), see Figure 1 below. 

The first step in the roadmap process was to identify the MAH scenarios where HOFs influence the outcome.  On the face of it this sounds straight forward. However studying the guidance and application of the roadmap process, from a human error point of view, the definitions and detail of MAH scenarios were not clear and were open to a certain amount of interpretation.

In order to identify and confirm the MAH scenarios at each operational site, the first step involved a workshop covering each designated plant area, importantly involving the relevant site based stakeholders. During the workshop, a review of the site COMAH Report or Safety Case and corresponding safety studies i.e. QRA, HAZOP etc, controls in place, incidents etc.

was the main focus of activity. The output from this process resembled a “Human Bow-Tie” identifying the specific involvement of people in the relevant activity associated with the up keep of each prevention, mitigation or control barrier.

The process of  tasks analysis and human error analysis followed standard industry practice as detailed in  Offshore Technology Report - OTO 1999 092, Human & Organisational Factors Assessment of Safety Critical Tasks, 2002. To complete this process, it was essential to involve internal technical support from the Human Factors Engineer, safety or process engineers and most importantly the supervisors, operators and technicians who carry out the tasks.

The  result of the workshops formed part of the overall safety critical task process and is detailed in Figure 2 below.

Figure 1 - HSE’s Human Factors Roadmap for Safety Critical Task Analysis
Figure 1 - HSE’s Human Factors Roadmap for Safety Critical Task Analysis

 In order to embed this process across the company in a consistent manner, in-house procedures were developed before any plans were implemented to start further work.

Human Error Analysis actions were followed up in number of ways, the focus being dependent on perceived severity, i.e. category 1 being the highest severity:

1. Where a significant risk was found as a result of human error, specific studies were carried out e.g. HAZOP to identify if further engineering controls were required.

2. Where procedural controls were required, STOP/HOLD points were added at specific steps in a procedure to highlight the hazard effect and risk control measures required. A counter signature by a 2nd person/supervisor was required before work could proceed.

3. Where an occupational safety related hazard was found, a safety, health, environment and operational integrity (SHE&OI) note was added explaining the hazard and risk control measures required to be adhered to at that specific point in the task.

4. If errors were recovered by engineering controls/equipment i.e. alarms, trips PSVs etc a check was carried out to ensure maintenance was up to date, inspections had been carried out and equipment conformed with the relevant performance standard.

The STOP/HOLD points are placed at specific task steps rather than a generic statement at the beginning of the procedure or mentioned separately in a work permit. This simple step allows increased control of potential human error as the counter signature required by a 2nd person or supervisor prior to the task proceeding allows time to reflect on the identified hazard and associated risk prior to commencing the next step.

A checklist for reviewing performance influencing factors (PIFs) was implemented to develop a consistent approach when ‘walk-throughs’ of tasks on site were carried out. Common issues found were incorrect or no valve tagging, gauges fitted at varying angles and unrecorded modifications to equipment e.g. bleed valves.

After completion of a new procedure, a review of training and competency was carried out. This required a clear link to be demonstrated between the task, training requirements and personal competency to ensure human error was minimised in that particular task.

How far are we on the journey?

During the workshops, a number of scenarios were identified where a single error in undertaking valve isolations could potentially lead to a incident. These scenarios became apparent to the workforce as a result of this process and it was recognised by various operators that they were not aware of the possible scenarios following any human errors. 

Based on this feedback, further safety studies and changes to isolation procedures are now planned to include STOP/HOLD points together with full details of the hazard effect and the risks associated with the activity.

Figure 2 - Major Accident Hazard Scenario Screening Process
Figure 2 - Major Accident Hazard Scenario Screening Process

As this subject is not widely understood, out-with Human Factors professionals, TEPUK realised that to get the full potential out of this process, the workforce needed to become ‘informed customers’. External training courses were considered but a decision was taken to carry out all training and awareness sessions in-house by people who understood how the company operated, their safety management systems and the culture at site. With the support of a human factors consultant, a specific 2-day training course for leaders/supervisors and a 1/2 day awareness session for operators/technicians were developed. Feedback from this latter course highlighted that the 2 hour session originally planned was insufficient and that we needed to be flexible in the training delivery location if we were to train as many of the workforce as possible. All training and awareness sessions are fully aligned with the SCTA process and are enhanced by using site based examples to help explain the principles.

The whole process has gained momentum at TEPUK with resources being allocated to support the assessment process and to facilitate updates to site procedures. This has latterly involved maintenance technicians as well as operators in the analysis and site walk through of tasks.

Implementing the initial process required more resources than originally envisaged and this became apparent as we progressed in the development of the methodology and throughout the workshops.  With the support and investment in resources from Management, the initiative  is progressing well across TEPUK sites with plans to involve project and modification engineers in addition to operators, maintenance technicians and inspection engineers.

Challenges along the way

Developing and implementing this process has been challenging and the following explain some of the learning points identified:

* Organisations need to be careful in their selection of consultants. The initial HF consultants employed at site prior to the implementation of the process did not fulfil the required competency requirements of IEHF and did not fully appreciate the requirements to approach SCTA in an effective manner. As a result, the workforce exposed to this initial HF work were somewhat confused, were not aware of the benefits of the SCTA process and were less accepting of implementing any changes.

* Require a clear strategy and common methodology.  A number of external consultants were used for SCTA. Without a TEPUK common process, the results obtained were not consistent across the various operational sites.

* Focus on Major risks. The process is more effective when priority is given to MAH scenarios that are deemed high risk from human error. It focuses both management and the workforce to use scarce resources more effectively.

* Close the loop (from MAH scenarios right through to training & competency). The increased level of detail required in documentation for high risk tasks must fully align with the actions identified from human error analysis and be linked to training and competency for that task.

* Integrate HF into the business, ensuring the workforce and management have sufficient knowledge and understanding of Human and Organisational Factors. For the SCTA process to be successful and add value, everyone involved in the process requires the relevant level of knowledge on Human and Organisational Factors and understand how this information links directly to site activities.

* Involve the employees (desk top HF studies with consultants are not the answer).  The initial studies which were not particularly successful were conducted mainly as desk top studies. These were found to be largely ineffective in understanding how a task is carried out. As a result, TEPUK now involve the workforce at each step in the process. This has resulted in significant benefits being realised both with employee buy in and their improved understanding of the issue.

TEPUK future plans, 2016 and beyond

This entire process is still very much work in progress but the foundations have been developed and implemented across all our operational sites. One benefit from implementing this approach has been the subsequent identification and realisation where risks of human error could affect the validity of environmental permits and consents, adversely impact operational downtime, potential damage to equipment and not previously considered, impact to future business continuity.

The next phase of development is to identify a process to quantify human error as part of the risk assessment process. Quantification of human error is used in circumstances where there is significant risk of a MAH from human error with the development of fault trees and utilises HF methods such as HEART and THERP. The resulting Human Error Prediction (HEP) will be used to populate the human error requirements of our fault trees and provide an overall risk reduction value that can be used for the risk assessment purposes.

TEPUK have focused their efforts on high risk tasks as a priority and until these have been fully addressed progress will be slow on those remaining tasks identified as medium and low safety critical tasks. However, due to the business value of addressing these issues, they will be incorporated and further developed in future plans.

About the authors

Ann Rosbrook is Head of Safety Engineering for Total E&P Ltd whose area of responsibility includes Total’s North Sea offshore assets and the their two onshore gas plants in Scotland. She has 25 years oil and gas experience working in various oil and gas operators, engineering service companies and a secondment in UK Government, primarily in HSE management roles across the UK, Egypt and Algeria.

Rosbrook is a chartered member of the Royal Society of Chemistry (CChem.MRSC), a chartered member of the Institute of Occupational Safety and Health (CMIOSH) and has an MSc in process safety and loss prevention.

George Petrie is Lead Human Factors Engineer at TOTAL E&P and has a background in engineering and a wide range of experience in the manufacturing, mining and oil & gas industry, including 18 years HSE experience with major projects, production, well services, planned maintenance programmes, shutdowns, hook-ups and greenfield design in various fields across the North Sea, Scandinavia, Netherlands, Kuwait, Italy and the UAE.

He is a a chartered member of the institute of ergonomics and human factors (C.ErgHF), Chartered health and safety practitioner (CMIOSH), member of the International Institute of Risk Safety Management (MIIRSM) and Registered Safety Practitioner (RSP).

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