Effective control of work systems critical to preventing incidents and injuries

Article published in the Regulator | Issue 1: 2018 

During 2017, NOPSEMA was notified of four dangerous occurrences involving workforce interaction with a cable or pipe. In each occurrence, personnel interacted with a cable or pipe which was thought to be safely isolated. Each occurrence had the potential for death or serious injury, and two could have resulted in a major accident event. While the circumstances surrounding each occurrence are unique, NOPSEMA’s investigations have identified some common contributing factors.

Positive identification

Immediately prior to each interaction, personnel did not positively identify the target cable or pipe. In three of the occurrences, an adjacent cable/pipe had been isolated and the live cable/pipe was mistakenly thought to be the isolated cable/pipe. In the fourth occurrence, the cable/pipe had been inadvertently skipped during the isolation process.

In each of the dangerous occurrences, the need to isolate the target cable/pipe was identified during job planning and performed as required prior to the commencement of the work. However, a variety of job-level factors contributed to the misidentification of the target cable/pipe. Some of these factors included supervision of work, communication, fatigue, and the physical layout of the job site. Following each occurrence, the responsible operator identified that the inclusion of drawings and schematics in the work documents would have likely assisted personnel in positively identifying the target cable/pipe.

Permit to work

In each of the dangerous occurrences, ambiguities and inconsistencies were identified within the permit to work (PTW) system. The PTW system is one of the main tools used to control work on a facility and operators typically identify it as a preventative control measure in their facility safety case. Deficiencies in the PTW system were identified following the Piper Alpha disaster in 1988—highlighting the importance of having a robust PTW system in place. The ambiguities and inconsistencies identified in these occurrences included:

  • poor quality of PTW system training and lack of refresher training

  • inappropriate permit type for the task

  • incorrect or missing information from the permits and attached job hazard analysis and/or risk assessment

  • discrepancies between the permits and job hazard analysis and/or risk assessment.

As an administrative control measure, a PTW system is susceptible to the same fallibilities as other administrative controls. As such, PTW systems should be subject to rigorous auditing and quality assurance to ensure they remain a robust control measure. Similarly, appropriate competence assurance processes should be implemented to ensure members of the workforce understand which situations require the application of the PTW system and their role and responsibilities in its application.

NOPSEMA reminds facility operators that they must take all reasonably practical steps to implement and maintain systems of work that are safe and without risk to health. A key element of work planning and control includes a robust PTW system supported by thorough risk assessments and job hazard analyses. Members of the workforce should be engaged in proactive hazard identification and risk reduction and supported through supervision. The provision of user-friendly procedures and appropriate training, tools and equipment should aim to assist the workforce in task-based planning and safe execution of work. These layers of defence interact with and complement each other to facilitate safe outcomes. Operators should ensure that each layer of defence is well designed, appropriately implemented, and subject to regular review and improvement to maintain the integrity of the overall system of work.