In 2021, we set up a sector-tax-funded initiative concerning the companies’ follow-up of the ESD system. As part of this, we sent a questionnaire to the companies and collected relevant documentation relating to the ESD system.

The survey confirms that the companies have good systems and expertise for following up the ESD system. There is nonetheless room for improvement, especially with regard to maintenance and verifications at older facilities, and the expertise of control room personnel.

We have already incorporated experience from this undertaking into our audit activities and are also working on potential improvements to the regulations.

Questions to the companies

The questions under consideration concerned the following topics:

  • Competence and training
  • Maintenance and verifications
  • Technical, operational and organisational performance requirements
  • Modifications, changes and new installations
  • Measures and restrictions in the case of weaknesses 
  • Challenges and experiences
  • Internal audits and revisions

The key findings from the feedback are described below:

Competence and training

Competence requirements are primarily implemented in the competence management system linked to different roles/functions in the company.

Some companies lacked competence requirements for control room and process operators for the ESD system. Most have established facility-specific competence requirements for technical personnel, but for a couple of companies there were no requirements for competence beyond a certificate of apprenticeship.

It is often a manager in conjunction with the individual employee who is responsible for ensuring that the individual has sufficient facility and system expertise in respect of the ESD system. It was unclear how to document and ensure that the individual has the necessary expertise for their role (see the Activities Regulations, section 21 concerning competence).

For relevant personnel onshore, few companies had formal requirements for facility-specific competence for the ESD system.

We would like to emphasize that, for compliance with NOG 070 and IEC 61508/61511, there are requirements regarding the necessary competence for personnel involved in the operation and maintenance of ESD systems.

Some companies are also making greater use of simulators for the training and instruction of personnel in handling failure, hazard and accident situations. When using simulator training, it is important that such training and drills are sufficiently realistic, so as to assist in handling different situations effectively (see the Activities Regulations, section 23).

Maintenance and verifications

In some cases, it was unclear how the responsible party complied with the minimum requirements for monitoring the performance and technical condition of the ESD system, as described in the Activities Regulations, section 47 concerning the maintenance programme, and the associated guideline (litera b).

This was of greatest relevance for older facilities not verified in accordance with the safety integrity levels defined in the IEC 61508/61511 standard and Norwegian Oil and Gas guideline 070 (NOG 070) under which all parts of the safety function are verified by an annual full-scale functional test.

NOG 070 describes that safety instrumented systems should preferably be tested as part of an integrated test, where the entire function is tested from end to end. The standard provisionally allows for partial testing to be performed, such as separate tests of inputs, logic and outputs.

If, for safety or operational reasons, such a solution is chosen, it is important that the tests overlap, so that the entire safety function is tested and documented.  This latter solution is described by several companies as part of their verification activity of the ESD system, while some companies have no overlap. This is justified by the reduced likelihood of accidental activation and shutdown.

Some companies use unplanned incidents, where ESD functions are tested as part of their verification activity.

For some companies, it was unclear which verification activities have been introduced to ensure compliance with their own performance requirements for operational and organisational barrier elements.

Challenges and experiences

From the feedback concerning the challenges and causes of failure in the companies’ ESD systems, the following are noteworthy:

  • The testing of ignition source isolation is time consuming.
  • Differentiation of PSD/ESD valves during testing, for example, of valve closure time.
  • Human error, such as forgotten blocking of safety features, errors in operation and maintenance.
  • Failure of technical equipment, including valve failures and logic failures.
  • Missing tags on contacts, breakers and protection used for ignition source isolation.  This complicates reporting on equipment history and actual incidents in which breakers trip, which in turn can lead to more extensive testing in order to verify functions.
  • Errors in design and incorrect/deficient quality of documentation.
  • Quality of documentation

The feedback related to challenges and experiences largely confirms the Petroleum Safety Authority Norway's experiences and findings from audits and follow-up of incidents.