ABSTRACT
Performance monitoring of safety functions was a legal requirement in Norway before the introduction of the IEC standards. Unfortunately, the performance indicators and targets that have been established are not aligned with the IEC requirements. The industry also seems to lack a common approach to how data are utilized for maintenance management, for example on how to adjust the intervals between functional tests. One approach was developed by Vatn (2007), and included in the OLF 070 guideline (OLF070 2004) on the application of the IEC 61508 and the IEC 61511 published by the Norwegian Oil Industry Association. Unfortunately, this approach has not been widely adopted by the Norwegian oil and gas industry, and possible changes to the test intervals are today mainly based on qualitative considerations.
