In this series, our head of Rig Inspection Services Steven Lee shares tips on how operators and owners can get through rig inspections with flying colours – and which pitfalls to avoid! Mr Lee has more than a hundred rig inspections under his belt, from all parts of the world. This chapter looks at Integrated Vessel Management Systems.
Integrated Vessel Management Systems can range in complexity depending on the offshore unit, but all essentially carry out the same purpose – to allow control and monitoring of numerous systems and monitoring of their parameters via a computer network. This can include fire and gas detection and protection, bilge and ballast systems, emergency shut down systems and power distribution to name but a few.
One of the many things that any good control systems inspector will check first is the alarm history and the network infrastructure status. All alarms will be reviewed to understand if they really are an issue and require further investigation, or if they are nuisance alarms, e.g. due to maintenance being carried out. The network infrastructure itself is key, as if just one process module is faulty it could affect the transmission of many different signals and affect the system response to commands.
Patch management is also extremely important as if any known bugs have occurred on similar systems they could have been fixed by the OEM. If the patch has not been implemented it could have an adverse effect on operations, although it is worth bearing in mind that some software updates might not be able to be installed during operations. Any unit that has an accurate software register and robust software management of change policy will be able to demonstrate to inspectors that they look after their systems.
During any function testing of systems, the correlation between what the system indicates and what is physically happening will be checked. The most challenging tests for a rig crew usually involve the emergency shut down (ESD) systems due to the disruption caused to the unit, where the cause and effect charts are compared against what actually happens when the shutdown is activated. These tests need to be well coordinated between the inspection team and rig crew to minimise disruption. Often these systems are not frequently tested so proper planning of the tests and especially the recovery will pay dividends for all involved.