Integrity, compliance and specialist risk consulting services group Lloyd’s Register announced in March the launch of a new Risk-based Inspection (RBI) service which combines hull integrity management with vessel classification (Class) to help minimise costs for operators of floating offshore installations (FOIs).

This initiative will help optimise inspec- tion regimes and provide value-add to Class by providing a more flexible approach to help operators mitigate risk and unplanned downtime in hull integrity management of floating units, such as floating production storage and offloading and floating liquefied natural gas vessels.

“RBI techniques may be used to provide justification for the assignment of Class, and may be systematically applied to a hull structure and associated components or to individual systems, subsystems or components,” says Lloyd’s Register Assurance Services COO Tim Walsh.

RBI detects and monitors systems, sub- systems, equipment and component degra- dation and results in the application of appropriate decision-making criteria to manage risk to acceptable levels.

To carry out a successful RBI programme, Lloyd’s Register highlights that certain tasks need to be performed, including identifica- tion and definition of functional and physical relationships, interactions and dependencies of components, definition of the operating conditions and loading associated with each inspectable component, identification of the Common Cause Failure of components, identification of the failure modes and degradation mechanism associated with individual components or group of components and identification of possible consequences owing to failure of components.

“The most common deterioration mecha- nisms associated with hull structure components can range from coating failures, through to fatigue and stress built into the structure during construction,” says Walsh. “RBI can help assess all of these issues and prioritise inspection needs.”

He adds that the key to understanding how classification, verification and integrity fit together is in understanding what differences there are between integrity management and classification schemes. Lloyd’s Register has investigated this in detail and has launched this new service, as these two schemes can be integrated, resulting in the overall optimisation of survey and inspection activities.

“While the marine industry focuses on Class, the oil and gas industry applies asset integrity management and more often than not, a risk-based approach,” highlights Walsh.

To overcome this disparity in maintenance and management regimes, there is a requirement of the Class societies to understand and appreciate what the FOI operators need, while conversely, the FOI operators need to understand what Class ‘does’. “We are leading this approach for industry,” he says.

Building to a Higher Standard

Lloyd’s Register notes that industry feedback has highlighted that some operators chose to design and build to an enhanced standard in order to minimise operational costs and maximise asset life. For example, operators decide to use a better coatings specification and better structural details.

However, under existing time-based survey cycles, operators do not receive credit from the Class society for these enhanced standards.

The new RBI service from Lloyd’s Register enables the operator to develop a survey and inspection regime, which is based on the current and expected future condition of the unit.

Lloyd’s Register Asset Integrity Services product development manager Rebecca Allison explains that Class gives operators a common standard set to a maximum risk level; however, risk is very much dependent on where the unit is located and not just the standards of building.

She notes that, when an RBI approach is used, it must be taken into consideration that units located in different regions will perform in a very different way. Site-specific assessments and environmental factors must be taken into account.

From Design Through to Asset Life Extension

Operators need to consider when to implement RBI; whether it is at the design stage or partway through life – experts endorse the earlier the better. Implementing at the design stage means that the RBI programme is tailored to the asset. Risk-based design can help build a more robust structure, and at this stage the design can also be modified around the risk-based inspection regime.

“RBI and Class regimes can work in tandem to optimise inspection and maintenance regimes, reduce costs, minimise downtime, and mitigate risk and shutdowns,” says Allison. However, adopting an RBI app- roach does require a mind-set change for both Class societies and operators. It is no longer about undertaking surveys at specific times. Rather, surveys are undertaken based on assessment of risk that each equipment and structural item poses.

RBI methodology is not limited to the oil and gas industry, as the military and defence industry and cargo shipment sector have also shown interest in this new approach, realising the operational efficiencies and cost sav- ings that can be achieved.

Allison notes that Lloyd’s Register has experience in the implementation and manage- ment of RBI for static equipment across the upstream and downstream oil and gas industry, as well as the petrochemicals and chemicals industries, helping operators reduce inspection points by 50% to 90% and reducing risk of failures by 80% to 90%.

The new service from Lloyd’s Register has been created in consultation with industry partners who form part of the Lloyd’s Register’s Offshore Technical Committee. The company states that it has already received significant interest from operators of FOIs.