A modified human reliability analysis for cargo operation in single point mooring (SPM) off-shore units

• Application of internal type-2 fuzzy sets into HEART approach.
• A robust tool proposal to predict human error and human reliability performance.
• Practical contribution to human reliability assessment in marine and off-shore industry.
• Improving safety and performance reliability at marine and off-shore industry.

A Single Point Mooring (SPM) unit is a widely recognised off-shore terminal facility in the marine industry since a considerable amount of liquid cargoes can easily be transferred into huge tankers such as VLCCs or ULCCs. Although the system presents high safety standards, any minor accidents due to human error may cause serious harm to the marine environment, human life and the commodity itself. Therefore, nominated crew on-board the tanker and the unit should be very careful during SPM cargo operations. At this point, human reliability plays a critical role in avoiding potential operational or technical failures. In this context, the aim of this paper is to perform a comprehensive human reliability assessment during cargo operations of an SPM unit to enhance maritime safety in off-shore units. The paper prompts a methodological extension of human error assessment and reduction technique (HEART) by incorporating interval type-2 fuzzy sets which overcome more of the uncertainty of experts’ judgement and expression in decision-making. The proposed approach not only provides theoretical insight but practical contribution to human reliability assessment in the marine and off-shore industries.