A Four-Step Safety Integrity Level Analysis of Numerous Subsea Control System Components

In this paper, a four-step safety integrity level (SIL) analysis is developed to analyze numerous components of the subsea control system based on the OREDA database. For this purpose, initially, a failure mode classification table is provided, aiming to identify the number of dangerous as well as the prevalent failure modes. Then, several parameters including component inventory, installation inventory, equipment units, failure events, and total time in service (per hour) are calculated. Also, failure rates are evaluated and the software checking is provided as the final step of the proposed framework. The results show that the dangerous failure modes occur in about 80 cases, and the leakage in the closed position is the failure mode occurring more than the other ones. Moreover, calculations indicate that the process isolation valve of the subsea X-mass tree has the largest values in all the referred parameters. Moreover, hydraulic coupling of the choke module and HC leak sensor are the two components with the highest value of failure rates. This article is available in the ASME Digital Collection at https://doi.org/10.1115/1.4051043.