FMEA of marine systems: moving from prescriptive to risk-based design and classification

摘要

For more than 100 years, the American Bureau of Shipping (ABS) has been developing standards - called Rules - for building and classing ships. Through experience, the Rules implicitly identify hazards and prescribe safeguards against them. For example, the Rules (1) address the reliability of propulsion and maneuvering systems to help safeguard against external hazards, (2) impose safety requirements on machinery Systems to help safeguard against hazards inherent in the machinery itself, and (3) specify minimum acceptable structural scantlings as a measure to safeguard against structural failure. The difficulty in fairly imposing prescriptive safeguards is the diversity of ship designs, operating scenarios, maintenance practices, and numerous other factors that affect the potential risk to which a ship is exposed. Inevitably, this means that the Rules may not be entirely comprehensive in some instances, while overly onerous in others. This paper describes the results of recent studies by ABS to provide risk-based guidelines for performing a failure mode and effects analysis (FMEA) on high-speed crafts and propulsion remote control systems. This approach describes how frequency and severity categories can be used in the FMEA to guide designers in assessing the risk and reliability of the system. Recognizing that many designers may not be familiar with these risk tools, the guideline provides step-by-step instructions on how to prepare, conduct, and document the analysis.