Track 2 Session 3

1:00 to 2:00 p.m. Wednesday March 28, 2012

RAMS Analysis Methodology: Regarding Safety Process Effects in System Availability

RAMS analysis has a main objective to define system availability, reliability and maintainability regarding critical equipment failures and safety issues. Often, reliability block diagrams (RBDs) are used to model the configuration; but in many cases for safety issues, incidents are the result of complex combined events that can be modeled also by fault tree analysis (FTA). In terms of the safety process, HAZOP has been the most common qualitative risk analysis technique applied to define hazards; but in most cases, process deviations that cause hazards are not quantified and they are not taken into account in RAM analysis despite the impact on system availability. Usually, RAM analysis and safety process analysis are carried out separately, but this presentation proposes to model the safety process events that cause system unavailability. Thus, a case study will be carried out to exemplify RAMS analysis using RBDs to model equipment failures and FTA to model safety process hazards that impact system availability. Such safety process hazards firstly are defined in HAZOP analysis and further modeled by FTA fitting a safety process effect block in the reliability block diagram. Therefore, it will be possible to compare system availability and reliability with and without safety process hazards.

Key Words: RAMS, HAZOP, FTA, Safety Process

Eduardo Calixto

ReliaSoft Corporation