Risk Ranking

A two-dimensional grid that combines Probability of Failure (PoF) on one axis and Consequence of Failure (CoF) on the other to produce a visual risk ranking. The matrix divides risk into categories (typically A through E or Low/Medium/High/Very High/Extreme) that determine inspection priority, interval, and strategy. Risk matrices provide a standardized framework for comparing and prioritizing risks across diverse equipment populations.

A quantitative or semi-quantitative measure of the likelihood that an equipment item will fail within a specified time period. PoF is determined by the generic failure frequency of the equipment type, modified by damage factors that account for specific active degradation mechanisms, and adjusted by a management system factor reflecting the quality of the facility's integrity management program.

A measure of the impact resulting from an equipment failure, encompassing safety (personnel injury/fatality), environmental (release to atmosphere/ground/water), production (lost throughput and business interruption), and equipment (repair/replacement cost). CoF is evaluated based on the worst credible release scenario, considering fluid properties, operating conditions, detection and isolation systems, and the surrounding environment.

A methodology that uses risk assessment to prioritize and plan inspection activities for pressurized and other equipment. RBI combines Probability of Failure (driven by damage mechanisms and equipment condition) with Consequence of Failure (driven by process hazards and safety impact) to rank equipment by risk and allocate inspection resources where they will have the greatest impact on risk reduction.

A numerical value representing the level of risk for an equipment item, calculated as the product of Probability of Failure and Consequence of Failure scores. Risk scores provide a continuous scale (1-25 in a 5x5 system) that enables granular prioritization within risk ranking categories and supports quantitative risk trending over time.