(54bs) Unrevealed Failures of Safeguards Used in Process Hazard Analysis - Improving and Understanding Functionality
AIChE Spring Meeting and Global Congress on Process Safety
2018
2018 Spring Meeting and 14th Global Congress on Process Safety
Global Congress on Process Safety
GCPS Poster Session
Monday, April 23, 2018 - 5:00pm to 7:00pm
Unrevealed failures of safeguards are a common âroot causeâ in process safety incident investigations. They are defined as systems or equipment that can remain in a failed state of operation without the knowledge of operations. The distinction between âdouble jeopardyâ and unrevealed failures are presented with examples and definitions to improve understanding of these issues when conducting PHAs.
Safeguards that may have unrevealed failures include switches to trip a piece of equipmentâs operation or alarm, check valves, and basic process control systems. The severity of consequences (hazards) associated with credited safeguards are factors for determining the interval of maintenance and the appropriate use of tools (additional devices). Additionally, the demand to function and equipment age (run to failure) issues should be included in the analysis of unrevealed failures.
The identification of these types of deficiencies (safeguards with unrevealed failures) in PHAs and operation systems can improve overall system performance in reducing and/or controlling process safety risks.