Quest Reliability has performed Root Cause Failure Analysis (RCFA) on many different systems involving many different materials and plant and equipment types and has specialized experience exceeding 20 years in RCFA as applied to static and rotating plant equipment.

While failure investigation is component specific, RCFA is system specific in that it applies not only to the engineering aspects of failure but to the human behavior and management decision making contributing to the failure.

Typically following the failure of a component, an investigation will be conducted and a report produced to describe the failure and related consequences.  A failure investigation will determine the cause of a component failure – e.g., prior material defect, overload, wrong part used – but it will generally not explain why the failure occurred or identify the most effective way/s of preventing future similar occurrences.

To understand the reasons why…a root cause investigation needs to be carried out.

Root Cause Failure Analysis consists of three fundamental components:

• Ability to describe and schematically represent an incident sequence and the contributing conditions;
• Methodology for identifying critical events or active failures to ensure the avoidance of similar failures in the future; and
• Methodology for systematically investigating the human, management and organizational factors that allowed the active failures to occur.

Root cause failure investigations are usually required where engineering failures have safety or regulatory consequences.  Performing RCFA is usually a mandatory requirement of regulatory authorities in cases involving serious harm or death.

The process of RCFA will vary by asset type and circumstances.  Typically, the first stage of an RCFA investigation involves establishing exactly what the failure event was and obtaining a full description of the sequence of events which led up to the failure.  This involves site surveys, interviews with personnel and examination of physical and documentary evidence.  Various techniques can be employed including casual charting, multiple events sequencing, sequential timed event plotting, barrier analysis and change analysis.  This stage is an essential part for failures which have safety related implications.

The next stage is focused on determining underlying or root causes.  In safety-related failures, causal loop or Tripod analysis methods not only assist with identifying root cause but identify contributing factors and fallible decision events.  This second stage also involves the examination of physical evidence by conducting a failure investigation and can employ physical testing and laboratory experiments to replicate damage mechanisms and contributing stresses that lead to failures.  Forensic engineering can also be employed to examine the original design principles and materials selection choices to determine if the failing components were fit-for-service.  The synthesis of all of these components yields a logical explanation and empirical or analytical evidence of the root cause of failure. 

The final stage of an RCFA investigation is in understanding how human behavior, management decision making and organizational factors have contributed to root cause and more importantly, what future behaviors, decision process and procedures are required to prevent active failures from occurring in the future.

For further information about Root Cause Failure Analysis, please contact us.