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Glossary of Failure Tracking Terms

The following terms are used throughout the failure tracking topics. For a full glossary of APM terms, see Glossary.

Term	Definition
Acknowledge Alarm	Acknowledging an alarm is a way to tell APM that someone has seen the indicator alarm and is taking appropriate action. For example, in response to an indicator alarm, you might create a work order and a failure record.
Asset Priority	A consequence priority number provides an indication of the relative priority of assets in the site. Priority numbers are calculated during an asset prioritization analysis. The priority number can be used to determine the order of work activities, and is used by the system to determine whether or not indicator alarms are shown on parent assets in the asset hierarchy. During the analysis, the priority number is determined by comparing the asset’s failure consequence scores to a set of rules. If the asset’s scores match a rule, the asset is assigned that rule’s priority number. The asset is always awarded the highest priority number that it matches. See also Failure Mode Consequence Priority.
Containment	A containment action controls or neutralizes the effects of a failure. The containment is meant to be temporary until a final agreed-upon solution is implemented.
Criticality Index	APM calculates a criticality index for asset failures to evaluate their suitability for root cause analysis. The index is calculated by multiplying the numbers assigned to the consequence priority, failure severity, and probability of recurrence. The larger the index number, the greater its criticality. See also Failure Mode Consequence Priority, Failure Severity, and Probability of Recurrence.
Downtime	Downtime is a period of time or a percentage of a timespan that an asset is not functioning, usually as the result of either a failure or routine maintenance.
Evident Failure	An evident failure is a failure mode whose effects become apparent to the operating crew under normal circumstances if the failure mode occurs on its own.
Failure	A failure is an event or state in which an asset cannot perform one or more of its required functions within the specified limits under specified conditions. A failure often requires that equipment be shut down and repaired.
Failure Classification	Failure classifications, along with failure types, allow failure modes and records to be grouped for easy identification. For example, useful failure types might be Electrical, Environmental, Mechanical, Operational, Safety, and so on. Examples of failure classifications are Lubrication, Operator Error, and Installation Defect.
Failure Mode	A failure mode is a single event that causes a functional failure. For example, if a pump’s impeller becomes worn, the pump cannot convey liquid at the required rate. Failure modes are analyzed in maintenance task analysis (MTA2), reliability-centered maintenance (RCM2), and failure modes, effects, and criticality (FMECA) analysis along with the action plans that prevent or mitigate failures. Safety instrumented function (SIF) analyses examine the risk of failure in safety devices, the effects and consequences of failure, and ways to reduce risk by putting safety provisions in place. For risk-based inspection (RBI) analyses, the failure of concern is loss of containment of pressurized equipment items. Examples of failure modes are small hole, crack, and rupture.
Failure Mode Consequence Priority	A failure’s or failure mode’s consequence priority provides an indication of the relative importance of the asset failure. The larger the number, the greater the severity of the failure. The priority can be used to recommend root cause analysis for a failure or to determine the order of action plan implementations. Consequence priorities are assigned to failure modes during risk assessment. In failure evaluation, the consequence priority is used in the calculation that determines whether the failure is suitable for root cause analysis. APM assigns the consequence priority by comparing the information to a set of customer-defined rules. The consequence priority rules can be based on the failure severity, relative risk (risk analysis only), failure costs, downtime costs, downtime, or a combination. For example, the Extreme consequence priority could be assigned to failures or failure modes whose total severity is greater than 25 or failure costs are more than $25,000. See also Asset Priority.
Failure Severity	A failure’s severity is used to indicate the seriousness of the failure. Three severity types are supported: • Potential: a condition that has been noticed that would result in an actual failure if the problem is not resolved. The actual failure has not yet occurred. Potential failures are normally reported as the result of an indicator reading that has raised a warning alarm against the asset. • Partial: the asset’s performance has decreased to a point where it is no longer performing one of its functions at the specified levels. The asset is still functioning. • Total: the asset’s performance has decreased to a point where the asset is no longer performing at its required level. The asset has completely failed.
Failure Statistics	Based on the current and prior failures for an asset and failure mode, APM calculates three types of statistics: time between failures (TBF), time between repairs (TBR), and restoration times (RT). • Time Between Failures (TBF): The time between the start of the previous failure and the start of the current failure. For the initial failure, the start date is determined to be the first available of the following options: • Original service date of the asset • Date of the first status change for the asset • Date of the first installation of the asset • Creation date and time for the failure The TBF is then calculated as the duration between the start date and the failure’s resolved-at date. APM calculates the mean time between failure (MTBF) as the average time between occurrences of a failure, assuming that the asset has a constant rate of failure. • Time Between Repairs (TBR): The time between the resolution of the previous record and the date on which the current failure occurred. TBR can also be calculated as TBF minus RT. • Restoration Time (RT): The time between the date and time when the current failure occurred and the date and time when it was returned to service.
Failure Type	Failure or anomaly types, along with classifications, allow failure modes and records to be grouped for easy identification. For example, useful types might be Electrical, Environmental, Mechanical, Operational, Safety, and so on. Examples of failure classifications are Lubrication, Operator Error, and Installation Defect.
Function Group	A function group is a way of identifying assets that are responsible for performing a particular function. For example, the “Pump Assembly” function group could be used to indicate the relationship between a centrifugal pump, 20 HP motor, and valves.
Hidden Failure	A hidden failure is a failure mode whose effects do not become apparent to the operating crew under normal circumstances if the failure mode occurs on its own.
Inspection Report	An inspection report is an APM document that inspectors use to record their analyses of the equipment or system for which they are responsible. The report summarizes the findings from one or more checksheets and includes recommendations and a summary of actions taken, such as alarm acknowledgments, follow-up tasks, follow-up work requests, failures and anomalies, and failure mode review requests.
Maintenance Task Analysis	Maintenance task analysis (MTA2) is APM’s unique strategy development methodology that enables the analysis team to quickly create and implement basic, technically-sound reliability programs. MTA2 is most effective when operational and maintenance knowledge about assets is well-documented and consistently used by employees. MTA2 provides an alternative to the resource-intensive RCM2 analysis, while still allowing you to identify the right work to improve performance across the plant. MTA2 methodology and tools allow the analysis team to: • Identify the assets to be analyzed • Identify the causes of asset failure • Recommend actions to prevent or mitigate failures
Operating Context	The operating context is the circumstances in which a physical asset or system is expected to operate.
PF Interval	The PF interval is the time between the point at which a potential failure becomes detectable and the point at which it degrades into a functional failure.
PF Interval Type	PF interval is usually tracked in units of time (hours, days, weeks, and so on). However, an asset that has a cumulative primary indicator can use a PF interval measured in indicator values, such as cycles or operating hours.
Primary Function	The function that constitutes the main reason why an asset or system is acquired by its owner or user.
Probability of Recurrence	Probability of recurrence is a user-defined value assigned to asset failure records. It consists of a description (for example, “Very probable”) and a number that is used to evaluate the failure’s suitability for root cause analysis. See also Criticality Index.
Problem, Cause, and Remedy	A problem is a site category that describes common problems on assets of certain types, such as “lubrication failure.” Using problem categories can simplify the analysis of equipment failures. Problem categories can be linked to Cause and Remedy categories. A cause is a site category that describes common causes of problems on assets of certain types. Each Problem category can be linked to many Cause and Remedy categories. Using problem categories can simplify the analysis of equipment failures. A remedy is a site category that describes common remedies of problems on assets of certain types. Each Problem category can be linked to many Cause and Remedy categories. Using problem categories can simplify the analysis of equipment failures.
RCA	See Root Cause Analysis (RCA).
RCA Recommendation	An RCA recommendation is the result of failure analysis. APM determines the recommendation based on the failure’s criticality index, as well as its status as either evident or hidden. The recommendation is assigned according to the position of the criticality index value in the RCA recommendation thresholds. Possible recommendations are: • RCA not required • RCA recommended • RCA required
RCM2	RCM2 is the reliability-centered maintenance process practiced by Bentley APM consultants. One of the features of RCM2 that distinguishes it from other interpretations of the RCM philosophy is that cross-functional groups of users and maintainers perform the analyses. After training, these analysis teams apply the process to their assets to produce robust and cost-effective asset reliability programs.
Relative Risk	Relative risk is one of the outputs from an asset prioritization analysis. It is the product of the probability of failure of an asset and the consequences of failure. Relative Risk = (Probability of Failure) x Sum (Consequence of Failure Scores)
Root Cause Analysis (RCA)	Root cause analysis is a methodology used to identify the causal factors for equipment failure. Its goal is to direct corrective measures at root causes to minimize the recurrence of problems. The RCA tools provided by APM incorporate both proactive and reactive approaches, allowing the analysis team to react to partial or full failures, as well as to investigate significant contributing causes to prevent failures.
Scheduled Actions	Scheduled actions are methods that can be set up to run automatically with a repeatable frequency. Each scheduled action defines: • The method to be run • The time the method should run • How often running the method should be repeated You can schedule actions to run at hourly, daily, weekly, monthly, and yearly time periods and specify the interval within that time period. For example, you could create a scheduled action that recalculates calculated indicators every two hours on Mondays, Wednesdays, and Fridays. Note: Only particular methods can be scheduled to run as actions. The selected methods are background processing actions within APM that do not generate any window or dialog user interaction.