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Recording Failure Data for RBI Failure Modes

You can record information about an asset’s failure costs, secondary damage, avoidance savings, statistics, and patterns.

When the team performs risk analysis on the failure mode, the costs incurred by the consequences (health and safety, environmental, reputation) are used in the calculation that determines avoidance savings (if the appropriate failure cost settings are enabled for the analysis).

This is also true of the economic consequence cost, although APM differentiates between the cost assigned to the consequence severity value and the result of the Economic Evaluation questionnaire. There are three possible ways to enter the economic consequence, depending on the analysis’ settings:

•	The results of the Economic Evaluation questionnaire are used automatically

•	If the Economic Evaluation questionnaire is not used, the selected economic severity’s monetary impact can be used

•	You can manually enter costs on the Failure Information view if criticality evaluation is not performed

Avoidance savings also take into account the cost of multiple failures and secondary damages.

In the Failure Information view, the Failure Data tab displays the estimated downtime, downtime costs, downtime per occurrence costs, failure costs, cost of multiple failures, and secondary damage cost. This tab also shows the consequence costs, if supported by the analysis’ failure mode settings. The following example shows the results when the detailed economic evaluation has been performed, as well as the other consequence evaluations:

When Calculate avoidance savings is selected, APM sums the following values to arrive at the savings:

•	Downtime costs

•	Failure costs

•	Occurrence costs

•	Consequence costs

•	Cost of multiple failures

•	Secondary damage costs

When the failure mode references an indicator with states, the avoidance savings amount is copied from the failure mode to failure records that are created when the indicator’s alarms are acknowledged.

On the Failure Pattern tab, you can record random, wear out, and infant mortality patterns. Typically, you will include information about failure patterns when you intend to use Isograph Availability Workbench to analyze and optimize action plans.

This topic explains how:

•	To Record Failure Data

•	To Record Failure Patterns

To Record Failure Data

1.	Open the analysis and select the Facilitation view.

2.	Double-click the failure mode to open the Maintenance Action Plan window.

3.	Make sure that editing is enabled.

4.	Select the Failure Information view and the Failure Data tab. This example shows the tab when criticality analysis has not been performed:

Note: If you performed economic evaluation during risk analysis, the results are displayed in the Failure costs area, and the values cannot be changed. If you performed evaluations for health and safety, environmental, or reputation consequences, the monetary values assigned to the selected severities are displayed in the Consequence costs area, and the values cannot be changed.

Tip: If the recommended action is failure-finding maintenance, you can click the Failure Finding Information button on the Failure Data tab. A dialog appears showing the calculation inputs for the failure finding-finding interval.

5.	Record the failure costs:

Setting Name

Description

Downtime

Estimated time that the asset would be out of service if the failure occurs.

Downtime costs

Estimated costs of the downtime if the failure occurs.

Failure costs

Estimated cost to the company if a failure occurs, excluding the cost of downtime.

Occurrence costs

Estimated fixed cost associated with a downtime occurrence. For example, this could be a fixed cost associated with restarting a machine after it has been shut down.

6.	Select Secondary damage if the failure mode causes failures on other assets. Enter the estimated cost and description of secondary damage.

7.	Calculate avoidance savings is selected by default so that APM sums the costs of the failure, consequences, multiple failures, and secondary damage. You can clear this option and enter the avoidance saving amount manually.

Note: If the action plan references an indicator, the avoidance savings amount can be copied to failure records created when the indicator’s alarms are acknowledged.

8.	Record failure statistics:

Setting Name

Description

Time between failure

The time between occurrences of the failure when inspections and/or preventative maintenance are performed. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Mean time to failure property in AWB.

Time to repair

The average time it takes to repair the asset and return it to service after a failure occurs.

To Record Failure Patterns

1.	Select the Failure Pattern tab.

2.	Record the failure patterns:

Setting Name

Description

Random failures

Random failures exhibit constant failure rate characteristics; that is, a random failure is just as likely to occur in the first year of operation as it is in the second or third years of operation. Random failures exhibit no infant mortality or wear-out characteristics. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Random On property in AWB.

MTTF for random failures

Estimate of the average, or mean time, until an asset’s first failure occurs.

Failure rate

APM automatically calculates the failure rate as the inverse of the MTTF. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s random rate property in AWB.

Wear out

Age-related failures that occur due to operational wear. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Wear out On property in AWB.

Wear out begins at

The operating age at which wear-out begins. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Wear out Start age property in AWB.

Majority will have failed by

How long after the wear-out period begins that the majority of assets of this type will have failed. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Wear out Duration property in AWB.

Infant mortality

Rate of failure during the period immediately following an asset’s commissioning for service. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Infant On property in AWB.

Infant mortality period

The length of time immediately following an asset’s commissioning for service until it reaches its useful life period. The infant mortality period is characterized by a progressive improvement in the failure rate. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Infant period property in AWB.

MTTF during infant mortality period

Estimate of the average, or mean time, until an asset’s first failure occurs during the infant mortality period.

Failure rate

APM automatically calculates the failure rate as the inverse of the MTTF during the infant mortality period. When failure mode optimization requires Isograph Availability Workbench, this attribute is mapped to the cause’s Infant Rate property in AWB.