Assigning Severity to Failure Effects

Feature Description

The severity field is used to assign a severity value to a failure effect. This value is used in a variety of ways by the eXpress software, including by such features as eXpress FMECA charts, Criticality Reports, failure severity-based subsets, and test weighting entity parameters. Although eXpress provides a typical set of default severity options, the Analyst can override this by defining custom severity levels (included with eXpress is a design template containing a custom severity Attribute that has been set up to provide MIL-STD-1629A severities).

Defining Severity & Compensating Provisions

There are several ways by which severity can be set. For lowest-level object failure effects (which list failure modes as their causes), the operator must specify the severity directly (this process is explained below). Once this has been done, the severity for all higher-order failure effects (either design effects or their hierarchically-inherited instances on assemblies) will be automatically calculated by eXpress using the most severe value that has been assigned to any of the causes listed for that effect. In both cases, however, the operator may override the severity. When a severity is overridden, a compensating provision should be entered to explain the change. A warning will be generated any time a provision has not been entered for a severity that is less than the most severe of its causes. Any provisions that are entered will be concatenated together when generating a FMECA grid.

How to Edit the Severity of a Failure Effect (using Grid View)

1	For object effects, select the object associated with the failure effect to be edited.
	Alternative: Severities can be edited for all design or object effects by invoking Grid View with nothing selected.
2	Click on the Grid View icon on the View toolbar .
3	If necessary, select either "Object Failure Effects" or "Design Failure Effects" from the Contents Type drop-box on the Grid Control panel.
4	Enable "Failure Effect Details" on the Grid Control panel.
5	Select the desired severity value in the Severity column. (The value can be copied from one failure effect to other rows in the column so that a given severity can easily be assigned to a batch of failure effects).

How to Edit the Severity of an Object Failure Effect (using Panels)

1	Select the object associated with the effect to be edited.
2	Choose the Failure Effects tab within the context panels.
3	Select the desired failure effect on the Failure Effects panel.
4	Click on the "Severity" button to the right of the grid.
5	Use the text area to enter or change the description for the selected failure effect.

How To Edit the Severity of a Design Failure Effect (using Panels)

1	Click on the background of the main design window to dehighlight everything.
2	Choose the Design Failure Effects tab within the context panels.
3	Select the desired failure effect on the Design Failure Effects panel.
4	Click on the "Severity" button to the right of the grid.
5	Select the desired severity from the Severity dropbox. If necessary, enter a text description into the Compensating Provisions edit box.

How To use Batch mode editing for Design Failure Effects (using the Design Menu)

1	Select the Design Menu.
2	Choose the Design Failure Effects .
3	Select the desired failure effect severity option [Delete, Delete All Delete All Object Effects, Delete All Intermediate Effects, Delete All Design Effects.
4	NOTE: Delete All will cause a Warning to be displayed and shift key to be held down to complete the Operation.

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