Risk analysis and optimization

The Analysis Window

When you open step 5, the Analysis Window appears at the bottom of the screen. Select an element on the canvas, and the failure chains it belongs to are laid out as a table, from the failure effect to the failure cause.

• Click the Analysis Window button on the right toolbar to close it and see more of the canvas. Click it again to reopen it.
• Drag the handle on its top edge to make it taller or shorter.

Step 5: rate the risk

1. 1Severity: click the red S box of the failure effect and enter a score. The first value applies right away. Changing a severity that is already rated opens a dialog asking for the reason, because severity needs a documented rationale.
2. 2Current prevention control (PC): the design activity already in place to keep the failure cause from occurring.
3. 3Current detection control (DC): the test or verification method that finds the failure before release.
4. 4Occurrence (O) and detection (D): click the value and choose from the list. It shows the rating criteria assigned to this document, with a description for each score.

The action priority (AP) is calculated automatically from severity, occurrence, and detection, and shown as H, M, or L.

Work with several chains

When an element belongs to more than one chain, up and down arrows and a chain number appear in the Analysis Window. The arrows switch between chains, and the chain shown in the window is marked on the canvas with bold outlines. Click Fit View on the right toolbar if the window covers the canvas.

The sun icon button on the right toolbar cycles through three highlight modes:

For example, Level 1 of the wiper document has two functions: wiping and parking. With all chains highlight on, selecting the failure effect where the wipers stop moving leaves only its two brush chains, and the other failure effects and the parking function disappear. Press Esc to clear the selection and see everything again.

Step 6: plan improvement actions

Select the failure cause again, and the optimization row appears at the bottom of the Analysis Window.

• Preventive action (PA): a design change that reduces how often the failure cause occurs.
• Detection action (DA): a test that finds the failure more reliably.
• Responsible person and target completion date.
• Status: starts as Open; update it as the work progresses.
• Expected occurrence and detection after the actions: the AP after the actions is recalculated right away.