Loss Scenario Table

Loss Scenario Tables are where you analyze the hazard causal factors for each unsafe control action in Astah System Safety.

Create a Loss Scenario Table

When you create a Loss Scenario Table, you specify the unsafe control action it analyzes.

1. Go to [Diagram] – [STAMP/STPA] – [Loss Scenario] from the main menu, or double-click [Loss Scenario] in the [STPA Procedure] tab.
   
   
2. A list of unsafe control actions appears. Choose the one you want to analyze and click [OK].
   
3. A blank table opens in the Diagram Editor.
   

Once you create a loss scenario for an unsafe control action, a circle icon appears next to it in the list, so you can see which unsafe control actions already have loss scenarios.

Hint Word

Hint Words are guide phrases that help you identify hazard causal factors. The Hint Word set you used in the Control Loop Diagram is already selected here. To open the Hint Words, click the [Hint Word Set] button.

Note: Switching the Hint Word set here also changes the set applied to the Control Loop Diagram, and clears the Hint Words already filled in for the other scenarios.

Add Hazard Causal Factor

1. Right-click the blank table and choose [Add HCF].
   
2. Enter a description of the hazard causal factor. When you finish, Astah assigns it an ID automatically. You can turn off automatic ID assignment.
   
3. Double-click the Hint Word field. A list of the Hint Words in the current set appears. Choose one and press Enter.
   
4. Finally, add a scenario. Double-click the Scenario field. In the [HCF] dialog, click [Add] and write the scenario.
   

You can add more than one scenario as needed.