Failure analysis

The accident resulted from several latent hazards, and lack of information required for situation awareness, as described in the following SASF chart ...

Trigger

Filter blockage at a condensate polisher

Component reliability

• A valve stuck open, enabled water penetration to the instrument air line during the air compression, applied to remove the blockage.
• PORV stuck open, after pressure release

  Guidelines about component reliability

Error-proofing

• The design relied on the operator's complying with the rules, and enabled performing maintenance procedures during production
• the design enabled performing actions that were not adequate for the system situation.

  Guidelines about rules defining proper scenarios, and keeping with the rules

  Guidelines about assuring the operator's awareness of the system situation

  Guidelines about protecting from operator's mistakes

Information flaw

• Excessive, overwhelming alarms
• Missing information regarding the component faults
• Conflicting indication of the situation
• Misleading indication of the PORV situation.

  Guidelines about the reliability of resilience add-ons

  Guidelines about the alarm design

Updated on 17 Apr 2016.