Safety Lifecycle & Management Flashcards
7 cards from real SIL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Safety Lifecycle & Management flashcards as text
Which of the following is a valid reason to reduce the proof test interval of a Safety Instrumented Function?
Answer: To compensate for a higher-than-expected dangerous failure rate and maintain SIL
If the dangerous failure rate is higher than assumed in the SIL verification, shortening the proof test interval can compensate and restore the required PFDavg.
What is the role of 'competency management' within functional safety management per IEC 61511?
Answer: Verifying that all persons involved in safety lifecycle activities have appropriate training and experience
Functional safety management requires that all personnel performing safety lifecycle activities possess documented competency in their specific roles.
During SIS commissioning, what is the purpose of pre-startup acceptance testing (PSAT)?
Answer: To verify that the installed SIS meets the Safety Requirements Specification before operation begins
PSAT verifies end-to-end that the installed SIS hardware and software configuration conforms to the SRS before the process is started.
What is 'safety lifecycle documentation' and why is it required throughout the lifecycle?
Answer: Records that demonstrate that each lifecycle phase has been completed correctly and provides traceability
Safety lifecycle documentation provides the evidence trail showing each phase was properly executed, supporting verification, audits, and future modifications.
Which scenario would trigger a formal re-validation of the Safety Requirements Specification?
Answer: A significant change in process operating conditions that alters the risk profile
If process conditions change significantly (e.g., higher pressures, new chemicals), the hazard and risk assessment must be revisited and the SRS re-validated.
What does IEC 61511 specify regarding the independence of the FSA team?
Answer: The FSA team must have a defined degree of independence from those responsible for the design and implementation
IEC 61511 requires that the FSA team have appropriate independence — the required level increases with the SIL and complexity of the system.
In the IEC 61511 safety lifecycle, what distinguishes 'verification' from 'validation'?
Answer: Verification checks that each lifecycle output meets its input requirements; validation confirms the final SIS meets the overall safety requirements
Verification checks conformance at each phase (built it right), while validation confirms the completed SIS achieves the intended safety function (built the right thing).