Risk Management & Mitigation Flashcards

What is the primary purpose of a Pre-Startup Safety Review (PSSR) in the context of process risk management?

Answer: To verify that safety requirements are met before commissioning a new or modified process

A PSSR confirms that all safety requirements, including training, procedures, and installed safeguards, are in place and correct before a new or modified process is started up.

In process safety, what is an 'initiating event' (also called 'initiating cause') in LOPA terminology?

Answer: The failure or error that begins the sequence of events leading to a hazardous event

The initiating event (or cause) is the failure, error, or condition that starts the accident sequence, such as a control valve failure or human error.

What does a 'bow-tie' diagram represent in process risk assessment?

Answer: Threats and preventive barriers on the left, the top event in the center, and consequences with mitigating barriers on the right

A bow-tie diagram visually links threats (left side) and preventive controls through a top event to consequences (right side) and mitigation controls, giving a complete accident scenario picture.

Which factor does NOT affect the Probability of Failure on Demand (PFD) of a Safety Instrumented Function (SIF)?

Answer: Color of the SIS enclosure panel

The physical color of an enclosure has no bearing on PFD; PFD is affected by test interval, diagnostics, component failure rates, and voting architecture.

What is 'risk tolerance' (also called 'tolerable risk') in the context of a safety lifecycle?

Answer: The level of risk accepted by society or an organization above which risk reduction measures are required

Tolerable risk is the threshold level of risk an organization or society is willing to accept; risk above this threshold requires additional risk reduction measures.

In the ALARP (As Low As Reasonably Practicable) principle, how should risk reduction decisions be made?

Answer: Risk reduction should continue until the cost of further reduction is grossly disproportionate to the safety benefit gained

ALARP requires that risk be reduced until the cost of further reduction becomes grossly disproportionate to the benefit, balancing safety improvement against practicability.

Which of the following best describes a 'functional safety assessment' (FSA) as required by IEC 61511?

Answer: An independent investigation to judge whether the functional safety objectives have been achieved at defined lifecycle phases

An FSA is an independent review conducted at defined phases of the safety lifecycle to verify that functional safety objectives and requirements have been properly achieved.