Risk Assessment & Hazard Analysis Flashcards

In a Hazard and Operability Study (HAZOP), what does the guideword 'MORE' signify?

Answer: Quantitative increase of a parameter above its intended value

The HAZOP guideword 'MORE' indicates a quantitative increase in a process parameter such as flow, temperature, or pressure beyond its design value.

Which risk reduction technique involves eliminating the hazard entirely rather than controlling it?

Answer: Inherently safe design

Inherently safe design (ISD) eliminates hazards at the source rather than adding protective barriers, representing the highest level in the safety hierarchy.

What does a Fault Tree Analysis (FTA) 'OR gate' indicate?

Answer: Any single input event is sufficient to cause the output event

An OR gate in FTA means that any one of the input events alone is sufficient to cause the output (top or intermediate) event.

In IEC 61511, the term 'Process Demand' refers to:

Answer: The rate at which the process requires the SIF to take action

Process demand rate is the frequency at which a hazardous condition arises that requires the safety instrumented function to respond.

Which layer of the Layers of Protection Analysis (LOPA) is NOT considered an Independent Protection Layer (IPL)?

Answer: Basic Process Control System (BPCS)

The BPCS is generally not credited as an IPL when it is also the initiating cause of the hazard scenario being analyzed.

What is the primary output of a quantitative risk assessment (QRA)?

Answer: Numerical estimates of risk expressed as frequency and consequence

QRA produces numerical risk estimates combining the frequency of an event with its consequences to support risk-informed decision making.

In the context of SIL determination, 'Risk Tolerance Criteria' defines:

Answer: The maximum level of risk that an organization deems acceptable

Risk tolerance criteria establish the maximum residual risk that an organization or regulator considers acceptable after all safeguards are applied.