CTC Hazard Analysis 2 — Questions and Answers
Question 1: Which hazard analysis technique uses a top-down, deductive approach to identify combinations of events that lead to an undesired top event?
- Failure Mode and Effects Analysis (FMEA)
- Fault Tree Analysis (FTA) (Correct answer)
- Hazard and Operability Study (HAZOP)
- Preliminary Hazard Analysis (PHA)
Correct answer: Fault Tree Analysis (FTA)
Fault Tree Analysis (FTA) is a top-down, deductive technique that uses Boolean logic to trace combinations of failures leading to a defined top-level undesired event.
Question 2: In a Hazard Analysis and Risk Assessment (HARA) for a test environment, the term 'severity' refers to:
- The likelihood that a hazard will occur during test operations
- The potential magnitude of harm if the hazardous event occurs (Correct answer)
- The difficulty of detecting a hazard before it causes harm
- The number of personnel potentially exposed to the hazard
Correct answer: The potential magnitude of harm if the hazardous event occurs
Severity describes the potential magnitude or seriousness of harm (injury, damage, or loss) that could result if a hazardous event actually occurs.
Question 3: A test conductor identifies that a pressure relief valve may fail to open during a high-pressure test. In FMEA terminology, this failure mode's 'detectability' rating reflects:
- How frequently the valve is expected to fail
- The consequence of the valve failing to the overall system
- The ability of current controls to detect the failure before it causes harm (Correct answer)
- The cost of replacing the pressure relief valve
Correct answer: The ability of current controls to detect the failure before it causes harm
Detectability in FMEA rates how effectively existing controls can identify a failure mode before it reaches the end user or causes harm.
Question 4: Which document formally establishes the hazard controls, residual risks, and responsible parties for a specific test operation?
- Test Procedure
- Hazard Control Plan (HCP) or Risk Mitigation Plan (Correct answer)
- System Safety Program Plan (SSPP)
- Environmental Impact Statement
Correct answer: Hazard Control Plan (HCP) or Risk Mitigation Plan
A Hazard Control Plan (or Risk Mitigation Plan) formally documents identified hazards, the controls applied, residual risk levels, and who is accountable for each control.
Question 5: During a live-fire test, an unexpected misfire occurs. According to standard hazard control hierarchy, the FIRST priority action should be to:
- Implement administrative procedures and warnings
- Substitute a less hazardous material or process
- Apply engineering controls to eliminate the hazard at the source (Correct answer)
- Provide personal protective equipment to personnel
Correct answer: Apply engineering controls to eliminate the hazard at the source
The hierarchy of controls places elimination/engineering controls at the top, meaning the preferred approach is to remove or control the hazard at its source before relying on administrative or PPE controls.
Question 6: A Risk Priority Number (RPN) in FMEA is calculated as:
- Severity × Occurrence
- Severity + Occurrence + Detectability
- Severity × Occurrence × Detectability (Correct answer)
- Severity × Detectability
Correct answer: Severity × Occurrence × Detectability
RPN = Severity × Occurrence × Detectability; this composite score helps prioritize which failure modes require the most urgent corrective action.
Question 7: In the context of hazard analysis, a 'residual risk' is best defined as:
- The risk level before any controls have been applied
- The risk that remains after all planned controls have been implemented (Correct answer)
- The risk associated with emergency response procedures
- The risk introduced by the hazard analysis process itself
Correct answer: The risk that remains after all planned controls have been implemented
Residual risk is the risk that persists after all risk controls have been applied; it must be evaluated and formally accepted by the appropriate authority.
CTC Hazard Analysis 2
Which hazard analysis technique uses a top-down, deductive approach to identify combinations of events that lead to an undesired top event?