Top 50 MCQs : HAZOP and LOPA Quiz

HAZOP and LOPA Quiz for Process Engineers

Test your knowledge as a Process Engineer. Select the best answer for each question and submit to see your score and the correct answers.

1. What is the primary objective of a HAZOP study?

a) To determine the root cause of past incidents. b) To identify potential hazards and operability problems. c) To select the most cost-effective process design. d) To assess the competency of the operating personnel.

2. A HAZOP study is a...

a) Qualitative risk assessment. b) Quantitative risk assessment. c) Semi-quantitative risk assessment. d) Financial audit.

3. At which stage of a project is a HAZOP study most effectively conducted?

a) Conceptual design. b) During construction. c) After commissioning. d) Detailed design phase.

4. The systematic examination in a HAZOP study is driven by the use of:

a) Checklists. b) Guidewords applied to process parameters. c) Fault Tree Analysis. d) Event Tree Analysis.

5. Which of the following is NOT a standard HAZOP guideword?

a) MORE b) LESS c) FASTER d) REVERSE

6. The HAZOP guideword 'AS WELL AS' is used to identify:

a) A quantitative increase in a parameter. b) An additional activity occurring. c) The complete absence of a parameter. d) A logical opposite of the design intent.

7. In a HAZOP, a "deviation" is a departure from the...

a) Operating instructions. b) Design intent. c) Maintenance schedule. d) Financial budget.

8. Who is typically responsible for leading a HAZOP study and ensuring its systematic execution?

a) The Plant Manager. b) A certified HAZOP Facilitator/Chairman. c) The Lead Process Engineer. d) The Safety Officer.

9. What is the primary document used to define the nodes in a HAZOP study?

a) Process Flow Diagram (PFD). b) Piping and Instrumentation Diagram (P&ID). c) Equipment data sheets. d) Cause and Effect Diagram.

10. The output of a HAZOP study is typically a list of:

a) Approved process changes. b) Recommendations for further action or study. c) Fines and penalties. d) Operator training manuals.

11. Which guideword would be most appropriate to consider the presence of an impurity in a process stream?

a) PART OF b) OTHER THAN c) REVERSE d) NO

12. A HAZOP team should ideally be:

a) Comprised solely of senior management. b) A multi-disciplinary team of experts. c) Limited to two experienced engineers. d) Made up of external consultants only.

13. What is a "node" in the context of a HAZOP study?

a) A critical piece of equipment. b) A specific point in the process where the design intent is well-defined. c) A meeting of the HAZOP team. d) A potential hazard identified.

14. The guideword 'LESS' applied to the parameter 'pressure' would signify:

a) A vacuum. b) A lower than expected pressure. c) A sudden depressurization. d) All of the above.

15. What is the primary role of the Scribe in a HAZOP meeting?

a) To lead the discussion. b) To provide technical expertise. c) To record the proceedings accurately and legibly. d) To approve the final recommendations.

16. Which of these is a limitation of the HAZOP methodology?

a) It is too simplistic for complex processes. b) It cannot be used for existing plants. c) Its effectiveness is highly dependent on the experience of the team. d) It provides a fully quantitative risk value.

17. The guideword 'REVERSE' is most applicable to which process parameter?

a) Temperature b) Pressure c) Flow d) Concentration

18. What does the term "operability" in HAZOP refer to?

a) The ease of starting up the plant. b) The ability of the plant to achieve the desired production under normal and abnormal conditions. c) The profitability of the process. d) The level of automation in the plant.

19. A HAZOP revalidation is typically performed:

a) Every month. b) Only after a major incident. c) Periodically, often every 5 years, or after a significant modification. d) Never, once the initial HAZOP is complete.

20. The combination of a guideword and a process parameter creates a...

a) Consequence. b) Safeguard. c) Deviation. d) Recommendation.

21. What is the purpose of analyzing the 'causes' of a deviation in a HAZOP?

a) To assign blame for potential failures. b) To understand the potential failure modes of equipment and human errors. c) To calculate the probability of the deviation occurring. d) To design the control system.

22. "Human error" as a cause in a HAZOP should be:

a) Avoided as it is not a technical failure. b) The only cause considered for manual operations. c) Specified with as much detail as possible (e.g., "operator fails to close valve"). d) Ignored if the system is automated.

23. Which of the following is NOT a process parameter typically considered in a HAZOP?

a) Flow b) Temperature c) Maintenance Cost d) Level

24. A "safeguard" identified in a HAZOP is a...

a) Measure in place to prevent the cause or mitigate the consequence of a deviation. b) Recommendation to improve the process. c) Potential cause of a deviation. d) Description of the process node.

25. A HAZOP study focuses on hazards associated with the...

a) Process itself. b) Financial performance of the plant. c) Environmental impact only. d) Transportation of final products.

26. What is the primary purpose of a Layer of Protection Analysis (LOPA)?

a) To identify all possible hazards in a process. b) To determine if the risk of a hazardous scenario is tolerable. c) To select the cheapest safety instruments. d) To write the operating procedures.

27. LOPA is considered a...

a) Qualitative risk assessment. b) Fully quantitative risk assessment. c) Semi-quantitative risk assessment. d) A design review method.

28. What is a fundamental requirement for a protective layer to be considered an Independent Protection Layer (IPL) in LOPA?

a) It must be a passive device. b) It must be fully automated. c) It must be independent of the initiating cause and other IPLs. d) It must be the most expensive option.

29. Which of the following would typically NOT qualify as an Independent Protection Layer (IPL)?

a) A properly designed pressure relief valve. b) A basic process control system (BPCS) that is also the initiating cause of the deviation. c) A safety instrumented system (SIS). d) A dike or bund for containing a spill.

30. The frequency of the initiating event in a LOPA is typically expressed in:

a) Dollars per year. b) Events per year. c) A qualitative ranking (High, Medium, Low). d) The number of fatalities.

31. What does the Probability of Failure on Demand (PFD) represent for an IPL?

a) The likelihood that the IPL will work when needed. b) The likelihood that the IPL will fail to perform its function when required. c) The initial cost of the IPL. d) The frequency of testing the IPL.

32. LOPA is typically performed:

a) Before a HAZOP study. b) As a standalone analysis without any prior hazard identification. c) After a HAZOP has identified significant hazardous scenarios. d) During the construction phase.

33. What is an "enabling condition" in the context of LOPA?

a) A condition that directly causes the initiating event. b) A condition that must be present for the initiating event to lead to the consequence. c) A successful operation of a safety function. d) The final consequence of a hazardous event.

34. In LOPA, the risk of a scenario is calculated by:

a) Adding the PFDs of all IPLs. b) Multiplying the initiating event frequency by the PFDs of all IPLs. c) Dividing the consequence severity by the initiating event frequency. d) Averaging the PFDs of all IPLs.

35. A "conditional modifier" in LOPA adjusts the likelihood of the consequence by considering factors such as:

a) The ignition probability of a flammable release. b) The cost of the equipment. c) The number of operators on shift. d) The age of the plant.

36. A human action, such as an operator responding to an alarm, can be considered an IPL if it meets specific criteria, including:

a) The operator is highly experienced. b) The action is part of the standard operating procedure. c) The operator has sufficient time, clear indication, and is trained for the specific action. d) The operator has a good safety record.

37. The target Mitigated Event Likelihood (MEL) in a LOPA is determined by the company's...

a) Production targets. b) Risk tolerance criteria. c) Maintenance budget. d) Insurance provider.

38. If the calculated Mitigated Event Likelihood (MEL) for a scenario is higher than the target MEL, what is the typical outcome?

a) The process is immediately shut down. b) The LOPA results are discarded. c) Additional IPLs are required to reduce the risk. d) The operating pressure must be reduced.

39. LOPA provides a direct input for determining the required...

a) Safety Integrity Level (SIL) for a Safety Instrumented Function (SIF). b) Number of operators for a plant. c) Maintenance schedule for all equipment. d) Size of the control room.

40. What does the principle of "independence" for an IPL mean?

a) The IPL is manufactured by a different company. b) The failure of the IPL is not caused by the initiating event or the failure of any other IPL. c) The IPL operates on a separate power supply. d) The IPL is physically located far from the process.

41. Which of these attributes is essential for an IPL?

a) Low cost. b) Auditability. c) Manual operation. d) Being the latest technology.

42. The initiating cause in a LOPA scenario is often identified during which prior study?

a) Environmental Impact Assessment. b) HAZOP. c) Financial Audit. d) Marketing Survey.

43. A risk matrix in LOPA typically relates:

a) Cost vs. Benefit. b) Consequence severity vs. Likelihood. c) Equipment size vs. Pressure rating. d) Operator experience vs. Task complexity.

44. What is a key benefit of using LOPA?

a) It eliminates the need for experienced engineers. b) It provides a consistent and defensible basis for risk-based decisions. c) It is a very quick and simple analysis to perform. d) It guarantees that no incidents will ever occur.

45. "Double jeopardy" in the context of process safety, and often avoided in HAZOP/LOPA, refers to:

a) A single failure causing two different consequences. b) Two independent and unrelated failures occurring simultaneously. c) A hazard that affects two different process units. d) A recommendation that is too expensive to implement.

46. Which of the following is an example of a passive IPL?

a) An emergency shutdown valve. b) A high-level alarm. c) A fire-resistant coating. d) An operator intervention.

47. LOPA helps to answer the question:

a) "What can go wrong?" b) "How safe is safe enough?" c) "Who is responsible?" d) "What is the capital cost?"

48. The effectiveness of an IPL is measured by its:

a) Physical size. b) Probability of Failure on Demand (PFD). c) Color. d) Manufacturer's warranty.

49. If a LOPA reveals a significant risk gap, what is the next logical step?

a) To immediately stop production. b) To re-do the HAZOP study. c) To evaluate and propose additional or improved IPLs. d) To accept the risk as it is.

50. The successful application of both HAZOP and LOPA is highly dependent on:

a) The software used. b) The accuracy of the process documentation (e.g., P&IDs). c) The size of the team. d) The location of the plant.

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One Response

Ahmed Taha Ahmed says:

November 4, 2025 at 12:06 pm

Thank you, very useful questions to review HAZOP and LOPA principle.

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Top 50 MCQs : HAZOP and LOPA Quiz

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