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GASCO exit exam questions and answers — Set 8 — Advanced Training for Liquefied Gas Tanker Cargo Operations

Set 8 of the Advanced Training for Liquefied Gas Tanker Cargo Operations (GASCO) exit exam bank — 30 of 710 questions, with the correct option marked and a one-line explanation for every one. Read it end to end, jump to a single set, or search it — then sit the same bank as a timed paper. The real DG Shipping exit exam is 30 marks with 15 to pass.

These are the bank's original groupings. Practising deals the whole bank out again every time you reshuffle, so a practice “Set 3” is a different 30 questions each time — the set numbers below are the source file's, and are only used here so the key stays navigable. Options are listed in their original order with fixed letters; when you practise, those move too.

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Set 8 — 30 GASCO exit exam questions with answers

1. Based on the principles of segregation, what would you classify the deck of an LNG carrier?

  • A. Gas dangerous spac
  • B. Gas dangerous zon
  • C. Gas safe zon
  • D. Gas safe spac
Answer: B — Gas dangerous zon
The open cargo-area deck is a gas-dangerous zone (hazardous area) under IGC classification.

2. What is the ideal location for a cargo tank from the shell plating, in any Gas tanker type?

  • A. less than 760 mm (30 inches) from the shell plating
  • B. less than 750 mm (29.5 Inches) from the ship sid
  • C. less than 740 mm (29 inches) from the main deck
  • D. less than 730 mm (28.7 inches) from the summer draft
Answer: A — less than 760 mm (30 inches) from the shell plating
IGC Code 2.4 requires cargo tanks to be at least 760 mm from the shell plating. Every option says 'less than', so the wording is wrong, but option 0 carries the correct 760 mm figure.

3. Which chapter of the IGC Code refers to the summary of minimum equipment requirements for an LNG carrier?

  • A. Chapter 18
  • B. Chapter19
  • C. Chapter 17
  • D. Chapter 16
Answer: B — Chapter19
The correct answer is Chapter19. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

4. Which statements is true in accordance with Chapter 15 of the IGC Code?

  • A. 95% of the total volume of the tank at reference temperatur
  • B. 96% of the total volume of the tank at reference temperatur
  • C. 97% of the total volume of the tank at reference temperatur
  • D. Cargo tanks onboard should not be filled higher 98% of the total volum
Answer: D — Cargo tanks onboard should not be filled higher 98% of the total volum
The correct answer is Cargo tanks onboard should not be filled higher 98% of the total volum. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

5. Exposure controls/personal protection in MSDS will not include,

  • A. OSHA permissible exposure limit (PEL), Threshold Limit Value (TLV), and any other exposure limit used or recommended
  • B. Appropriate handling controls
  • C. Appropriate engineering controls
  • D. Individual protection measures, such as personal protective equipment.
Answer: B — Appropriate handling controls
The correct answer is Appropriate handling controls. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

6. Which of these is not a possibility if by accident the insulation spaces are over pressurized?

  • A. Membrane collaps
  • B. Lifting of insulation safety valves
  • C. Initiation of emergency shut down
  • D. Tripping of cargo pump
Answer: D — Tripping of cargo pump
The correct answer is Tripping of cargo pump. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

7. Fire-fighting measures shown in MSDS will not include,

  • A. Suitable (and unsuitable) extinguishing media
  • B. Specific hazards arising from the chemical (e.g., nature of any hazardous combustion products)
  • C. Training requirement for firefighting and Special protective equipment
  • D. Special protective equipment and precautions for fire-fighters
Answer: C — Training requirement for firefighting and Special protective equipment
The correct answer is Training requirement for firefighting and Special protective equipment. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

8. What should be the typical content of oxygen in inert gas produced by an inert gas generator onboard an LNG carrier?

  • A. 0.5%
  • B. 12.6%
  • C. 7.5%
  • D. 13%
Answer: A — 0.5%
The correct answer is 0.5%. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

9. If an LNG sale document is marked as Free on Board (FOB), after discharge who is the owner of the "heel' retained onboard?

  • A. Seller owns the heel and may keep it onboard as he controls the vessel
  • B. Seller owns the heel and may heel out
  • C. Buyer owns the heel and may keep it onboard as he controls vessel 6
  • D. Seller owns the heel and may keep It to mix with the next cargo
Answer: C — Buyer owns the heel and may keep it onboard as he controls vessel 6
Under FOB the buyer takes title at loading and charters/controls the vessel, so the heel after discharge belongs to the buyer.

10. What is the temperature at which gas saturates and the water vapor present begins to condense?

  • A. Boiling point
  • B. Condensate point
  • C. Vapor point
  • D. Dew point
Answer: D — Dew point
The correct answer is Dew point. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

11. Identify the correct name for a gas or mixture of gases, containing insufficient oxygen to initiate and support combustion where oxygen content is not greater than 5% by volume.

  • A. Inert gas
  • B. Cold gas
  • C. Anti - fire gas
  • D. Anti - oxygen gas
Answer: A — Inert gas
The correct answer is Inert gas. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

12. What is the designed boil-off rate for a typical membrane type LNG carrier?

  • A. 0.15% of full cargo tank capacity / day
  • B. 0.05% of full cargo tank capacity / day
  • C. 0.25% of full cargo tank capacity / day
  • D. 0.5% of full cargo tank capacity / day
Answer: A — 0.15% of full cargo tank capacity / day
Typical design BOR for membrane LNG carriers (NO96/Mk III) is about 0.15% of cargo volume per day (newer ships ~0.1%).

13. What is done with Normal Boil - off (NBO) vapour?

  • A. It is removed to maintain the cargo temperature and pressure
  • B. It is retained in the tanks as it has no effect
  • C. It is vented to atmospher
  • D. It is collected and stored in the buffer tank
Answer: A — It is removed to maintain the cargo temperature and pressure
The correct answer is It is removed to maintain the cargo temperature and pressure. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

14. Which of these factors is not considered when calculating the heel to be retained onboard?

  • A. Duration of ballast passage
  • B. Saturated vapor pressuree of the cargo
  • C. Weather forecast for the loaded passage
  • D. Level restriction due to sloshing effect
Answer: C — Weather forecast for the loaded passage
Heel is retained to keep the tanks cold on the ballast voyage, so the calculation uses the ballast passage duration, the boil-off (governed by the cargo's vapour pressure and heat ingress) and sloshing fill limits. The weather on the loaded passage plays no part.

15. Onboard a LNG tanker, with NO 96 containment system, what happens to the cargo when a cargo tank suffers a major primary barrier failure?

  • A. The cargo will flood the primary insulation spac
  • B. The cargo will flow out to shipsid
  • C. All the cargo will boil - off immediately
  • D. The cargo will freeze up
Answer: A — The cargo will flood the primary insulation spac
With NO96, the secondary barrier holds the leak; on primary barrier failure liquid fills the primary insulation space.

16. During a cargo handling operation which of the following precautions need not be observed to deal with spillage?

  • A. Deck spray pump (IMO) system on standby mod
  • B. Protective clothing used
  • C. Constant patrol of cargo area maintained
  • D. Shore spill team on standby mod
Answer: D — Shore spill team on standby mod
The correct answer is Shore spill team on standby mod. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

17. What is the main danger when discharging a damaged cargo tank in a normal manner?

  • A. Discharging pump will trip due to debris in the tank
  • B. Discharging time will be shorter due to lesser cargo in the tank
  • C. Collapse of secondary membranee due to high differential head
  • D. Collapse of the primary membranee due to high differential head
Answer: D — Collapse of the primary membranee due to high differential head
The correct answer is Collapse of the primary membranee due to high differential head. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

18. What is the definition for the term "minor failure of membrane?

  • A. Activation of gas detection equipment for insulation despite of purging with nitrogen
  • B. Fatigue cracks develop with obvious signs of pressuree rise and the presence of methane vapor
  • C. Porosity of membranee which allows limited liquid into insulation spaces
  • D. Minor fatigue cracks, passing liquid into the insulation space and becomes gaseous
Answer: D — Minor fatigue cracks, passing liquid into the insulation space and becomes gaseous
A minor membrane failure is small fatigue cracks/porosity allowing small amounts of liquid into the insulation space where it vaporises and is detected as gas.

19. Onboard an LNG carrier, under what circumstances is purging or gassing up with LNG vapor is critical prior to cool down of cargo tanks?

  • A. If nitrogen has been used for inerting
  • B. If inert gas has been used for inerting
  • C. If time available for cool down is very short
  • D. If shore supply for cool down is not availabl
Answer: B — If inert gas has been used for inerting
The correct answer is If inert gas has been used for inerting. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

20. In a membrane class LNG tanker, why is the cargo tank pressure increased from 20 mbar g to 150 mbar g at the end of operation?

  • A. To overcome back pressuree from the vent lin
  • B. To speed up the inerting process
  • C. To purge all equipment and pipelines thoroughly
  • D. To test the tanks prior to aerating
Answer: C — To purge all equipment and pipelines thoroughly
Raising inert gas pressure to ~150 mbarg at the end of inerting is used to pressurise and purge dead ends, equipment and pipelines thoroughly.

21. What is the consequence of ice formation in a cargo tank?

  • A. Burst in the discharge lin
  • B. Formation of cold spot in ballast tank
  • C. Possible damagee to the cargo pump during discharging
  • D. Icing - up of the discharge pump
Answer: C — Possible damagee to the cargo pump during discharging
The correct answer is Possible damagee to the cargo pump during discharging. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

22. Onboard a membrane class LNG Tanker, what is the ideal tank pressure to be maintained during the warming up operation?

  • A. Lowest possible pressuree to have good heat transfer process
  • B. Equal to atmospheric pressuree to allow for free flow of cargo vapor
  • C. Any pressuree is acceptabl
  • D. >150 mbar gauge to give good suction for the HD compressors
Answer: D — >150 mbar gauge to give good suction for the HD compressors
During warm-up a relatively high tank pressure increases vapour density, improving heat transfer and HD compressor mass flow.

23. Or the GT NO 96 containment system, what is the recommended cargo tanks inerting operation completion methane content?

  • A. 5% by volume of methane or mor
  • B. Less than 3% volume of methan
  • C. 7% by volume of methane or mor
  • D. 9% by volume of methane or mor
Answer: B — Less than 3% volume of methan
Inerting after warm-up continues until hydrocarbon (methane) content is below about 2-3% by volume, before aeration.

24. Onboard a membrane class LNG tanker what is the ideal pressure differential to be maintained between the cargo tank and insulation spaces (IS)?

  • A. IS pressuree < cargo tank pressure
  • B. IS pressuree > cargo tank pressure
  • C. IS pressuree = cargo tank pressure
  • D. IS pressuree = cargo tank pressuree + ibar
Answer: A — IS pressuree < cargo tank pressure
Insulation space pressure must be kept below cargo tank pressure so the membrane is pressed against the insulation and not lifted/collapsed.

25. When using the breathing apparatus, the person is warned of low air volume remaining in his air bottle by the meter needle in the red zone and

  • A. a whistle sounding off
  • B. a slight difficulty in breathing
  • C. the life line being tug 3 times by the outside controller
  • D. his own judgement of his bottle becoming colder upon emptying
Answer: A — a whistle sounding off
The correct answer is a whistle sounding off. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

26. What is the parameter which influences the separation of nitrogen in a membrane type generator, which uses hollow fiber membranes to produce nitrogen from air?

  • A. Cooling rate of nitrogen
  • B. Warming up rate of nitrogen
  • C. Permeation rate of nitrogen
  • D. Freezing rate of nitrogen
Answer: C — Permeation rate of nitrogen
Hollow-fibre membranes separate gases by differing permeation rates; O2, CO2 and H2O permeate faster than nitrogen, leaving N2-rich product.

27. The steam heaters onboard LNG tankers work based on "heat transfer" principles. It is important to note the gas volume/liquid volume ratio of LNG at -161.5°C', What is the correct ratio?

  • A. 161:1
  • B. 632:1
  • C. 505:1
  • D. 404:1
Answer: B — 632:1
The correct answer is 632:1. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

28. Why level gauges fitted onboard LNG carriers are of the "closed" type?

  • A. It restricts release of liquid or vapor to atmosphere when in us
  • B. It is cost effectiv
  • C. It is easy to install
  • D. It is maintenance -- fr
Answer: A — It restricts release of liquid or vapor to atmosphere when in us
The correct answer is It restricts release of liquid or vapor to atmosphere when in us. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

29. You are in charge of man - entry into an enclosed space. Which of the following will you check using portable gas detectors?

  • A. Atmospheric pressure
  • B. Toxicity
  • C. Dew point
  • D. Temperatur
Answer: B — Toxicity
The correct answer is Toxicity. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

30. Onboard an LNG carrier in port, the wheelhouse is unmanned. What will be the watch station of the duty cargo officer?

  • A. Engine control room
  • B. Cargo control room
  • C. Electrical equipment room
  • D. Officer's cabin
Answer: B — Cargo control room
In port the duty cargo officer keeps watch in the cargo control room.

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