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GASCO exit exam questions and answers — Set 9

Set 9 of the Advanced Training for Liquefied Gas Tanker Cargo Operations (GASCO) exit exam bank — 30 of 351 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 9 — 30 GASCO exit exam questions with answers

1. 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.

2. 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
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

3. 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.

4. 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
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

5. 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
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

6. 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
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

7. 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.

8. 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
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

9. 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.

10. 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.

11. 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.

12. 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
Retaining a small heel of LNG cargo on ballast voyages maintains tank cryogenic temperatures, minimizes thermal shock, and avoids lengthy pre-cooling at the loading port.

13. Onboard an LNG tanker, the main cargo pumps are installed at the bottom of the tripod mast located in the after end of cargo tanks, Which factor should be adjusted to maximize discharge rate?

  • A. Vapor supply capacity
  • B. Trim
  • C. List
  • D. Gas burning capacity
Answer: B — Trim
The correct answer is Trim. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

14. In ship's ESDS, an automatic electrical system which energizes ESDS due to temperature change of the sensor, fitted at each tank domes and both manifold platforms is known as

  • A. Automatic fusible elements
  • B. Automatic push button
  • C. Infrared gas detection system
  • D. Automatic heat sensors
Answer: A — Automatic fusible elements
ESDS automatic fusible thermal elements are designed to melt between 98°C and 104°C during a fire, depressurizing the pneumatic loop and tripping the emergency shutdown system.

15. Which of the following will not cause an activation of the ESDS?

  • A. Differential pressuree between cargo tank and atmosphere - too low
  • B. Differential pressuree between cargo tank and primary insulation space - too low
  • C. Differential pressuree between primary and secondary insulation space - too low
  • D. Manual push button and fusible elements
Answer: C — Differential pressuree between primary and secondary insulation space - too low
ESDS automatic fusible thermal elements are designed to melt between 98°C and 104°C during a fire, depressurizing the pneumatic loop and tripping the emergency shutdown system.

16. Where can electrical equipment classified as exib be used?

  • A. In Zones 0, 1 and 2
  • B. In Zones 1 and 2
  • C. In Zones 0 and 2
  • D. In Zones 0 and 1
Answer: B — In Zones 1 and 2
The correct answer is In Zones 1 and 2. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

17. What is the latest propulsion solution introduced to the LNG shipping industry?

  • A. Steam turbines
  • B. Duel - Fuel Diesel Electric (DFDE)
  • C. Low - speed diesel with a BOG reliquefaction plant
  • D. Gas turbin
Answer: B — Duel - Fuel Diesel Electric (DFDE)
The correct answer is Duel - Fuel Diesel Electric (DFDE). This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

18. Onboard an LNG carrier, with NO 96 containment system, what will happen when pressure inside primary space is equal to cargo tank pressure?

  • A. Primary barrier strips will be shifted from its original position
  • B. Primary barrier strips will be pressed hard onto primary insulation box
  • C. Primary barrier will collapse inward
  • D. Nothing will happen - no damagee to primary barrier
Answer: D — Nothing will happen - no damagee to primary barrier
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

19. Which are the international bodies that provide regulatory standards for electrical equipment certification?

  • A. IEEC and CENELEC
  • B. IEC and CENELEC
  • C. IEEC and ISO
  • D. IMO and ISO
Answer: B — IEC and CENELEC
The correct answer is IEC and CENELEC. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

20. After the removal of bulk water from damaged insulation space, Why is it so important to dry out the spaces until the atmosphere dew point is -40°C or lower

  • A. As there is a possibility for water being trapped and remaining in the insulation spaces
  • B. As there is a posisbility of mud collected at the bottom of the insulation spaces
  • C. To cool down the cargo tanks for immediate loading of cargo
  • D. To avoid the accumulation of rust dust at the bottom of the insulation spac
Answer: A — As there is a possibility for water being trapped and remaining in the insulation spaces
The correct answer is As there is a possibility for water being trapped and remaining in the insulation spaces. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

21. The commercially viable propulsion systems for Deepsea LNG tanker ships will not include,

  • A. Conventional plant with steam turbines and dual fired boilers
  • B. Bual-Fuel Diesel Electric (DFDE) plant
  • C. Slow Speed Diesel with a Boil-Off Gas (BOG) Reliquefaction Plant
  • D. Medium speed Diesel with a BOG Reliquefaction plant
Answer: D — Medium speed Diesel with a BOG Reliquefaction plant
The correct answer is Medium speed Diesel with a BOG Reliquefaction plant. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

22. What should the Master of an LNG carrier do if the CTS fails?

  • A. Use the gauging reports of shore receiving tanks.
  • B. Inform the Company and receivers. Use manual gauging and tank tables
  • C. Inform the terminal and activate ESD button
  • D. Suspend cargo operation till CTS is repaired
Answer: C — Inform the terminal and activate ESD button
The correct answer is Inform the terminal and activate ESD button. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

23. As per IGC Code the "design loads" for a particular cargo containment system, which calculation is a requirement?

  • A. Crack load
  • B. Sloshing load
  • C. Hydrostatic load
  • D. Damage load
Answer: B — Sloshing load
The correct answer is Sloshing load. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

24. The carriage of LNG cargo requires a certificate for trading called as___________.

  • A. International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk
  • B. International Pollution Prevention Certificate for the Carriage of Noxious Liquid Substances in Bulk (NLS Certificate)
  • C. The International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code), has been mandatory under OLAS chapter VII
  • D. International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk
Answer: A — International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk
The correct answer is International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

25. If an LNG sale document is marked as Delivered Ex Ship (DES), after discharge who is the owner of the 'heel' retained onboard?

  • A. Heel belongs to the buyer
  • B. Heel belong to the seller
  • C. Heel belongs 50% to the buyer and 50% to the seller
  • D. Heel belongs 75% to the buyer and 25% to the seller
Answer: B — Heel belong to the seller
Retaining a small heel of LNG cargo on ballast voyages maintains tank cryogenic temperatures, minimizes thermal shock, and avoids lengthy pre-cooling at the loading port.

26. At what temperature will methane change from vapour to liquid at atmospheric pressure?

  • A. -141.5°C
  • B. -161.5°C
  • C. -151.5°C
  • D. -131.5°C
Answer: B — -161.5°C
The correct answer is -161.5°C. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

27. What is the critical temperature and pressure of methane?

  • A. -145.5°C and 44.7 bars
  • B. -82.5°C and 47,4 bars
  • C. -82.5°C and44.7 bars
  • D. -161.5°C and 47.4 bars
Answer: C — -82.5°C and44.7 bars
The correct answer is -82.5°C and44.7 bars. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

28. Typical inert gas consists of approximately 0.5% Oxygen, 15% Carbon dioxide, 0.5% Carbon monoxide, Oxides of nitrogen and Sulphur dioxide. Which gas forms nearly 84% of the Inert gas?

  • A. Propan
  • B. Nitrogen
  • C. Butan
  • D. Methan
Answer: B — Nitrogen
The correct answer is Nitrogen. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

29. What are the two main contractual arrangements used in LNG shipping?

  • A. Delivery Ex - Ship (DES) and Freight On Board (FOB)
  • B. Delivery Ex - Ship (DES) and Free On Board (FOB)
  • C. Delivery Ex Shore (DES) and Free On Board (FOB)
  • D. Delivery On Board (DOB) and Free On Board (FOB)
Answer: B — Delivery Ex - Ship (DES) and Free On Board (FOB)
The correct answer is Delivery Ex - Ship (DES) and Free On Board (FOB). This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

30. Natural and shale gas deposits are not supported by_____________.

  • A. Conventional and non-associated gas deposits which are called natural gas deposits
  • B. Natural gas deposits which are much closer to the surface just under the seal
  • C. Shale gas deposits which are deposits of natural gas found in shale formations.
  • D. Shale gas deposits which are much less deep than the conventional deposits
Answer: D — Shale gas deposits which are much less deep than the conventional deposits
The correct answer is Shale gas deposits which are much less deep than the conventional deposits. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

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