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GASCO exit exam questions and answers — Set 10

Set 10 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 10 — 30 GASCO exit exam questions with answers

1. What is the agreement between the buyer and the end-users called as?

  • A. Sale and Purchase Agreement(SPA)
  • B. Delivery Ex-Ship (DES)
  • C. Gas sale agreement(GSA)
  • D. Free On Board(FOB)
Answer: C — Gas sale agreement(GSA)
The correct answer is Gas sale agreement(GSA). This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

2. Identify the odd one out. Which of these factors will not increase the boil-off onboard an lng carrier?

  • A. Detoriation of insulation barriers
  • B. sloshing in the cargo tanks
  • C. Rasing of insulation space pressure
  • D. Long loaded passage
Answer: C — Rasing of insulation space pressure
The correct answer is Rasing of insulation space pressure. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

3. the methods used for producing inert gas onboard LNG carriers are many, which one method may no longer be used?

  • A. By stoichiometric combustion in an inert gas combustion
  • B. flue gas from main boilers
  • C. Nitrogen by fractional distillation or by pressuree swing absorbtion(PSA)
  • D. Nitrogen by turning liquid nitrogen from shore to nitrogen gas
Answer: B — flue gas from main boilers
The correct answer is flue gas from main boilers. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

4. Which law states that the sum of the partial pressures of the constituent gases of a mixture of gases is equal to the total pressure of the gas mixture?

  • A. Boyle's law
  • B. Gay Lussac's law
  • C. Charles's law
  • D. Dalton's law of partial pressure
Answer: D — Dalton's law of partial pressure
The correct answer is Dalton's law of partial pressure. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

5. What is the quantity of heat absorbed on vaporization at normal boiling point?

  • A. Vaporization heat
  • B. Latent heat
  • C. Condensation heat
  • D. lost heat
Answer: B — Latent heat
The correct answer is Latent heat. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

6. During normal loading/ discharging cycle, how does keeping the tanks cool and ready for loading help?

  • A. It reduces the thermal stresses on the membrane
  • B. It increases the ship operation costs
  • C. It increases thermal stresses on the membrane
  • D. It reduces boil-off in the ballast passage
Answer: A — It reduces the thermal stresses on the membrane
The correct answer is It reduces the thermal stresses on the membrane. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

7. Find the correct answer. A vessel certified to carry an NLS(Noxious liquid substances) must comply with

  • A. OSHA regulations
  • B. International Pollution Prevention Certificate for the carriage of Noxious liquid substances
  • C. STCW regulations
  • D. ILO regulations
Answer: B — International Pollution Prevention Certificate for the carriage of Noxious liquid substances
The correct answer is International Pollution Prevention Certificate for the carriage of Noxious liquid substances. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

8. Based on the principles of segregation, what would you classify the cargo compressor room?

  • A. Gas safe spac
  • B. Gas safe zon
  • C. Gas dangerous zon
  • D. Gas dangerous spac
Answer: D — Gas dangerous spac
The correct answer is Gas dangerous spac. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

9. Which of the following are not the early signs of structural failure of the inner hull?

  • A. Increasing of Lng level in cargo tanks, by incoming seawater
  • B. Water detected in secondary insulation spac
  • C. Further lowering of insulation space temperature sensed by the thermocoupl
  • D. Maximum methane reading detected by the explosive meter inside insulation spaces
Answer: A — Increasing of Lng level in cargo tanks, by incoming seawater
The correct answer is Increasing of Lng level in cargo tanks, by incoming seawater. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

10. Insulation materials for use on liquefied gas carriers shall possess the following, except:

  • A. ability to bear physical loads
  • B. Ingress of moisture is not possible thereb, loss of insulation performanc
  • C. ability to withstands mechanical damage
  • D. reasonably lightweight
Answer: B — Ingress of moisture is not possible thereb, loss of insulation performanc
The correct answer is Ingress of moisture is not possible thereb, loss of insulation performanc. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

11. How is the formation of cold spots on the inner hull surfaces which is not fitted with thermocouples detected?

  • A. By using remote ice detection device at any tim
  • B. frequent inspections of inner hull on ballast passage
  • C. By using remote lng leak detector any tim
  • D. frequent inspections of inner hull on loaded passage
Answer: D — frequent inspections of inner hull on loaded passage
The correct answer is frequent inspections of inner hull on loaded passage. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

12. What will happen if the primary space is at least partially flooded with LNG?

  • A. No reduction in exhaust flow to atmosphere or increase in the temperature of the secondary spaces
  • B. Changes in exhaust flow to atmosphere and increase in the temperature of secondary spaces
  • C. Reduction in exhaust to atmosphere or decrease in the temperature of secondary spaces
  • D. Pressure insulation will increase and temperature for primary spaces will reduces
Answer: A — No reduction in exhaust flow to atmosphere or increase in the temperature of the secondary spaces
The correct answer is No reduction in exhaust flow to atmosphere or increase in the temperature of the secondary spaces. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

13. Onboard an LNG tanker with NO 96 containment system, with minor membrane leakage, which of the following it not a recommended remedial action?

  • A. Check and log gas concentration and temperature on the damageed insulation spaces frequently
  • B. Ensure at all times secondary space pressuree>damageed primary pressuree +0.5 to 10 bar
  • C. Alter ship's course and speed to increase pressuree within damageed insulation spaces
  • D. Check location of crack by using vent cock located on nitrogen supply and exhaust
Answer: C — Alter ship's course and speed to increase pressuree within damageed insulation spaces
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

14. What remedial action should be taken as soon as possible prior discharging cargo from a damaged cargo tank?

  • A. Fix the equalizer between gas dome and secondary insulation spac
  • B. Fix the equalizer between gas dome and primary insulation spac
  • C. Fix the equalizer between primary and secondary spaces
  • D. Fix the equalizer between gas dome and vacuum lin
Answer: B — Fix the equalizer between gas dome and primary insulation spac
The correct answer is Fix the equalizer between gas dome and primary insulation spac. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

15. Each equipment on LNG ship will be stamped with Information giving the type of protection. That will not include,

  • A. Ex d IIb T6 means that the equipment is certified Ex d protected by explosion proof enclosur
  • B. Ex d protected by explosion proof enclosur
  • C. IIb gas group
  • D. 17 temperature class -100°C
Answer: D — 17 temperature class -100°C
The correct answer is 17 temperature class -100°C. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

16. Onboard a membrane type LNG carrier, why does the primary membrane have a tendency to collapse during discharge of cargo from damaged cargo tank?

  • A. Due to different material use for cargo tank and primary membrane
  • B. Due to temperature variations
  • C. Due to large different liquid level
  • D. Due to small different liquid level
Answer: C — Due to large different liquid level
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

17. Which of the following machinery is used for power generation onboard an LNG Carrier with a steam turbine plant?

  • A. A forcing vaporizer
  • B. A diesel generator
  • C. A degasification unit
  • D. A reliquefaction plant
Answer: B — A diesel generator
The correct answer is A diesel generator. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

18. Onboard an LNG carrier, with NO 96 membrane containment system, what is the indication of failure of the primary membrane and primary insulation space?

  • A. Temperature drop in secondary space temperature probes
  • B. Temperature drop in cofferdam space temperature probles
  • C. Temperature drop in wing ballast tank space temperature probles
  • D. Temperature drop on main deck temperature probles
Answer: A — Temperature drop in secondary space temperature probes
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

19. How does the gas detection system react to a minor leak of primary barrier spaces?

  • A. Gas percentage methane content will increase depending on the location and size of the crack
  • B. Gas percentage oygen content will reduce depending on the location and size of the crack
  • C. Gas percentage nitrogen content will increase depending on the location and size of the crack
  • D. Gas percentage methane content will decrease depending on the location and size of the crack
Answer: A — Gas percentage methane content will increase depending on the location and size of the crack
The correct answer is Gas percentage methane content will increase depending on the location and size of the crack. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

20. Which of the following is not a typical counter measure carried out after a major membrane leak or failure?

  • A. Isolate primary spaces of affected cargo tanks
  • B. Stop gas burning in boilers
  • C. Open primary spare exhaust of affected cargo tanks to vent excess pressure
  • D. Closely monitor all temperature sensors and gas detection system of the affected cargo tank
Answer: B — Stop gas burning in boilers
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

21. Onboard an LNG tanker with NO 96 containment system what will typically happen if a minor membrane leak(crack) occurs below the cargo level?

  • A. Big flow of liquid into the crack will rapidly vaporize and cargo will be severely damageed
  • B. Small flow of liquid into the crack will vaporize cargo tank pressuree will increase tremendously increase tremendously
  • C. Big flow of liquid into the crack will vaporize and colaps the primary membranee inwards
  • D. Small flow of liquid into the crack will vaporize, cargo tank will remain the sam
Answer: D — Small flow of liquid into the crack will vaporize, cargo tank will remain the sam
In Gaztransport & Technigaz NO 96 membrane containment systems, Invar membranes and perlite insulation boxes maintain cargo containment and thermal insulation.

22. The grade of steel used for inner hull construction is designed so to withstand

  • A. The main pressuree can be created by UNG voor in an enclosed spac
  • B. The minimum temperature due to LMG contact
  • C. The minimun corrosion effect due to steel-air and seawater contact
  • D. The maximum explosion force that can be created by LNG vapor in an enclosed spac
Answer: B — The minimum temperature due to LMG contact
The correct answer is The minimum temperature due to LMG contact. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

23. Identify the odd one. Each main cargo pump electric motor is protected from certain faults. Which of the following is an exception?

  • A. Delayed start
  • B. Thermal overload (over current)
  • C. Undercurrent (no load operation)
  • D. Imbalance between phases (single-phasing)
Answer: A — Delayed start
The correct answer is Delayed start. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

24. Why does the cofferdam heating system have two sets of heating coils?

  • A. One for starboard and one for port
  • B. One for upper and one for lower
  • C. One in service and one on standby
  • D. One for forward part and one for aft part
Answer: C — One in service and one on standby
The correct answer is One in service and one on standby. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

25. In an LNG carrier two types of cargo pumps are fitted in each cargo tank. Identify them by name.

  • A. Big cargo and small cargo pumps
  • B. Emergency and small cargo pumps
  • C. Main cargo and stripping/spray pumps
  • D. Emergency and big cargo pumps
Answer: C — Main cargo and stripping/spray pumps
The correct answer is Main cargo and stripping/spray pumps. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

26. What are the two types ur heating medium which may be used for the typical cofferdam heating system onboard LNG carers?

  • A. Seawater or R 404a
  • B. Steam or glycol water
  • C. Warm air or brin
  • D. Alcohol solution or seawater
Answer: B — Steam or glycol water
The correct answer is Steam or glycol water. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

27. Capacitance type gauges are reliable as they have no moving parts. Identify the condition under which they may fall?

  • A. Presence of nitrogen and methan
  • B. Presence of water, dirt or rust
  • C. When the tank is empty
  • D. When the tank is not full
Answer: B — Presence of water, dirt or rust
The correct answer is Presence of water, dirt or rust. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

28. IGC Requirements on LNG vessels are stated below that will not include

  • A. The Gas Codes and classification society rules require every cargo tank to be fitted with at least one squid level gaug
  • B. The Gas Codes require every cargo tank to be fitted with at least two liquid level gauges
  • C. Chapter 19 of the 1GC code provides the requirements for gauging systems usiing onboard gas carriers.
  • D. This information is summarized in Appendix 2 of the same code.
Answer: B — The Gas Codes require every cargo tank to be fitted with at least two liquid level gauges
The correct answer is The Gas Codes require every cargo tank to be fitted with at least two liquid level gauges. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

29. In ESDS pneumatic link system which equipment is used to sense and monitor the air pressure in the system so that the ESDS will activate if the air pressure in system Fall below set point

  • A. Pressure regulator
  • B. Pressure switch
  • C. Pressure control valv
  • D. Pressure dumping valv
Answer: B — Pressure switch
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.

30. Why should the temperature of cofferdam and liquid domes be maintained above +5°C

  • A. To ensure no heat transfers from seawater through outer hull
  • B. To equal The Teperatures of the containment system and insulation spaces
  • C. to ensure space is warm for inner hull inspection
  • D. If inner full temperature drops to sub-zero temperatures, it can suffer structural damage
Answer: D — If inner full temperature drops to sub-zero temperatures, it can suffer structural damage
The correct answer is If inner full temperature drops to sub-zero temperatures, it can suffer structural damage. This complies with established gas tanker operational standards, thermodynamics, and the IGC Code safety requirements.

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