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BIGF exit exam questions and answers — Set 3 — Basic Training for Ships subject to the IGF Code

Set 3 of the Basic Training for Ships subject to the IGF Code (BIGF) exit exam bank — 30 of 429 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 3 — 30 BIGF exit exam questions with answers

1. Cargo containment system is the arrangement for containment of cargo including where fitted with

  • A. primary barriers
  • B. associated insulations
  • C. secondary barriers
  • D. All of the above
Answer: D — All of the above
IGC Code 1.2: the cargo containment system includes primary and secondary barriers (where fitted), associated insulation and intervening spaces.

2. ______________ is the process in which vapour boil- off from acrgo tanks is condensed in a cargo condenser in which the coolant is a refrigerant gas such as R 22.

  • A. Boil-off
  • B. Cascade Reliquefaction Cycle
  • C. BLEVE
  • D. Boiling Point
Answer: B — Cascade Reliquefaction Cycle
In the cascade reliquefaction cycle, cargo boil-off vapour is compressed and condensed in a cargo condenser cooled by a refrigerant gas such as R22, which is itself cooled by a separate refrigeration cycle. The liquid cargo is then returned to the tanks.

3. _____________ is the process occurring within the impeller of a pump when pressure at the inlet to the impeller falls below the vapour pressure of the liquid being pumped.

  • A. Cascade Reliquefaction Cycle
  • B. Boil-off
  • C. Cavitation
  • D. BLEVE
Answer: C — Cavitation
Cavitation happens when impeller inlet pressure falls below the liquid's vapour pressure, so vapour bubbles form.

4. In Cavitation process, the bubbles of vapour that are formed collapse with impulsive force in the _________ pressure regions of the impeller.

  • A. medium
  • B. lower
  • C. higher
  • D. zero
Answer: C — higher
Vapour bubbles formed at low pressure collapse violently when carried into the higher-pressure regions of the impeller, which erodes it.

5. Cavitation effect can cause significant damage to the

  • A. pumps may lose suction
  • B. impeller surfaces
  • C. both (a) and (b)
  • D. none of the above
Answer: C — both (a) and (b)
Cavitation is the formation and violent collapse of vapour bubbles at low-pressure points in a pump. The collapse pits and erodes the impeller surfaces, and the vapour also makes the pump lose suction and capacity.

6. What are checked during the certificate of Fittness?

  • A. structure
  • B. All of the above
  • C. equipment
  • D. fittings
Answer: B — All of the above
Before a Certificate of Fitness is issued under the IGC or IBC Code, the ship's structure, equipment and fittings are all surveyed to confirm they meet the Code. All of these items are checked.

7. ___________ ia the isolating space on a ship between two adjacent steel bulkheads or deck

  • A. Cofferdam
  • B. Cargo conatinment system
  • C. Compressor pumps
  • D. Cavitation
Answer: A — Cofferdam
IGC Code 1.2: a cofferdam is the isolating space between two adjacent steel bulkheads or decks.

8. Cofferdam is the isolating space on a ship between __________

  • A. both (a) and (b)
  • B. none of the above
  • C. deck
  • D. two adjacent steel bulkheads
Answer: A — both (a) and (b)
A cofferdam is an empty space between two adjacent steel bulkheads or decks, used to separate cargo tanks from other spaces. It acts as a barrier against leaks, gas and heat, as required by the IGC and IBC Codes.

9. ___________ is the reliquefied gases which collect in the condenser and which are then returned to the cargo tanks.

  • A. BLEVE
  • B. Cofferdam
  • C. Condensate
  • D. Aerating
Answer: C — Condensate
Condensate is the liquid formed when boil-off vapour is compressed and cooled in the reliquefaction plant condenser. It collects in the condenser or receiver and is returned to the cargo tanks, reducing cargo loss and controlling tank pressure.

10. Compression Ratio is the ratio of the absolute _____________ the discharge from a compressor divided by the absolute pressure at the suction

  • A. mass
  • B. temperature
  • C. pressure
  • D. volume
Answer: C — pressure
Compression ratio compares absolute pressures: absolute discharge pressure divided by absolute suction pressure. It indicates the work done by each compressor stage in gas carrier reliquefaction plants and is limited to control discharge temperature.

11. _____________ is the ratio of the absolute pressure at the discharge from a compressor divided by the absolute pressure at the suction

  • A. Temperature Ratio
  • B. Compression Ratio
  • C. Compressing ratio
  • D. Freezing ratio
Answer: B — Compression Ratio
The ratio of absolute discharge pressure to absolute suction pressure of a compressor is called the compression ratio. High ratios raise discharge temperature, so reliquefaction plants use multi-stage compression with intercooling to keep it within limits.

12. Natural gas contains ________ quantities of heavier hydrocarbons

  • A. zero
  • B. medium
  • C. bigger
  • D. smaller
Answer: D — smaller
Natural gas is mainly methane, with smaller quantities of heavier hydrocarbons such as ethane, propane and butane plus some nitrogen. These heavier fractions affect the boiling point, density and methane number of LNG used as fuel under the IGF Code.

13. Natural gas contains smaller quantities of ______hydrocarbons

  • A. medium
  • B. heavier
  • C. lighter
  • D. partial
Answer: B — heavier
Natural gas consists predominantly of methane and contains only smaller quantities of heavier hydrocarbons such as ethane, propane and butane. The proportion of these heavier components varies with the gas field and influences LNG composition and quality.

14. Natural gas contains smaller quantities of heavier ________

  • A. hydrocarbons
  • B. carbons
  • C. nitrogen
  • D. oxygen
Answer: A — hydrocarbons
Natural gas is mainly methane, with smaller quantities of heavier hydrocarbons (ethane, propane, butane) plus some N2/CO2.

15. Natural gas contains smaller quantities of heavier hydrocarbons collectively called as _________

  • A. Neutral Gas Liquid
  • B. Natural Gas Limit
  • C. Natural Gas Liquid
  • D. Nitrogen Gas Liquid
Answer: C — Natural Gas Liquid
Natural Gas Liquids (NGL) refer to the heavier hydrocarbon components (ethane, propane, butane, pentane plus) separated from raw natural gas streams.

16. What are the things Natural gas contains in varying amounts?

  • A. carbondioxide
  • B. hydrocarbon
  • C. All of the above
  • D. water
Answer: C — All of the above
Raw natural gas contains methane, ethane, propane, butane, inert gases (nitrogen, helium), and acid contaminants (CO2, H2S, mercaptans).

17. What are the acid gases removed in liquefaction plant?

  • A. carbon dioxide
  • B. none of the above
  • C. both (a) and (b)
  • D. hydrogen sulphide
Answer: C — both (a) and (b)
Acid gases like carbon dioxide (CO2) and hydrogen sulfide (H2S) must be scrubbed from natural gas before liquefaction to prevent corrosion and freezing.

18. In liquefaction plant which gas is removed as it freezes at a temperature above boiling point of Liquified Natural Gas

  • A. methane
  • B. ethane
  • C. carbon dioxide
  • D. hydrocarbons
Answer: C — carbon dioxide
Carbon dioxide freezes at -78.5°C, well above the liquefaction temperature of LNG (-162°C), and must be removed to prevent solid plugging in heat exchangers.

19. In liquefaction plant which toxic compound is removed?

  • A. All of the above
  • B. nitrogen sulphide
  • C. hydrogen sulphide
  • D. carbondioxide
Answer: C — hydrogen sulphide
Hydrogen sulfide (H2S) is a highly toxic, corrosive gas removed during gas sweetening processes to meet safety and transport specifications.

20. In liquefaction plant, fractionating unit name the gas which is split?

  • A. Butane
  • B. none of the above
  • C. Propane
  • D. both (a) and (b)
Answer: D — both (a) and (b)
In a gas liquefaction plant the fractionating unit separates the heavier natural gas liquids from the methane stream. The LPG fraction is split into its components, propane and butane, so both gases are produced by fractionation.

21. In liquefaction plant, which gas is liquefied into end product?

  • A. Oxygen
  • B. none of the above
  • C. hydrogen
  • D. Methane
Answer: D — Methane
In an LNG liquefaction plant, the purified, chilled methane stream is liquefied and sent to cryogenic storage tanks as the final LNG product.

22. What is the atmospheric boiling point of methane gas?

  • A. atmospheric boiling point is +172deg C
  • B. atmospheric boiling point is - 162deg C
  • C. atmospheric boiling point is +192deg C
  • D. atmospheric boiling point is +162deg C
Answer: B — atmospheric boiling point is - 162deg C
The boiling point of methane at normal atmospheric pressure (1.013 bar) is approximately -161.5°C (standard rounded to -162°C).

23. The basic liquefaction processes in current use are

  • A. Pre-cooled mixed refrigerant process
  • B. Pure refrigerant cascade process
  • C. All of the above
  • D. Mixed refrigerant process
Answer: C — All of the above
Major commercial LNG liquefaction cycles include the C3MR (propane pre-cooled mixed refrigerant) process, cascade cycles, and nitrogen expansion loops.

24. In Pre-cooled mixed refrigerant process, what is MCR

  • A. Multi Component Refrigerant
  • B. Multi Cascade Refinement
  • C. Minimum Combination Refrigerant
  • D. Multi Cascade Refrigerant
Answer: A — Multi Component Refrigerant
MCR stands for Multi-Component Refrigerant (or Mixed Refrigerant), utilizing a optimized blend of nitrogen, methane, ethane, and propane.

25. In Pre-cooled mixed refrigerant process, Multi Component Refrigerant is a combination of

  • A. both (a) and (b)
  • B. none of the above
  • C. mixed refrigerant cycles
  • D. pure refrigerant cascadecycles
Answer: A — both (a) and (b)
The mixed refrigerant stream in LNG liquefaction plants consists of tailored mixtures of nitrogen, methane, ethane/ethylene, propane, and butane.

26. Liquefied Petroleum Gas is obtained from the refining of __________

  • A. All of the above
  • B. crude oil
  • C. Vegetable oil
  • D. fatty oil
Answer: B — crude oil
Commercial LPG is produced both by extracting NGLs from natural gas processing and through fractional distillation and catalytic cracking of crude oil.

27. In production of chemical gases, from Propane which gas is produced indirectly

  • A. ammonia
  • B. All of the above
  • C. vinyl chloride
  • D. ethylene
Answer: B — All of the above
Propane dehydrogenation and petrochemical cracking processes produce chemical intermediates such as propylene, ethylene, and downstream derivatives.

28. In production of chemical gases, The ethylene stream can be synthesized with chlorine to manufacture __________

  • A. vinyl chloride
  • B. ethylene
  • C. All of the above
  • D. ammonia
Answer: A — vinyl chloride
Ethylene is chlorinated to form ethylene dichloride (EDC), which is then thermally cracked to produce Vinyl Chloride Monomer (VCM) for PVC production.

29. In production of chemical gases, The methane stream is first reformed with steam into _________

  • A. nitrogen
  • B. hydrogen
  • C. vinyl chloride
  • D. carbondioxide
Answer: B — hydrogen
In chemical synthesis, methane is reacted with high-temperature steam over a nickel catalyst in steam methane reforming (SMR) to produce hydrogen and carbon monoxide.

30. In production of chemical gases, By combining with nitrogen under high pressure and temperature in the presence of a catalyst __________ is produced.

  • A. hydrogen
  • B. carbondioxide
  • C. ammonia
  • D. vinyl chloride
Answer: C — ammonia
Ammonia is synthesized industrially via the Haber-Bosch process by reacting reformed hydrogen with atmospheric nitrogen under high pressure and temperature over an iron catalyst.

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