AIGF exit exam questions and answers — Advanced Training for Ships subject to the IGF Code

All 468 questions from the Advanced Training for Ships subject to the IGF Code (AIGF) exit exam bank, 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.

Bank last rebuilt 13 Oct 2026.

Practise these AIGF questions AIGF mock exit exam, 30 marks AIGF exit exam sets and syllabus

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Set 1 — 30 AIGF exit exam questions with answers

1. Insulation spaces are continually supplied with an inert gas as part of ______________

A. leak detection system
B. lever detection system
C. lever defining system
D. leak defining system

Answer: A — leak detection system

Under the IGF Code, insulation spaces and interbarrier spaces surrounding liquefied gas fuel tanks are continuously supplied with dry inert gas (nitrogen) to prevent moisture ingress and enable rapid leak detection by gas monitoring.

2. In IGF Code, Secondary barrier means

A. none of the above
B. to prevent the lowering of the temperature of the ship’s structure to an unsafe level
C. the liquid-resisting outer element of a fuel containment system designed to afford temporary containment of any envisaged leakage of liquid fuel through the primary barrier
D. both (a) and (b)

Answer: D — both (a) and (b)

Under the IGF Code, a secondary barrier is the liquid-resisting outer element of a fuel containment system designed to afford temporary containment of any envisaged leakage of liquid fuel through the primary barrier and prevent lowering the ship's hull structure temperature to unsafe levels.

3. In IGF Code, Secondary protection means

A. the liquid-resisting outer element of a fuel containment system designed to afford temporary containment of any envisaged leakage of liquid fuel through the primary protection
B. failure of the first barrier will not lead to a hazard because of the secondary protection
C. failure of the first barrier will lead to a hazard because of the primary protection
D. the liquid-resisting outer element of a fuel containment system designed to afford temporary containment of any envisaged leakage of liquid fuel through the secondary protection

Answer: B — failure of the first barrier will not lead to a hazard because of the secondary protection

In IGF Code safety philosophy, secondary protection ensures that any failure or leakage of the primary fuel barrier will not escalate into a catastrophic hazard to the ship or personnel.

4. What concept is applied to minimize the probability of a gas explosion in a machinery space with gas- fuelled machinery ?

A. none of the above
B. both (a) and (b)
C. Emergency Shutdown-protected machinery spaces
D. Gas safe machinery spaces

Answer: B — both (a) and (b)

IGF Code chapter 5 allows two machinery space concepts for gas-fuelled machinery: gas safe machinery spaces, where all gas piping is double-walled or enclosed, and ESD-protected machinery spaces, where gas is cut off and equipment shut down on gas detection. Both are applied.

5. What is Gas safe machinery spaces?

A. both (a) and (b)
B. Arrangements in machinery spaces are such that the spaces are considered non-hazardous
C. none of the above
D. Arrangements in machinery spaces are such that the spaces are considered gas safe under all conditions, normal as well as abnormal conditions

Answer: D — Arrangements in machinery spaces are such that the spaces are considered gas safe under all conditions, normal as well as abnormal conditions

IGF Code 2.2 defines a gas safe machinery space as one where the arrangements make the space gas safe under all conditions, normal and abnormal, which means it is inherently gas safe. In practice all gas supply piping inside the space is double-walled or in a gas-tight enclosure.

6. What is Emergency Shutdown-protected machinery spaces?

A. Arrangements in machinery spaces are such that the spaces are considered gas safe under all conditions, normal as well as abnormal conditions
B. Arrangements in machinery spaces are such that the spaces are considered non-hazardous under normal conditions, but under certain abnormal conditions may have the potential to become hazardous
C. none of the above
D. both (a) and (b)

Answer: B — Arrangements in machinery spaces are such that the spaces are considered non-hazardous under normal conditions, but under certain abnormal conditions may have the potential to become hazardous

IGF Code 2.2 defines an ESD-protected machinery space as one considered non-hazardous under normal conditions but which may become hazardous under certain abnormal conditions. On gas detection the gas supply is automatically shut off and all non-certified safe electrical equipment is disconnected.

7. What will be the Gas safe machinery space failure?

A. none of the above
B. single failure may result in a gas release into the space
C. single failure cannot lead to release of fuel gas into the machinery space
D. probable maximum leakage scenario due to technical failures

Answer: C — single failure cannot lead to release of fuel gas into the machinery space

In the gas safe machinery space concept all gas piping in the space is double-walled or enclosed in a gas-tight ventilated duct, so a single failure cannot lead to release of fuel gas into the machinery space.

8. Potential dangers to be avoided include

A. exposure of ship materials to temperatures below acceptable limits
B. All the above
C. flammable fuels spreading to locations with ignition sources
D. toxicity potential

Answer: B — All the above

The IGF Code functional requirements aim to avoid flammable fuel spreading to locations with ignition sources, toxicity hazards, and exposure of ship materials to temperatures below acceptable limits. All the listed dangers are therefore to be avoided.

9. The design life of fixed liquefied gas fuel containment system __________ whichever is greater

A. both (a) and (b)
B. none of the above
C. should not be less than the design life of the ship
D. 20 years

Answer: A — both (a) and (b)

Under the IGF Code the design life of a fixed liquefied gas fuel containment system shall not be less than the design life of the ship, and not less than 20 years, whichever is greater, so both conditions apply.

10. In Liquefied gas fuel containment, The design life of portable tanks shall not be less than

A. both (a) and (b)
B. sthe design life of the ship
C. none of the above
D. 20 years

Answer: D — 20 years

The IGF Code requires the design life of portable liquefied gas fuel tanks to be not less than 20 years.

11. The design of the secondary barrier, including spray shield if fitted will be __________

A. physical, mechanical or operational events within the liquefied gas fuel tank
B. All the above
C. it is capable of containing any envisaged leakage of liquefied gas fuel for a period of 15 days
D. failure of a support or an attachment to the hull structure will not lead to loss of liquid tightness of both the primary and secondary barriers

Answer: B — All the above

IGF Code 6.4.3 requires the secondary barrier (including any spray shield) to contain any envisaged leakage for 15 days, to be unaffected by events in the tank that could cause primary barrier failure, and to ensure that failure of a support or hull attachment does not cause loss of liquid tightness of both barriers. All the listed points therefore apply.

12. The partial secondary barrier include means to detect a leak in the primary barrier, provision such as a _____________

A. spray shield to deflect any liquefied gas fuel down into the partial secondary barrier
B. none of the above
C. both (a) and (b)
D. means to dispose of the liquid which may be by natural evaporation

Answer: C — both (a) and (b)

Where a partial secondary barrier is used, it must have means to detect a leak in the primary barrier, provisions such as a spray shield to deflect liquid fuel down into the partial secondary barrier, and means to dispose of the liquid, which may be by natural evaporation. Both provisions are required.

13. What are the fundamentals to safety gas carriers?

A. All the above
B. air locks
C. segregation
D. seperation

Answer: A — All the above

Gas safety on gas carriers and gas-fuelled ships is founded on keeping gas-dangerous and gas-safe areas apart: segregation of fuel and cargo systems, separation of spaces, and air locks between hazardous and non-hazardous areas. All are fundamental.

14. In design loads, Load categories contains __________

A. All the above
B. accidental load
C. environmental load
D. permanent load

Answer: A — All the above

IGF Code 6.4.9 classifies the design loads on fuel containment systems into permanent, functional, environmental and accidental loads, so all the listed categories apply.

15. In design loads, the extent to which these loads depends on the ____________

A. type of water
B. type of tank
C. Man taking sounding
D. design engineer

Answer: B — type of tank

The IGF Code states that the extent to which the various design loads must be considered depends on the type of tank (for example Type A, B, C or membrane), as described in the tank-type specific requirements.

16. Permanent loads- Gravity loads depends on __________

A. loads caused by towers
B. weight of tank
C. All the above
D. thermal insulation weight load

Answer: C — All the above

Gravity (permanent) loads comprise the weight of the tank, its thermal insulation, and the loads caused by towers and other attachments, so all the listed items contribute.

17. Gravity loads of structures and equipment acting ____________ on the tank

A. from air
B. from bottom
C. from no where
D. externally

Answer: D — externally

In the IGF Code design of fuel tanks, permanent loads include gravity loads of the tank, its insulation and attached structures and equipment acting externally on the tank. They are taken into account with functional, environmental and accidental loads.

18. What is called Functional loads?

A. Loads arising from the operational use of the tank system
B. none of the above
C. The weight of tank, thermal insulation, loads caused by towers and other attachments
D. Gravity loads of structures and equipment acting externally on the tank

Answer: A — Loads arising from the operational use of the tank system

Under IGF Code 6.4.15, functional loads are those arising from the operational use of the tank system, such as internal pressure, thermal loads from cooling down, vapour pressure and sloshing. Permanent loads such as the tank's own weight are a separate category.

19. Permanent external loads

A. none of the above
B. Loads arising from the operational use of the tank system
C. The weight of tank, thermal insulation, loads caused by towers and other attachments
D. loads of structures and equipment acting externally on the tank

Answer: D — loads of structures and equipment acting externally on the tank

Permanent external loads are the gravity loads of structures and equipment acting externally on the tank, as distinguished from the tank's own gravity loads.

20. Gravity loads

A. The weight of tank, thermal insulation, loads caused by towers and other attachments
B. Loads arising from the operational use of the tank system
C. loads of structures and equipment acting externally on the tank
D. none of the above

Answer: A — The weight of tank, thermal insulation, loads caused by towers and other attachments

In the IGF Code, gravity loads are the weight of the tank, its thermal insulation, and the loads caused by towers and other attachments. They form part of the permanent loads.

21. In structural analysis, ___________ may be used in combination with, or instead of, theoretical calculations.

A. integrity
B. dynamic tests
C. Model tests
D. gravity tests

Answer: C — Model tests

The IGF Code allows model tests to be used in combination with, or instead of, theoretical calculations in the structural analysis of fuel containment systems, for example for sloshing loads.

22. In Load scenarios, What are the most unfavourable scenarios for all relevant phases are considered?

A. construction
B. handling
C. testing
D. All the above

Answer: D — All the above

Fuel containment structural design must evaluate the most unfavorable loading combinations across all operating phases, including bunkering, full load, sea voyage, sloshing, and emergency conditions.

23. Reliquefaction systems has to be sized in a sufficient way also in case of ____________

A. effective consumption
B. no or low consumption
C. greater consumption
D. high consumption

Answer: B — no or low consumption

Reliquefaction systems on LNG-fueled ships must be sized with sufficient redundancy to manage boil-off gas during periods of low or zero engine fuel consumption (such as port stays).

24. Thermal oxidation is done by consumption of the vapours according to the __________________.

A. regulations for ship
B. regulations for consumers
C. regulations for flag
D. regulations for cargo

Answer: B — regulations for consumers

Thermal oxidation of excess boil-off gas is carried out using Gas Combustion Units (GCU) or auxiliary boilers in compliance with environmental and consumer regulations.

25. Insulation spaces is provided to monitor the _______________

A. the quantity of fuel being supplied to individual spaces
B. the quantity of gas being supplied to individual spaces
C. the quantity of liquid being supplied to individual spaces
D. the quantity of vapour being supplied to individual spaces

Answer: B — the quantity of gas being supplied to individual spaces

The IGF Code requires that where insulation spaces are continually supplied with inert gas as part of a leak detection system, means are provided to monitor the quantity of gas supplied to individual spaces. An unusual increase in supply indicates a leak.

26. In Gravity tank, what is the design pressure?

A. greater than 0.07 MPa gauge at the bottom of the tank
B. not greater than 0.07 MPa gauge at the bottom of the tank
C. not greater than 0.07 MPa gauge at the top of the tank
D. greater than 0.07 MPa gauge at the top of the tank

Answer: C — not greater than 0.07 MPa gauge at the top of the tank

Gravity tanks used for fuel storage have a maximum design vapor pressure not exceeding 0.07 MPa (0.7 bar) gauge measured at the top of the tank.

27. What will be covered by cofferdams acting as secondary barriers?

A. Tanks for high-flashpoint liquids
B. Tanks for high-flashpoint oils
C. Tanks for low-flashpoint liquids
D. Tanks for water

Answer: C — Tanks for low-flashpoint liquids

Tanks containing low-flashpoint liquid fuels require surrounding cofferdams or void spaces acting as secondary barriers to isolate them from adjacent compartments.

28. How is cofferdam arranged?

A. With gas detection and no possibility for water filling upon detection of leakage
B. With gas detection and possibility for water filling upon detection of leakage
C. With no gas detection and possibility for water filling upon detection of leakage
D. With no gas detection and no possibility for water filling upon detection of leakage

Answer: B — With gas detection and possibility for water filling upon detection of leakage

Cofferdams surrounding fuel tanks are fitted with continuous gas detection systems and arrangements for emergency water filling or inert gas purging upon detecting fuel leaks.

29. How will be the access to tanks and cofferdams?

A. be indirect from closed deck
B. be indirect from open deck
C. be direct from closed deck
D. be direct from open deck

Answer: D — be direct from open deck

Direct access to fuel tanks and surrounding cofferdams should be provided directly from open weather decks to avoid passing through enclosed accommodation or service spaces.

30. What is the minimum clear opening of hatches or manholes?

A. no less than 600 by 600 mm
B. none of the above
C. no greater than 800 by 800 mm
D. no less than 6000by 800 mm

Answer: A — no less than 600 by 600 mm

The IGF Code specifies that access hatches and manholes into fuel storage holds and void spaces must have a minimum clear opening of not less than 600 mm by 600 mm.

Set 2 — 30 AIGF exit exam questions with answers

1. What is the minimum clear opening of horizontal openings?

A. no greater than 500 by 500 mm
B. no greater than 600 by 600 mm
C. no less than 600 by 600 mm
D. no less than 500 by 500 mm

Answer: C — no less than 600 by 600 mm

The minimum clear opening of horizontal access openings into fuel hold spaces and tank connection spaces under the IGF Code is not less than 600 mm by 600 mm.

2. What is the minimum clear opening of hatches or manholes through the length and breadth of the space?

A. less than 600 mm by 800 mm at the height of more than 600 mm from the bottom
B. not less than 600 mm by 800 mm at the height of not more than 600 mm from the bottom
C. not less than 600 mm by 800 mm at the height of more than 600 mm from the bottom
D. less than 600 mm by 800 mm at the height of not more than 600 mm from the bottom

Answer: B — not less than 600 mm by 800 mm at the height of not more than 600 mm from the bottom

For vertical access through the length and breadth of hold spaces, manholes must provide a minimum clear opening of not less than 600 mm by 800 mm at a sill height of not more than 600 mm.

3. In pump room, what are the basic things present?

A. continuous gas detection
B. both (a) and (b)
C. ventilation of the space
D. none of the above

Answer: B — both (a) and (b)

Spaces containing fuel pumps and compressors (pump rooms or fuel preparation rooms) must have continuous gas detection and effective mechanical ventilation of the space, so both are basic provisions.

4. Pressure relief systems is for which type of fuel tanks?

A. both (a) and (b)
B. high-flashpoint liquid fuel tanks
C. none of the above
D. low-flashpoint liquid fuel tanks

Answer: D — low-flashpoint liquid fuel tanks

Pressure relief systems are mandatory for all low-flashpoint liquid and compressed gas fuel tanks to prevent overpressurization exceeding design limits.

5. What test is for Type A independent tanks?

A. hydropneumatic test
B. hydrostatic test
C. both (a) and (b)
D. hydrodynamic test

Answer: C — both (a) and (b)

Type A independent tanks are tested by a hydrostatic or hydropneumatic test to verify their strength and tightness, so both are acceptable test methods.

6. For Type B tanks, the maximum primary membrane stress under test conditions of the yield will not _____________

A. exceed 90%
B. exceed 50%
C. not exceed 90%
D. not exceed 50%

Answer: A — exceed 90%

IGC/IGF Type B tank criteria: under test conditions the primary membrane stress shall not exceed 90% of yield. Read with the stem 'will not ___', the answer is 'exceed 90%'.

7. For Type B tanks, the maximum primary maximum bending stress under test conditions of the yield will not _____________

A. exceed 50%
B. not exceed 50%
C. not exceed 90%
D. exceed 90%

Answer: A — exceed 50%

For Type B independent tanks, the maximum primary bending stress under test conditions must not exceed 50% of the material yield strength.

8. For Type C tanks, What is the pressure vessel to a hydrostatic test at a pressure measured at the top of the tanks ?

A. not less than 1.5 Po
B. not greater than 2.5 Po
C. less than 1.5 Po
D. greater than 2.5 Po

Answer: A — not less than 1.5 Po

Type C independent pressure vessel tanks must undergo a hydrostatic pressure test at a pressure not less than 1.5 times the maximum design vapor pressure (1.5 Po).

9. What is the temperature of the water used for the test above the nilductility transition temperature of the material?

A. below 30°C
B. equal to 30°C
C. above 30°C
D. at least 30°C

Answer: D — at least 30°C

Water used for hydrostatic pressure testing of cryogenic tank materials must have a temperature of at least 30°C above the nil-ductility transition (NDT) temperature of the steel to prevent brittle fracture.

10. In Non destructive testing, What is the design temperatures?

A. colder than –500°C
B. colder than –200°C
C. colder than –10°C
D. colder than –300°C

Answer: C — colder than –10°C

Non-destructive testing (NDT) and impact toughness testing are mandatory for materials operating at design temperatures colder than -10°C.

11. During test, what is tested in valves?

A. operation of the valve
B. colour of the valve
C. length of the valve
D. width of the valve

Answer: A — operation of the valve

During factory and pre-commissioning testing of cryogenic valves, functional operation, seat tightness, and pressure containment are verified under operating temperatures.

12. Which type of test covers the fracture acceptable after a 180° bend?

A. Bend tests
B. Charpy V-notch impact tests
C. All of the above
D. Tensile tests

Answer: A — Bend tests

Bend tests of welded joints verify ductility and root soundness, requiring that no fracture or crack develops after undergoing a standard 180° guided bend.

13. What IS prevented in good mechanical strength?

A. prevent damage
B. none of the above
C. harmful
D. thermal expansion

Answer: A — prevent damage

Piping systems require adequate constructive mechanical strength and support to prevent mechanical damage, vibration fatigue, and structural deformation.

14. Mechanical strength is impracticable or would cause ________

A. lower local stresses
B. none of the above
C. excessive local stresses
D. no stress

Answer: C — excessive local stresses

Where excessive rigid piping supports would induce unacceptable thermal contraction stresses, flexible loops or expansion bellows are incorporated.

15. In allowable loads, liquid pressure surge during transfer operations cause

A. superimposed dead loads
B. live loads
C. superdead loads
D. superimposed loads

Answer: D — superimposed loads

Allowable piping loads account for superimposed forces, thermal contraction, and hydraulic pressure surges (water hammer) during rapid valve closure.

16. High pressure gas piping systems have ____________

A. sufficient destructive strength
B. sufficient constructive strength
C. insufficient constructive strength
D. insufficient destructive strength

Answer: B — sufficient constructive strength

High-pressure gas fuel piping systems (operating above 10 bar) must possess sufficient constructive strength and verified wall thickness to withstand extreme operating pressures.

17. High pressure gas piping systems are confirmed by carrying out stress analysis of

A. destresses due to the length of the piping system
B. stresses due to the length of the piping system
C. destresse due to the weight of the piping system
D. stresses due to the weight of the piping system

Answer: D — stresses due to the weight of the piping system

High-pressure gas piping stress analysis verifies that combined stresses resulting from internal pressure, thermal expansion, dynamic ship motions, and piping self-weight remain within permissible limits.

18. In allowable stress, When the design temperature is _________ a complete stress analysis all the stresses happens.

A. plus 1100 C
B. minus 2200 C
C. minus 110 C
D. plus 220 C

Answer: C — minus 110 C

For cryogenic fuel piping with design temperatures colder than -110°C, a comprehensive computerized thermal stress and flexibility analysis is required.

19. The arrangement and installation of gas piping provides the necessary flexibility to maintain the _________

A. abstinence of the piping system
B. division of the piping system
C. integrity of the piping system
D. cutting of the piping system

Answer: C — integrity of the piping system

Piping installation must provide sufficient flexibility through pipe bends, loops, and bellows to absorb thermal movements and preserve piping structural integrity.

20. _______________ comply with a standard acceptable to the Administration, taking into account the design pressure.

A. tubes
B. All of the above
C. Flanges
D. pipes

Answer: B — All of the above

The IGF Code requires pipes, tubes, flanges and other piping components to comply with a standard acceptable to the Administration, taking into account the design pressure. All the listed items are covered.

21. In Piping fabrication, for bellows and expansion joints used in vapour service, a ____________ than defined in is accepted.

A. lower minimum design pressure
B. higher minimum design pressure
C. higher maximum design pressure
D. lower maximum design pressure

Answer: A — lower minimum design pressure

For bellows and expansion joints in low-pressure vapor service, a lower minimum design pressure may be accepted where protected by upstream relief devices.

22. In Piping fabrication, All valves and expansion joints used in ____________

A. high pressure gas systems
B. low pressure gas systems
C. low pressure pipe system
D. high pressure pipe system

Answer: A — high pressure gas systems

All valves, expansion joints, and fittings used in high-pressure gas fuel systems must be type-approved by the Administration for the intended pressure and temperature.

23. In Piping fabrication, The piping system shall be joined by welding with a ____________

A. maximum of tanks connections
B. maximum of flange connections
C. minimum of tanks connections
D. minimum of flange connections

Answer: D — minimum of flange connections

Gas fuel piping systems must be joined primarily by butt welding with a minimum number of flanged connections to reduce potential leak paths.

24. In Piping fabrication, Gaskets shall be protected against ____________

A. mild occurance
B. light
C. blow-out
D. All of the above

Answer: C — blow-out

Flange gaskets in gas fuel piping must be constructed of blowout-proof spiral-wound metallic or composite materials to prevent catastrophic gasket failure.

25. In Piping fabrication, ____________ are protected against blow-out.

A. nut
B. liner
C. seal
D. Gaskets

Answer: D — Gaskets

Gaskets in cryogenic and pressurized gas fuel service must be protected against blowout by tongue-and-groove or raised-face spigot flange construction.

26. Piping fabrication and joining details shall comply with ___________

A. parallel connections
B. Indirect connections
C. Direct connections
D. Diverted connections

Answer: C — Direct connections

Direct piping connections and fabrication details must strictly comply with recognized classification society rules and IGF Code standards.

27. In Expansion joints of Piping fabrication, Where bellows and expansion joints are provided in accordance with _____________

A. bellows shall be protected against icing
B. bellows are removed
C. bellows are disconnected
D. bellows shall be unprotected against icing

Answer: A — bellows shall be protected against icing

Where expansion bellows are installed in open deck piping, they must be protected by external sheaths to prevent icing and physical damage.

28. In Expansion joints of Piping fabrication, In other connections,___________ is joined in accordance but for other exceptional cases the Administration or its Recognized Organization may consider alternative arrangements.

A. Piping connections
B. presssure gauge
C. steel joints
D. temperature meter

Answer: A — Piping connections

Piping connections must be fabricated in accordance with approved welding procedures; alternative mechanical joints require special consideration by the Administration.

29. In Direct connections of Piping fabrication, ____________ with complete penetration at the root may be used in all applications

A. lap joints
B. corner joints
C. U-groove weld
D. Butt-welded joints

Answer: D — Butt-welded joints

Full-penetration butt-welded joints with 100% root penetration are approved and preferred for all fuel piping applications.

30. In Direct connections of Piping fabrication, For design temperatures colder than__________ butt welds will be either double welded or equivalent to a double welded butt joint.

A. plus 5000°C
B. minus 10°C
C. plus 100°C
D. minus 500°C

Answer: B — minus 10°C

For design temperatures colder than -10°C, butt welds must be double-welded or equivalent full-penetration welds subject to 100% volumetric non-destructive testing.

Set 3 — 30 AIGF exit exam questions with answers

1. In Piping fabrication, For design pressures in ______________ and design temperatures of minus 10°C or colder, backing rings will be removed.

A. 30 bar
B. 20 bar
C. 10 bar
D. 40 bar

Answer: C — 10 bar

In piping fabrication, for design pressures exceeding 10 bar and design temperatures of -10°C or colder, backing rings must be completely removed to prevent stress concentrations.

2. In Piping fabrication, For design pressures in 10 bar and design temperatures of ___________, backing rings will be removed.

A. minus 5°C
B. plus 10°C
C. minus 10°C
D. plus 5°C

Answer: C — minus 10°C

Backing rings must be removed from fuel piping butt welds when design pressures reach 10 bar and temperatures are -10°C or colder to eliminate root crevices and fatigue notches.

3. In Direct connections of Piping fabrication, ____________ with sleeves and related welding, having dimensions in accordance with recognized standards

A. socket welded joints
B. U- welded joints
C. T - welded joints
D. Slip-on welded joints

Answer: D — Slip-on welded joints

Slip-on welded sleeve joints must have standardized dimensions and are restricted to low-temperature or low-pressure auxiliary lines.

4. In Direct connections of Piping fabrication, Slip-on welded joints are only be used for instrument lines and open-ended lines with an ___________

A. internal diameter of 50 mm or more
B. external diameter of 50 mm or more
C. external diameter of 50 mm or less
D. internal diameter of 50 mm or less

Answer: C — external diameter of 50 mm or less

Slip-on welded joints are only permitted for open-ended lines and instrumentation lines having an external diameter of 50 mm or less.

5. In Direct connections of Piping fabrication, Slip-on welded joints are only be used for instrument lines and design temperatures not colder than _______________

A. minus 1000°C
B. minus 55°C
C. plus 55°C
D. minus 5000°C

Answer: B — minus 55°C

Slip-on welded joints are restricted to auxiliary piping systems with design temperatures not colder than -55°C.

6. In Direct connections of Piping fabrication, ____________ used for accessory lines and instrumentation lines with external diameters of 25 mm or less.

A. threaded coupling
B. All of the above
C. glued coupling
D. Screwed couplings

Answer: D — Screwed couplings

Screwed couplings are permitted only for accessory and instrumentation lines with an external diameter of 25 mm or less.

7. In Direct connections of Piping fabrication, Screwed couplings used for accessory lines and instrumentation lines with _______________

A. internal diameters of 25 mm or less
B. internal diameters of 25 mm or more
C. external diameters of 25 mm or less
D. external diameters of 25 mm or more

Answer: C — external diameters of 25 mm or less

Under IGF Code piping rules, threaded screwed fittings are limited to small-bore instrumentation and sampling lines of 25 mm OD or less.

8. In Direct connections of Flanged connections, Flanges in flange connections will be of ____________

A. t-welded type
B. slip-on or socket welded type
C. U welded type
D. butt welded type

Answer: B — slip-on or socket welded type

Flanged connections in fuel piping systems are generally restricted to welding neck, slip-on, or socket welded types approved for cryogenic service.

9. In Direct connections of Flanged connections, For all piping except open ended, what restrictions is applied?

A. For design temperatures colder than minus 55°C, only welded slip on flanges shall be used
B. For design temperatures colder than minus 55°C, only welded threaded flanges shall be used
C. For design temperatures colder than minus 55°C, only welded neck flanges shall be used
D. For design temperatures colder than minus 55°C, only welded lap flanges shall be used

Answer: C — For design temperatures colder than minus 55°C, only welded neck flanges shall be used

For design temperatures colder than -55°C, only approved welding neck flanges with full penetration butt welds are permitted on fuel piping.

10. In Direct connections of Flanged connections, For all piping except open ended, For design temperatures ___________ only welded neck flanges shall be used.

A. colder than minus 4400°C
B. colder than minus 55°C
C. colder than minus 3400°C
D. colder than minus 1000°C

Answer: B — colder than minus 55°C

Welding neck flanges are mandatory for all pressurized cryogenic fuel piping operating at temperatures colder than -55°C.

11. In Direct connections of Flanged connections, For design temperatures ____________ slip-on flanges shall not be used in nominal sizes above 100 mm

A. colder than minus 30°C
B. colder than minus 150°C
C. colder than minus 20°C
D. colder than minus 10°C

Answer: D — colder than minus 10°C

Slip-on flanges must not be used for nominal pipe sizes exceeding 100 mm when design temperatures are colder than -10°C.

12. In Direct connections of Flanged connections, For design temperatures colder than minus 10°C slip-on flanges will not be used in nominal sizes _________

A. above 10 mm
B. above 100 mm
C. above 250 mm
D. above 500 mm

Answer: B — above 100 mm

For temperatures colder than -10°C, slip-on flanges are prohibited for nominal pipe sizes above 100 mm due to thermal stress and bending limitations.

13. In Direct connections of Flanged connections, welded flanges shall not be used in nominal sizes _______________

A. below 50 mm
B. below 25 mm
C. above 25 mm
D. above 50 mm

Answer: D — above 50 mm

Socket welded flanges are prohibited on cryogenic gas piping for nominal pipe diameters above 50 mm.

14. Deep well pump is the type of ____________ cargo pump found on gas carriers.

A. diaphragm
B. reciprocating
C. centrifugal
D. gear

Answer: C — centrifugal

Deep-well pumps used on liquefied gas carriers and fuel tanks are vertical multi-stage centrifugal pumps submerged at the bottom of the tank.

15. In Deep well pump, the prime mover is usually an ________

A. hydraulic motor
B. none of the above
C. electric motor
D. both (a) and (b)

Answer: D — both (a) and (b)

The prime mover of a deep-well cargo pump is an explosion-proof electric motor or hydraulic motor mounted externally on top of the tank dome.

16. In Deep well pump, the motor is usually mounted on the top of the ________________

A. drives via long transmission shaft
B. none of the above
C. cargo tanks
D. both (a) and (b)

Answer: C — cargo tanks

A deepwell pump's electric/hydraulic motor is mounted on top of the cargo tank and drives the submerged impeller through a long transmission shaft. 'Cargo tanks' fills the blank; the shaft option does not fit grammatically.

17. In Deep well pump, the motor is usually mounted on the top of the cargo tanks and drives via ________

A. long transmission shaft
B. the pump assembly located in the bottom of the tank
C. through a double seal arrangement
D. All of the above

Answer: D — All of the above

The electric or hydraulic motor on top of the tank drives the submerged impeller stack at the bottom of the tank via an elongated vertical shaft enclosed in the discharge column.

18. In deep well pump, the cargo discharge pipeline surrounds the drive shaft and also it __________

A. heats up the bearings
B. the shaft bearings are cooled
C. both answer b and c
D. lubricated by the liquid being pumped

Answer: C — both answer b and c

In deep-well pump design, the discharge column pipe surrounds the central drive shaft and utilizes the pumped cargo liquid for lubricating the shaft intermediate bearings.

19. What is the mandatory design feature for fuel piping containing LNG on ships subject to IGF Code?

A. Double-walled piping with inert gas purging or ventilation in inter-barrier space
B. Single wall heavy duty schedule 160 steel
C. Plastic lined copper piping
D. Flexible rubber hose with steel braid

Answer: A — Double-walled piping with inert gas purging or ventilation in inter-barrier space

IGF Code mandates double-walled piping to prevent gas leakage into enclosed ship spaces.

20. Under the IGF Code, at what concentration of the lower flammable limit (LFL) does gas detection in gas fuel ducts and ESD-protected machinery spaces initiate automatic shutdown of the gas fuel supply?

A. 100% LFL
B. 50% LFL
C. 40% LFL
D. 5% LFL

Answer: C — 40% LFL

The IGF Code requires an alarm at 20% LFL and automatic shutdown of the gas fuel supply at 40% LFL (two detectors) in gas fuel ducts and ESD-protected machinery spaces.

21. What gas is used to inert LNG fuel tanks and supply lines prior to gas-freeing?

A. Carbon Dioxide
B. Dry Nitrogen gas
C. Argon
D. Compressed Air

Answer: B — Dry Nitrogen gas

High-purity dry Nitrogen prevents formation of explosive mixtures during inerting.

22. What type of LNG tank is self-supporting independent Type C under IGF/IGC Code?

A. Prismatic Type A tank requiring full secondary barrier
B. Membrane tank integrated into hull
C. Spherical Kvaerner-Moss tank
D. Pressure vessel tank designed for working pressure above 2 bar gauge

Answer: D — Pressure vessel tank designed for working pressure above 2 bar gauge

Type C tanks are pressure vessels that do not require a full secondary barrier.

23. What safety device protects LNG fuel tanks from overpressure during BOG accumulation?

A. Vacuum relief valve only
B. Safety relief valves vented to dedicated vent mast
C. Automatic water spray valve
D. Rupture disc discharging into engine room

Answer: B — Safety relief valves vented to dedicated vent mast

Relief valves discharge safely into atmosphere high above deck via vent masts.

24. What parameter is monitored continuously in the inter-barrier space of LNG membrane tanks?

A. Oil content and pH
B. Water level and salinity
C. Oxygen percentage only
D. Gas concentration and temperature

Answer: D — Gas concentration and temperature

Monitoring gas and temperature detects primary barrier leaks early.

25. What type of gas detector is preferred for hydrocarbon gas detection in inert atmospheres?

A. Catalytic bead detector
B. Flame ionization detector
C. Infrared (IR) gas detector
D. Electrochemical cell

Answer: C — Infrared (IR) gas detector

IR gas detectors do not require oxygen to operate accurately, unlike catalytic bead sensors.

26. What is the function of the BOG (Boil-Off Gas) compressor on LNG fueled vessels?

A. Compress boil-off gas for use as fuel in main/auxiliary engines or boilers
B. Vent gas into cargo holds
C. Condense BOG back to sea water
D. Cool engine jacket water

Answer: A — Compress boil-off gas for use as fuel in main/auxiliary engines or boilers

BOG compressors raise gas pressure to required fuel injection levels.

27. What requirement applies to electrical equipment installed in IGF fuel preparation rooms?

A. Drip-proof industrial motor
B. Non-explosion proof with warning label
C. Standard marine IP54 enclosure
D. Certified safe type (Ex-d, Ex-i, Ex-e) for Zone 1 hazardous area

Answer: D — Certified safe type (Ex-d, Ex-i, Ex-e) for Zone 1 hazardous area

Hazardous Zone 1 areas mandate certified explosion-proof electrical equipment.

28. What emergency procedure is required before bunkering LNG fuel from shore or barge?

A. Purge fuel tank with sea water
B. Start main engine to load generator
C. Sign Ship-to-Shore Safety Checklist and test ESD link
D. Disable gas alarms to prevent false trips

Answer: C — Sign Ship-to-Shore Safety Checklist and test ESD link

Ship-to-Shore checklist ensures mutual safety readiness and functional emergency shutdown.

29. Regarding personal protective equipment (PPE) and safety gear in Advanced IGF Code, what is the mandatory safety standard required under STCW Code Table A-V/3-2?

A. Non-mandatory recommendation
B. Optional compliance based on crew discretion
C. Applicable only when vessel is anchored
D. Full compliance with approved STCW safety procedures and SMS protocols

Answer: D — Full compliance with approved STCW safety procedures and SMS protocols

STCW Code Section A-V/3-2 requires strict adherence to approved safety protocols for Advanced IGF Code.

30. In Liquefied Petroleum Gas, propane and butane can be shipped

A. seperately
B. none of the above
C. as a mixture
D. both (a) and (b)

Answer: D — both (a) and (b)

Propane and butane, the two main LPG components, can be shipped separately as individual products or as a mixture, so both options are correct.

Set 4 — 30 AIGF exit exam questions with answers

1. In Liquefied Petroleum Gas, __________ can be shipped seperately or as a mixture.

A. both (a) and (b)
B. none of the above
C. propane
D. butane

Answer: A — both (a) and (b)

Both propane and butane are LPG products that can be shipped separately or as a mixture, so the blank is completed by both.

2. Liquefied Petroleum Gas may be

A. refinery by-products
B. All of the above
C. may be produced in conjunction with natural gas
D. may be produced in conjunction with crude oil

Answer: B — All of the above

LPG may be produced as a refinery by-product, or recovered in conjunction with natural gas production and crude oil production, so all the listed sources apply.

3. MARVS means

A. Minimum Allowable Relief Valve Setting
B. Maximum Allowable Relief Valve Setting
C. Maximum Allowed Regional Valve Setting
D. Minimum Allotted Relief Valve Setting

Answer: B — Maximum Allowable Relief Valve Setting

MARVS means Maximum Allowable Relief Valve Setting of a fuel or cargo tank. This is the highest pressure at which the tank's pressure relief valves may be set, as defined in the IGC and IGF Codes, and it is a basis of the tank's design.

4. Maximum Allowable Relief Valve Setting on a ship's cargo tank as stated on the __________

A. refinery by-products
B. ship's Certificate of Fitness
C. free from chemical
D. production of conjunction with crude oil

Answer: B — ship's Certificate of Fitness

Under the IGC Code the MARVS of each cargo tank is stated on the ship's International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk.

5. What is MLC?

A. Multi Liquid Column
B. Meters Liquid Column
C. Meters Limit Column
D. Multi Limit Column

Answer: B — Meters Liquid Column

MLC stands for metres liquid column, a measure of pressure expressed as the height (head) of a column of liquid. It is used for pump heads in cargo pumping.

6. Meters Liquid Column is a unit of ________ used in some cargo pumping operations.

A. volume
B. pressure
C. none of the above
D. mass

Answer: B — pressure

Metres liquid column expresses pressure as the head of a column of the pumped liquid, which is why it is used for cargo pump delivery head.

7. What is Mollier diagram?

A. graphic method of representing ship route
B. graphic method of representing heat quantities of a refrigerant
C. graphic method of representing ship design
D. All of the above

Answer: B — graphic method of representing heat quantities of a refrigerant

A Mollier (pressure-enthalpy) diagram is a graphic method of representing the heat quantities (enthalpy) of a refrigerant or liquefied gas and its condition at different temperatures and pressures. It is used to analyse reliquefaction cycles.

8. In Mollier diagram, graphic method of representing heat quantities and the conditions of liquefied gas at different ____________

A. density
B. volume
C. pressure
D. temperature

Answer: D — temperature

The Mollier diagram shows the heat content and state (liquid, vapour, mixture) of a liquefied gas at different temperatures and pressures, so temperature completes the statement.

9. What re the gases associated with Natural Gas Liquid?

A. Butane
B. All of the above
C. Ethane
D. Propane

Answer: B — All of the above

Natural gas liquids are the heavier hydrocarbons separated from natural gas, mainly ethane, propane and butane (plus pentanes), so all the listed gases apply.

10. What is oxygen analyser?

A. Instrument used to measure propane concentrations in percentage by volume
B. Instrument used to measure ethane concentrations in percentage by volume
C. Instrument used to measure oxygen concentrations in percentage by volume
D. Instrument used to measure butane concentrations in percentage by volume

Answer: C — Instrument used to measure oxygen concentrations in percentage by volume

An oxygen analyser is an instrument that measures oxygen concentration as a percentage by volume. It is used to check inerting and to confirm a safe atmosphere (21% O2) before entry.

11. In oxygen analyser which gas in measured?

A. Propane
B. oxygen
C. Pentane
D. Butane

Answer: B — oxygen

Oxygen analyzers measure oxygen volumetric concentration (0-21% O2) in enclosed spaces to verify breathable conditions or inerting completeness.

12. What is oxygen deficient atmosphere?

A. atmosphere containing less than 11 percent oxygen by volume
B. atmosphere containing less than 21 percent oxygen by volume
C. atmosphere containing less than 11 percent oxygen by pressure
D. atmosphere containing less than 21 percent oxygen by pressure

Answer: B — atmosphere containing less than 21 percent oxygen by volume

An oxygen-deficient atmosphere is one containing less than the normal 21% oxygen by volume. Spaces should read 21% O2 before entry without breathing apparatus.

13. How is peroxide formed?

A. none of the above
B. chemical combination of cargo liquid with atmosphere oxygen
C. both (a) and (b)
D. chemical combination of vapour with atmosphere oxygen

Answer: C — both (a) and (b)

Peroxides are formed by the slow autoxidation of unsaturated chemical gas monomers (like 1,3-butadiene or isoprene) when exposed to atmospheric oxygen.

14. Chemical combination of cargo liquid with oxygen from other source and vapour with oxygen from other source forms __________

A. Formation of Peroxide
B. Formation of Oxygen
C. Formation of oxide
D. Formation of Ethane

Answer: A — Formation of Peroxide

Contact between reactive chemical monomers and atmospheric oxygen results in the formation of hazardous, unstable peroxides.

15. Qualities for Peroxide is

A. none of the above
B. highly reactive
C. both (a) and (b)
D. potential hazard

Answer: C — both (a) and (b)

Peroxides are highly reactive substances that can decompose violently, give off oxygen and support or start combustion. They are therefore both highly reactive and a potential hazard, and need careful segregation, temperature control and inhibitors where required.

16. In some cases, Peroxide is

A. unstable
B. both (a) and (b)
C. none of the above
D. potential hazard

Answer: B — both (a) and (b)

Certain peroxides are powerful chemical oxidizing agents capable of causing spontaneous decomposition and violent explosions.

17. How is polymer formed?

A. The chemical union of two or more molecules of the same compound to form a larger molecule of a new compound
B. The chemical union of two or more molecules of the same compound to form a smaller molecule of a new compound
C. The chemical reaction of one molecule of the same compound to form a smaller molecule of a new compound
D. The chemical reaction of one molecule of the same compound to form a larger molecule of a new compound

Answer: A — The chemical union of two or more molecules of the same compound to form a larger molecule of a new compound

Polymerization is a chemical reaction in which monomer molecules combine together to form large repeating polymer chains, releasing substantial exothermic heat.

18. What is the process for the chemical union of two or more molecules of the same compound to form a larger molecule of a new compound called?

A. Vaporization
B. Gas freeing
C. Static electricity
D. Polymerisation

Answer: D — Polymerisation

Polymerization is the chemical reaction where monomer units bond together, which if uncontrolled on ships can generate dangerous temperatures and pressures.

19. What is a Primary Barrier in liquified gas tanks?

A. seperating barrier between liquid and gas
B. Inner surface designed to contain the cargo when the cargo containment system includes a secondary barrier
C. nothing special barrier
D. chemical combination of cargo liquid with oxygen from other source

Answer: B — Inner surface designed to contain the cargo when the cargo containment system includes a secondary barrier

The primary barrier is the inner liquid-tight containment boundary designed to directly hold cryogenic cargo or fuel under normal operating conditions.

20. ___________ is a refrigerant gas?

A. B65
B. R22
C. C24
D. A22

Answer: B — R22

R22 (chlorodifluoromethane / HCFC-22) is a synthetic halogenated hydrocarbon gas historically used as an industrial refrigerant.

21. What is the full chemical name of R22?

A. monochloro difluoromethane
B. monoflouride difluoromethane
C. monochloride dimethane
D. monochloro dimethane

Answer: A — monochloro difluoromethane

R22 is chlorodifluoromethane (CHClF2), often called monochlorodifluoromethane. It is an HCFC refrigerant that is being phased out under the Montreal Protocol and MARPOL Annex VI because it depletes the ozone layer.

22. What are the characteristics of R22?

A. All of the above
B. colourless
C. non-flammable
D. odourless

Answer: A — All of the above

R22 is a non-flammable, colorless, faint-ether-odor gas with a boiling point of -40.8°C at atmospheric pressure.

23. R22 is virtually non-toxic with a _______

A. TLV of 1,000 ppm
B. TLV of 2 ppm
C. TLV of 500 ppm
D. TLV of 30 ppm

Answer: A — TLV of 1,000 ppm

R22 has a low acute toxicity profile with a standard Threshold Limit Value - Time Weighted Average (TLV-TWA) of 1,000 ppm.

24. What is relative liquid density?

A. The chemical union of two or more molecules of the same compound to form a larger molecule of a new compound
B. The mass of the gas at a given temperature compared with the mass of an equal volume of gas at the same temperature at a different given temperature
C. The mass of a liquid at a given temperature compared with the mass of an equal volume of fresh water at the same temperature at a different given temperature
D. Inner surface designed to contain the cargo when the cargo containment system includes a secondary barrier

Answer: C — The mass of a liquid at a given temperature compared with the mass of an equal volume of fresh water at the same temperature at a different given temperature

Relative liquid density is the dimensionless ratio of the mass of a liquid volume to the mass of an equal volume of pure fresh water at reference temperature.

25. What is relative vapour density?

A. Inner surface designed to contain the cargo when the cargo containment system includes a secondary barrier
B. The chemical union of two or more molecules of the same compound to form a larger molecule of a new compound
C. The mass of a liquid at a given temperature compared with the mass of an equal volume of fresh water at the same temperature at a different given temperature
D. The mass of a vapour compared with the mass of an equal volume of air, both at standard condition of temperature and pressure

Answer: D — The mass of a vapour compared with the mass of an equal volume of air, both at standard condition of temperature and pressure

Relative vapor density is the ratio of the mass of a gas volume to the mass of an equal volume of dry air at standard temperature and pressure (Air = 1.0).

26. What is restricted gauging?

A. none of the above
B. system employing a device, which penetrates the tank and which when in use permits a small quantity of cargo vapour to be expelled to the atmosphere.
C. the device is kept completely closed when the device is not in use
D. both (a) and (b)

Answer: D — both (a) and (b)

Restricted gauging uses an ullage device designed to limit the release of vapor during level measurement, such as sounding tubes with shut-off balls.

27. In restricted gauging, when the device is not in use

A. the device is kept open
B. none of the above
C. the device is kept operated
D. the device is kept completely closed

Answer: D — the device is kept completely closed

In restricted gauging arrangements, the measurement orifice is kept tightly closed when not in active use to prevent flammable vapor escape.

28. What is roll over?

A. The pressure at which a vapour is in equilibrium with its liquid at a specific temperature
B. The phenomenon where the stabilty of two stratified layers of liquid of differing relative density distributed resulting in a spomtaneous rapid mixing of the layers accompanied in the case of liquefied gases, by violent vapour evolution
C. Heat energy given to or taken from a substance which raises or lowers its temperature
D. The mass of the gas at a given temperature compared with the mass of an equal volume of gas at the same temperature at a different given temperature

Answer: B — The phenomenon where the stabilty of two stratified layers of liquid of differing relative density distributed resulting in a spomtaneous rapid mixing of the layers accompanied in the case of liquefied gases, by violent vapour evolution

Roll-over is a phenomenon in LNG storage tanks where stratification of two liquid layers of differing densities destabilizes, resulting in sudden, violent mixing and massive boil-off vapor generation.

29. What is Saturated Vapour Pressure?

A. The pressure at which a vapour is in equilibrium with its liquid at a specific temperature
B. The mass of the gas at a given temperature compared with the mass of an equal volume of gas at the same temperature at a different given temperature
C. Heat energy given to or taken from a substance which raises or lowers its temperature
D. The phenomenon where the stabilty of two stratified layers of liquid of differing relative density distributed resulting in a spomtaneous rapid mixing of the layers accompanied in the case of liquefied gases, by violent vapour evolution

Answer: A — The pressure at which a vapour is in equilibrium with its liquid at a specific temperature

Saturated Vapor Pressure is the equilibrium pressure exerted by the vapor phase above its liquid in a closed system at a specific temperature.

30. What is sensible heat?

A. The liquid resisting outer element of a cargo containment system designed to provide temporary containment of a leakage of liquid cargothrough the primary barrier
B. The phenomenon where the stabilty of two stratified layers of liquid of differing relative density distributed resulting in a spomtaneous rapid mixing of the layers accompanied in the case of liquefied gases, by violent vapour evolution
C. The pressure at which a vapour is in equilibrium with its liquid at a specific temperature
D. Heat energy given to or taken from a substance which raises or lowers its temperature

Answer: D — Heat energy given to or taken from a substance which raises or lowers its temperature

Sensible heat is thermal energy transferred to or from a substance that results in a measurable change in temperature without changing its physical phase.

Set 5 — 30 AIGF exit exam questions with answers

1. What is specific gravity?

A. The ratio of the density of a solid at a given temperature to the density ofsolid at a standard temperature
B. The ratio of the density of a liquid at a given temperature to the density of fresh water at a standard temperature
C. The ratio of the density of a molecule at a given temperature to the density of molecule at a standard temperature
D. The ratio of the density of a gas at a given temperature to the density of gas at a standard temperature

Answer: B — The ratio of the density of a liquid at a given temperature to the density of fresh water at a standard temperature

Specific gravity is the ratio of the density of a substance to the density of fresh water (1,000 kg/m³) at a specified reference temperature.

2. What is specific heat?

A. The quantity of energy in kilojoules required to change the temperature of 1 kg mass of the substance by 1 degC.
B. The ignition of material brought by a heat producing chemical reaction within the material itself without exposure to an external source ignition
C. none of the above
D. The electrical charge produced on disimilar materials caused by relative motion between each when in contact

Answer: A — The quantity of energy in kilojoules required to change the temperature of 1 kg mass of the substance by 1 degC.

Specific heat capacity is the amount of heat energy (kJ) required to raise the temperature of 1 kilogram of a substance by 1°C (or 1 Kelvin).

3. What is spontaneous combustion?

A. The electrical charge produced on disimilar materials caused by relative motion between each when in contact
B. The ignition of material brought by a heat producing chemical reaction within the material itself without exposure to an external source ignition
C. The quantity of energy in kilojoules required to change the temperature of 1 kg mass of the substance by 1 degC.
D. none of the above

Answer: B — The ignition of material brought by a heat producing chemical reaction within the material itself without exposure to an external source ignition

Spontaneous combustion is the ignition of a material resulting from internal self-heating due to slow exothermic oxidation reactions without an external spark or flame.

4. What is Static electricity ?

A. none of the above
B. The quantity of energy in kilojoules required to change the temperature of 1 kg mass of the substance by 1 degC.
C. The electrical charge produced on disimilar materials caused by relative motion between each when in contact
D. alternating current

Answer: C — The electrical charge produced on disimilar materials caused by relative motion between each when in contact

Static electricity is the accumulation of electric charge on surfaces caused by contact, separation, and relative friction of dissimilar flowing materials.

5. What is superheated vapour?

A. The density of a gas or vapour inder specified conditions of temperature and pressure
B. detecting heat of gases or vapours
C. phenomenon generated in a pipeline system where there is a change in the heat of liquid in the line
D. Vapour removed from contact with its liquid and heated beyond its boiling temperature

Answer: D — Vapour removed from contact with its liquid and heated beyond its boiling temperature

Superheated vapor is vapor heated to a temperature above its boiling saturation temperature at a given pressure.

6. What is surge pressure?

A. pressure measuring instrument used for detecting gases or vapours
B. The density of a gas or vapour inder specified conditions of temperature and pressure
C. phenomenon generated in a pipeline system where there is a change in the rate of flow of liquid in the line
D. Vapour pressureremoved from contact with its liquid and heated beyond its boiling temperature

Answer: C — phenomenon generated in a pipeline system where there is a change in the rate of flow of liquid in the line

Surge pressure (hydraulic shock / water hammer) is a rapid pressure spike generated in a pipeline when fluid velocity suddenly changes due to quick valve closure.

7. LNG as fuel, Sulphur Oxide (SOx) and particulates emissions are ---------- compared to diesel or heavy fuel oil powered vessels.

A. great
B. both a and c
C. negligible.
D. more

Answer: C — negligible.

Using LNG as marine fuel virtually eliminates sulfur oxide (SOx) and particulate matter (PM) emissions (reducing them by over 95-99%) compared to heavy fuel oil.

8. LNG reduces CO2 emissions by --------in general, compared to diesel or heavy fuel oil powered vessels.

A. 25 to 30 percent
B. 10 to 15 percent
C. negligible
D. 5 to 10 percent

Answer: A — 25 to 30 percent

LNG combustion produces approximately 20% to 25-30% lower carbon dioxide (CO2) emissions compared to conventional heavy fuel oil (HFO) due to its higher hydrogen-to-carbon ratio.

9. Engine efficiency can be increased by utilising existing turbo charger with the __________

A. All the above
B. Not rematching existing turbo charger
C. Not modifying turbo chargers to meet tyre 2 and 3 emission standards
D. latest man disel turbo charger

Answer: D — latest man disel turbo charger

Engine efficiency can be improved by retrofitting or rematching with a latest-generation high-efficiency turbocharger (such as the latest MAN Diesel units). The other options are negated and describe not doing so.

10. Basic thing for a hybrid turbo charger is

A. Does not runs at very high speed
B. an altenator is attached to a blower end
C. Doesn't requires cooling system
D. All the above

Answer: B — an altenator is attached to a blower end

A hybrid turbocharger incorporates an electric motor-generator attached to the turbocharger rotor shaft to generate electricity from excess exhaust gas energy.

11. NOX and SOX emission can be controlled by using which type of fuel

A. Heavy fuel oil
B. marine diesel oil
C. petrol
D. LNG

Answer: D — LNG

Using natural gas (LNG) as fuel enables vessels to meet IMO Tier III NOx limits in Emission Control Areas (ECAs) without requiring post-combustion SCR systems.

12. low specific fuel oil consumption at all loads can be achieved by

A. medium rating propulsion engines
B. derating a propulsion engines
C. low rating propulsion engines
D. high rating propulsion engines

Answer: B — derating a propulsion engines

Engine derating optimizes engine timing, compression ratio, and turbocharging for lower continuous service power, minimizing specific fuel oil consumption (SFOC).

13. ________ causes the changes in engine power on speed distinguishing rating for Slow steaming market

A. rerating
B. increase the rating
C. flow rating
D. derating

Answer: D — derating

Engine derating lowers maximum continuous rating (MCR) to match slower vessel operating speeds, optimizing thermal efficiency and reducing fuel consumption.

14. What is mean by hybrid turbo charging?

A. it also generates hydrogen
B. it also generates electricity
C. it also generates water
D. None of the above

Answer: B — it also generates electricity

Hybrid turbocharging uses high exhaust gas energy to drive a shaft-mounted alternator, generating shipboard electrical power and reducing auxiliary engine running hours.

15. A ____________ is attached with a hybrid turbo charger

A. pump
B. None of the above
C. motor
D. alternator

Answer: D — alternator

An alternator/motor is mounted directly onto the turbocharger shaft in a hybrid turbocharger arrangement.

16. What is the RPM of a turbo charger?

A. 6000
B. 7000
C. 9000
D. 5000

Answer: C — 9000

Marine engine turbocharger rotors operate at high rotational speeds typically ranging from 9,000 to over 20,000 RPM depending on turbocharger frame size.

17. ___________ is required for the alternator fitted with HYBRID turbo charger

A. None of the above
B. cooling system
C. circulating system
D. heating system

Answer: B — cooling system

Dedicated water or air cooling jackets are fitted to the high-speed alternator attached to a hybrid turbocharger to dissipate electrical heat.

18. In addition to fuel savings WHRS gives

A. large CO2 reduction
B. All of the above
C. large NOX reduction
D. large sox reduction

Answer: B — All of the above

A waste heat recovery system turns exhaust energy into electrical or steam power, so less fuel is burned in generators and boilers. The fuel saving brings a proportional reduction in CO2, NOx and SOx emissions.

19. Waste heat recovery system pay back time is _________

A. medium
B. None of the above
C. short
D. long

Answer: C — short

Due to high marine fuel savings, modern marine Waste Heat Recovery Systems have relatively short economic payback periods on large container ships and tankers.

20. _________ on the hull is done to increase the vessel hydrodynamic performance

A. removal of paints on the hull
B. addition of water on the hull
C. addition of oil on the hull
D. removal of fouling on the hull

Answer: D — removal of fouling on the hull

Regular removal of biofouling and application of low-friction silicone hull coatings significantly reduces hydrodynamic drag and ship resistance.

21. Derating is an engine for reduction of the vessels maximum speed to increase the efficiency by limiting the __________

A. potential power output
B. None of the above
C. kinetic power output
D. total output

Answer: A — potential power output

Derating an engine reduces maximum service power output and matches turbocharging and injection timing to optimal lower load profiles for maximum fuel efficiency.

22. Derating is an engine for ________ of the vessels maximum speed to increase the efficiency by limiting the potential power output

A. reduction
B. increase
C. production
D. addition

Answer: A — reduction

Derating limits the potential maximum power output of the propulsion engine to operate at peak thermodynamic efficiency during slow steaming.

23. Derating is an engine for reduction of the vessels _______ speed to increase the efficiency by limiting the potential power output

A. normal
B. minimum
C. None of the above
D. maximum

Answer: D — maximum

Derating lowers the engine's maximum continuous rating, and with it the ship's maximum speed. Running nearer the optimum point improves SFOC.

24. What is meant by engine performance optimization?

A. automatic increase of engine efficiency
B. mechanical increase of engine efficiency
C. non automatic increase of engine efficiency
D. manual increase of engine efficiency

Answer: A — automatic increase of engine efficiency

Engine performance optimization automatically adjusts fuel injection timing, exhaust valve timing, and scavenge air pressure to maintain peak firing pressures across all loads.

25. ______ requires thermal energy from the exhaust gas and convert it into electrical energy

A. None of the above
B. recirculation recovery system
C. manual heat recovery system
D. waste heat recovery system

Answer: D — waste heat recovery system

Waste Heat Recovery Systems (WHRS) utilize exhaust gas economizers, steam turbines, and power turbines to convert waste thermal energy into electrical power.

26. Waste heat recovery system requires _______ energy from the exhaust gas and convert it into electrical energy

A. kinetic
B. potential
C. thermal
D. dynamic

Answer: C — thermal

WHRS extracts residual thermal energy from high-temperature engine exhaust gases to drive a steam turbine-generator set.

27. Waste heat recovery system requires thermal energy from the _______ gas and convert it into electrical energy

A. inert
B. exhaust
C. energise
D. None of the above

Answer: B — exhaust

Main engine exhaust gas holds significant waste thermal energy that can be recovered by combined steam and gas turbine systems.

28. Turbo charger refitting increases efficieny and reduce emissions of _______ engine

A. main
B. side
C. left
D. right

Answer: A — main

Retrofitting advanced turbochargers on main propulsion engines optimizes scavenge air mass flow, improves combustion efficiency, and lowers emissions.

29. Turbo charger refitting _______ efficieny and reduce emissions of main engine

A. balance
B. equalize
C. decrease
D. increases

Answer: D — increases

Turbocharger upgrading increases engine thermodynamic efficiency and lowers specific emissions across intermediate engine load ranges.

30. Upgrading Turbo charger to ________ will increase efficiency

A. VTA technology
B. ATV technology
C. to A technology
D. Vat tehnology

Answer: A — VTA technology

Variable Turbine Area (VTA) technology incorporates adjustable nozzle vanes to optimize exhaust gas velocity and scavenge air pressure at all engine loads.

Set 6 — 30 AIGF exit exam questions with answers

1. Upgrading _______ to VTA technology will increase efficiency

A. exhaust boiler
B. None of the above
C. propulsion shaft
D. Turbo charger

Answer: D — Turbo charger

Upgrading standard turbochargers with Variable Turbine Area (VTA) technology optimizes scavenge pressure and enhances low-load combustion efficiency.

2. Upgrading Turbo charger to VTA technology will _______ efficiency

A. equalize
B. decrease
C. increase
D. balance

Answer: C — increase

VTA turbochargers increase part-load fuel efficiency and engine responsiveness by adjusting nozzle blade angles to match exhaust mass flow.

3. _______ efficiency can be increased by utilising existing turbo charger with the latest man disel turbo charger

A. Motor
B. propeller
C. Engine
D. All the above

Answer: C — Engine

Propulsion engine efficiency is maximized by matching modern turbocharging systems with optimized fuel injection and electronic valve control.

4. What is mean by jet assist systems?

A. None of the above
B. giving compressed air from an external source to aid compresser will acceleration in turbo chargers
C. to give compressed air service to auxiliary engines
D. to give compressed air supply for cleaning sewage treatment plant

Answer: B — giving compressed air from an external source to aid compresser will acceleration in turbo chargers

Jet assist systems inject compressed air into the turbocharger compressor casing to accelerate the rotor and eliminate turbo lag during rapid engine acceleration.

5. LNG engines reduces CO2 emission by how much ?

A. 15-20%
B. 45-50%
C. 25-30%
D. 35-40%

Answer: C — 25-30%

Natural gas fueled dual-fuel engines achieve a 20% to 25-30% reduction in carbon dioxide (CO2) emissions compared to standard heavy fuel oil.

6. LNG has fuel reduces Nox emission by about

A. 90%
B. 100%
C. 91%
D. 92%

Answer: A — 90%

Low-pressure dual-fuel gas engines (Otto cycle) reduce nitrogen oxide (NOx) emissions by up to 85-90%, complying inherently with IMO Tier III limits.

7. LNG has fuel reduces sox emission by about

A. 92%
B. 91%
C. 90%
D. almost negligible

Answer: D — almost negligible

Because natural gas contains virtually no sulfur, SOx emissions from LNG-fueled engines are almost zero (negligible).

8. Advantages of VTA turbo charger

A. an alternator is attached to a blower end
B. reduces the fuel consumption
C. to eliminates the need for auxiliary blower
D. All the above

Answer: B — reduces the fuel consumption

A VTA (Variable Turbine Area) turbocharger has an adjustable nozzle ring that matches turbine area to engine load. This raises scavenge air pressure at part load and improves combustion, which mainly reduces specific fuel oil consumption and also smoke and emissions in low-load operation.

9. Turbo charger works efficiently in _________

A. entire load of the engine
B. start of the engine
C. None of the above
D. partial load of the engine

Answer: A — entire load of the engine

Modern turbochargers are designed to operate efficiently across the entire engine load envelope from idle to 100% MCR.

10. The low pressure XDF tecnhnology concept is based on the __________

A. exhaust gas principle
B. None of the above
C. sewage plant principle
D. lean burn principle

Answer: D — lean burn principle

WinGD low-pressure X-DF dual-fuel engines operate on the lean-burn Otto cycle, premixing low-pressure gas with scavenge air before pilot fuel ignition.

11. XDF engine provide which benefit

A. low pressure gas supply
B. pilot fuel quantity below 1%
C. All the above
D. DF engine can be operated on gas from ideal

Answer: C — All the above

Low-pressure X-DF technology offers IMO Tier III compliance without exhaust gas aftertreatment, lower gas supply pressure (<16 bar), and reduced capital costs.

12. _______ engine provide pilot fuel quantity below 1%

A. YDF
B. XTF
C. GDF
D. XDF

Answer: D — XDF

WinGD X-DF engines require very small amounts of pilot diesel fuel (less than 1% of total energy at high loads) to ignite the lean gas-air mixture.

13. Particulate matters emissions reduced to almost zero in which technology

A. high pressure XDF
B. low pressure YDF
C. low pressure XDF
D. high pressure YDF

Answer: C — low pressure XDF

Particulate matter (PM) and soot emissions are reduced to near zero in low-pressure lean-burn gas engines due to clean methane combustion.

14. Which type of engine does not need exhaust gas treatment system

A. GDF engines
B. ZDF engines
C. XDF engines
D. YDF engines

Answer: C — XDF engines

Low-pressure dual-fuel Otto cycle engines meet IMO Tier III NOx limits in gas mode without needing Selective Catalytic Reduction (SCR) or Exhaust Gas Recirculation (EGR).

15. What are the advantages of Mr. diesel process man engine

A. All the above
B. diesel process maintain
C. load response unchanged
D. low preignition or no knocking

Answer: A — All the above

MAN ME-GI engines utilize high-pressure gas injection on the Diesel cycle, delivering high thermal efficiency, zero knock risk, and minimal methane slip.

16. Mr otto process LNG engine has got following advantage

A. All the above
B. reduction in nox emissions
C. low pressure gas injection
D. gas mixture is important

Answer: A — All the above

Otto-cycle low-pressure gas engines operate with low gas supply pressures (<10-16 bar), simpler fuel gas supply systems, and low Tier III NOx emissions.

17. Derating of the propulsion engine can be achieved by

A. All the above
B. modifying fuel valves
C. simming between crosscuts and piston rods
D. rematching the turbo chargers

Answer: A — All the above

Engine derating can be achieved by installing smaller turbocharger nozzle rings, adjusting fuel injection profiles, and modifying electronic control parameters.

18. Disadvantage of rerating a engine is

A. this may require additional denox measures
B. increased specific fuel oil consumption
C. this may require additional sox measures
D. None of the above

Answer: A — this may require additional denox measures

Rerating or modifying engine combustion for higher maximum pressure without proper tuning may elevate peak combustion temperatures, potentially increasing NOx formation.

19. Disadvantage of hybrid turbo charger is

A. doesn’t require lubrication
B. heat generated is less
C. doesn’t require cooling
D. heat generated is more

Answer: D — heat generated is more

Disadvantages of hybrid turbochargers include increased mechanical complexity, additional electrical cooling requirements, and higher capital expense.

20. Advantage of hybrid turbo charger is

A. it recovers cold energy
B. it is doing nothing
C. it decreses the power of the main engine
D. it recovers hot energy

Answer: D — it recovers hot energy

The main advantage of a hybrid turbocharger is the recovery of waste exhaust energy to generate electrical power, reducing auxiliary diesel generator fuel consumption.

21. Hybrid turbo charger is useful in __________

A. None of the above
B. cutting down garbage from the ship
C. cutting down emission from the ship
D. cutting down sewage from the ship

Answer: C — cutting down emission from the ship

A hybrid turbocharger uses surplus exhaust energy to drive an alternator, reducing the running of auxiliary diesel generators. Less fuel is burned, cutting the ship's exhaust emissions.

22. In Requirements for internal combustion engines of Piston type, gas can leak ___________ into the auxiliary system medium

A. invariably
B. indirectly
C. differently
D. directly

Answer: D — directly

IGF Code 10.3 notes that in piston-type gas engines, gas can leak directly into auxiliary system media such as lubricating oil, cooling water or the crankcase. For this reason these systems need gas detection and venting arrangements.

23. In Requirements for internal combustion engines of Piston type, gas can leak directly into the ______________

A. main system medium
B. secondary system medium
C. primary system medium
D. auxiliary system medium

Answer: D — auxiliary system medium

IGF Code 10.3 notes that in piston-type gas engines gas can leak directly into the auxiliary system medium, such as lubricating oil or cooling water. Such systems therefore need means to extract and vent the gas.

24. In Requirements for internal combustion engines of Piston type, the gas extracted from ____________are vented to a safe location in the atmosphere.

A. secondary systems media
B. main systems media
C. primary systems media
D. auxiliary systems media

Answer: D — auxiliary systems media

Where gas can leak into auxiliary system media such as lube oil or cooling water in piston engines, IGF Code 10.3 requires the gas extracted from these media to be vented to a safe location in the open air. This prevents a flammable atmosphere building up in the machinery space.

25. In Requirements for internal combustion engines of Piston type, the crankcase of a trunk piston type engines are fitted with a means of ______________

A. automatically injecting inert gas
B. manually injecting inert gas
C. manually forcing inert gas
D. automatically forcing inert gas

Answer: B — manually injecting inert gas

For trunk piston engines, where gas may accumulate in the crankcase, the course material states that the crankcase is fitted with a means of manually injecting inert gas so that a hazardous atmosphere can be inerted before it can ignite.

26. In Requirements for internal combustion engines of Piston type, if combustion has not been detected by the engine monitoring system within an engine specific time after the opening of the fuel supply valve, the ____________________-

A. fuel supply valve shall be automatically shut off
B. fuel supply valve shall be manually switched on
C. fuel supply valve shall be manually shut off
D. fuel supply valve shall be automatically switched on

Answer: A — fuel supply valve shall be automatically shut off

Under IGF Code 10.3, if the engine monitoring system does not detect combustion within an engine-specific time after the fuel supply valve opens, the fuel supply valve must close automatically and the start sequence ends. This stops unburnt gas collecting in the engine and exhaust.

27. In case of shut-off of the gas fuel supply, the engines are capable of continuous operation by ________ only without interruption

A. oil fuel
B. gas fuel
C. oxygen fuel
D. vapour fuel

Answer: A — oil fuel

IGF Code 10.3 requires dual-fuel engines to be able to continue operating on oil fuel alone, without interruption, if the gas fuel supply is shut off.

28. An automatic system shall be fitted to change over from __________

A. oil fuel operation to oil fuel operation
B. oil fuel operation to gas fuel operation
C. vapour fuel operation to oil fuel operation
D. gas fuel operation to oil fuel operation

Answer: D — gas fuel operation to oil fuel operation

The IGF Code requires an automatic system to change over from gas fuel operation to oil fuel operation, and vice versa, with minimum fluctuation of engine power.

29. In the case of unstable operation on engines when gas firing, the engine shall automatically change to ______________

A. gas fuel mode
B. fuel mode
C. oil fuel mode
D. vapour fuel mode

Answer: C — oil fuel mode

If an engine runs unstably while gas firing, the IGF Code requires it to change over automatically to oil fuel mode so that power is kept and unburnt gas does not accumulate.

30. A ship, irrespective of the date of construction, which is converted to __________ for main or auxiliary machinery on or after date of entry into force shall comply with IGF Code

A. dual fuel
B. multi fuel
C. consume gas
D. All the above

Answer: D — All the above

Under SOLAS II-1/56 and the IGF Code, a ship of any construction date that is converted on or after the entry-into-force date to use gas or other low-flashpoint fuels, whether dual fuel, multi fuel or gas only, must comply with the IGF Code.

Set 7 — 30 AIGF exit exam questions with answers

1. How shall a ship be converted to __________ for main machinery after date of entry into force shall comply with IGF Code?

A. All the above
B. low-flashpoint fuel
C. consume gas
D. dual fuel

Answer: A — All the above

Under SOLAS II-1/56 and the IGF Code, a ship of any construction date that is converted after entry into force to use low-flashpoint fuel, gas, or dual fuel in its main machinery must comply with the IGF Code. All the listed conversions are covered.

2. A ship be converted to __________ for auxiliary machinery after date of entry into force shall comply with IGF Code?

A. All the above
B. dual fuel
C. low-flashpoint fuel
D. use of gas as fuel

Answer: A — All the above

A ship converted after the IGF Code entered into force to use low-flashpoint fuel, including gas or dual fuel, in its main or auxiliary machinery must comply with the IGF Code under SOLAS II-1/56, whatever its date of construction. All the listed conversions are covered.

3. In power generation including propulsion and other energy converters, the exhausts system are configured to prevent ____________

A. accumulation of un-burnt gaseous fuel
B. accumulation of burnt gaseous fuel
C. none of the above
D. both (a) and (b)

Answer: A — accumulation of un-burnt gaseous fuel

IGF Code 10.2 requires exhaust systems of power generation and other energy converters to be configured to prevent any accumulation of unburnt gaseous fuel.

4. In power generation including propulsion and other energy converters, the strength to withstand the worst case over pressure due to ignited gas leaks to contain an ignitable gas and air mixture are fitted with ______________

A. closable non-return valve system
B. single nonreturn valves system
C. two nonreturn valves system
D. Pressure relief systems

Answer: D — Pressure relief systems

IGF Code 10.2 requires engine components or systems that may contain an ignitable gas and air mixture, and that are not strong enough to withstand the worst-case overpressure from ignited gas leaks, to be fitted with suitable pressure relief systems.

5. In power generation including propulsion and other energy converters, what is vented away from where personnel may normally be present?

A. disarm
B. explosive gas
C. safe
D. slump

Answer: B — explosive gas

Under IGF Code 10.2 the explosion or pressure relief venting from energy converters must be led away from where personnel may normally be present, so that ignited gas is discharged safely.

6. In power generation including propulsion and other energy converters, All energy converters shall have ________

A. secondary exhaust system
B. separate exhaust system
C. combined exhaust system
D. primary exhaust system

Answer: B — separate exhaust system

IGF Code 10.3.1 requires every energy converter, such as an engine, boiler or turbine burning gas fuel, to have its own separate exhaust system. This stops unburnt gas or an explosion travelling from one unit into another through a shared exhaust.

7. In Requirements for internal combustion engines of Piston type, The exhaust system shall be equipped with ____________ to prevent excessive explosion pressures.

A. explosion relief ventilation
B. primary relief ventilation
C. gravity ventilation
D. circuit relief ventilation

Answer: A — explosion relief ventilation

IGF Code 10.3 requires the exhaust system of piston engines to have explosion relief ventilation sufficiently dimensioned to prevent excessive explosion pressures if unburnt gas ignites, for example after a misfire.

8. In Requirements for internal combustion engines of Piston type, for engines where the space _____________ with the crankcase.

A. above the piston is in direct communication
B. below the piston is in direct communication
C. below the piston is in indirect communication
D. above the piston is in indirect communication

Answer: B — below the piston is in direct communication

IGF Code 10.3 requires a detailed evaluation of the hazard of gas accumulating in the crankcase for engines where the space below the piston is in direct communication with the crankcase, as in trunk piston engines.

9. In Requirements for internal combustion engines of Piston type, each engine other than _______________ are fitted with vent systems independent of other engines for crankcases and sumps

A. two-stroke crosshead diesel engines
B. single-stroke crosshead diesel engines
C. single-stroke crosshead petrol engines
D. two-stroke crosshead petrol engines

Answer: A — two-stroke crosshead diesel engines

IGF Code 10.3 requires each engine, other than two-stroke crosshead diesel engines, to have vent systems for crankcases and sumps that are independent of other engines. This stops gas from one engine reaching another.

10. In case of shut-off of one fuel supply, the engines are capable of _____________ by an alternative fuel with minimum fluctuation of the engine power

A. non-continuous operation
B. continuous operation
C. unstable operation
D. stable operation

Answer: B — continuous operation

For multi-fuel engines the IGF Code requires that if one fuel supply is shut off, the engine can continue operating on an alternative fuel with minimum fluctuation of engine power.

11. In case of shut-off of one fuel supply, the engines are capable of continuous operation by an alternative fuel with _______________

A. higher fluctuation of the engine power
B. maximum fluctuation of the engine power
C. minimum fluctuation of the engine power
D. nil fluctuation of the engine power

Answer: C — minimum fluctuation of the engine power

The IGF Code requires that on shut-off of one fuel supply, multi-fuel engines continue operating on the alternative fuel with minimum fluctuation of the engine power, so propulsion and electrical supply are not disrupted.

12. In the case of unstable operation on an engine when using a particular fuel the engine are ______________ change to an alternative fuel mode.

A. instructed
B. manual
C. programmed
D. automatically

Answer: D — automatically

The IGF Code requires an engine that runs unstably on a particular fuel to change over automatically to an alternative fuel mode, without relying on operator action.

13. What are designed to prevent any accumulation of gaseous fuel?

A. shaft
B. Combustion chambers
C. bulkhead valves
D. overhead valves

Answer: B — Combustion chambers

The IGF Code requires combustion chambers (and uptakes) of gas-fired boilers and other consumers to be designed to prevent any accumulation of gaseous fuel, which could otherwise explode on ignition.

14. VTA turbo charger works on __________ load range of the engine efficiently

A. entire
B. final step
C. None of the above
D. starting load range

Answer: A — entire

A VTA turbocharger adjusts its turbine nozzle area to the exhaust gas flow, so it delivers optimal scavenge air pressure and works efficiently over the entire load range of the engine.

15. Two stage turbo charging of auxiliary engines increases

A. not extensive experience in component design
B. All of the above
C. fuel consumption high
D. reduce emissions

Answer: D — reduce emissions

Two-stage turbocharging gives higher charge air pressure and efficiency, enabling better combustion and Miller timing. This lowers fuel consumption and reduces emissions, particularly NOx.

16. Alternate marine power provides power to _______

A. air conditioner
B. All of the above
C. Main sea water pump
D. Main fire pump

Answer: B — All of the above

Alternative Maritime Power (shore power/cold ironing) supplies all of the ship's hotel and auxiliary loads at berth, including AC, pumps and the fire pump.

17. Disadvantages of Cold ironing

A. compatible for tankers
B. huge investment for setting up of equipments for AMP
C. All of the above
D. problems not pertaining to cost

Answer: B — huge investment for setting up of equipments for AMP

Cold ironing (Alternative Maritime Power - AMP) requires substantial capital investment for shore power substations, high-voltage shipside transformers, and cable management systems.

18. Energy recovery can be achieved by _________

A. Not fixing flettner rotors
B. fixing sails or wings
C. Not fixing kite
D. All of the above

Answer: B — fixing sails or wings

Wind-assisted propulsion technologies, such as rotor sails, rigid wings, and suction sails, harness aerodynamic wind force to reduce main propulsion fuel consumption.

19. The advantage of hydrogen powered vessels is _______

A. there is no emission of nox
B. there is no emission of CO2
C. there is no emission of SO2
D. All of the above

Answer: D — All of the above

Hydrogen fuel cell propulsion vessels emit zero greenhouse gases and zero criteria air pollutants (emitting only water vapor), offering completely clean maritime transport.

20. ________ produces electricity from the main proposion engine

A. main geenrator
B. shaft generator
C. auxiliary geenrator
D. ordinary generator

Answer: B — shaft generator

A shaft generator is driven by the main propulsion engine or propeller shaft, producing electrical power at sea using the high fuel efficiency of the main engine.

21. Shaft generator produces electricity from the _________

A. None of the above
B. side proposion engine
C. main proposion engine
D. left engine

Answer: C — main proposion engine

A shaft generator utilizes mechanical rotational power from the main propulsion engine shaft to generate shipboard electricity, eliminating the need to run auxiliary diesel generators at sea.

22. Prime surgreen focuses towards fulfilling of all emission standards from the _____________

A. None of the above
B. Director General of Shipping
C. Mercantile Marine department
D. International Maritime Organisation

Answer: D — International Maritime Organisation

Maritime green shipping initiatives focus on meeting and exceeding IMO greenhouse gas reduction targets, EEDI/CII ratings, and Tier III emission limits.

23. Prime surgreen focuses towards fulfilling of all _________ standards from the International Maritime Organisation

A. depletion
B. emission
C. None of the above
D. omision

Answer: B — emission

Environmental regulations set by the IMO mandate continuous reductions in vessel greenhouse gas emissions, SOx, NOx, and particulate matter.

24. ________ increases efficieny and reduce emissions of main engine

A. propulsion shaft cleaning
B. turbo charger refitting
C. None of the above
D. exhaust boiler cleaning

Answer: B — turbo charger refitting

Retrofitting high-efficiency turbochargers improves scavenge air pressure and combustion efficiency, reducing specific fuel consumption and exhaust emissions.

25. Reducing fouling of engine parts can be achieved by using ___________

A. VTA technology
B. None of the above
C. ATV technology
D. Vat tehnology

Answer: A — VTA technology

Variable Turbine Area (VTA) turbochargers reduce engine carbon deposits and fouling by maintaining optimal air-to-fuel ratios during low-load operation.

26. Disadvantage of LNG fuel is

A. emission of CO2
B. emission of NOX
C. release of unburned methane into atmosphere
D. emission of sox

Answer: C — release of unburned methane into atmosphere

A primary environmental challenge of Otto-cycle gas engines is methane slip, where unburned methane escapes into the exhaust stream.

27. Burners are designed to maintain _____________ under all firing conditions.

A. spontaneous combustion
B. stable combustion
C. explosive combustion
D. unstable combustion

Answer: B — stable combustion

Gas burners on marine auxiliary boilers are engineered with specialized flame stabilizers and air registers to maintain stable combustion under all firing rates.

28. On the pipe of each gas burner a _______________ are fitted

A. automatically operated shut-off valve
B. manually operated shut-off valve
C. manually operated switch-on valve
D. automatically operated switch-on valve

Answer: B — manually operated shut-off valve

Each gas burner supply pipe must be equipped with a local manual shut-off valve in addition to automated double block and bleed safety valves.

29. The exhausts are appropriately configured to prevent any accumulation of ___________

A. un-burnt fuel gas
B. none of the above
C. burnt fuel gas
D. both (a) and (b)

Answer: A — un-burnt fuel gas

Exhaust uptakes and boiler flues on gas-fueled vessels are configured to prevent pockets or dead zones where unburned fuel gas could accumulate.

30. Pressure relief systems within the exhaust uptakes to be lead to a ______________ location away from personnel.

A. non-hazardous
B. toxic
C. hazardous
D. risky

Answer: A — non-hazardous

Pressure relief vents on boiler exhaust ducts and gas supply systems must discharge to safe non-hazardous open-air locations clear of personnel and air intakes.

Set 8 — 30 AIGF exit exam questions with answers

1. In gas turbine may be fitted in a gas-tight enclosure a ____________ in the gas supply piping may be accepted within this enclosure

A. pressure above 30 bar
B. pressure above 10 bar
C. pressure above 50 bar
D. pressure below 10 bar

Answer: B — pressure above 10 bar

When marine gas turbines are housed in gas-tight enclosures, fuel gas piping with pressures exceeding 10 bar may be approved within the ventilated enclosure.

2. What is the full redundancy for ventilation for the enclosure for ESD protected machinery spaces ?

A. 2x100% capacity fans from different electrical circuits
B. 2x200% capacity fans from same electrical circuits
C. 2x100% capacity fans from same electrical circuits
D. 2x200% capacity fans from different electrical circuits

Answer: A — 2x100% capacity fans from different electrical circuits

Ventilation for ESD-protected machinery enclosures must feature 100% redundancy with two independent extraction fans powered from separate electrical circuits.

3. Each __________ are fitted with an automatic shutdown device for high exhaust temperatures.

A. pelton wheel
B. none of the above
C. both (a) and (b)
D. turbine

Answer: D — turbine

IGF Code (gas turbines, 10.5): each turbine shall be fitted with an automatic shutdown device for high exhaust temperatures.

4. Fuel cells design are to ensure that any single failure in active components of the fuel cell system not lead to ____________

A. loss of propulsion
B. loss of efficiency
C. loss of manoeuring
D. loss of brake air

Answer: A — loss of propulsion

Marine fuel cell installations must be designed with redundancy so that a single failure in any active component will not result in total loss of vessel propulsion or steering.

5. To make a fuel cell space non hazardous, all fuel pipes are enclosed in a gas tight _________

A. loss of propulsion
B. double open space
C. single enclosure
D. ring space

Answer: C — single enclosure

A fuel cell space can be treated as non-hazardous when all fuel pipes in it are enclosed in a gas-tight enclosure (double-walled pipe or duct), so a leak cannot reach the space (IMO interim guidelines for fuel cell installations).

6. The fuel cell space is fitted with gas detection and an _______________ for Emergency ShutDown protected machinery spaces.

A. programmed shut down system
B. instructed shut down system
C. automatic shut down system
D. manual shut down system

Answer: C — automatic shut down system

Fuel cell compartments must be fitted with continuous gas detection systems and automated emergency shutdown (ESD) systems to isolate fuel upon leak detection.

7. For fuel cell systems with aggregate power ______________, the installation of the whole fuel cell system in the same compartment may be accepted by the Administration

A. lower than 375 kW
B. lower than 500 kW
C. lower than 775 kW
D. lower than 275 kW

Answer: A — lower than 375 kW

Small fuel cell systems with an aggregate power below 375 kW may be installed in a single compartment subject to approval by the Administration.

8. Fuel tanks located above the bulkhead deck shall be shielded with ________ insulation towards accommodation.

A. class A-120
B. class A-90
C. class A-60
D. class A-80

Answer: C — class A-60

Fuel tanks situated on open decks above the bulkhead deck must be shielded from accommodation spaces, service spaces, and control stations by A-60 class thermal insulation.

9. ______________used for refrigeration or cooling of fuel must be compatible with the fuel.

A. boiler
B. freezing
C. Refrigerants
D. Griller

Answer: C — Refrigerants

Refrigerants utilized in fuel reliquefaction and gas cooling systems must be chemically compatible with the fuel and non-reactive in the event of heat exchanger leakage.

10. Heat exchangers can be repaired on board without ___________

A. heat sources
B. external sources
C. power sources
D. internal sources

Answer: B — external sources

Plate and shell-and-tube fuel heat exchangers are arranged with isolation valves and bypasses to allow maintenance and tube cleaning on board without external assistance.

11. What is arranged to enable each fuel storage tank to be safely gasfreed and to be safely filled with fuel gas from a gas-free condition?

A. storage tank
B. Gas Combining Unit
C. heat exchangers
D. piping system

Answer: D — piping system

Dedicated piping connections must be provided to allow each fuel storage tank to be safely inerted, gas-freed with air, and re-gassed from a gas-free state.

12. Dry air only applicable for which type of tankvwhere condensation and icing due to cold surfaces is an issue?

A. cargo tanks
B. storage tanks
C. fuel tanks
D. liquid tanks

Answer: C — fuel tanks

Dry air purging is utilized to dry fuel tanks and hold spaces prior to gassing up to eliminate moisture and prevent ice formation on cryogenic surfaces.

13. The ship's motion shall include ______________

A. surge
B. heave
C. sway
D. All the above

Answer: D — All the above

Structural design of fuel tanks must account for all six degrees of ship motion: rolling, pitching, yawing, surging, swaying, and heaving.

14. What properties are adequate for the intended service to Thermal insulation and other materials used in liquefied gas fuel containment systems?

A. All the above
B. absorption of the liquefied gas fuel
C. solubility in the liquefied gas fuel
D. compatibility with the liquefied gas fuels

Answer: A — All the above

Under the IGF Code, thermal insulation and other materials in liquefied gas fuel containment systems must have properties adequate for the intended service, including compatibility with the liquefied gas fuel, solubility in it, and absorption of it. All the listed properties apply.

15. The properties for Thermal insulation the range should be how much

A. neutral
B. minimum
C. between temperature in service and 5°C below the minimum design temperature
D. zero

Answer: C — between temperature in service and 5°C below the minimum design temperature

Thermal insulation properties must be tested and certified across the temperature range between operational service conditions and 5°C below the minimum design temperature.

16. The properties for Thermal insulation and other materials including composites tested how much should be the minimum Design temperature should not be lower than__________

A. plus196°C
B. minus196°C
C. plus196°F
D. minus196°F

Answer: B — minus196°C

Materials used in cryogenic LNG fuel containment systems must be impact tested at design temperatures down to -196°C to verify ductility against brittle failure.

17. _________ refers to the usage of other power supply sources to feed power to the ship

A. alternate marine power system
B. ship marine power system
C. None of the above
D. alternate feed power system

Answer: A — alternate marine power system

Alternative Marine Power (AMP / Cold Ironing) supplies electrical power to the vessel from the shoreside grid while berthed, allowing auxiliary engines to be shut down.

18. _______ reduces the emission by the ship by a great margin

A. main marine power system
B. auxiliary marine power system
C. alternate marine power system
D. None of the above

Answer: C — alternate marine power system

Shore power connection (AMP) drastically reduces local port emissions of NOx, SOx, PM, and greenhouse gases while ships are berthed in port.

19. Alternate Marine Power provides powers to

A. lights
B. refrigerator
C. All of the above
D. air conditioner

Answer: C — All of the above

AMP supplies high-voltage electrical power to all shipboard consumers, including hotel loads, refrigeration, lighting, and auxiliary pumps.

20. Which type of vessel has got the biggest disadvantage with reference to Alternate Marine Power?

A. tanker
B. bulK carrier
C. passenger ships
D. container

Answer: A — tanker

Tankers face significant safety challenges with shore power connections due to hazardous area zoning and potential ignition risks during cargo operations.

21. Speed recovery solutions can save fuel upto

A. 1%
B. 20-30%
C. 2%
D. 4-11%

Answer: D — 4-11%

Speed reduction and operational efficiency measures (slow steaming and hull optimization) can deliver substantial fuel savings of 4% to 11% or more.

22. Coating is done to reduce ___________

A. air resistance
B. oil resistance
C. None of the above
D. hull sytems

Answer: A — air resistance

Aerodynamic superstructure fairings and low-friction hull coatings reduce aerodynamic and hydrodynamic resistance, improving overall vessel propulsive efficiency.

23. ________ is an engine for reduction of the vessels maximum speed to increase the efficiency by limiting the potential power output

A. over rating
B. rerating
C. None of the above
D. derating

Answer: D — derating

Engine derating involves limiting the maximum power rating of a marine engine to optimize its thermal efficiency and specific fuel consumption at lower operating speeds.

24. LNG fuel should have after treatment systems like ___________

A. oxidation catalyst
B. nitrogen catalyst
C. hydrogen catalyst
D. helium catalyst

Answer: A — oxidation catalyst

Methane oxidation catalysts (MOC) are exhaust aftertreatment devices designed to oxidize residual unburned methane (methane slip) in lean-burn gas engine exhausts.

25. _______ should have after treatment systems like oxidation catalyst

A. petrol
B. LNG fuel
C. coal
D. gas fuel

Answer: B — LNG fuel

LNG-fueled lean-burn Otto-cycle engines utilize oxidation catalysts to reduce carbon monoxide, unburned hydrocarbons, and methane slip.

26. Slow steaming is otherwise called

A. maxrating of the engine
B. rerating of the engine
C. derating of the engine
D. duerating of the engine

Answer: C — derating of the engine

Slow steaming is an operational strategy that involves reducing vessel transit speed and derating main engines to achieve significant fuel and emissions savings.

27. The cooling jacket of a hybrid turbo charger is made up of which material

A. aluminium
B. stainless steel
C. steel
D. silver

Answer: A — aluminium

The water-cooling jacket on high-speed hybrid turbocharger alternators is commonly fabricated from corrosion-resistant marine aluminum alloys.

28. GCU means ___________________

A. Gas Consumption Unit
B. Gas Combustion Unit
C. Goods Combustion Unit
D. Gas Combining Unit

Answer: B — Gas Combustion Unit

GCU stands for Gas Combustion Unit, a dedicated thermal oxidizer on LNG-fueled ships that safely burns excess boil-off gas when engines cannot consume it.

29. _____________ utilized for gas freeing of tanks may be provided externally to the ship.

A. Green gas
B. Non-Toxic gas
C. Toxic gas
D. Inert gas

Answer: D — Inert gas

Inert gas (such as liquid nitrogen) used for purging and gas-freeing fuel tanks may be supplied from shoreside tanker trucks during bunkering or drydocking.

30. Spaces surrounding fuel tanks is filled with which type of air?

A. vapour
B. cool air
C. moistured air
D. dry air

Answer: D — dry air

Hold spaces surrounding independent Type C fuel tanks are filled with dry air or inert gas and continuously monitored for pressure and flammable gas.

Set 9 — 30 AIGF exit exam questions with answers

1. What is electrically bonded in ship's structure?

A. All gasketed pipe joints
B. All non-gasketed pipe joints
C. fresh water line
D. sea water line

Answer: A — All gasketed pipe joints

All gasketed pipe joints, flanges, and flexible hoses in fuel systems must be electrically bonded with copper bonding straps to prevent static charge accumulation.

2. All pipelines isolated in a liquid full condition are provided with ___________

A. diaphgramvalves
B. butterfly valves
C. relief valves
D. control valves

Answer: C — relief valves

Thermal relief valves must be installed on any pipeline section that can be isolated while full of liquid to prevent overpressurization from thermal expansion.

3. Pipework contain ____________ which is thermally insulated to an extent which will minimize condensation of moisture

A. low temperature liquid
B. high temperature liquid
C. low pressure liquid
D. high pressure liquid

Answer: A — low temperature liquid

Cryogenic fuel pipework is thermally insulated with aerogel, polyurethane, or perlite to prevent ambient heat ingress and avoid structural moisture condensation.

4. Pipework contain low temperature liquid or gas which is thermally insulated to an extent which will ___________

A. maximize condensation of moisture
B. minimize evaporation of moisture
C. maximize evaporation of moisture
D. minimize condensation of moisture

Answer: D — minimize condensation of moisture

Thermal insulation on cryogenic gas piping prevents excessive heat ingress into the fuel and prevents heavy condensation and frost formation on external pipe surfaces.

5. Piping other than fuel supply piping, what is arranged in the double wall piping?

A. none of the above
B. sea water
C. fresh water
D. cabling

Answer: D — cabling

Instrumentation cabling and tracing lines associated with gas fuel supply systems may be routed inside double-wall piping ducts provided they are Ex-certified.

6. Piping other than cabling, what is arranged in the double wall piping?

A. fuel supply piping
B. fresh water
C. none of the above
D. sea water

Answer: A — fuel supply piping

Fuel supply piping is routed inside double-walled outer ducts to contain any potential inner pipe leakage and provide an extraction pathway for gas detection.

7. What is provided that they do not create a source of ignition compromise the integrity of the double pipe?

A. closure
B. drain
C. entry
D. duct

Answer: D — duct

Double-wall ducts must be structurally designed and certified so that internal components do not create ignition sources or compromise duct integrity.

8. In the minimum wall thickness, t=(to + b + c)/(1 - a/100)(mm), What is to?

A. allowance for bending
B. corrosion allowance
C. theoretical thickness
D. design pressure

Answer: C — theoretical thickness

In the standard pipe wall thickness formula, 'to' represents the theoretical design wall thickness required to withstand internal working pressure.

9. Indicators fitted on the ____________ ,the engine control room and the manoeuvring platform operation of Main engine

A. none of the above
B. navigation bridge,
C. Pump room
D. Deck

Answer: B — navigation bridge,

The navigation bridge must be equipped with essential propulsion status indicators, gas trip alarms, and emergency shutdown controls.

10. Where is permanently installed gas detectors fitted?

A. remote operation
B. both (a) and (b)
C. the tank connection spaces
D. in all ducts around gas pipes

Answer: B — both (a) and (b)

Permanently installed gas detectors are fitted in tank connection spaces, double-wall pipe ducts, fuel preparation rooms, and machinery space exhaust hoods.

11. Where is redundant gas detection systems be provided?

A. ESD-protected detection space
B. ESD-protected machinery space
C. ESD-unprotected machinery space
D. ESD-unprotected detection space

Answer: B — ESD-protected machinery space

Redundant gas detection systems with dual optical/infrared detectors are mandatory in ESD-protected machinery spaces to ensure immediate fail-safe trip capability.

12. In which area electrical equipment or wiring are not installed unless essential for operational purposes or safety enhancement?

A. safe area
B. hazardous areas
C. protected area
D. Gas free area

Answer: B — hazardous areas

Electrical equipment and wiring must not be installed in hazardous zones unless strictly necessary for operational or safety functions and certified explosion-proof (Ex-rated).

13. How is the lighting system in hazardous areas be divided ?

A. at least five branch circuits
B. at least three branch circuits
C. single circuits
D. at least two branch circuits

Answer: D — at least two branch circuits

Lighting systems in explosion-hazardous areas must be divided between at least two independent branch circuits to prevent total darkness upon single-circuit tripping.

14. Where will the switches and protective devices interrupt all poles or phases are provided

A. non-hazardous area
B. Gas area
C. toxic area
D. hazardous area

Answer: A — non-hazardous area

Electrical switches, circuit breakers, and motor protection devices controlling hazardous area circuits must be located in non-hazardous gas-safe areas.

15. The liquefied gas fuel containment system structure and its structural components shall withstand _______________ without loss of containment

A. loads liable to occur during its construction
B. testing
C. All the above
D. anticipated use in service

Answer: C — All the above

The IGF Code requires the fuel containment structure and its components to withstand all loads liable to occur during construction, testing and anticipated use in service without loss of containment. All the listed phases apply.

16. The liquefied gas fuel containment system structure and its structural components shall withstand loads liable to occur during its ____________ without loss of containment.

A. testing
B. All the above
C. anticipated use in service
D. construction

Answer: B — All the above

The containment structure must withstand loads arising during its construction, testing and anticipated use in service without loss of containment, so all the listed phases are covered.

17. In Ultimate Design Conditions –the design shall take into account proper combinations of which type of loads?

A. All the above
B. External pressure
C. Dynamic loads due to the motion of the ship in all loading conditions
D. Internal pressure

Answer: A — All the above

Ultimate limit state design of fuel tanks accounts for simultaneous combinations of internal vapor pressure, liquid weight, hull girder deflection, and dynamic acceleration forces.

18. What are the accident design conditions addressed in IGF Code?

A. Collision
B. All the above
C. Fire
D. Flooded compartment causing buoyancy on tank

Answer: B — All the above

Accidental design conditions under the IGF Code evaluate extreme events including collision, grounding, secondary barrier liquid flooding, and external fire envelope exposure.

19. The hull structure may be designed as a secondary barrier where the liquefied gas fuel temperature at atmospheric pressure is not below minus 55°C on ______________

A. the design can be such that this temperature will not result in unacceptable hull stresses
B. the hull material can be suitable for the liquefied gas fuel temperature at atmospheric pressure
C. both (a) and (b)
D. none of the above

Answer: C — both (a) and (b)

The ship's inner hull structure may serve as a secondary barrier only when the fuel temperature at atmospheric pressure is not colder than -55°C and approved cryogenic grade steel is used.

20. In ship design and arrangement is to provide for

A. refuelling systems
B. mechanical protection of power generation equipment
C. space arrangements
D. All the above

Answer: D — All the above

IGF Code 5.1 states that the goal of ship design and arrangement is to provide for the safe location, space arrangements and mechanical protection of power generation equipment, fuel storage systems, fuel supply equipment and refuelling systems. All the listed items are covered.

21. the fuel when carried in a fuel containment system requiring a complete or partial secondary barrier, hold spaces shall be segregated from the sea by a double bottom.is carried at temperatures below ___________,

A. 0ºC
B. minus 10ºC
C. plus 10ºC
D. none of the above

Answer: B — minus 10ºC

Where fuel is carried in a containment system requiring a complete or partial secondary barrier at temperatures below minus 10°C, the hold spaces must be segregated from the sea by a double bottom. Below minus 55°C a longitudinal bulkhead forming side tanks is also required.

22. the fuel when carried in a fuel containment system requiring a complete or partial secondary barrier, at temperatures below ____________, the ship shall also have a longitudinal bulkhead forming side tanks

A. plus 55ºC
B. none of the above
C. minus 55ºC
D. 0ºC

Answer: C — minus 55ºC

IGF Code 5.3 requires that when fuel is carried in a containment system needing a complete or partial secondary barrier, at temperatures below minus 55°C, the ship must have a longitudinal bulkhead forming side tanks. This protects the hull and tank from side damage and low-temperature effects.

23. Liquefied gas fuel containment systems can be designed in accordance with ___________ environmental conditions

A. north Indian ocean
B. north Antartic
C. north Atlantic
D. north Pacific

Answer: C — north Atlantic

The IGF Code requires liquefied gas fuel containment systems to be designed for North Atlantic environmental conditions and the corresponding long-term sea state scatter diagrams for unrestricted navigation.

24. Liquefied gas fuel containment systems can be designed with suitable safety margins such as ___________

A. being appropriate for uncertainties in loads
B. the environmental conditions anticipated for the liquefied gas fuel containment system's design life and the loading conditions appropriate for them
C. All the above
D. to withstand in the intact condition

Answer: C — All the above

The IGF Code requires containment systems to be designed with suitable safety margins to withstand, in the intact condition, the environmental conditions anticipated over their design life and the related loading conditions. The margins must also allow for uncertainties in loads, structural modelling, fatigue and corrosion. All the listed points apply.

25. What criteria to be considered when establishing functional loads?

A. All the above
B. Internal pressure
C. Thermally induced loads
D. External pressure

Answer: A — All the above

When establishing functional loads, the IGF Code considers internal pressure, external pressure, thermally induced loads, vibration, interaction loads and sloshing. All the listed criteria apply.

26. What are the cases Internal pressure in Liquefied gas fuel containment safety principles ?

A. both (a) and (b)
B. Po shall not be less than the gauge vapour pressure of the liquefied gas fuel at a temperature of 45°C
C. Po shall not be less than MARVS
D. none of the above

Answer: A — both (a) and (b)

For internal pressure the IGF Code requires the design vapour pressure Po to be not less than the MARVS. For tanks without temperature control, Po must also be not less than the gauge vapour pressure of the fuel at 45°C, so both cases apply.

27. External design pressure loads can be based on the difference between the

A. No need to consider any pressure while designing
B. minimum internal pressure and the maximum external pressure to which any portion of the tank
C. inside temperature and outside temperature
D. none of the above

Answer: B — minimum internal pressure and the maximum external pressure to which any portion of the tank

The IGF Code bases external design pressure loads on the difference between the minimum internal pressure (maximum vacuum) and the maximum external pressure to which any portion of the tank may be subjected simultaneously.

28. Where the liquefied gas fuel temperature at atmospheric pressure is not____________ the hull structure may be designed as a secondary barrier

A. below minus 55°C
B. below 255°C
C. below plus 55°C
D. above plus 55°C

Answer: A — below minus 55°C

The IGF Code allows the hull structure to act as a secondary barrier only where the liquefied gas fuel temperature at atmospheric pressure is not below minus 55°C, and the hull material and design are suitable for that temperature.

29. Stationary thermally induced loads shall be considered for liquefied gas fuel containment systems where

A. both (a) and (b)
B. operating temperature may give rise to significant thermal stresses
C. none of the above
D. the design supporting arrangements or attachments

Answer: A — both (a) and (b)

Stationary thermally induced loads must be considered where the design supporting arrangements or attachments, and the operating temperature, may give rise to significant thermal stresses. Both conditions apply.

30. The static component of loads resulting _____________ can be considered.

A. both (a) and (b)
B. All the above
C. loads from associated structure and equipment,
D. from interaction between liquefied gas fuel containment system and the hull structure,

Answer: A — both (a) and (b)

Under the IGF Code tank design rules, the static loads to be considered include those from interaction between the fuel containment system and the hull structure, and those from associated structure and equipment. Both sources are included.

Set 10 — 30 AIGF exit exam questions with answers

1. Environmental loads are not otherwise classified as a ____________

A. permanent load
B. accidental load
C. functional load
D. All the above

Answer: D — All the above

IGF Code 6.4.1 defines environmental loads as loads on the fuel containment system caused by the surroundings, such as ship motions, wave loads, wind and ice, that are not otherwise classed as permanent, functional or accidental loads.

2. In dynamic loads reduction, Account may due to necessary ___________

A. both (a) and (b)
B. none of the above
C. speed reduction
D. variation of heading

Answer: A — both (a) and (b)

When determining dynamic loads, the IGF Code allows account to be taken of the reduction in loads from the necessary speed reduction and variation of heading in heavy weather. Both apply.

3. The accelerations acting on tanks shall be estimated at their centre of gravity and includes which type of components?

A. All the above
B. transverse acceleration: motion accelerations of sway, yaw and roll and gravity component of roll
C. vertical acceleration: motion accelerations of heave, pitch and, possibly roll
D. longitudinal acceleration: motion accelerations of surge and pitch and gravity component of pitch

Answer: A — All the above

The IGF Code estimates the accelerations acting on tanks at their centre of gravity from three components. Vertical acceleration comes from heave, pitch and possibly roll; transverse from sway, yaw and roll plus the gravity component of roll; and longitudinal from surge and pitch plus the gravity component of pitch. All are included.

4. The dynamic component of loads resulting from interaction between ___________

A. the hull structure
B. liquefied gas fuel containment systems
C. All the above
D. including loads from associated structures and equipment

Answer: C — All the above

The IGF Code considers the dynamic component of loads from interaction between the liquefied gas fuel containment system and the hull structure, including loads from associated structures and equipment. All the listed elements apply.

5. Accidental loads are loads that are imposed on a liquefied gas fuel containment system and it's supporting arrangements under ______________ conditions

A. unplanned
B. both (a) and (b)
C. none of the above
D. abnormal

Answer: B — both (a) and (b)

The IGF Code defines accidental loads as loads imposed on a fuel containment system and its supporting arrangements under abnormal and unplanned conditions, such as collision or flooding. Both terms apply.

6. The structural design can take into account the possibility of ________

A. buckling
B. plastic deformation
C. All the above
D. fatigue failure

Answer: C — All the above

The IGF Code requires the structural design to take into account the possibility of plastic deformation, buckling and fatigue failure. All the listed failure modes are considered.

7. With reference to load calculation LRFD means ____________________

A. Load Resistance Factor Design
B. Load Resistance Fever Design
C. Level Reaction Factor Design
D. Level Resistance Factor Design

Answer: A — Load Resistance Factor Design

LRFD means Load and Resistance Factor Design. Partial safety factors are applied separately to the loads and to the structural resistance, and the IGF Code permits this method for containment systems.

8. In Structural analysis, The design analyses is based on accepted principles of ___________

A. strength of materials
B. statics load
C. All the above
D. dynamics load

Answer: C — All the above

The IGF Code requires design analyses of fuel containment systems to be based on accepted principles of statics, dynamics and strength of materials. All the listed principles apply.

9. Simplified methods or simplified analyses may be used to calculate the ____________

A. dynamics effects
B. statics effects
C. theory effects
D. load effects

Answer: D — load effects

The IGF Code permits simplified methods or simplified analyses to be used to calculate load effects, provided they are conservative.

10. In structural analysis, the most unfavourable scenarios for all relevant phases during ____________ shall be considered

A. handling stage
B. All the above
C. testing stage
D. construction stage

Answer: B — All the above

The IGF Code requires the most unfavourable scenarios for all relevant phases to be considered, including construction, handling, testing and in-service conditions. All the listed phases apply.

11. How is Structural capacity determined?

A. analysis
B. testing
C. none of the above
D. both (a) and (b)

Answer: D — both (a) and (b)

Under the IGF Code, the structural capacity of fuel containment system parts is determined by analysis, testing, or a combination of the two, depending on the tank type and the failure modes being checked.

12. How is Structural capacity determined by simplified linear elastic analysis or by Code provisions?

A. Plastic deformation and buckling shall be considered
B. both (a) and (b)
C. Analysis shall be based on characteristic load values
D. none of the above

Answer: B — both (a) and (b)

When structural capacity is found by simplified linear elastic analysis or by code provisions, IGF Code 6.4 requires the analysis to use characteristic load values, and plastic deformation and buckling must also be considered. Both conditions therefore apply.

13. How is Structural capacity How is analysis based on characteristic load values follows for Environmental Loads?

A. For wave loads; most probable largest load encountered during 108 wave encounters
B. strength Values
C. Specified Values
D. Expected Values

Answer: A — For wave loads; most probable largest load encountered during 108 wave encounters

For environmental loads, the IGF Code takes the characteristic wave load as the most probable largest load encountered during 10^8 wave encounters, which represents the ship's long-term North Atlantic exposure.

14. Stresses may be further limited by ____________

A. All the above
B. fatigue analysis
C. buckling criteria
D. crack propagation analysis

Answer: A — All the above

Under the IGF Code, allowable stresses may be further limited by fatigue analysis, crack propagation analysis and buckling criteria. All the listed limits apply.

15. On what basis analysis based on characteristic load values for Permanent Loads?

A. Expected Values
B. Dynamic Valves
C. Expected Load History, but not less than 108 cycles
D. Specified Values

Answer: A — Expected Values

In the IGF Code table of characteristic load values, permanent loads are taken at their expected values.

16. On what basis analysis based on characteristic load values for Functional Loads?

A. Specified Values
B. Dynamic Valves
C. Expected Values
D. Expected Load History, but not less than 108 cycles

Answer: A — Specified Values

In the IGF Code table of characteristic load values, functional loads are taken at their specified values, such as design pressure and design temperature.

17. On what basis analysis based on characteristic load values for Environmental Loads?

A. Specified Values
B. Dynamic Valves
C. Expected Values
D. Expected Load History, but not less than 108 cycles

Answer: D — Expected Load History, but not less than 108 cycles

For fatigue analysis, the IGF Code takes the characteristic environmental load as the expected load history, but not less than 10^8 cycles.

18. Fracture mechanics analyses of fatigue crack growthis carried out by?

A. Crack propagation paths in the structure
B. The time required for a crack to propagate to cause a leakage from the tank
C. Crack growth rate
D. All the above

Answer: D — All the above

IGF Code fracture mechanics analyses of fatigue crack growth must document the crack propagation paths in the structure, the crack growth rate, and the time needed for a crack to propagate far enough to cause leakage from the tank. All are required.

19. The accidental design condition is a design condition for _________ with extremely LOW PROBABILITY of occurrence

A. accidental loads
B. static load
C. environmental load
D. gravity load

Answer: A — accidental loads

The accidental design condition evaluates abnormal load cases such as hull damage, external fire, or containment leakage to ensure the ship's survivability.

20. IMDG Code means

A. Indian Maritime Dangerous Goods Code
B. International Maritime Dangerous Goods Code
C. International Maritime Deck Goods Code
D. International Marine Dangerous Goods Code

Answer: B — International Maritime Dangerous Goods Code

The IMDG Code is the International Maritime Dangerous Goods Code, regulating the safe seaborne transport of packaged dangerous goods.

21. Reliquefaction of vapours method chosen shall be capable of maintaining tank pressure ___________ of the tank for a period of 15 days assuming full tank at normal service pressure

A. above the set volume
B. above the set pressure
C. below the set volume
D. below the set pressure

Answer: D — below the set pressure

IGF Code 6.9 requires a reliquefaction system or other pressure control method to keep the fuel tank pressure below the set pressure of its relief valves for at least 15 days, assuming a full tank at normal service pressure and no fuel being used.

22. How is reliquefaction system be designed and calculated?

A. direct system where evaporated fuel is compressed, condensed and returned to cargo tanks
B. direct system where evaporated fuel is compressed, condensed and returned to fuel tanks
C. an indirect system where evaporated fuel is compressed, condensed and returned to cargo tanks
D. an indirect system where evaporated fuel is compressed, condensed and returned to fuel tanks

Answer: B — direct system where evaporated fuel is compressed, condensed and returned to fuel tanks

A direct reliquefaction system compresses the evaporated fuel (boil-off gas), condenses it and returns it to the fuel tanks. The IGF Code accepts it as one method of fuel tank pressure control.

23. Which method is used in case of a single failure of the fuel tank pressure and temperature can be maintained by another service/system ?

A. Refrigerants system and its supporting auxiliary services
B. Primary system and its supporting auxiliary services
C. The non-availability of the system and its supporting auxiliary services
D. The availability of the system and its supporting auxiliary services

Answer: D — The availability of the system and its supporting auxiliary services

The IGF Code requires the availability of the pressure control system and its supporting auxiliary services to be such that, after a single failure, fuel tank pressure and temperature can still be maintained by another service or system.

24. ___________ are for maintaining the pressure and temperature of the gas fuel tanks within their design ranges

A. Heat exchangers
B. Primary system
C. Freezing
D. none of the above

Answer: A — Heat exchangers

Heat exchangers in the reliquefaction or pressure control system are essential for keeping the pressure and temperature of gas fuel tanks within their design ranges. The IGF Code therefore requires a standby heat exchanger.

25. Heat exchanger's standby heat exchanger have a capacity ____________ of the largest required capacity for pressure control.

A. lack of 25%
B. need of 25%
C. in excess of 25%
D. inadequacy of 25%

Answer: C — in excess of 25%

The IGF Code requires heat exchangers essential to tank pressure and temperature control to have a standby unit with a capacity in excess of 25% of the largest required capacity for pressure control.

26. Interbarrier and hold spaces associated with cargo containment systems for ______________ requiring full or partial secondary barriers shall be inerted with a suitable dry inert gas

A. Inert gas
B. flammable gases
C. inflammable gases
D. Green gas

Answer: B — flammable gases

Interbarrier and hold spaces of containment systems for flammable gases requiring full or partial secondary barriers must be inerted with a suitable dry inert gas. This keeps a non-flammable atmosphere in case of primary barrier leakage.

27. Interbarrier and hold spaces associated with cargo containment systems are kept inerted with make-up gas provided by a shipboard _________________

A. flammable gas generation system
B. toxic gas generation system
C. inert gas generation system
D. Green gas generation system

Answer: C — inert gas generation system

Inerted interbarrier and hold spaces are kept inerted with make-up gas from a shipboard inert gas generation system, or from shipboard storage sufficient for at least 30 days' normal consumption.

28. Equipment for the provision of _______________ of suitable quality to satisfy the expected demand for dry air shall be provided.

A. insufficient moistured air
B. insufficient dry air
C. sufficient dry air
D. sufficient moistured air

Answer: C — sufficient dry air

Where dry air is used for spaces around fuel tanks, the IGF Code requires equipment to provide sufficient dry air of suitable quality to meet the expected demand.

29. The connections to the gas piping systems are _______________

A. non-permanent
B. permanent
C. hazardous
D. non-hazardous

Answer: A — non-permanent

To prevent fuel gas flowing back into the inert gas system, the IGF Code requires inert gas connections to the gas piping system to be non-permanent, for example a removable spool piece. Two non-return valves may be used instead.

30. In connections to the gas piping systems, what are substituted for the valves?

A. single nonreturn valves
B. two nonreturn valves
C. multi nonreturn valves
D. two return valves

Answer: B — two nonreturn valves

Connections from inert gas systems to gas fuel piping must have two non-return valves and a spool piece to prevent backflow of gas into inert systems.

Set 11 — 30 AIGF exit exam questions with answers

1. How is the arrangement for each space being inerted ?

A. none of the above
B. groups
C. isolated
D. multi space

Answer: C — isolated

Each space subject to inerting must be arranged with independent isolation valves and local sampling connections.

2. What is provided for controlling pressure in isolated spaces?

A. two nonreturn valves
B. closable non-return valve
C. relief valves
D. single nonreturn valves

Answer: C — relief valves

Pressure relief valves must be provided on all isolated inerted spaces to prevent overpressurization during purging.

3. What is the goal of material and general pipe design?

A. to ensure the safe handling of pipes
B. to ensure the safe handling of gas fuel
C. to ensure the safe handling of drinking water
D. to ensure the safe handling of cargoes

Answer: B — to ensure the safe handling of gas fuel

The goal of material and general piping design under the IGF Code is to ensure the safe, leak-free containment and handling of gas fuel under all operating conditions.

4. Under which condition goal of material and general pipe design works?

A. only on limited conditions
B. under all operating conditions
C. based on the best condition
D. based on the fuel

Answer: B — under all operating conditions

Piping systems and fuel containment materials must maintain ductile mechanical properties under all foreseeable operating conditions down to design minimum temperatures.

5. What does goal of material and general pipe design minimize?

A. risk personnel
B. both (a) and (b)
C. none of the above
D. the risk to the ship

Answer: B — both (a) and (b)

The IGF Code goal for material and general pipe design is to ensure safe handling of gas fuel under all operating conditions, minimising the risk to the ship, personnel and the environment. Both listed risks are minimised.

6. What is fuel piping capable of?

A. eliminate vaccum space
B. eliminate thermal expansion
C. absorbing thermal expansion
D. absorbing vaccum space

Answer: C — absorbing thermal expansion

Fuel piping arrangements must incorporate expansion loops or bellows capable of absorbing thermal contraction during cryogenic cooldown.

7. In Provision made in Functional requirements, fuel tanks from excessive stresses are due to _________

A. none of the above
B. pressure movement
C. vaccum movement
D. thermal movement

Answer: D — thermal movement

Functional requirements under the IGF Code mandate that fuel tanks and piping must be protected from excessive stresses caused by thermal contraction and expansion.

8. What is not essential to the structural completeness of the ship's hull?

A. An independent tank
B. none of the above
C. Dependent tank
D. Enclosed tank

Answer: A — An independent tank

An independent tank is a self-supporting fuel container that does not contribute to the structural strength or completeness of the ship's hull.

9. Which tank contains the fuel-containment envelope which forms part of the ship's hull and by the same loads which stress the contiguous hull structure?

A. none of the above
B. Gravity tank
C. Integral tank
D. both (a) and (b)

Answer: C — Integral tank

An integral tank is a fuel containment envelope that forms part of the ship's hull structure and is stressed by the same loads as the adjacent hull.

10. Which type of test covers the tensile strength not less than the specified minimum tensile strength?

A. Charpy V-notch impact tests
B. Tensile tests
C. Bend tests
D. All of the above

Answer: B — Tensile tests

Tensile testing of welded piping joints verifies that the ultimate tensile strength is not less than the specified minimum tensile strength of the base metal.

11. Which type of test conducted at the temperature prescribed for the base material being joined?

A. Tensile tests
B. All of the above
C. Bend tests
D. Charpy V-notch impact tests

Answer: D — Charpy V-notch impact tests

Charpy V-notch impact tests are conducted at prescribed minimum design temperatures to verify material resistance to brittle fracture.

12. What is the unit of P, design pressure?

A. K
B. Pa
C. bar
D. mm

Answer: C — bar

In piping design formulas, design pressure 'P' is standardly expressed in bar (or MPa).

13. In the theoretical thickness, to=PD/(20Ke + P) (mm), What is D?

A. pressure volume
B. theoretical thickness
C. outside diameter
D. PRESSURE

Answer: C — outside diameter

In the standard pipe wall thickness formula, 'D' represents the outside diameter of the pipe.

14. In the theoretical thickness, What is the unit of D, outside diameter?

A. Newtons
B. Bar
C. km
D. mm

Answer: D — mm

In pipe wall thickness calculations, outside diameter 'D' is standardly measured in millimeters (mm).

15. In IGF Code, Gas only engine means

A. two stroke engine
B. a power generating engine capable of operating on gas-only and not able to switch over to of fuel operation
C. four stroke engine
D. a power generating engine capable of operating on gas-only and able to switch over to oil fuel operation

Answer: B — a power generating engine capable of operating on gas-only and not able to switch over to of fuel operation

IGF Code 2.2: a gas-only engine can operate on gas fuel only and cannot switch over to oil fuel operation.

16. When assessing LNG fire risk in Hazardous and Safety Zones for LNG bunkering, which possible source of ignition would be caused by X ray apparatus, radioactive material, absorption of energy leads to heating up?

A. Lightning strike
B. lonizing radiation
C. Ultrasound
D. Adiabatic compression and shock wave

Answer: B — lonizing radiation

EN 1127-1 ignition sources: ionizing radiation (X-ray apparatus, radioactive material) can cause ignition through energy absorption and heating.

17. Nitrogen pipes shall only be led through well ventilated spaces. Nitrogen pipes in enclosed spaces shall

A. Be fully welded
B. Have only a minimum of flange connections as needed for fitting of valves; and
C. Be as short as possible.
D. All of above

Answer: D — All of above

Nitrogen pipes routed through enclosed spaces must be all-welded, well-ventilated, and protected against accidental damage to prevent asphyxiation hazards.

18. In IGF Code, Certified safe type means

A. electrical equipment that is certified safe by the relevant authorities recognized by the Administration for operation in a flammable atmosphere based on a recognized standard
B. an enclosed space exceeding the maximum overpressure the container
C. measures provided to prevent the explosion pressure int a container
D. space is designed for, by releasing the overpressure through designated openings

Answer: A — electrical equipment that is certified safe by the relevant authorities recognized by the Administration for operation in a flammable atmosphere based on a recognized standard

Under the IGF Code, 'certified safe type' refers to electrical equipment certified by recognized authorities (ATEX/IECEx) for safe operation in flammable atmospheres.

19. Risk analysis is to be carried out in relevent accident scenarios to determine

A. Damage and deformities to the hull
B. Load and resistance factors
C. Damage to the machineries
D. Enviromental pollution

Answer: A — Damage and deformities to the hull

Accident scenario risk analysis evaluates collision, grounding, and fire impacts to determine potential damage and deformities to the ship's hull and fuel containment.

20. What according to you shall be fitted in every bunkering line close to the connectin point?

A. A manually operated valve.
B. A combined manually operated and remote valve.
C. A remote operated valve.
D. none of the above.

Answer: B — A combined manually operated and remote valve.

A combined manually operated stop valve and remote emergency shutdown valve must be fitted in every bunkering line close to the manifold connection point.

21. Fuel lines outside the machinery spaces shall be installed and protected so as to minimize

A. The risk of injury to personnel
B. Damage to the ship in case of leakage
C. Risk of pollution
D. All of above

Answer: D — All of above

The IGF Code requires fuel lines outside machinery spaces to be installed and protected so as to minimise the risk of injury to personnel, damage to the ship, and pollution in case of leakage. All the listed aims apply.

22. In the type of Fuel tank liquid level gauges, What is indirect devices?

A. which do not determine the amount of fuel by weighing ur in line flow metering
B. which determine the amount of fuel by weighing or out-line fow metering
C. which determine the amount of fuel by weighing or in-line fiove metering
D. which do not determine the amount of fuel by weighing or out-lite flove tretering

Answer: C — which determine the amount of fuel by weighing or in-line fiove metering

IGF Code 15.4.1: indirect devices determine the amount of fuel by means such as weighing or in-line flow metering. The options have OCR errors but the meaning is clear.

23. Fire Blankets are used for

A. Smothering of tire
B. Ccoling of fire (
C. Inhicition of fire
D. Starvation uf fire

Answer: A — Smothering of tire

Fire blankets are utilized for rapid smothering of small localized fires by depriving the flames of oxygen.

24. Piping systems, containment and over-pressure relief arrangements are

A. Such that there is no fuel gases enter non hazardous area
B. Of suitable design, construction and installation for their intended application shali be provided.
C. Such that in case of any leakage gases are led to atmosphere
D. Arranged in such a way that chances of fire and explosions are reduced

Answer: B — Of suitable design, construction and installation for their intended application shali be provided.

IGF Code functional requirement (3.2): piping systems, containment and over-pressure relief arrangements of suitable design, construction and installation for their intended application shall be provided.

25. Self Contained Breathing Apparatus used for

A. fire fighting
B. rescue operations
C. both (a) and (b)
D. none of the above

Answer: C — both (a) and (b)

Self-Contained Breathing Apparatus (SCBA) is mandatory for emergency entry, firefighting, and rescue operations in toxic or oxygen-deficient atmospheres.

26. A zone where ship traffic and other activities should be monitored during bunkering is known as:

A. Hazardous Zone
B. Safety Zone
C. Monitoring and security area
D. None of the above

Answer: C — Monitoring and security area

ISO 20519 and the IGF bunkering guidance define a monitoring and security area around the bunkering operation where ship traffic and other activities are monitored; the safety zone is the smaller area around the transfer where only essential persons are allowed.

27. Following any reasonably foreseeable failure during risk assessment consideration shall be given to the

A. Hazards associated with physical layout, operation and maintenance
B. Condition of ships machineries
C. Condition of cargo holds
D. Condition of the ships structure and hull

Answer: A — Hazards associated with physical layout, operation and maintenance

Risk assessments under the IGF Code evaluate potential failure modes related to physical layout, hazardous zone boundaries, and maintenance access.

28. Each liquefied gas fuel tank shall have an overflow control and be fitted with

A. High liquid leveglarm operating independently of other liquid level indicators and giving an audible and visual warning when activated.
B. An additional sensor operating independently of the high liquid level alarm shall automatically actuate a shutoff valve
C. The position of the sensors in the liquefied gas fuel tank shall be capable of being verified before commissioning.
D. All of above 132 k.

Answer: D — All of above 132 k.

IGF Code 15.5: overflow control requires an independent high-level alarm, an additional independent sensor that automatically closes a shutoff valve, and sensor positions that can be verified before commissioning, so all apply. 'All of above' has stray OCR text.

29. Measure of the resistance of natural gas to detonation when it is burned as a fuel in an engine is:

A. fuel in an engine is: Q al Calonfic value
B. Wobbe Number
C. The Methane Number (MN)
D. none of the above

Answer: C — The Methane Number (MN)

The Methane Number (MN) measures the knock resistance of a fuel gas in internal combustion engines, analogous to the Octane Number for gasoline.

30. The drip tray shall be thermally insulated from the ship's structure

A. To prevent any cracks in hull in case of leakage
B. So that the surrounding deck structures are not exposed to unacceptable cooling, in case of leakage of liquid fuel.
C. To prevent immdiate evaporation of liquid fuel due to high ambient temerature
D. To ensure that the liquid fuel remains liquid till is drained to appropriate tank

Answer: B — So that the surrounding deck structures are not exposed to unacceptable cooling, in case of leakage of liquid fuel.

Drip trays beneath bunkering manifolds must be thermally insulated from the deck structure to prevent cryogenic cooling and brittle fracture of the hull.

Set 12 — 30 AIGF exit exam questions with answers

1. What does hazardous area zone O includes?

A. any pipework for density-relief
B. any pipework for quantity-relief
C. any pipework for pressure-relief
D. any pipework for volume-relief

Answer: C — any pipework for pressure-relief

IGF Code 12.5.1: hazardous area zone 0 includes the interiors of fuel tanks and any pipework for pressure-relief or other venting systems for fuel tanks.

2. The hood or casing shall be equipped with _____ _

A. wind driven ventilation
B. natural ventilation
C. stack ventilation
D. mechanical exhaust ventilation

Answer: D — mechanical exhaust ventilation

Exhaust hoods over gas fuel machinery must be equipped with continuous mechanical extraction ventilation providing negative pressure.

3. LNG is bought and sold on its calorific content, which is expressed in ____.

A. Barrels (bbl)
B. Million British thermal units (MMBtu)
C. Cubic metres (m³)
D. Long tons (LT)

Answer: B — Million British thermal units (MMBtu)

LNG is traded on its energy content, not its volume or mass, so contracts and invoices use million British thermal units (MMBtu). The energy is calculated from the volume transferred, the density and the gross calorific value of the cargo.

4. The critical pressure of ethanol is approximately ____.

A. 61.5 bar abs
B. 30 bar abs
C. 6 bar abs
D. None of the above

Answer: A — 61.5 bar abs

Ethanol's critical temperature is about 241°C and its critical pressure about 61 to 63 bar absolute. Above the critical temperature it cannot be liquefied by pressure alone, whatever pressure is applied.

5. A fuel preparation room on a gas-fuelled ship typically contains which equipment?

A. HP vaporiser
B. BOG compressor
C. Glycol (heating medium) skid
D. All of the above

Answer: D — All of the above

The IGF Code defines a fuel preparation room as a space containing pumps, compressors and/or vaporisers used to condition fuel. HP vaporisers, boil-off gas compressors and the glycol-water heating skid serving the vaporisers are usually located there.

6. Fuel tanks shall be designed to withstand the ____ of the fuel under conditions of the upper ambient design temperature.

A. Full gauge vapour pressure
B. Full gauge absolute pressure
C. Full gauge liquid pressure
D. Full gauge atmospheric pressure

Answer: A — Full gauge vapour pressure

For pressure-type fuel storage the IGF Code requires the tank to withstand the full gauge vapour pressure of the fuel at the upper ambient design temperature. The tank must therefore stay safe even if refrigeration or pressure control is lost.

7. Electrical equipment installed in explosion-hazardous spaces and areas ____.

A. Should have a routine maintenance schedule as per the PMS
B. Must be inspected and surveyed as required by the Administration
C. Should have procedures and information for in-service inspection, maintenance and testing
D. All of the above

Answer: D — All of the above

Certified safe electrical equipment keeps its protection only if properly looked after. The IGF Code and IEC 60079-17 require planned maintenance, inspection and survey as the Administration requires, and documented procedures for in-service inspection, maintenance and testing.

8. In limit state design of fuel containment systems, Accident Limit States (ALS) ____.

A. Correspond to the maximum load-carrying capacity
B. Correspond to degradation due to the effect of cyclic loading
C. Concern the ability of the structure to resist accidental situations
D. None of the above

Answer: C — Concern the ability of the structure to resist accidental situations

The IGF and IGC Codes use limit state design. Ultimate limit states relate to maximum load-carrying capacity, fatigue limit states to degradation under cyclic loading, and accident limit states to the structure's ability to resist accidental situations such as collision or flooding.

9. The ventilated duct around a gas fuel pipe should be pressure tested to show that it can withstand the expected ____ at gas pipe rupture.

A. Least pressure
B. Lower pressure
C. Maximum pressure
D. Minimum pressure

Answer: C — Maximum pressure

If the inner gas pipe ruptures, the outer duct or double wall must contain the leak until the gas supply is shut off. The IGF Code therefore requires the duct to be pressure tested for the maximum pressure expected at a gas pipe rupture.

10. As per the IGF Code, the bunkering system shall be so arranged that ____.

A. No leakage can ever take place from the bunker hose
B. No gas is discharged to the atmosphere during filling of storage tanks
C. The bunkering system withstands fluctuations in loading pressure
D. The bunkering system withstands fluctuations in ambient temperature

Answer: B — No gas is discharged to the atmosphere during filling of storage tanks

The IGF Code requires the bunkering system to be arranged so that no gas is discharged to the atmosphere during filling of the storage tanks. Displaced vapour is handled by a vapour return line or by top spray and tank pressure control instead of venting.

11. Two valves in series in a pipe, with a third valve allowing pressure to be released from the pipe section between them, is known as a ____.

A. Double blow and bleed valve
B. Double blast and bleed valve
C. Double block and bleed valve
D. Double block and blow valve

Answer: C — Double block and bleed valve

A double block and bleed arrangement has two shut-off (block) valves in series and a bleed valve that vents the space between them. The IGF Code requires it on the gas supply to each consumer so gas cannot leak into the machinery space when the supply is shut.

12. For overflow control of a fuel tank, what will an additional sensor operating independently of the high liquid level alarm do?

A. Only give a second audible alarm on the bridge
B. Automatically actuate a shut-off (ESD) valve
C. Allow the crew to manually actuate a shut-off valve
D. Start a transfer pump to move fuel to another tank

Answer: B — Automatically actuate a shut-off (ESD) valve

The IGF Code requires a sensor independent of the high level alarm to automatically close a shut-off valve, the bunkering ESD valve, so the tank cannot become liquid full or overflow even if the operator misses the alarm.

13. Fuel storage tanks and fuel piping must be capable of being emptied, purged and vented. Before venting with dry air, what must be done to avoid an explosive atmosphere in the tanks and pipes?

A. Inerting
B. Gassing up
C. Cooling down
D. None of the above

Answer: A — Inerting

Going straight from fuel gas to air would pass through the flammable range. The IGF Code requires tanks and piping to be inerted first, usually with nitrogen, until the hydrocarbon content is low enough, and only then aerated with dry air.

14. The probability of a gas explosion in a machinery space with ____ fuelled machinery shall be minimised.

A. Gas
B. Low-flashpoint
C. Both gas and other low-flashpoint fuels
D. None of the above

Answer: C — Both gas and other low-flashpoint fuels

The IGF Code applies to ships using gases or other low-flashpoint liquids as fuel. Its functional requirements include minimising the probability of a gas explosion in machinery spaces with gas or low-flashpoint fuelled machinery.

15. The fuel containment system shall be so designed that a leak from the tank or its connections does not ____.

A. Harm persons on board
B. Endanger the ship
C. Pollute the environment
D. All of the above

Answer: D — All of the above

The IGF Code functional requirements state that the fuel containment system must be designed so that a leak from the tank or its connections does not endanger persons on board, the environment or the ship.

16. If portable tanks are used for fuel storage, the design of the fuel containment system shall be ____.

A. Equivalent to permanently installed tanks
B. Less stringent than permanently installed tanks
C. Up to the owner's discretion
D. Dependent on the age of the vessel

Answer: A — Equivalent to permanently installed tanks

The IGF Code requires a portable fuel tank's containment system to be equivalent to that of permanently installed tanks, including its supports, securing, connections and ESD arrangements.

17. A risk assessment shall be conducted to ensure that risks arising from the use of ____ affecting persons on board, the environment, and the structural strength or integrity of the ship are addressed.

A. Gas fuel
B. Low-flashpoint fuel
C. Both gas and other low-flashpoint fuels
D. None of the above

Answer: C — Both gas and other low-flashpoint fuels

IGF Code Chapter 4 requires a risk assessment covering the use of gas or other low-flashpoint fuels. It must identify and address risks to persons on board, the environment, and the structural strength and integrity of the ship.

18. What is a tankscope used for?

A. Measuring hydrocarbon vapour concentration in inerted atmospheres
B. Measuring carbon monoxide in inerted atmospheres
C. Measuring oxygen content in inerted atmospheres
D. Measuring hydrogen sulphide in inerted atmospheres

Answer: A — Measuring hydrocarbon vapour concentration in inerted atmospheres

A tankscope uses non-catalytic sensing, such as a hot-wire thermal conductivity or infrared sensor, to measure hydrocarbon concentration by volume in oxygen-deficient or inert atmospheres. Catalytic explosimeters cannot work there.

19. Fuel containment systems and machinery spaces containing sources that might release gas into the space shall be arranged and located such that ____.

A. A gas leakage will not affect personnel in any space
B. A fire or explosion in either will not lead to an unacceptable loss of power
C. A leakage will never reach the accommodation area
D. The ship can never suffer a blackout

Answer: B — A fire or explosion in either will not lead to an unacceptable loss of power

An IGF Code functional requirement is that a fire or explosion in a fuel containment space or gas-source machinery space must not cause an unacceptable loss of power, or make equipment in other compartments inoperable.

20. What is the minimum ventilation capacity required for fuel preparation rooms (pump and compressor rooms) under the IGF Code?

A. 30 air changes per hour
B. 20 air changes per hour
C. 12 air changes per hour
D. 6 air changes per hour

Answer: A — 30 air changes per hour

The IGF Code requires mechanical ventilation of at least 30 air changes per hour in fuel preparation rooms, so any gas leaking from pumps, compressors or vaporisers is diluted and removed quickly.

21. What is the major constituent of liquefied natural gas?

A. Methane
B. Styrene
C. Acrylonitrile
D. Polybutadiene

Answer: A — Methane

LNG is mostly methane, typically 85 to 99% depending on the source, with smaller amounts of ethane, propane, butane and nitrogen. It is carried at about -162°C at near atmospheric pressure.

22. Ventilation systems in gas-fuel spaces are required mainly to avoid ____.

A. Gas accumulation
B. Gas separation
C. Gas maintenance
D. None of these

Answer: A — Gas accumulation

Ventilation in tank connection spaces, fuel preparation rooms and ESD-protected machinery spaces dilutes and removes leaked gas. This stops gas from building up into a flammable concentration and keeps detection meaningful.

23. Causes such as improper hose connection, excessive movement of the loading arm or transfer system, or the supply vessel drifting or sailing away with the hose still connected can lead to which event during LNG bunkering?

A. Leaks from LNG pumps, pipes, hoses or tanks
B. Inadvertent disconnection of hoses
C. Overfilling or overpressure of the vessel's fuel tanks
D. External impact

Answer: B — Inadvertent disconnection of hoses

These causes put mechanical strain on the transfer connection and can pull the hose apart. Bunkering systems therefore use ESD links and emergency release couplings (dry break-away couplings) to isolate and separate safely.

24. Personnel should not enter or work in a tank or enclosed space until ____.

A. It has been ventilated for at least ten minutes
B. Safe working conditions have been confirmed and an entry permit issued
C. The oxygen reading is just below 21%
D. The flammable gas reading is below the UFL

Answer: B — Safe working conditions have been confirmed and an entry permit issued

Entry is allowed only after the atmosphere has been tested and found safe, with oxygen at 21% and flammable and toxic gases at or below their limits. Precautions must be in place and a permit issued under SOLAS XI-1/7 and the company procedures.

25. Under IGF Code Chapter 11, the water spray system protecting exposed parts of fuel storage tanks located on open deck shall provide a uniform application rate of at least:

A. 20 l/min/m2 for horizontal surfaces only
B. 4 l/min/m2 for horizontal surfaces and 10 l/min/m2 for vertical surfaces
C. 10 l/min/m2 for horizontal projected surfaces and 4 l/min/m2 for vertical surfaces
D. 2 l/min/m2 for all surfaces

Answer: C — 10 l/min/m2 for horizontal projected surfaces and 4 l/min/m2 for vertical surfaces

IGF Code 11.5 requires the water spray system for cooling and fire prevention to cover exposed tank parts with at least 10 l/min/m2 on horizontal projected surfaces and 4 l/min/m2 on vertical surfaces, the same rates used for gas carriers.

26. The permanently installed dry chemical powder system required by the IGF Code for the bunkering station area shall have a capacity of at least:

A. 1.5 kg/s for a minimum of 30 seconds
B. 10 kg/s for a minimum of 10 seconds
C. 5 kg/s for a minimum of 2 minutes
D. 3.5 kg/s for a minimum of 45 seconds

Answer: D — 3.5 kg/s for a minimum of 45 seconds

IGF Code 11.6.1 requires a fixed dry chemical powder system covering all possible leak points at the bunkering station, with a capacity of at least 3.5 kg/s for a minimum of 45 seconds, plus a portable dry powder extinguisher nearby.

27. Which extinguishing medium is most effective for extinguishing a small LNG fire at a leaking bunkering flange once the leak has been isolated?

A. Sea water jet directed into the burning pool
B. Dry chemical powder
C. Low-expansion foam
D. Carbon dioxide from a portable extinguisher

Answer: B — Dry chemical powder

Dry chemical powder interrupts the combustion chain reaction and is the primary agent for extinguishing gas fires, which is why the IGF Code requires a fixed dry powder system at the bunkering station. Water jets onto LNG increase vaporisation.

28. Why must a water jet never be directed onto a pool of spilled LNG?

A. Water lowers the auto-ignition temperature of methane
B. Water freezes instantly and blocks the scuppers permanently
C. The relatively warm water greatly increases the rate of vaporisation and intensifies the fire
D. Water reacts chemically with methane to form a toxic gas

Answer: C — The relatively warm water greatly increases the rate of vaporisation and intensifies the fire

Water is far warmer than LNG at about minus 162 degrees C, so applying it to a pool causes violent boiling and a large increase in vapour generation, enlarging the fire. Water spray should instead be used to cool surrounding structures and protect personnel.

29. For a burning LNG pool that cannot be extinguished safely, which agent is used to reduce vapour generation and radiant heat?

A. Carbon dioxide flooding
B. High-expansion foam
C. Straight water jet
D. Sand

Answer: B — High-expansion foam

High-expansion foam blankets the LNG pool, insulating it from radiant heat feedback and reducing vapour boil-off and flame height. It controls rather than extinguishes the fire, allowing the leak to be isolated and the fuel to burn out safely.

30. A jet fire is burning from a pressurised gas fuel line. The correct action before extinguishing the flame is to:

A. Open the vent mast to reduce pressure into the fire area
B. Apply a water jet directly to the flame to blow it out
C. Isolate the fuel supply at source, cooling the surroundings with water spray meanwhile
D. Extinguish the flame immediately with dry powder and then look for the leak

Answer: C — Isolate the fuel supply at source, cooling the surroundings with water spray meanwhile

If a gas jet fire is extinguished while gas is still escaping, an unignited vapour cloud forms that may explode on re-ignition. The supply must first be isolated, for example by the ESD and master gas fuel valve, while water spray cools exposed structures.

Set 13 — 30 AIGF exit exam questions with answers

1. According to the IGF Code, which statement on fire detection in tank connection spaces and fuel preparation rooms is correct?

A. Smoke detectors alone are always sufficient
B. Only manual call points are required
C. Fire detection is not required in these spaces if gas detection is fitted
D. Smoke detectors alone are not considered sufficient for rapid detection of a fire

Answer: D — Smoke detectors alone are not considered sufficient for rapid detection of a fire

IGF Code 11.7 requires a fixed fire detection and alarm system in spaces such as tank connection spaces and fuel preparation rooms, and states that smoke detectors alone shall not be considered sufficient for rapid detection of a fire; heat or flame detectors are also needed.

2. Under the IGF Code, a space containing a fuel containment system that is adjacent to a machinery space of category A shall be separated from it by:

A. A cofferdam of at least 300 mm
B. A cofferdam of at least 900 mm or an A-60 class division
C. A steel bulkhead without insulation
D. A B-15 class division only

Answer: B — A cofferdam of at least 900 mm or an A-60 class division

IGF Code 11.3 requires the space containing the fuel containment system to be separated from category A machinery spaces and other high fire risk rooms by a cofferdam of at least 900 mm or by A-60 class insulation, to limit heat input to the tank.

3. When fuel storage tanks are located on open deck, the IGF Code requires isolating valves in the fire main so that:

A. The water spray system can be supplied from sea water ballast pumps
B. Fire hoses can be connected to the bunkering line
C. Damaged sections of the fire main can be isolated
D. The fire main can be drained into the fuel tank

Answer: C — Damaged sections of the fire main can be isolated

IGF Code 11.4 requires isolating valves to be fitted in the fire main where fuel tanks are on open deck so that damaged sections can be isolated, allowing water supply to be maintained to the remaining hydrants and the water spray system.

4. A sudden explosive vaporisation that may occur when a large quantity of LNG is spilled onto water, without combustion, is known as:

A. Boiling liquid expanding vapour explosion (BLEVE)
B. Flashback
C. Rollover
D. Rapid phase transition (RPT)

Answer: D — Rapid phase transition (RPT)

Rapid phase transition is the near-instantaneous vaporisation of LNG on contact with water, producing a pressure wave without combustion. It is one reason the bunkering manifold area is protected and spills overboard are avoided. BLEVE involves rupture of a heated pressurised vessel.

5. Methanol used as fuel under MSC.1/Circ.1621 presents a particular fire-fighting problem because:

A. It reacts violently with dry powder
B. Its flame is almost invisible in daylight, and alcohol-resistant foam is needed
C. It cannot burn in air at normal temperatures
D. It is heavier than water and sinks below the foam

Answer: B — Its flame is almost invisible in daylight, and alcohol-resistant foam is needed

Methanol burns with a pale, nearly invisible flame in daylight, so heat detection or thermal imaging is needed to find the fire. Being water-miscible it breaks down ordinary foam, so the interim guidelines require alcohol-resistant foam systems.

6. In fighting a fire near an LNG fuel tank on open deck, the main purpose of the fixed water spray system is to:

A. Wash spilled LNG into the tank connection space
B. Extinguish the LNG fire by smothering
C. Dilute the LNG to below its flammable limit inside the tank
D. Cool the tank and its surroundings so that relief valves do not lift and structures are protected

Answer: D — Cool the tank and its surroundings so that relief valves do not lift and structures are protected

The water spray system keeps exposed tank surfaces, domes and adjacent structures cool, limiting pressure rise and boil-off and preventing structural damage. Extinguishment of gas fires relies on isolation of the fuel and dry chemical powder.

7. On a gas-fuelled ship, the master gas fuel valve for each gas-consuming machinery space must be located:

A. At the bunkering station only
B. On the fuel tank dome only
C. Outside the machinery space, and be operable from within it, from outside it and from the navigation bridge
D. Inside the engine room adjacent to the engine only

Answer: C — Outside the machinery space, and be operable from within it, from outside it and from the navigation bridge

IGF Code 9.4 requires a master gas fuel valve, situated outside the machinery space, on the supply to each machinery space. It must be operable from safe locations inside the machinery space, from outside it and from the navigation bridge so it can be closed in an emergency.

8. Which of the following will automatically close the master gas fuel valve under the IGF Code?

A. Engine speed falling below 50% MCR
B. Low level in the daily service diesel tank
C. Gas detection of 40% LFL in the ventilated duct around the gas pipe or loss of ventilation in that duct
D. High jacket cooling water temperature

Answer: C — Gas detection of 40% LFL in the ventilated duct around the gas pipe or loss of ventilation in that duct

IGF Code Table 1 (Chapter 15) lists gas detection reaching 40% LFL in the double pipe duct and loss of ventilation in the duct among conditions that automatically shut the master gas fuel valve, isolating gas from the machinery space.

9. In an ESD-protected machinery space, at what gas concentration must the IGF Code shutdown of gas supply and disconnection of non-certified electrical equipment be activated?

A. 5% LFL
B. 60% LFL
C. 10% LFL
D. 40% LFL

Answer: D — 40% LFL

In ESD-protected machinery spaces gas detection gives an alarm at 20% LFL, and at 40% LFL the safety system shuts off gas supply to the space and disconnects all electrical equipment that is not of certified safe type, removing ignition sources.

10. In the event of a significant LNG leak in the fuel preparation room, the first priority action is to:

A. Activate the emergency shutdown to isolate the fuel supply and raise the alarm
B. Enter the room to locate the leak with a portable detector
C. Open the room doors to the engine room to improve ventilation
D. Start the gas combustion unit at full load

Answer: A — Activate the emergency shutdown to isolate the fuel supply and raise the alarm

The immediate response to a fuel leak is to stop the release by activating the ESD, which closes tank and master gas fuel valves, and to raise the alarm. Entry into the gas-filled space without isolation and proper protection is dangerous.

11. When responding to a cryogenic LNG spill on deck, personnel should approach the area:

A. From upwind, wearing cryogenic protective equipment
B. Only from below the spill
C. From downwind, to stay out of the visible vapour cloud's path
D. From any direction, since LNG vapour is non-toxic

Answer: A — From upwind, wearing cryogenic protective equipment

Approaching from upwind keeps responders out of the drifting vapour cloud, which is cold and may be within the flammable range. Cryogenic gloves, face shield and protective clothing protect against cold burns from liquid or very cold surfaces.

12. Stainless steel drip trays and a water curtain at the LNG bunkering manifold are primarily intended to:

A. Prevent static electricity build-up
B. Protect the hull and deck steel from brittle fracture caused by a cryogenic spill
C. Collect rainwater from the manifold area
D. Cool the bunker hose during transfer

Answer: B — Protect the hull and deck steel from brittle fracture caused by a cryogenic spill

Ordinary hull steel becomes brittle at LNG temperatures. Drip trays of cryogenic-grade stainless steel collect leaks, and the water curtain flows over the ship's side below the manifold to keep the shell plating warm, preventing cold-induced brittle fracture.

13. During LNG bunkering, which event typically initiates ESD stage 2 (ESD-2) in the ship-shore link?

A. Change of watch on the receiving ship
B. Excessive movement of the ship that approaches the limit of the transfer system, leading to emergency release
C. Completion of the agreed bunker quantity
D. A minor gas alarm at 20% LFL in the engine room

Answer: B — Excessive movement of the ship that approaches the limit of the transfer system, leading to emergency release

ESD-1 stops transfer pumps and closes ESD valves. ESD-2 activates the emergency release coupling or system to disconnect the hose or arm safely, typically when vessel drift or excessive movement threatens to exceed the safe operating envelope.

14. The purpose of an emergency release coupling (ERC) in an LNG bunkering hose string is to:

A. Provide electrical continuity between ship and bunker vessel
B. Measure the quantity of LNG delivered
C. Purge the hose with nitrogen after transfer
D. Allow quick separation with minimal spillage, with self-closing valves on both sides

Answer: D — Allow quick separation with minimal spillage, with self-closing valves on both sides

An emergency release coupling separates the transfer system in an emergency such as excessive vessel movement. Valves close on both halves, limiting the LNG released to a very small quantity and preventing damage to the hose, manifold and ships.

15. Liquid LNG trapped between two closed valves in a pipeline section is dangerous because:

A. Heat ingress vaporises the liquid and can raise pressure enough to rupture the pipe
B. It reacts with the pipe material to form peroxides
C. It solidifies and blocks the line permanently
D. It cools the pipe below absolute zero

Answer: A — Heat ingress vaporises the liquid and can raise pressure enough to rupture the pipe

Trapped LNG absorbs heat, boils and expands about 600 times as vapour, so pressure in a blocked-in section can rise rapidly. Hence pipelines that may be isolated liquid-full must be fitted with relief valves and lines drained or purged after use.

16. Part C-1 of the IGF Code requires that drills and emergency exercises on board a gas-fuelled ship:

A. Be conducted only during the annual flag state survey
B. Be held at regular intervals, with gas-related exercises that may include tabletop exercises and review of procedures
C. Be carried out only by shore emergency teams
D. Be limited to abandon ship drills

Answer: B — Be held at regular intervals, with gas-related exercises that may include tabletop exercises and review of procedures

IGF Code Chapter 17 requires regular drills and emergency exercises. Gas-related exercises may include tabletop exercises, review of fuelling procedures, response to contingencies, tests of equipment for contingency response, and checks that crew are trained in their emergency duties.

17. Before LNG bunkering commences, the IGF Code requires the master of the receiving ship and the representative of the bunkering source to agree in writing on:

A. The engine room watch schedule
B. Only the price and quantity of fuel
C. The ship's next port of call
D. The transfer procedure, including cooling down and gassing up if needed, the maximum transfer rate at all stages and the volume to be transferred

Answer: D — The transfer procedure, including cooling down and gassing up if needed, the maximum transfer rate at all stages and the volume to be transferred

IGF Code Chapter 18 requires written agreement on the transfer procedure including cool-down and, if necessary, gassing-up, the maximum transfer rate at all stages, the volume to be transferred and the action to be taken in an emergency, together with a completed bunkering safety checklist.

18. LNG bunkering hoses used on gas-fuelled ships shall be designed for a bursting pressure of not less than:

A. 1.1 times the relief valve setting
B. Five times the maximum pressure the hose can be subjected to during bunkering
C. The hydrostatic test pressure of the fuel tank
D. Twice the design pressure of the receiving tank

Answer: B — Five times the maximum pressure the hose can be subjected to during bunkering

As for liquefied gas cargo hoses, IGF Code bunkering requirements specify that hoses are designed for a bursting pressure of not less than five times the maximum pressure the hose may experience during bunkering, giving a large safety margin.

19. Why is the bunker line pre-cooled with a small flow of LNG before full-rate transfer begins?

A. To test the gas detection system
B. To avoid thermal shock to the piping and to limit flash gas generation and pressure rise
C. To warm the bunker tank before filling
D. To dry out moisture with warm vapour

Answer: B — To avoid thermal shock to the piping and to limit flash gas generation and pressure rise

Introducing LNG at full rate into warm piping causes severe thermal stresses and rapid vaporisation. Gradual pre-cooling at low rate lets pipes contract evenly and reduces flash gas, keeping the receiving tank pressure under control before the rate is increased.

20. During bunkering, the receiving tank pressure is rising. Spraying incoming LNG through the top spray line will:

A. Have no effect on pressure
B. Increase the tank pressure more quickly
C. Raise the liquid temperature
D. Cool and condense vapour in the ullage space, reducing tank pressure

Answer: D — Cool and condense vapour in the ullage space, reducing tank pressure

Top spray filling distributes cold liquid through the vapour space, cooling and partly condensing the vapour so that tank pressure falls. Bottom filling does not contact the vapour and generally allows pressure to rise as vapour is compressed by the rising liquid.

21. To reduce the risk of stratification and rollover when bunkering LNG whose density differs from that already in the tank, recommended practice is to:

A. Top-fill when the incoming LNG is denser and bottom-fill when it is lighter
B. Always bottom-fill regardless of density
C. Stop the BOG compressor during bunkering
D. Always top-fill regardless of density

Answer: A — Top-fill when the incoming LNG is denser and bottom-fill when it is lighter

Denser LNG introduced at the top sinks and mixes with the tank contents, while lighter LNG introduced at the bottom rises through it. Either way the cargo mixes rather than forming stable layers of different density, preventing a later rollover.

22. What is the function of the vapour return line during LNG bunkering?

A. To return vapour displaced from the receiving tank to the bunkering facility and control tank pressure
B. To supply nitrogen to the engine room
C. To vent excess vapour to the atmosphere through the vent mast
D. To deliver LNG to the main engine

Answer: A — To return vapour displaced from the receiving tank to the bunkering facility and control tank pressure

As liquid enters the receiving tank, vapour is displaced and boil-off increases. The vapour return line sends this vapour back to the supplier so that the receiving tank pressure stays within limits without venting, as the IGF Code prohibits venting during filling.

23. On completion of LNG bunkering and before the hose is disconnected, the bunker line and hose should be:

A. Purged with compressed air
B. Left full of LNG to keep them cold
C. Filled with fresh water
D. Drained of liquid and purged with nitrogen

Answer: D — Drained of liquid and purged with nitrogen

The IGF Code requires means to drain bunkering lines and arrangements for inerting and gas-freeing. Draining residual LNG and purging with nitrogen ensures no liquid or flammable vapour is released when the connection is broken.

24. According to ISO 20519, the 'safety zone' around an LNG bunkering operation is the area:

A. Where passengers may embark freely
B. In which only dedicated, essential personnel and activities are allowed and ignition sources are controlled
C. Defined only by port state marine traffic control
D. Inside the receiving ship's accommodation

Answer: B — In which only dedicated, essential personnel and activities are allowed and ignition sources are controlled

ISO 20519 and SGMF guidance define the safety zone as the area around the bunkering station where only essential personnel and activities are permitted and potential ignition sources are controlled, sized from the hazard assessment of a credible LNG release.

25. What is the correct action if communication between the receiving ship and the bunkering source is lost during LNG transfer?

A. Increase the transfer rate to finish quickly
B. Continue at reduced rate and use hand signals
C. Continue as normal since the ESD link is automatic
D. Stop the transfer, using ESD if necessary, until communication is restored

Answer: D — Stop the transfer, using ESD if necessary, until communication is restored

Continuous reliable communication is a condition of the bunkering safety checklist. If it is lost, transfer must be stopped, by ESD if needed, and not resumed until communication is re-established, since neither party can coordinate response to an incident.

26. Why is an insulating flange or single non-conductive section commonly fitted in the LNG bunker transfer system?

A. To prevent stray currents and incendive sparking at the connection between ship and bunkering source
B. To allow the hose to be disconnected quickly
C. To insulate the LNG thermally against heat ingress
D. To measure the LNG flow rate

Answer: A — To prevent stray currents and incendive sparking at the connection between ship and bunkering source

Differences in electrical potential between ship and shore or barge can produce stray currents and sparking when hoses are connected or disconnected. An insulating flange breaks electrical continuity, removing this ignition source, in line with ISO 20519 and ISGOTT practice.

27. Under the IGF Code, the maximum filling limit of a liquefied gas fuel tank at the reference temperature is normally:

A. 85%
B. 95%
C. 98%
D. 100%

Answer: C — 98%

IGF Code 6.8 sets the filling limit at 98% at the reference temperature, with the loading limit derived from the ratio of liquid densities at reference and loading temperature. This leaves vapour space for expansion so the tank never becomes liquid-full.

28. Since LNG is traded on energy content, the energy delivered during bunkering is calculated from:

A. Volume delivered only
B. Mass of the bunker hose
C. Volume delivered, LNG density and gross calorific value derived from composition
D. Tank pressure and temperature only

Answer: C — Volume delivered, LNG density and gross calorific value derived from composition

The delivered energy equals the liquid volume multiplied by density and calorific value, both determined from the LNG composition analysed from representative samples. This is why gauging, temperature measurement and sampling are needed in custody transfer.

29. For truck-to-ship LNG bunkering, the quantity transferred is usually measured by:

A. The ship's draft survey
B. The sounding pipe of the bunker tank
C. A mass flow meter (such as a Coriolis meter) or weighing of the truck
D. The engine fuel consumption meter

Answer: C — A mass flow meter (such as a Coriolis meter) or weighing of the truck

Truck deliveries are relatively small, so gauge-based tank measurements are imprecise. Coriolis mass flow meters or weighbridge readings before and after delivery give the transferred mass, which is combined with composition data to determine energy delivered.

30. LNG samples for determining the composition of a bunker delivery are normally taken:

A. At the start of cool-down from the hose drain
B. From the boil-off gas in the receiving tank
C. During steady transfer, vaporised completely, and analysed by gas chromatograph
D. From the vent mast after bunkering

Answer: C — During steady transfer, vaporised completely, and analysed by gas chromatograph

A representative sample is taken from the liquid line during steady-state flow, completely vaporised so that lighter components do not separate, and analysed by gas chromatography. The composition gives density, calorific value and methane number.

Set 14 — 30 AIGF exit exam questions with answers

1. The IGF Code requires control of the bunkering operation to be possible from:

A. A safe location remote from the bunkering station, where tank pressure and level can be monitored
B. The bunker barge only
C. The bunkering station only
D. The navigation bridge only, with no other location

Answer: A — A safe location remote from the bunkering station, where tank pressure and level can be monitored

IGF Code Chapter 8 requires control of bunkering from a safe remote location, with tank pressure, level and overfill alarms monitored there, so the operator is not exposed at the manifold and can initiate shutdown without approaching a leak.

2. The IGF Code was made mandatory under SOLAS through:

A. Chapter II-2, Regulation 4, entering into force on 1 January 2010
B. Chapter VII, Part C, entering into force on 1 July 2002
C. MARPOL Annex VI, Regulation 14
D. Chapter II-1, Part G, entering into force on 1 January 2017

Answer: D — Chapter II-1, Part G, entering into force on 1 January 2017

Amendments to SOLAS Chapter II-1 added Part G, which makes the International Code of Safety for Ships using Gases or other Low-flashpoint Fuels mandatory. It entered into force on 1 January 2017 for new ships and ships converted to such fuels.

3. For the purposes of the IGF Code, a low-flashpoint fuel is a gaseous or liquid fuel with a flashpoint:

A. Lower than 60 degrees C
B. Lower than 23 degrees C
C. Lower than 0 degrees C
D. Above 60 degrees C

Answer: A — Lower than 60 degrees C

The IGF Code defines low-flashpoint fuel as gaseous or liquid fuel with a flashpoint lower than 60 degrees C, which is the SOLAS limit for ordinary fuel oil. Fuels such as LNG, methanol and ethanol therefore fall within its scope.

4. To which of the following ships does the IGF Code NOT apply?

A. Gas carriers covered by the IGC Code using their cargo as fuel
B. Ferries using LNG dual-fuel engines
C. Bulk carriers converted to use LNG
D. Container ships using LNG as fuel

Answer: A — Gas carriers covered by the IGC Code using their cargo as fuel

Gas carriers complying with the IGC Code, including those burning boil-off cargo as fuel, are excluded because the IGC Code already regulates their gas fuel systems. The IGF Code applies to other ships using gases or low-flashpoint fuels.

5. Under STCW Regulation V/3, advanced training for service on ships subject to the IGF Code is required for:

A. Masters, engineer officers and all personnel with immediate responsibility for the care and use of fuels and fuel systems
B. Only the chief engineer
C. All ratings forming part of a navigational watch only
D. Catering staff on passenger ships

Answer: A — Masters, engineer officers and all personnel with immediate responsibility for the care and use of fuels and fuel systems

STCW Regulation V/3 requires masters, engineer officers and all personnel with immediate responsibility for the care and use of fuels and fuel systems on ships subject to the IGF Code to hold a certificate in advanced training. Others with safety duties need basic training.

6. To obtain the STCW certificate in advanced training for ships subject to the IGF Code, a candidate must, in addition to basic training, have at least one month of approved seagoing service including:

A. One dry-docking of a gas-fuelled ship
B. Six months as engineer officer of the watch
C. A minimum of three bunkering operations on IGF ships, two of which may be replaced by approved simulator training
D. At least ten cargo discharges on a gas carrier

Answer: C — A minimum of three bunkering operations on IGF ships, two of which may be replaced by approved simulator training

STCW Regulation V/3 requires at least one month of approved seagoing service including at least three bunkering operations on board ships subject to the IGF Code. Two of these may be replaced by approved simulator training on bunkering, in addition to completing the advanced course.

7. How often must holders of STCW certificates for service on ships subject to the IGF Code provide evidence of continued professional competence?

A. Only once, the certificate is valid for life
B. Every ten years
C. At intervals not exceeding five years
D. Every year

Answer: C — At intervals not exceeding five years

STCW Regulation V/3 requires seafarers holding basic or advanced IGF certificates to establish continued competence at intervals not exceeding five years, normally through approved seagoing service on IGF ships within the period or by completing approved refresher training.

8. Where a gas-fuelled ship's design deviates from the prescriptive requirements of the IGF Code, approval may be based on:

A. The engine maker's warranty
B. The crew's operating experience only
C. Alternative design per SOLAS II-1/55, demonstrating equivalent safety by engineering analysis
D. A letter from the shipowner

Answer: C — Alternative design per SOLAS II-1/55, demonstrating equivalent safety by engineering analysis

The IGF Code is goal-based. Fuel arrangements that differ from the prescriptive provisions may be accepted as an alternative design under SOLAS regulation II-1/55, where an engineering analysis shows the functional requirements and an equivalent level of safety are met.

9. Ships using methanol or ethanol as fuel are currently guided by which IMO instrument?

A. MSC.1/Circ.1621, Interim guidelines for the safety of ships using methyl/ethyl alcohol as fuel
B. Resolution A.868(20)
C. MARPOL Annex II
D. MSC.1/Circ.1280

Answer: A — MSC.1/Circ.1621, Interim guidelines for the safety of ships using methyl/ethyl alcohol as fuel

Part A-1 of the IGF Code contains detailed requirements only for natural gas. For methyl and ethyl alcohol, IMO issued interim guidelines in MSC.1/Circ.1621 (2020), applied together with the general provisions of the IGF Code.

10. In the IGF Code, the specific requirements for ships using natural gas as fuel are contained in:

A. Part C-1
B. Part B-1
C. Part D
D. Part A-1

Answer: D — Part A-1

The IGF Code is arranged as Part A (general requirements), Part A-1 (specific requirements for natural gas), Part B-1 (manufacture, workmanship and testing), Part C-1 (drills, emergency exercises and operation) and Part D (training).

11. The risk assessment required by the IGF Code must consider, among other things:

A. Loss of function, component damage, fire, explosion and electric shock arising from the use of low-flashpoint fuels
B. Only commercial risks to the cargo
C. Only risks to the ship's schedule
D. Only crew fatigue

Answer: A — Loss of function, component damage, fire, explosion and electric shock arising from the use of low-flashpoint fuels

IGF Code 4.2 requires a risk assessment using acceptable and recognised techniques, considering as a minimum loss of function, component damage, fire, explosion and electric shock, with the risks eliminated or mitigated as necessary.

12. Before an LNG fuel tank is taken out of service for dry-docking, the correct sequence of operations after stripping the liquid is:

A. Aeration directly from the cold, gas-filled condition
B. Warm-up, inerting with nitrogen, then aeration with dry air
C. Inerting, cool-down, then gassing-up
D. Aeration with air, then warm-up, then inerting

Answer: B — Warm-up, inerting with nitrogen, then aeration with dry air

The tank is first warmed up by circulating hot vapour to evaporate residual liquid, then inerted with nitrogen to remove methane, and only then aerated with dry air. Admitting air directly to a gas-filled tank would create a flammable mixture.

13. After dry-dock, an inerted LNG fuel tank is 'gassed up' before cool-down. Gassing-up means:

A. Displacing the inert gas with natural gas vapour
B. Filling the tank with dry air
C. Pressurising the tank with nitrogen to test for leaks
D. Venting the tank to atmosphere

Answer: A — Displacing the inert gas with natural gas vapour

Nitrogen is non-condensable at LNG temperatures and would raise tank pressure and hinder the reliquefaction or pressure control. Gassing-up replaces the nitrogen with LNG vapour, after which the tank can be cooled down and filled.

14. Why must the cool-down of an LNG fuel tank be carried out gradually at a controlled rate?

A. To limit thermal stresses in the tank and its supports from uneven contraction
B. To raise the tank pressure to the relief valve setting
C. To allow the nitrogen to freeze before filling
D. To prevent the tank from warming up

Answer: A — To limit thermal stresses in the tank and its supports from uneven contraction

Rapid cooling creates large temperature differences across the tank shell, insulation and supports, causing excessive thermal stress. Cool-down rates and maximum temperature differences recommended by the tank designer are observed until the tank is ready to receive liquid.

15. Why is dry inert gas or dry air with a low dew point used when inerting or aerating fuel tanks and hold spaces?

A. To remove static charges from the tank
B. To raise the flashpoint of LNG
C. To increase the oxygen content of the tank
D. To prevent condensation and ice formation on cold surfaces

Answer: D — To prevent condensation and ice formation on cold surfaces

Moist gas would condense and freeze on cold tank surfaces and in valves and instruments, causing blockages and damage. The IGF Code requires dry inert gas or dry air of low dew point for inerting and for the atmosphere of spaces surrounding fuel tanks.

16. The IGF Code requires nitrogen generators or nitrogen storage installed in a separate compartment outside the engine room to be provided with:

A. A fixed CO2 flooding system only
B. A gas combustion unit
C. An LNG drip tray
D. Mechanical exhaust ventilation and a low oxygen alarm

Answer: D — Mechanical exhaust ventilation and a low oxygen alarm

Nitrogen leaking into a compartment displaces oxygen and can asphyxiate personnel without warning. IGF Code 6.14 therefore requires such compartments to have mechanical exhaust ventilation and a low oxygen alarm.

17. To prevent backflow of flammable gas into the nitrogen system, the inert gas supply connection to the fuel system shall be:

A. Connected through the engine room fresh water system
B. Non-permanent, or fitted with two non-return valves
C. Connected directly to the vent mast
D. Permanently connected with a single gate valve

Answer: B — Non-permanent, or fitted with two non-return valves

The IGF Code requires connections from the inert gas system to gas piping to be non-permanent, such as a removable spool, or alternatively fitted with two non-return valves, so that fuel gas cannot flow back into the inert gas system and spaces it serves.

18. Why must an LNG fuel tank and piping be inerted before admitting dry air during gas-freeing?

A. Air alone cannot remove water
B. Inerting increases tank pressure for testing
C. Nitrogen improves the strength of the steel
D. Mixing methane directly with air would pass through the flammable range

Answer: D — Mixing methane directly with air would pass through the flammable range

If air were introduced while methane is present, the mixture would pass through the 5 to 15% flammable range. Purging first with nitrogen reduces the methane concentration so that subsequent aeration can be done without creating a flammable atmosphere.

19. When warming up an LNG fuel tank, the warm-up is generally considered complete when:

A. The tank pressure reaches the relief valve setting
B. Ice forms on the tank dome
C. The oxygen content inside reaches 21%
D. No liquid remains and the tank structure temperatures have risen well clear of cryogenic levels

Answer: D — No liquid remains and the tank structure temperatures have risen well clear of cryogenic levels

Warm-up evaporates any remaining LNG and raises the temperature of the tank structure. It is complete when no liquid is left and temperature sensors show the structure well above cryogenic levels, so that inerting can then proceed without further boil-off.

20. Which first aid treatment is correct for a cold burn caused by contact with LNG?

A. Apply hot water above 50 degrees C immediately
B. Apply ointment and bandage tightly
C. Rub the area vigorously with snow
D. Gently warm the affected area with lukewarm water and do not rub it

Answer: D — Gently warm the affected area with lukewarm water and do not rub it

Cold burns should be thawed gently by immersion in or flushing with lukewarm water, never hot water, and must not be rubbed because frozen tissue is easily damaged. Loose clothing is removed if not frozen to skin and medical advice obtained.

21. A catalytic (pellistor) combustible gas detector is unsuitable for measuring hydrocarbon content in a nitrogen-inerted tank because:

A. It is too sensitive and always alarms
B. It only measures oxygen
C. It reacts only with hydrogen sulphide
D. It needs oxygen to oxidise the gas on its sensor and gives false low readings in inert atmospheres

Answer: D — It needs oxygen to oxidise the gas on its sensor and gives false low readings in inert atmospheres

The catalytic sensor measures heat produced as the gas burns on a heated element, which requires sufficient oxygen. In an inert atmosphere no combustion occurs, so it reads falsely low. Infrared instruments or tankscopes measuring percent by volume are used instead.

22. Before use, a portable gas detector should be function checked by:

A. A bump test with a known test gas to confirm a correct response and alarm
B. Holding it in sunlight to warm the sensor
C. Shaking it to check the battery
D. Exposing it to engine exhaust

Answer: A — A bump test with a known test gas to confirm a correct response and alarm

A bump test exposes the detector to test gas of known concentration to confirm that the sensors respond and alarms activate. Full calibration is carried out periodically according to the maker's instructions, and records are kept.

23. The main health hazard to personnel from a nitrogen leak in an enclosed space is:

A. Asphyxiation due to oxygen displacement, without warning by smell
B. Toxic poisoning by nitrogen
C. Explosion of nitrogen
D. Severe skin irritation

Answer: A — Asphyxiation due to oxygen displacement, without warning by smell

Nitrogen is colourless, odourless and non-toxic, but it displaces oxygen. A person entering an oxygen-deficient atmosphere may lose consciousness after a few breaths without warning, so oxygen must be measured before entry into any space connected to inert gas systems.

24. Natural gas vapour from LNG presents which main health hazard to personnel?

A. Acute toxicity at low concentrations
B. Severe corrosive skin burns from the vapour
C. Asphyxiation in high concentrations, as it displaces oxygen
D. Radioactivity

Answer: C — Asphyxiation in high concentrations, as it displaces oxygen

Methane is not toxic but acts as a simple asphyxiant by displacing oxygen in enclosed spaces. The cold liquid and vapour also cause cold burns. Its flammability is the main other hazard, so both oxygen and hydrocarbon content are checked before entry.

25. Ammonia, being considered as a future marine fuel, differs from LNG in that it is:

A. Highly toxic and corrosive to eyes, skin and lungs
B. Lighter than hydrogen
C. Non-toxic and odourless
D. Unable to burn under any conditions

Answer: A — Highly toxic and corrosive to eyes, skin and lungs

Ammonia is toxic at low concentrations and corrosive to the eyes, skin and respiratory tract, which requires toxic gas detection and special PPE. It is flammable only in a narrow, high concentration range. LNG vapour, by contrast, is non-toxic but highly flammable.

26. Hot work in a fuel preparation room on a gas-fuelled ship should only be carried out:

A. After informing the bridge by phone only
B. Under a hot work permit after isolation and gas-freeing of the fuel system and confirmation of a gas-free atmosphere
C. Whenever the engine is running on diesel
D. If the gas detection system is switched off

Answer: B — Under a hot work permit after isolation and gas-freeing of the fuel system and confirmation of a gas-free atmosphere

Hot work in or near gas-dangerous areas is a high-risk operation. It requires a permit-to-work with risk assessment, isolation, inerting and gas-freeing of the affected systems, atmosphere testing, and continuous monitoring and fire watch during the work.

27. Which personal protective equipment is required when connecting or disconnecting an LNG bunker hose?

A. A lifejacket only
B. Ear defenders only
C. Cryogenic gloves, face shield or visor, and protective clothing covering the skin
D. Cotton gloves and safety shoes only

Answer: C — Cryogenic gloves, face shield or visor, and protective clothing covering the skin

Personnel at the manifold may be exposed to cryogenic liquid or vapour jets when couplings are made or broken. Insulated cryogenic gloves, eye and face protection and clothing without exposed skin are required to prevent cold burns.

28. At atmospheric pressure, LNG boils at approximately:

A. Minus 196 degrees C
B. Minus 162 degrees C
C. Minus 42 degrees C
D. Minus 104 degrees C

Answer: B — Minus 162 degrees C

LNG, being mainly methane, boils at about minus 162 degrees C at atmospheric pressure, while propane boils at about minus 42 degrees C, ethylene at about minus 104 degrees C and nitrogen at about minus 196 degrees C.

29. The flammable range of methane in air is approximately:

A. 4% to 75% by volume
B. 1.8% to 9.5% by volume
C. 15% to 28% by volume
D. 5% to 15% by volume

Answer: D — 5% to 15% by volume

Methane burns in air only between about 5% and 15% by volume. Below 5% the mixture is too lean and above 15% too rich. Butane has a range of about 1.8 to 8.5%, hydrogen about 4 to 75% and ammonia about 15 to 28%.

30. Cold methane vapour released from an LNG spill initially stays near the deck, but becomes lighter than air when warmed above approximately:

A. plus 25 degrees C
B. Minus 110 degrees C
C. 0 degrees C
D. Minus 162 degrees C

Answer: B — Minus 110 degrees C

Methane at ambient temperature is lighter than air, but the cold vapour from boiling LNG is denser than air. As it warms above about minus 110 degrees C it becomes buoyant and rises, which is why a spill initially forms a low-lying visible cloud.

Set 15 — 30 AIGF exit exam questions with answers

1. One volume of LNG produces approximately how many volumes of natural gas at ambient temperature and atmospheric pressure?

A. 60
B. 600
C. 6000
D. 6

Answer: B — 600

LNG expands about 600 times when it vaporises and warms to ambient conditions. This expansion ratio explains both the economy of storing gas as a liquid and the large vapour cloud or pressure rise that a small liquid release can produce.

2. Which property of methanol makes it more hazardous to personnel than LNG in case of leakage?

A. It is toxic by ingestion, inhalation and skin absorption
B. It boils at minus 162 degrees C
C. It cannot form flammable mixtures
D. It is lighter than air at all temperatures

Answer: A — It is toxic by ingestion, inhalation and skin absorption

Methanol is a liquid at ambient temperature with a flashpoint of about 12 degrees C, and it is toxic if swallowed, inhaled or absorbed through the skin. It is also miscible with water, which affects both pollution response and fire-fighting.

3. Hydrogen as a fuel has a particularly wide flammable range in air of approximately:

A. 1.8% to 9.5% by volume
B. 4% to 75% by volume
C. 6% to 36% by volume
D. 5% to 15% by volume

Answer: B — 4% to 75% by volume

Hydrogen is flammable between about 4% and 75% by volume in air and has very low ignition energy, so almost any leak may ignite. Methane is 5 to 15%, propane about 2.1 to 9.5% and methanol about 6 to 36%.

4. Under the IGF Code, the permanently installed gas detection system shall give an alarm when the gas concentration reaches:

A. 5% LFL
B. 20% LFL
C. 100% LFL
D. 60% LFL

Answer: B — 20% LFL

IGF Code Chapter 15 requires gas detectors to activate an audible and visual alarm at 20% LFL. Safety actions such as shutdown of gas supply are activated at 40% LFL. For ventilated ducts around gas pipes in gas-safe machinery spaces the alarm may be set at 30% LFL.

5. An air lock between a hazardous area and a non-hazardous space, as defined in the IGF Code, consists of:

A. Two fire doors spaced at least 5 m apart
B. A curtain of water spray
C. Gastight bulkheads with two gastight doors spaced at least 1.5 m and not more than 2.5 m apart
D. A single weathertight door

Answer: C — Gastight bulkheads with two gastight doors spaced at least 1.5 m and not more than 2.5 m apart

The IGF Code defines an air lock as a space enclosed by gastight bulkheads with two gastight doors spaced at least 1.5 m and not more than 2.5 m apart, so that both doors are not open at the same time, preventing gas passing into the safe space.

6. Areas on open deck within 3 m of a fuel tank outlet, bunker manifold valve or fuel pipe flange are classified under the IGF Code as:

A. Hazardous area zone 2
B. Non-hazardous area
C. Hazardous area zone 1
D. Hazardous area zone 0

Answer: C — Hazardous area zone 1

Under IGF Code 12.5, zone 0 is the interior of fuel tanks and associated piping, while zone 1 includes open deck areas within 3 m of fuel tank outlets, gas or vapour outlets, bunker manifold valves, other fuel valves and fuel pipe flanges. Zone 2 surrounds zone 1 areas.

7. Ventilation of the duct around double-walled gas fuel piping should be arranged as:

A. Natural ventilation only
B. Mechanical under-pressure (exhaust) ventilation, so that any leak is drawn to gas detection and a safe outlet
C. No ventilation, the duct is sealed
D. Supply ventilation pressurising the duct with engine room air

Answer: B — Mechanical under-pressure (exhaust) ventilation, so that any leak is drawn to gas detection and a safe outlet

Under-pressure ventilation of the duct ensures leaked gas is extracted past gas detectors and discharged to a safe location in the open air, rather than escaping into the machinery space. Loss of ventilation causes automatic closure of the master gas fuel valve.

8. An ESD-protected machinery space concept relies on:

A. Inerting the machinery space with nitrogen
B. Running the engine on diesel only
C. Double-walled gas piping throughout so no leak can occur
D. Single-wall gas piping with automatic shutdown of gas supply and isolation of non-certified equipment on gas detection

Answer: D — Single-wall gas piping with automatic shutdown of gas supply and isolation of non-certified equipment on gas detection

In an ESD-protected machinery space, gas piping may be single-walled. Under abnormal conditions involving gas hazards, emergency shutdown automatically isolates gas supply and disconnects non-certified safe equipment, while equipment operating during such conditions is of certified safe type.

9. Under the IGF Code, the outlets of fuel tank pressure relief valve vent masts shall be located at a height above the weather deck not less than:

A. B/10 or 3 m, whichever is less
B. 2 m above the deck
C. B/3 or 6 m, whichever is greater, and 6 m above working areas and walkways
D. 1 m above the highest point of the tank

Answer: C — B/3 or 6 m, whichever is greater, and 6 m above working areas and walkways

IGF Code 6.7.2 requires vent mast outlets at a height of not less than B/3 or 6 m, whichever is greater, above the weather deck and 6 m above working areas and walkways, so that vented gas disperses safely away from personnel.

10. Vent mast outlets for fuel tank pressure relief shall be arranged at a distance from the nearest air intake or opening to accommodation, service and control spaces of at least:

A. 10 m
B. 3 m
C. 1.5 m
D. 25 m

Answer: A — 10 m

The IGF Code requires pressure relief vent exits to be at least 10 m from the nearest air intake, air outlet or opening to accommodation, service and control spaces and other non-hazardous areas, preventing vented gas being drawn into safe spaces.

11. Under the IGF Code, a liquefied gas fuel tank with a volume exceeding 20 m3 shall be fitted with:

A. One pressure relief valve only
B. No relief valve if a GCU is fitted
C. At least two pressure relief valves of approximately equal capacity
D. A bursting disc only

Answer: C — At least two pressure relief valves of approximately equal capacity

The IGF Code requires fuel storage tanks over 20 m3 to have at least two pressure relief valves of approximately equal capacity, so that one can be isolated for maintenance or fail without losing overpressure protection. Smaller tanks may have one.

12. Using the deterministic method of the IGF Code, liquefied gas fuel tanks are to be located at least what distance inboard from the ship's side shell?

A. 2 m in all cases
B. B/10 or 3 m, whichever is greater
C. B/2
D. B/5 or 11.5 m, whichever is less, but not less than 760 mm

Answer: D — B/5 or 11.5 m, whichever is less, but not less than 760 mm

IGF Code 5.3.3 requires fuel tanks to be located at least B/5 or 11.5 m, whichever is less, inboard from the ship's side, and not less than 760 mm from the shell, protecting them from collision damage. A probabilistic alternative is also permitted.

13. Under the IGF Code, pressure control of an LNG fuel tank by venting fuel vapour to atmosphere is:

A. Acceptable only in port
B. Not acceptable except in emergency situations
C. Acceptable whenever the GCU is out of service
D. Acceptable as the normal method

Answer: B — Not acceptable except in emergency situations

IGF Code 6.9 requires tank pressure and temperature to be kept within design limits by means such as reliquefaction, consumption in engines, thermal oxidation or pressure accumulation. Venting of fuel vapour to atmosphere for pressure control is not acceptable except in an emergency.

14. As an alternative to a mechanically ventilated duct, the IGF Code permits the space between the inner and outer pipe of double-walled gas fuel piping to be:

A. Filled with fresh water
B. Pressurised with inert gas at a pressure greater than the gas fuel pressure, with alarms for loss of inert gas pressure
C. Left open to the engine room
D. Filled with lubricating oil

Answer: B — Pressurised with inert gas at a pressure greater than the gas fuel pressure, with alarms for loss of inert gas pressure

IGF Code 9.6 allows gas piping in machinery spaces to be enclosed in a double wall with the annular space pressurised with inert gas above the fuel pressure. Any leak then flows inward, and loss of inert gas pressure is alarmed.

15. Methane slip from gas-fuelled engines is most significant in:

A. Low-pressure dual-fuel engines operating on the Otto cycle, especially at low load
B. High-pressure gas injection engines on the Diesel cycle
C. Diesel engines on MGO
D. Steam turbines

Answer: A — Low-pressure dual-fuel engines operating on the Otto cycle, especially at low load

Methane slip is unburned methane escaping with the exhaust, mainly from premixed lean-burn Otto-cycle engines where gas trapped in crevices escapes combustion, worsening at low loads. High-pressure Diesel-cycle gas injection engines have much lower slip.

16. Methane slip reduces the greenhouse benefit of LNG because methane's global warming potential over 100 years is roughly:

A. Equal to that of CO2
B. 1000 times that of CO2
C. Half that of CO2
D. 28 to 30 times that of CO2

Answer: D — 28 to 30 times that of CO2

Methane is a much more potent greenhouse gas than CO2, with a 100-year global warming potential of roughly 28 to 30 and much higher over 20 years. Small amounts of unburned methane can therefore offset part of the CO2 reduction from LNG.

17. Which operational practice minimises methane emissions from an LNG fuel system?

A. Venting boil-off regularly to keep pressure low
B. Managing tank pressure by consumption, reliquefaction or GCU rather than venting
C. Purging the bunker lines to atmosphere with natural gas
D. Running engines at very low load for long periods

Answer: B — Managing tank pressure by consumption, reliquefaction or GCU rather than venting

Venting releases methane directly to the atmosphere. Boil-off should be handled by consumption in engines or boilers, reliquefaction or a gas combustion unit, and lines purged with nitrogen. Prolonged low-load operation increases methane slip.

18. LNG-fuelled ships can meet IMO Tier III NOx limits in ECAs without exhaust aftertreatment when using:

A. Diesel engines on heavy fuel oil
B. High-pressure Diesel-cycle gas engines in all cases
C. Low-pressure Otto-cycle dual-fuel engines in gas mode
D. Any engine burning MGO

Answer: C — Low-pressure Otto-cycle dual-fuel engines in gas mode

Lean-burn low-pressure Otto-cycle gas engines have low combustion temperatures and meet Tier III NOx limits in gas mode without SCR or EGR. High-pressure gas injection Diesel-cycle engines generally need SCR or EGR to meet Tier III.

19. What flashpoint defines a 'low flashpoint fuel' under the IGF Code?

A. Less than 60 degC
B. Less than 100 degC
C. Exactly 0 degC
D. Higher than 60 degC

Answer: A — Less than 60 degC

A low flashpoint fuel has a flashpoint lower than permitted under SOLAS II-2/4 para 2.1.1, i.e. less than 60 degC; such fuels are not necessarily cryogenic.

20. On the Safety Data Sheet, how is boiling point defined?

A. The temperature at which a solid turns into a liquid
B. The temperature at which a liquid's saturated vapour pressure equals the surrounding atmospheric pressure
C. The lowest temperature at which a liquid forms an ignitable mixture in air
D. The pressure exerted by a vapour in equilibrium with its liquid

Answer: B — The temperature at which a liquid's saturated vapour pressure equals the surrounding atmospheric pressure

The deck defines boiling point as the temperature at which a liquid's saturated vapour pressure equals the atmospheric pressure surrounding it.

21. By roughly how much does a Dual-Fuel Diesel Electric (DFDE) system improve vessel efficiency over traditional steam turbines?

A. Around 5-10%
B. Around 50-60%
C. Around 25-30%
D. Around 75-80%

Answer: C — Around 25-30%

DFDE systems burn both HFO/MDO and BOG, improving vessel efficiency by around 25-30% over traditional steam turbines.

22. What type of tank is the LNG fuel tank, and how is it insulated?

A. IMO Type A membrane tank with no insulation
B. An open atmospheric tank
C. A Type B prismatic tank with foam glass
D. IMO Type C independent tank with vacuum perlite insulation

Answer: D — IMO Type C independent tank with vacuum perlite insulation

The LNG Fuel Tank is specified as a Cylindrical IMO Type C Independent Tank (both ellipsoidal heads) with Vacuum Perlite Insulation.

23. Who is the IGF advanced course aimed at?

A. Deck and engineering officers and personnel responsible for handling fuels and fuel systems under the IGF Code
B. Only galley staff
C. Passengers only
D. Shore-based accountants

Answer: A — Deck and engineering officers and personnel responsible for handling fuels and fuel systems under the IGF Code

The course is aimed at deck and engineering officers and any personnel with immediate responsibility for decisions on handling IGF-Code fuels and for the care and use of fuel and fuel systems on the vessel.

24. Which set of regulations must an LNG fuel system comply with?

A. COLREGs, ISM, ISPS and MLC
B. IGF Code, SOLAS, MARPOL and STCW
C. ISO 9001, OHSAS, REACH and GDPR
D. IMDG, IBC, IGC and BCH

Answer: B — IGF Code, SOLAS, MARPOL and STCW

The deck lists the governing instruments as the IGF Code, SOLAS, MARPOL and STCW for safe handling, storage and operation of LNG onboard.

25. Where must fuel gas conditioning and preparation be undertaken?

A. Inside the main engine room
B. Anywhere convenient on deck
C. In a space outside of the engine room (common with the Tank Connection Space or a separate Fuel Preparation Room)
D. Inside the accommodation block

Answer: C — In a space outside of the engine room (common with the Tank Connection Space or a separate Fuel Preparation Room)

The deck states fuel gas conditioning and preparation must be undertaken in a space outside of the engine room, either common with the Tank Connection Space or as a separate Fuel Preparation Room.

26. Where can low pressure fuel pumps and their motors be fitted?

A. Only outside the tank
B. Only on the engine itself
C. Only on the bunker manifold
D. Inside or outside the tank

Answer: D — Inside or outside the tank

For low pressure fuel supply, pumps are fitted inside or outside the tank, and the pump motors can likewise be fitted inside or outside the tank.

27. What is inerting?

A. Removing air from a space and replacing it with an inert gas
B. Filling a tank completely with seawater
C. Heating the tank to ambient temperature
D. Painting the tank interior to prevent corrosion

Answer: A — Removing air from a space and replacing it with an inert gas

Inerting is defined here as removing air from a space and replacing it with an inert gas of some description.

28. What is the stated purpose of the IGF Code?

A. To set fuel prices for the maritime industry
B. To provide an international standard for ships using gases or other low-flashpoint fuels to enhance safety and mitigate risks
C. To certify ship cooks and stewards
D. To regulate passenger ticketing

Answer: B — To provide an international standard for ships using gases or other low-flashpoint fuels to enhance safety and mitigate risks

The IGF Code aims to provide an international standard for ships using gases or other low-flashpoint fuels to enhance safety and mitigate risks associated with these fuels.

29. During the operation, how should communications be treated by all parties involved?

A. Checked only at the start of the operation
B. Left to the most senior person alone
C. Regularly and positively checked and confirmed, with back-up methods maintained
D. Assumed to be working unless someone complains

Answer: C — Regularly and positively checked and confirmed, with back-up methods maintained

Communications should be regularly and positively checked and confirmed by all parties, with standard and back-up links maintained — including across watch handovers.

30. How and when must the ESD system be tested?

A. Only once a year in port
B. In both warm and cold modes, prior to and after cool down
C. Only in warm mode before bunkering
D. Only after an incident has occurred

Answer: B — In both warm and cold modes, prior to and after cool down

The ESD system must be tested in both warm and cold modes (prior to and after cool down) to ensure it is operational and ready in an emergency.

Set 16 — 18 AIGF exit exam questions with answers

1. What is the maximum bunkering rate confirmed at the pre-bunkering meeting?

A. 1,750m³/h
B. 85m³/h
C. 2,000m³/h
D. 450m³/h

Answer: D — 450m³/h

The pre-bunkering meeting confirms the bunkering method, the maximum bunkering rate of 450m³/h, and the total volume of 2 x 1,750m³.

2. According to the objectives, which quantities must be measured, calculated and recorded for low flash point fuels?

A. Maximum fill quantity, on-board quantity (OBQ), minimum remain on board (ROB) and fuel consumption
B. Only the colour and odour of the fuel
C. Crew rotation and watch schedules
D. Hull paint thickness

Answer: A — Maximum fill quantity, on-board quantity (OBQ), minimum remain on board (ROB) and fuel consumption

The objectives list maximum fill quantity, OBQ, minimum ROB and fuel consumption — measured/recorded in liquid and vapour forms as appropriate.

3. Which technical specification governs the LNG bunkering operations risk assessment?

A. ISO 9001
B. ISO/TS 18683
C. MARPOL Annex VI
D. SOLAS Chapter II-2

Answer: B — ISO/TS 18683

The deck states the bunkering operations risk assessment should be undertaken in accordance with ISO/TS 18683, which is specific to the supply of LNG as fuel to ships.

4. Which of these is an IGF fuel covered in this deck?

A. Heavy fuel oil (HFO)
B. Marine diesel oil (MDO)
C. LNG (Liquefied Natural Gas)
D. Crude oil

Answer: C — LNG (Liquefied Natural Gas)

The deck lists IGF fuels as LNG (Liquefied Natural Gas), LPG (Liquefied Petroleum Gas) and other low-flashpoint fuels such as methanol and ethanol.

5. Which three properties make IGF fuels especially hazardous in a spill or leak?

A. Colour, odour, and viscosity
B. Density, salinity, and pH
C. Conductivity, opacity, and pressure
D. Flammability, cryogenic temperature, and toxicity

Answer: D — Flammability, cryogenic temperature, and toxicity

IGF fuels carry three core hazards: flammability (fire/explosion), cryogenic temperatures (cold burns and steel brittleness), and toxicity (e.g. methanol/ethanol vapours).

6. What does the IGF Code provide mandatory provisions for?

A. The arrangement, installation, control and monitoring of machinery, equipment and systems using low-flashpoint fuels
B. The price of marine fuel
C. Crew wages and rest hours
D. Cargo manifest documentation only

Answer: A — The arrangement, installation, control and monitoring of machinery, equipment and systems using low-flashpoint fuels

The IGF Code contains mandatory provisions for the arrangement, installation, control and monitoring of machinery, equipment and systems using low-flashpoint fuels, focusing initially on LNG.

7. When was the IGF Code adopted by the IMO?

A. January 2000
B. June 2015
C. December 2020
D. June 1995

Answer: B — June 2015

The IGF Code — the International Code of Safety for Ships using Gases or other Low-Flashpoint Fuels — was adopted by the IMO in June 2015.

8. What three things must be present to create a flame of any kind?

A. Pressure, salt water and light
B. Nitrogen, fuel and cold
C. Oxygen, fuel and a heat source
D. Fuel, water and a spark only

Answer: C — Oxygen, fuel and a heat source

To create a flame we must have three things: oxygen, fuel and a heat source.

9. What does this topic require you to be able to do with gas detection instruments?

A. Manufacture new sensors onboard
B. Replace all portable units with fixed ones
C. Avoid using any portable detectors
D. Use the instruments associated with specific gases and calibrate them correctly

Answer: D — Use the instruments associated with specific gases and calibrate them correctly

The objective is the use of gas detection instruments associated with specific gases and correct calibration.

10. How is compliance defined in this material?

A. Adhering to laws, regulations, standards, and ethical practices
B. Following only the captain's verbal orders
C. Doing whatever is cheapest for the company
D. Meeting deadlines regardless of method

Answer: A — Adhering to laws, regulations, standards, and ethical practices

Compliance is the act of adhering to laws, regulations, standards, and ethical practices, which maintains safety, legality and ethical standards.

11. What does risk assessment fundamentally involve?

A. Only recording incidents after they happen
B. Identifying, analyzing, and evaluating risks
C. Estimating fuel consumption
D. Scheduling crew rest hours

Answer: B — Identifying, analyzing, and evaluating risks

Risk assessment involves identifying, analyzing, and evaluating risks — it is crucial for ensuring the safety of operations involving low-flashpoint fuels.

12. Why is conducting risk analysis on board described as crucial?

A. It replaces the need for any crew training
B. It is only needed for the ship's paperwork audit
C. It identifies hazards, evaluates risks and drives mitigation while ensuring IGF Code compliance
D. It guarantees zero fuel consumption

Answer: C — It identifies hazards, evaluates risks and drives mitigation while ensuring IGF Code compliance

Risk analysis identifies potential hazards, evaluates risks and implements mitigation, ensuring compliance with the IGF Code and enhancing overall safety of ship operations.

13. What is the purpose of this risk assessment exercise?

A. To calculate the ship's fuel consumption
B. To design a new LNG fuel tank
C. To schedule the crew's shore leave
D. To conduct a sample risk assessment for an IGF fuel ship, identifying hazards, evaluating risks and implementing mitigation measures

Answer: D — To conduct a sample risk assessment for an IGF fuel ship, identifying hazards, evaluating risks and implementing mitigation measures

The exercise is to conduct a sample risk assessment for an IGF fuel ship — focusing on identifying potential hazards, evaluating risks and implementing mitigation measures.

14. What is the core purpose of having safety plans on board an IGF ship?

A. Ensuring safety and compliance with the IGF Code
B. Reducing the crew's pay
C. Increasing the vessel's cargo capacity
D. Replacing the need for any crew training

Answer: A — Ensuring safety and compliance with the IGF Code

Safety plans matter because they ensure safety on board and compliance with the IGF Code.

15. Which publication provides guidance on general shipboard maintenance and enclosed space entries?

A. The ship's lunch menu
B. The Code of Safe Working Practice for Merchant Seafarers
C. The manufacturer's paint catalogue
D. The vessel's crew list

Answer: B — The Code of Safe Working Practice for Merchant Seafarers

The Code of Safe Working Practice for Merchant Seafarers provides a wealth of information about general shipboard tasks regarding maintenance and enclosed space entries.

16. How does breathing apparatus keep external gases out of the wearer's lungs?

A. It chemically converts toxic gas to oxygen
B. It cools the incoming air below freezing
C. A full face mask seals the face and maintains a positive internal pressure so only cylinder air is breathed
D. It filters the surrounding air through carbon

Answer: C — A full face mask seals the face and maintains a positive internal pressure so only cylinder air is breathed

The full face mask creates a seal and maintains positive internal pressure, preventing ingress of external gases so the wearer breathes only the clean air from the cylinder.

17. Under the IGF Code, what must be done to systems holding flammable or toxic vapours before maintenance work?

A. Repainting the pipework
B. Increasing the pressure
C. Adding more fuel
D. Gas-freeing of the systems

Answer: D — Gas-freeing of the systems

The IGF Code requires gas-freeing of systems containing flammable/toxic vapours before repair and maintenance work.

18. Which is a core general firefighting guideline for a fire involving hazardous fuel?

A. Always wear appropriate protective equipment and self-contained breathing apparatus
B. Approach the fire bare-handed to feel the heat
C. Never evacuate, regardless of danger
D. Pour the fuel onto the fire to dilute it

Answer: A — Always wear appropriate protective equipment and self-contained breathing apparatus

General guidelines stress full protective gear and self-contained breathing apparatus, evacuating if necessary, containing the fire only if safe, and avoiding direct contact with the substance.

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AIGF exit exam questions and answers — Advanced Training for Ships subject to the IGF Code

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