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CHEMCO exit exam questions and answers — Set 18 — Advanced Training for Chemical Tanker Cargo Operations

Set 18 of the Advanced Training for Chemical Tanker Cargo Operations (CHEMCO) exit exam bank — 30 of 663 questions, with the correct option marked and a one-line explanation for every one. Read it end to end, jump to a single set, or search it — then sit the same bank as a timed paper. The real DG Shipping exit exam is 30 marks with 15 to pass.

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Set 18 — 30 CHEMCO exit exam questions with answers

1. What is the purpose of a Safety Data Sheet (SDS) for a chemical cargo?

  • A. Employee performance evaluation
  • B. Product advertising
  • C. Providing information on chemical hazards
  • D. Financial statement disclosure
Answer: C — Providing information on chemical hazards
An SDS (or MSDS) gives the hazards, safe handling, PPE, first aid, fire-fighting and spill measures for a product. SOLAS VI/5-1 requires an MSDS to be provided for MARPOL Annex I cargoes and fuel oil, and cargo information is mandatory for IBC Code products.

2. Which hazard symbol represents a substance that can catch fire easily?

  • A. Flame
  • B. Skull and crossbones
  • C. Exclamation mark
  • D. Corrosion
Answer: A — Flame
The flame pictogram, as used in GHS and the IMDG flammable classes, identifies flammable gases, liquids and solids. The skull and crossbones indicates acute toxicity, the exclamation mark indicates harmful or irritant substances, and the corrosion symbol indicates corrosives.

3. What is the primary function of a scrubber in air pollution control?

  • A. Increase emissions
  • B. Remove pollutants from exhaust gases
  • C. Enhance visibility in the environment
  • D. Produce harmful by-products
Answer: B — Remove pollutants from exhaust gases
An exhaust gas cleaning system (scrubber) washes exhaust gas, usually with seawater or caustic solution, to remove sulphur oxides and particulates. MARPOL Annex VI Reg. 4 accepts it as an equivalent means of meeting the sulphur limits.

4. In chemical storage and carriage, what is the purpose of segregating incompatible chemicals?

  • A. Simplify inventory management
  • B. Enhance colour coding
  • C. Prevent accidental reactions
  • D. Facilitate rapid disposal
Answer: C — Prevent accidental reactions
Incompatible products can react violently, producing heat, toxic gases or pressure, if they mix through leaks or common lines. The IBC Code and the USCG compatibility chart therefore require segregation, such as separate tanks, piping and venting, or cofferdams.

5. Which hazard symbol represents a substance that poses an immediate (acute) toxic health hazard?

  • A. Flame
  • B. Skull and crossbones
  • C. Exclamation mark
  • D. Corrosion
Answer: B — Skull and crossbones
The skull and crossbones pictogram indicates acute toxicity, meaning a substance that can cause death or serious harm after short exposure by swallowing, skin contact or inhalation, as with IMDG Class 6.1 toxic substances.

6. What does the term 'hazardous area classification' refer to?

  • A. Identifying areas with high productivity
  • B. Designating areas with potential fire or explosion risks
  • C. Analysing areas with minimal chemical exposure
  • D. Classifying areas based on marketing strategies
Answer: B — Designating areas with potential fire or explosion risks
Hazardous area classification divides spaces into zones 0, 1 and 2 according to how likely a flammable atmosphere is to be present (IEC 60092-502, IBC/IGC Codes). This determines which certified safe electrical equipment may be installed there.

7. What is the primary purpose of a chemical spill response plan?

  • A. Minimise public awareness
  • B. Maximise chemical production
  • C. Ensure rapid disposal of spilled chemicals
  • D. Minimise environmental and health risks
Answer: D — Minimise environmental and health risks
A spill response plan, such as the shipboard SMPEP, sets out reporting, containment and clean-up actions and the responsibilities of each crew member, so that a spill is dealt with quickly to reduce harm to people and the marine environment.

8. Under the IBC Code, cargo tanks of a ship type 1 must be located inboard from the side shell plating, at the summer load line, by at least:

  • A. B/5 or 11.5 m, whichever is less
  • B. B/15 or 2 m, whichever is less
  • C. 760 mm only
  • D. B/10 or 8 m, whichever is greater
Answer: A — B/5 or 11.5 m, whichever is less
IBC Code 2.6 requires type 1 ship cargo tanks to be at least B/5 or 11.5 m (whichever is less) inboard of the side shell, and never less than 760 mm from the shell plating, giving maximum protection against collision damage.

9. For both ship type 1 and ship type 2, the IBC Code requires cargo tanks to be located above the moulded line of the bottom shell plating at centreline by not less than:

  • A. B/15 or 6 m, whichever is less
  • B. B/5 or 11.5 m, whichever is less
  • C. 2 m in all cases
  • D. 760 mm in all cases
Answer: A — B/15 or 6 m, whichever is less
IBC Code 2.6 places type 1 and type 2 cargo tanks at least B/15 or 6 m (whichever is less) above the bottom shell at centreline, protecting them against grounding damage. Type 3 ships have no such location requirement.

10. For a ship type 2, the minimum distance of cargo tanks from the side shell plating required by the IBC Code is:

  • A. 760 mm
  • B. B/5
  • C. 11.5 m
  • D. No requirement
Answer: A — 760 mm
IBC Code 2.6.1.2 requires type 2 ship cargo tanks to be not less than 760 mm from the shell plating, plus the bottom clearance of B/15 or 6 m. The larger B/5 or 11.5 m side clearance applies only to type 1 ships.

11. Which IBC ship type is intended to carry products with sufficiently severe environmental and safety hazards that require the maximum preventive measures against cargo escape?

  • A. Ship type 1
  • B. Ship type 2
  • C. Ship type 3
  • D. Ship type 4
Answer: A — Ship type 1
IBC Code 2.1.2 defines a type 1 ship as a chemical tanker for products with very severe environmental and safety hazards requiring maximum preventive measures. Type 2 covers appreciably severe hazards and type 3 sufficiently severe hazards needing a moderate degree of containment.

12. Where in the IBC Code chapter 17 table is the minimum ship type for a product indicated?

  • A. Column e
  • B. Column c
  • C. Column f
  • D. Column k
Answer: A — Column e
In the IBC Code chapter 17 summary of minimum requirements, column e gives the ship type (1, 2 or 3). Column c gives the MARPOL pollution category, column f the tank type and column k the vapour detection requirement.

13. Under the IBC Code, the quantity of a product required to be carried in a ship type 1 must not exceed how much in any one tank?

  • A. 1,250 m3
  • B. 3,000 m3
  • C. 5,000 m3
  • D. 700 m3
Answer: A — 1,250 m3
IBC Code 16.1 limits a product required to be carried in a type 1 ship to 1,250 m3 in any one tank, and a product required to be carried in a type 2 ship to 3,000 m3 in any one tank, limiting the quantity released if a tank is breached.

14. A product whose chapter 17 entry requires ship type 2 is to be loaded. What is the largest volume of it the IBC Code permits in a single cargo tank?

  • A. 3,000 m3
  • B. 1,250 m3
  • C. 10,000 m3
  • D. 2,000 m3
Answer: A — 3,000 m3
IBC Code 16.1 limits products requiring a type 2 ship to 3,000 m3 in any one tank (1,250 m3 for type 1 products), so that the potential outflow from a damaged tank is restricted.

15. According to the IBC Code, a gravity tank is a tank having a design pressure at the top of the tank not greater than:

  • A. 0.07 MPa gauge
  • B. 0.7 MPa gauge
  • C. 0.007 MPa gauge
  • D. 0.25 MPa gauge
Answer: A — 0.07 MPa gauge
IBC Code chapter 4 defines a gravity tank as one with a design pressure not greater than 0.07 MPa gauge at the top of the tank; a pressure tank has a design pressure greater than 0.07 MPa gauge. Tank type is shown in column f of chapter 17.

16. Which description correctly defines an integral tank in the IBC Code?

  • A. A tank forming part of the ship's hull and stressed with the adjacent hull structure
  • B. A self-supporting tank not contributing to hull strength
  • C. A cylindrical pressure vessel mounted on deck
  • D. A tank used only for cargo residues and slops
Answer: A — A tank forming part of the ship's hull and stressed with the adjacent hull structure
IBC Code 4.1 defines an integral tank as a cargo containment envelope forming part of the ship's hull, stressed in the same manner and by the same loads as the contiguous hull structure. An independent tank is self-supporting and is not part of the hull structure.

17. Under the IBC Code, cargoes that react in a hazardous manner with each other must be segregated by a cofferdam, void space, pump room, empty tank or tank containing a mutually compatible cargo, and also have:

  • A. Separate pumping and piping systems and separate tank venting systems
  • B. A common vent riser fitted with a flame screen
  • C. A shared stripping line with a single blank flange
  • D. Only a portable hose connection between tanks
Answer: A — Separate pumping and piping systems and separate tank venting systems
IBC Code 3.1.4 requires mutually reactive cargoes to be separated by a cofferdam, void, pump room, empty tank or tank with a compatible cargo, and to have separate pumping, piping and venting systems so the cargoes cannot meet through shared equipment.

18. What gives stainless steel cargo tanks their resistance to corrosion?

  • A. A thin, self-healing chromium oxide passive film on the surface
  • B. A zinc-rich primer applied at the shipyard
  • C. Cathodic protection by magnesium anodes
  • D. A rubber lining bonded to the steel
Answer: A — A thin, self-healing chromium oxide passive film on the surface
Stainless steel resists corrosion because its chromium content forms a thin, invisible chromium oxide passive layer. If damaged or contaminated it must be re-passivated, typically with a nitric acid based solution, before carrying aggressive cargoes.

19. Why should seawater not be left standing in stainless steel cargo tanks for long periods?

  • A. Chlorides break down the passive film and cause pitting corrosion
  • B. Seawater hardens the steel and makes it brittle
  • C. Seawater dissolves the nickel content completely
  • D. Salt deposits increase the tank's design density
Answer: A — Chlorides break down the passive film and cause pitting corrosion
Chloride ions attack the passive chromium oxide film of stainless steel, causing localised pitting and crevice corrosion. Tanks washed with seawater are therefore given a final fresh-water rinse and dried promptly, which also prevents chloride contamination of the next cargo.

20. Which statement regarding phenolic epoxy tank coatings is correct?

  • A. They have wider chemical resistance than plain epoxy but must be checked against the coating maker's resistance list for each cargo
  • B. They are suitable for every cargo listed in the IBC Code without restriction
  • C. They cannot be used for any vegetable oils
  • D. They are the preferred coating for concentrated nitric acid
Answer: A — They have wider chemical resistance than plain epoxy but must be checked against the coating maker's resistance list for each cargo
Phenolic epoxies resist a broader range of chemicals than standard epoxy, but no coating is universal. The coating manufacturer's resistance list, including any restrictions on temperature, previous cargo and exposure time, must be checked before every cargo is accepted.

21. Under the IBC Code, cargo tanks must be segregated from machinery spaces, accommodation and service spaces and drinking-water and stores for human consumption by:

  • A. Cofferdams, void spaces, cargo pump rooms, empty tanks, oil fuel tanks or similar spaces
  • B. A single plate bulkhead only
  • C. Insulation panels with fire rating A-60 only
  • D. A water curtain system
Answer: A — Cofferdams, void spaces, cargo pump rooms, empty tanks, oil fuel tanks or similar spaces
IBC Code 3.1 requires cargo tanks (and residue and slop tanks) to be separated from machinery, accommodation and service spaces and from drinking water and stores by cofferdams, voids, cargo pump rooms, empty tanks, oil fuel tanks or similar spaces, avoiding single-bulkhead contact.

22. Mechanical ventilation of a cargo pump room on a chemical tanker under the IBC Code must provide at least:

  • A. 30 air changes per hour based on the total volume of the space
  • B. 6 air changes per hour
  • C. 2 air changes per hour
  • D. 45 air changes per hour
Answer: A — 30 air changes per hour based on the total volume of the space
IBC Code 12.1.6 requires ventilation of cargo handling spaces such as cargo pump rooms of not less than 30 changes of air per hour based on the total volume of the space, with exhaust drawn from below the floor plates where heavy vapours collect.

23. Under the IBC Code, high-velocity vent outlets of a controlled tank venting system must be at least what height above the weather deck or fore-and-aft gangway?

  • A. 3 m
  • B. 1 m
  • C. 6 m
  • D. 10 m
Answer: A — 3 m
IBC Code 8.3 requires controlled venting outlets to be at least 6 m above the weather deck or gangway, but this may be reduced to 3 m where approved high-velocity vent valves discharge vapour upward at not less than 30 m/s.

24. Under the IBC Code, controlled venting outlets must be located at least what horizontal distance from the nearest air intake or opening to accommodation, service and machinery spaces and from ignition sources?

  • A. 10 m
  • B. 3 m
  • C. 5 m
  • D. 25 m
Answer: A — 10 m
IBC Code 8.3 requires controlled venting outlets to be at least 10 m from the nearest air intake or opening to enclosed spaces containing ignition sources and from deck machinery or equipment that may be an ignition hazard.

25. What is the main advantage of fitting each cargo tank of a parcel chemical tanker with its own submerged deepwell pump and dedicated line?

  • A. Many grades can be carried and handled simultaneously with full segregation
  • B. It removes the need for any cargo tank venting
  • C. It allows cargo to be discharged without any shore manifold connection
  • D. It eliminates the need for tank cleaning between cargoes
Answer: A — Many grades can be carried and handled simultaneously with full segregation
On parcel tankers each tank normally has its own deepwell or submerged pump and a dedicated line to the manifold. This gives complete segregation between grades, reduces contamination risk and allows several parcels to be loaded or discharged at once.

26. What is the principal hazard if a shore emergency shutdown valve closes too quickly while a chemical tanker is loading at a high rate?

  • A. A pressure surge that may rupture hoses, loading arms or pipelines
  • B. Static discharge inside the cargo tank
  • C. An immediate vacuum in the cargo tank
  • D. Overheating of the cargo pump motor
Answer: A — A pressure surge that may rupture hoses, loading arms or pipelines
Rapid closure of a valve against a flowing liquid column converts the liquid's momentum into a pressure surge (liquid hammer). ESD valve closure times and loading rates must therefore be agreed between ship and terminal to keep surge pressures within hose and pipeline limits.

27. Under the IBC Code, ships carrying toxic or flammable products, or both, must be equipped with at least how many instruments designed and calibrated for testing the specific vapours?

  • A. Two
  • B. One
  • C. Three
  • D. Four
Answer: A — Two
IBC Code 13.2 requires ships carrying toxic or flammable products to carry at least two instruments designed and calibrated for testing for the specific vapours concerned. Column k of chapter 17 shows whether toxic (T) or flammable (F) vapour detection is needed.

28. In IBC Code chapter 17, the letters 'T' and 'F' in column k indicate:

  • A. Toxic and flammable vapour detection requirements
  • B. Temperature class and fire protection
  • C. Tank type and filling limit
  • D. Tripartite agreement and flag approval
Answer: A — Toxic and flammable vapour detection requirements
Column k of the IBC Code chapter 17 table gives the vapour detection requirement: T means toxic vapour detection and F means flammable vapour detection. Both may be required for the same product.

29. Why must the high-level alarm on a cargo tank be independent of the tank gauging system?

  • A. So that failure of the gauge does not also disable the overfill warning
  • B. So that it can be used instead of the gauge for cargo calculations
  • C. So that it only operates when the ship is in port
  • D. So that it can be reset by the terminal
Answer: A — So that failure of the gauge does not also disable the overfill warning
An independent high-level alarm provides a second barrier against overfilling. If the primary gauging system fails or gives a false reading, the independent alarm still warns the operator in time to stop loading or divert the flow.

30. When a chemical tanker uses a vapour emission control (vapour return) system, which monitoring arrangement is required in the vapour collection main?

  • A. A pressure sensor with high and low pressure alarms
  • B. A flow meter with a totaliser only
  • C. A temperature sensor with a high temperature trip only
  • D. A sight glass at the manifold
Answer: A — A pressure sensor with high and low pressure alarms
IMO guidance on vapour emission control systems (MSC/Circ.585) requires the vapour collection main to have a pressure sensor giving high and low pressure alarms, so that over-pressure or vacuum in the tanks is detected before the P/V valves or tanks are overstressed.

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