CHEMCO exit exam questions and answers — Set 3 — Advanced Training for Chemical Tanker Cargo Operations
Set 3 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 3 — 30 CHEMCO exit exam questions with answers
1. Most minor spills of oil products are caused by
- A. equipment failure
- B. human error
- C. major casualties
- D. unforeseeable circumstances
Answer: B — human error
Industry statistics from ITOPF and OCIMF show that most small operational spills, especially during loading, discharging and bunkering, result from human error such as wrong valve settings, inattention or overfilling rather than equipment failure.
2. Containment and Damage Control: identify which step is of the highest importance for personal protection?
- A. Don required PPE as determined from the MSDS. Contain liquid material using barriers, such as absorbents, rags or other equipment suitable to dam the flow.
- B. Fight fire (if any), being careful to use firefighting methods compatible with the material involved.
- C. Shut off or otherwise stem the spill at the source.
- D. Contain liquid material using barriers, such as absorbents, rags or other equipment suitable to dam the flow.
Answer: A — Don required PPE as determined from the MSDS. Contain liquid material using barriers, such as absorbents, rags or other equipment suitable to dam the flow.
Personal protection comes first: responders must don the PPE identified in the SDS (MSDS) for the product before approaching the spill, and only then contain the liquid with absorbents or barriers. Without proper PPE, any other control action exposes personnel to toxic or corrosive hazards.
3. What is used to incinerate solid and liquid wastes arising from the operation of the ship?
- A. Incinerator
- B. Oily water separation
- C. ISM Screen
- D. Fire Sprinkler Cleaner
Answer: A — Incinerator
A shipboard incinerator, approved to the IMO standard under MARPOL Annex VI regulation 16, is used to burn solid and liquid wastes generated during the ship's normal operation, such as sludge and garbage, within permitted limits.
4. Oil Pollution Regulations require any transfer, or discharge of oil, or oily mixtures be recorded in the
- A. Pollution Control Record
- B. Bridge log
- C. Oil Record book
- D. Masters log
Answer: C — Oil Record book
MARPOL Annex I requires every oil transfer, ballasting, tank cleaning, discharge and disposal of oil residues to be recorded in the Oil Record Book, Part I for machinery space operations and Part II for cargo and ballast operations on oil tankers.
5. The Volatile Organic Compound (cargo vapor) Management Plan is required on what type of vessel?
- A. Tank sensors
- B. Container vessels
- C. Ro-ro vessels
- D. Crude Oil Carriers
Answer: D — Crude Oil Carriers
MARPOL Annex VI regulation 15.6 requires every tanker carrying crude oil to have on board and implement an approved VOC Management Plan to control emissions of volatile organic compounds during loading, voyage and discharge.
6. Your vessel is carrying 24,000 barrels (3816 cubic metres) of oil for discharge. The cargo hoses have an inside diameter of eight inches. The container around the loading manifold must hold _________.
- A. three barrels
- B. four barrels
- C. six barrels
- D. eight barrels
Answer: A — three barrels
Under US 33 CFR 155 requirements reflected in the USCG question bank, the size of the fixed spill containment under each loading manifold is based on the inside diameter of the transfer hose. For an eight-inch hose the bank requires a container capacity of three barrels.
7. It is generally NOT allowed to clean up an oil spill by using __________.
- A. a boom
- B. suction equipment
- C. chemical agents
- D. skimmers
Answer: C — chemical agents
Chemical dispersants are generally not permitted for oil spill cleanup without specific approval from the coastal State, because they spread oil into the water column and can harm marine life. Booms, skimmers and suction equipment are the preferred mechanical recovery means.
8. The total quantity of oil discharged at sea on new tankers must not exceed:
- A. 1/15000 of the total quantity of that particular cargo of which the residue formed part
- B. 1/20000 of the total quantity of that particular cargo of which the residue formed part
- C. 1/25000 of the total quantity of that particular cargo of which the residue formed part
- D. 1/30000 of the total quantity of that particular cargo of which the residue formed part
Answer: D — 1/30000 of the total quantity of that particular cargo of which the residue formed part
MARPOL Annex I regulation 34 limits the total quantity of oil discharged into the sea by an oil tanker delivered after 31 December 1979 to 1/30,000 of the total quantity of the particular cargo of which the residue formed part. Older tankers were allowed 1/15,000.
9. A starting interlock in the ODME ensures
- A. the monitoring equipment is fully operational before commencing the discharge of the oil effluent at sea
- B. prevents malfunctioning of the system
- C. that an alarm is given off when the system malfunctions
- D. stops discharge of the oil effluent when the oil content exceeds 5 part per million
Answer: A — the monitoring equipment is fully operational before commencing the discharge of the oil effluent at sea
The starting interlock of the ODME prevents the overboard discharge valve from being opened until the monitoring system is fully operational, as required by the IMO ODME guidelines under MARPOL Annex I regulation 31, so no effluent is discharged unmonitored.
10. A gas venting system on a tanker that has gas lines in each tank connected to a common gas main running the full length of the ship is called:
- A. A gas-main system
- B. A common-main system
- C. A vent-main system
- D. An independent system
Answer: B — A common-main system
In a common-main venting system each cargo tank's vent line connects to a common header running the length of the deck, which leads to a mast riser or vent stack. This differs from an independent system where each tank has its own P/V valve and vent.
11. Pneumatically Operating Valve; what is the most critical component for correct valve operation, based on your shipboard experience of running such a system?
- A. Valve orifice
- B. The Diaphragm
- C. Valve stem
- D. The valve springs
Answer: B — The Diaphragm
In a pneumatically operated valve the actuator diaphragm converts air pressure into stem movement. If the diaphragm is torn, hardened or leaking, the valve will not open or close fully, so its condition is the most critical factor for correct operation.
12. Advantages of using inert gas, pick one that is the main reason for its application,
- A. No explosive mixtures can form in the tank.
- B. Reduces corrosion.
- C. Voyage cleaning of tanks is unnecessary.
- D. Reduces pumping time because of positive pressure in the tanks.
Answer: A — No explosive mixtures can form in the tank.
The main purpose of an inert gas system, as required by SOLAS II-2 regulation 4.5.5, is to keep the oxygen content in cargo tanks below 8% so that a flammable mixture cannot form. Reduced corrosion is only a secondary benefit.
13. Cargo system Valves can be categorized in many ways: identify one operation that can be classified as, manual remote,
- A. Local or remote actuation: Local control means the operator is at the valve and controls it directly.
- B. When the valve is located some distance from the operator such as at the bottom of the cargo tank, it is then necessary to install a reach rod for remote actuation.
- C. A reach rod assembly is a series of steel rods coupled to connect the stem of the valve in the tank to a valve operating stand on deck.
- D. In automated cargo systems, the valves are frequently operated using hydraulic or pneumatic motors connected to the stem
Answer: C — A reach rod assembly is a series of steel rods coupled to connect the stem of the valve in the tank to a valve operating stand on deck.
A reach rod assembly is the classic manual remote valve operation: a series of steel rods coupled to the valve stem in the tank allows the valve to be operated by hand from a deck stand. Local control and hydraulic or pneumatic actuation fall into other categories.
14. Acidic solutions are formed in cargo tanks of tankers
- A. when sulphur compounds in oil cargoes react with water
- B. when sulphur compounds in oil cargoes react with oxygen
- C. when sulphur compounds in oil cargoes react with hydrocarbon gas
- D. when sulphur compounds in oil cargoes react with chemicals
Answer: A — when sulphur compounds in oil cargoes react with water
Sulphur compounds in oil cargoes, particularly hydrogen sulphide and mercaptans, react with water present in tanks to form acidic solutions, which accelerate corrosion of tank structures and coatings.
15. An inert gas generator burns what oil to generate inert gas ?
- A. Crude oil
- B. Gas oil
- C. Heavy oil
- D. Diesel oil
Answer: B — Gas oil
An inert gas generator burns a clean, low-sulphur distillate fuel such as gas oil in a combustion chamber, producing flue gas with low oxygen content and minimal sulphur oxides, which is then cooled and scrubbed before delivery.
16. Back flow of inert gas is prevented by:
- A. An isolating valve
- B. The deck water seal
- C. A valve provided in the scrubber
- D. The deck mechanical non-return valve
Answer: B — The deck water seal
The deck water seal is the principal device preventing the back flow of hydrocarbon gas from the cargo tanks to the IG plant and machinery spaces, as required by the FSS Code chapter 15. The non-return valve is an additional safeguard.
17. Tank coating requirements developed by IMO are applicable to
- A. new crude oil tankers of 5000 GRT and above
- B. new crude oil tankers of 5000 DWT and above
- C. new crude oil tankers of 500 GRT and above
- D. new crude oil tankers of 500 DWT and above
Answer: B — new crude oil tankers of 5000 DWT and above
The IMO Performance Standard for Protective Coatings of cargo oil tanks, made mandatory by SOLAS II-1 regulation 3-11, applies to new crude oil tankers of 5,000 tonnes deadweight and above.
18. A deepwell pump is a type of ___________.
- A. screw pump
- B. centrifugal pump
- C. eductor
- D. gear pump
Answer: B — centrifugal pump
A deepwell pump is a vertical centrifugal pump with the impeller at the tank bottom, driven through a long shaft by a motor on deck. It is widely used on chemical and product tankers for segregated cargo handling.
19. Bottom washing:
- A. is done to remove traces of the previous cargo
- B. will remove heavy wax sediments at the tank bottom
- C. is not effective when carrying a small quantity of refined products
- D. cannot be done with chemical solvents
Answer: A — is done to remove traces of the previous cargo
Bottom washing is carried out with fixed tank cleaning machines directed at the tank bottom to remove traces and residues of the previous cargo before loading a new one or before inspection.
20. The total capacity of all slop tanks on an oil tanker normally should be
- A. 1% of the total oil carrying capacity of ship
- B. 2% of the total oil carrying capacity of ship
- C. 3% of the total oil carrying capacity of ship
- D. 4% of the total oil carrying capacity of ship
Answer: C — 3% of the total oil carrying capacity of ship
MARPOL Annex I regulation 29 requires slop tanks with a total capacity of not less than 3% of the oil carrying capacity of the ship, reduced to 2% in certain cases such as where segregated ballast or COW arrangements allow.
21. An inert gas system is required to be fitted:
- A. On all tankers of above 20,000 tonnes deadweight
- B. On product tankers of above 20,000 tonnes deadweight
- C. On crude oil tankers of above 20,000 tonnes deadweight
- D. On chemical tankers of above 20,000 tonnes deadweight
Answer: C — On crude oil tankers of above 20,000 tonnes deadweight
The original SOLAS 1974 as amended by the 1978 Protocol required inert gas systems on crude oil tankers of 20,000 tonnes deadweight and upwards. Current SOLAS II-2 regulation 4.5.5 extends this to oil and chemical tankers of 8,000 dwt and above built after 2016.
22. Centrifugal pumps are otherwise known as
- A. Reciprocating pumps
- B. Gravity pumps
- C. Positive discplacement pumps
- D. Hydro-dynamic pumps
Answer: D — Hydro-dynamic pumps
Centrifugal pumps are hydro-dynamic or rotodynamic pumps: they impart velocity to the liquid with a rotating impeller and convert it to pressure in the volute. Positive displacement pumps such as reciprocating and screw types work on a different principle.
23. The ring main pipeline system is extensively used on:
- A. VLCCs
- B. Crude oil tankers
- C. Medium range tankers
- D. Product carriers
Answer: D — Product carriers
Product carriers carry several grades simultaneously and need flexible segregation, so the ring main pipeline system, which allows several tanks to be connected in different combinations, is widely used on them. Crude carriers normally use direct line systems.
24. Class B fires are caused by
- A. combustible solids
- B. flammable liquids
- C. flammable gases
- D. electricity
Answer: B — flammable liquids
Class B fires involve flammable liquids such as oil, petrol and solvents. Class A covers combustible solids, Class C flammable gases (in the European system), and electrical fires are treated separately.
25. Use of Pressure-Vacuum (PV) Relief Valve; label the diagram correctly,
- A. 1-IG Main; 2-Deck Isolating Valve ; 3- Vent Main; 4- By-Pass Valve; 5- PV valve; 6- Tank Isolating Valve
- B. 1-Deck Isolating Valve; 2- Vent Main; 3- IG Main; 4- By-Pass Valve; 5- PV valve; 6- Tank Isolating Valve
- C. 1-Deck Isolating Valve; 2- IG Main; 3- Vent Main; 4- By-Pass Valve; 5- PV valve; 6- Tank Isolating Valve
- D. 1-Deck Isolating Valve; 2- IG Main; 3- Vent Main; 4- By-Pass Valve; 5 - Tank Isolating Valve; 6- PV valve
Answer: C — 1-Deck Isolating Valve; 2- IG Main; 3- Vent Main; 4- By-Pass Valve; 5- PV valve; 6- Tank Isolating Valve
In the standard IG and venting diagram the deck isolating valve is followed by the IG main and the vent main, with a by-pass valve, the PV valve on the tank and the tank isolating valve. This sequence reflects the arrangement shown in the IMO model course illustration.
26. Cargo tank fill alarm indicator panels:
- A. are normally fitted on the bridge and sometimes on deck
- B. are normally fitted in the engine control room and sometimes on deck
- C. are normally fitted on the bridge and sometimes in the engine control room
- D. are normally fitted in the cargo control room and sometimes on deck
Answer: D — are normally fitted in the cargo control room and sometimes on deck
Cargo tank high level and overfill alarm indicator panels are normally fitted in the cargo control room where the officer on watch monitors cargo operations, with repeaters or audible and visual alarms on deck as required by IBC Code 15.19 and SOLAS.
27. Identify the equipment in the IG system correctly,
- A. 1-O2 Analyzer ; 2-Demister; 3-Air Intake-Gas Freeing; 4- Regulating Valves; 5- Blowers
- B. 1- Demister; 2-O2 Analyzer; 3-Air Intake-Gas Freeing; 4- Regulating Valves; 5- Blowers
- C. 1- Demister; 2-O2 Analyzer; 3 - Blowers ; 4- Regulating Valves; 5- Air Intake-Gas Freeing
- D. 1- Demister; 2-O2 Analyzer; 3-Regulating Valves; 4-Air Intake-Gas Freeing ; 5- Blowers
Answer: B — 1- Demister; 2-O2 Analyzer; 3-Air Intake-Gas Freeing; 4- Regulating Valves; 5- Blowers
In the IG system diagram the flue gas passes through the scrubber and demister, the oxygen analyser monitors the gas, the air intake is used for gas freeing, and the regulating valves and blowers control delivery. The sequence demister, O2 analyser, air intake, regulating valves and blowers matches the model course illustration.
28. Tank level measurement by gauging tape and plumb bob: find the labeling combination that is correct,
- A. 1- Reference Point; 2-Tape Cut; 3-Bob Cut; 4-Ullage; 5- Innage
- B. 1- Reference Point; 2-Tape Cut; 3-Bob Cut; 4-Innage; 5- Ullage
- C. 1- Bob Cut; 2-Reference Point; 3-Tape Cut; 4-Ullage; 5- Innage
- D. 1- Innage; 2-Tape Cut; 3-Bob Cut; 4-Ullage; 5- Reference Point
Answer: A — 1- Reference Point; 2-Tape Cut; 3-Bob Cut; 4-Ullage; 5- Innage
In tape and bob gauging the reference point is at the top of the gauging pipe, the tape cut and bob cut show where the product wets the tape, and ullage is measured from the reference point to the liquid surface while innage is measured from the bottom. This gives the labelling reference point, tape cut, bob cut, ullage, innage.
29. Cargo discharging: find a statement that ensures safe cargo discharging from start to finish,
- A. When the vessel arrives at the discharge port, the inert gas system should be tested and ready for operation in due time for discharge.
- B. Before pumping of cargo oil is started, the inert gas system should be in operation and connected to the deck line, with the pressure control in the "automatic" position.
- C. Cargo discharge should not be commenced until all the conditions have been checked; tanks should be re- pressurized if required
- D. During discharge the oxygen content and pressure of the inert gas in the inert gas main should be continuously recorded as per regulation.
Answer: D — During discharge the oxygen content and pressure of the inert gas in the inert gas main should be continuously recorded as per regulation.
During discharge SOLAS and the FSS Code require the oxygen content and pressure in the inert gas main to be continuously indicated and recorded, so that the tanks remain inerted and at positive pressure throughout the operation from start to finish.
30. Automatic shutdown systems independent of operator intervention: how to ensure that it will work correctly?
- A. Express approval for their use is required from both the flag administration and the port state authorities.
- B. Automatic shutdown systems are normally designed to shut the main cargo tank filling valve if the liquid level rises above the maximum level permitted.
- C. Ensure that the activation point is set accurately, and that the operation of the device is checked by simulation whenever the system is recommissioned.
- D. If the ship and shore shutdown circuits are to be linked their operation should be checked before cargo transfer begins; if not, the terminal should be informed of the closing rate of the ship's valves.
Answer: D — If the ship and shore shutdown circuits are to be linked their operation should be checked before cargo transfer begins; if not, the terminal should be informed of the closing rate of the ship's valves.
If ship and shore automatic shutdown circuits are linked, their operation must be tested before transfer begins. If they are not linked, the terminal must be told the ship's valve closing rate so that surge pressure from a sudden shutdown can be avoided, as advised in ISGOTT.
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