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REFRESHER exit exam questions and answers — Set 2

Set 2 of the Refresher Course for STCW Modular Courses (REFRESHER) exit exam bank — 30 of 88 questions, with the correct option marked and a one-line explanation for every one. Read it end to end, jump to a single set, or search it — then sit the same bank as a timed paper. The real DG Shipping exit exam is 30 marks with 15 to pass.

These are the bank's original groupings. Practising deals the whole bank out again every time you reshuffle, so a practice “Set 3” is a different 30 questions each time — the set numbers below are the source file's, and are only used here so the key stays navigable. Options are listed in their original order with fixed letters; when you practise, those move too.

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Set 2 — 30 REFRESHER exit exam questions with answers

1. If ignited, which material would be a class B fire?

  • A. Wood
  • B. Paper
  • C. Diesel Oil
  • D. Magnesium
Answer: C — Diesel Oil
Class B fires are specifically defined as fires involving flammable liquids, such as diesel oil, gasoline, or paints.

2. Which of the listed extinguishing agents is NOT suitable for fighting a liquid paint fire?

  • A. Water
  • B. Foam
  • C. Dry chemical
  • D. Carbon dioxide
Answer: A — Water
Water should not be used on liquid paint fires as it can spread the burning liquid and increase the surface area of the fire.

3. Which extinguishing agent is most effective on a mattress fire?

  • A. Dry Chemical
  • B. Water
  • C. Foam
  • D. CO2
Answer: B — Water
Water is the most effective agent for mattress fires because it penetrates deep into the material to cool the seat of the fire, preventing deep-seated re-ignition.

4. You are fighting a fire in a watertight compartment using hoses and river water. Stability may be reduced because of:

  • A. Reduction of water in the storage tanks
  • B. Reduction of KG to the minimum allowable
  • C. Increase in free surface which reduces the metacentric height (GM)
  • D. Progressive down flooding
Answer: C — Increase in free surface which reduces the metacentric height (GM)
Free surface effect occurs when a compartment is partially filled with water, causing the center of gravity to shift and significantly reducing the metacentric height (GM), affecting stability.

5. When used to fight fire, carbon dioxide:

  • A. Is lighter than air
  • B. Has a greater cooling effect than water
  • C. Is effective if used promptly on an oil fire
  • D. Is harmless to cargo and crew
Answer: C — Is effective if used promptly on an oil fire
CO2 is a clean, non-conductive gas that effectively displaces oxygen, making it ideal for immediate response to oil fires in confined spaces.

6. Carbon dioxide as a firefighting agent has which advantage over other agents?

  • A. It is most effective on a per unit basis.
  • B. It is cheaper.
  • C. It causes minimal damage.
  • D. It is safer for personnel.
Answer: C — It causes minimal damage.
CO2 is a non-residue-forming gas, meaning it causes minimal damage to sensitive machinery or electronic equipment compared to water or powder.

7. To prevent the spread of fire by convection you should:

  • A. Cool the bulkhead around the fire
  • B. Close all openings to the area
  • C. Remove combustibles from direct exposure
  • D. Shut off all electrical power
Answer: B — Close all openings to the area
Convection spreads fire via the movement of hot gases. Closing all openings (like fire doors and dampers) restricts the flow of these gases, containing the fire.

8. What is NOT a characteristic of carbon dioxide fire-extinguishing agents?

  • A. Non-corrosive
  • B. Will not deteriorate in storage
  • C. Effective on electrical equipment
  • D. Effective even if ventilation is not shut down
Answer: D — Effective even if ventilation is not shut down
CO2 is effective only if the space is sealed. If ventilation is not shut down, the gas will dissipate, and oxygen will return, allowing the fire to continue.

9. Foam extinguishes a fire by:

  • A. Destroying the burning materials
  • B. Absorbing the burning material
  • C. Smothering the burning material
  • D. Chemical reaction with the burning material
Answer: C — Smothering the burning material
Foam works by creating a barrier (blanket) over the liquid fuel, which cuts off the oxygen supply (smothering) and prevents the release of flammable vapors.

10. Immediately after a class "B" fire has been extinguished by the use of foam, crewmen should:

  • A. Be careful not to disturb the foam blanket
  • B. Wade through the foam blanket to evenly distribute the foam
  • C. Sweep the foam blanket overboard and secure firefighting equipment
  • D. Carefully apply a low velocity fog over the foam blanket
Answer: A — Be careful not to disturb the foam blanket
Disturbing the foam blanket allows oxygen to reach the fuel, potentially causing the fire to reignite. The blanket must remain intact until the area is confirmed safe.

11. The most likely location for a liquid cargo fire to occur on a tanker would be:

  • A. In the midships house
  • B. In the pump room
  • C. At the vent header
  • D. At the main deck manifold
Answer: B — In the pump room
The pump room is a high-risk area on tankers due to the concentration of piping, valves, and moving parts associated with cargo transfer, often carrying flammable liquids.

12. You should be most concerned about a possible explosion or fire in fuel tanks:

  • A. When underway as the fuel is moved by wave action
  • B. During fueling when the fuel strikes fuel already in the tank
  • C. Shortly after fueling when fuel vapors gather
  • D. During fueling when the fuel first strikes the tank bottom
Answer: D — During fueling when the fuel first strikes the tank bottom
Fueling operations pose the highest risk of static electricity discharge or spill ignition when the initial stream strikes the tank bottom, creating turbulence and vapor.

13. You have carbon tetrachloride as part of the cargo. If a fire breaks out in the general area, what is the major danger from the carbon tetrachloride?

  • A. It will explode if exposed to a flame
  • B. It will burn rapidly once ignited
  • C. You cannot use water to fight the fire because it will react with the carbon tetrachloride
  • D. Phosgene gas may be formed if it comes in contact with hot metal
Answer: D — Phosgene gas may be formed if it comes in contact with hot metal
Carbon tetrachloride decomposes when exposed to high heat or flame, producing phosgene gas, which is extremely toxic and lethal to personnel.

14. Radiation can cause a fire to spread by:

  • A. Burning liquids flowing into another space
  • B. Heated gases flowing through ventilation systems
  • C. The transfer of heat across an unobstructed space
  • D. Transmitting the heat of a fire through the ship’s metal
Answer: C — The transfer of heat across an unobstructed space
Radiation is the transfer of heat through electromagnetic waves across space, meaning it does not require direct contact or a medium to ignite nearby combustibles.

15. To prevent the spread of fire by conduction, you should:

  • A. Close all openings to the area
  • B. Shut off all electric power
  • C. Cool the bulkheads around the fire
  • D. Remove combustibles from direct exposure
Answer: C — Cool the bulkheads around the fire
Conduction transfers heat through solid materials like steel bulkheads. Cooling these bulkheads with water absorbs the heat and prevents the fire from reaching adjacent compartments.

16. You notice smoke coming from an open laundry room doorway. After activating the fire alarm, which of the following would you do FIRST?

  • A. Acquire the nearest self-contained breathing apparatus.
  • B. Break out the nearest fire hose.
  • C. Attempt to determine what is burning.
  • D. Wait for the fire team to arrive and assist as directed.
Answer: C — Attempt to determine what is burning.
Immediate assessment is required to determine the nature and extent of the fire so that the correct firefighting strategy and agents can be utilized efficiently.

17. You are on watch at night in port and discover a fire in #1 hatch. Which action should you take FIRST?

  • A. Advise the Chief Mate and Master
  • B. Sound the general alarm
  • C. Release carbon dioxide into the hatch
  • D. Lead a fire hose to the hatch
Answer: B — Sound the general alarm
Sounding the general alarm is the highest priority to alert the entire crew, initiate the mustering process, and organize the response team.

18. Which of the following is NOT identified on the vessel's fire control plan?

  • A. Fire and emergency signals
  • B. Gas detector
  • C. Fire control plan
  • D. Dry chemical monitor
Answer: A — Fire and emergency signals
The fire control plan shows the location of safety equipment; however, general emergency signals are specified in the Muster List and Safety Training Manual, not the fire control plan.

19. The high velocity fog tip used with the all-purpose firefighting nozzle should always be:

  • A. Stowed separately in a clip or rack at each fire station
  • B. Coated with heavy grease to prevent corrosion
  • C. Attached to the all-purpose nozzle by a chain
  • D. Painted red to be identified as emergency equipment
Answer: C — Attached to the all-purpose nozzle by a chain
The high-velocity fog tip is attached by a chain to ensure it remains readily available at the fire station for immediate changeover, preventing loss during the urgency of firefighting.

20. The most common and widely used cooling agent used for fighting fires on merchant vessels is:

  • A. Water
  • B. Carbon dioxide
  • C. Steam smothering
  • D. Flue gas
Answer: A — Water
Water is the most common and versatile cooling agent on ships. It effectively absorbs heat by changing from liquid to vapor, cooling burning surfaces, and creating a steam blanket to smother the fire.

21. The primary function(s) of an automatic sprinkler system is(are) to:

  • A. Limit the spread of fire and control the amount of heat produced
  • B. Extinguish the fire which triggers it
  • C. Alert the crew to the fire
  • D. Protect people in the areas which have sprinkler heads
Answer: A — Limit the spread of fire and control the amount of heat produced
Automatic sprinkler systems are primarily designed for fire control. They limit the spread of fire by cooling the area and surrounding structure while keeping the fire intensity manageable until active firefighting intervention arrives.

22. If a portable carbon dioxide fire extinguisher has been partially discharged, it should be immediately:

  • A. Tagged ’empty' and stowed separately from charged extinguishers
  • B. Weighed and the charge loss recorded before being returned to its rack
  • C. Given to the chief engineer for recharging
  • D. Tagged and restowed properly in its rack
Answer: A — Tagged ’empty' and stowed separately from charged extinguishers
Any partially discharged extinguisher is unreliable and may not have sufficient pressure or agent for a real emergency. It must be tagged 'empty' and moved to a separate storage area to prevent it from being mistaken for a fully charged unit.

23. Which statement about firefighting foam is TRUE?

  • A. Foam is most effective on burning liquids which are flowing.
  • B. To be most effective, foam should be directed at the base of the fire.
  • C. Foam can ONLY be used to extinguish class A fires.
  • D. Foam conducts electricity
Answer: D — Foam conducts electricity
Foam creates a seal over the surface of burning liquids, making it highly effective for running fuel fires. It separates the fuel from oxygen, preventing reignition and effectively suppressing vapors.

24. Which of the following hazards is associated with fuel oil fires?

  • A. Reduced fire-fighting effectiveness due to low oxygen content
  • B. Emission of highly flammable vapors
  • C. Emission of noxious gases
  • D. Flashover of confined vapor clouds
Answer: D — Flashover of confined vapor clouds
Fuel oil fires in confined engine room spaces can lead to rapid heat accumulation and the build-up of flammable vapors. If these vapors reach their lower explosive limit, a 'flashover' or explosion can occur, posing a severe threat to the vessel.

25. A carbon dioxide fire extinguisher is required to be recharged if the weight loss exceeds what percentage of the weight of the charge?

  • A. One percent
  • B. Ten percent
  • C. Seven percent
  • D. Five percent
Answer: B — Ten percent
According to maritime regulations and manufacturers' standards, a carbon dioxide extinguisher must be recharged if the weight of the agent lost exceeds 10% of the original charged weight. This ensures the unit remains effective for the intended discharge duration.

26. Fire hydrant valves on a crude oil tanker shall be isolated from the crude oil washing system by

  • A. Spade blanks
  • B. Face blanks
  • C. Non-return valves
  • D. Automatic closing valves
Answer: A — Spade blanks
Spade blanks (also known as slip blinds) provide a positive, physical barrier between the fire main and the crude oil washing system. This is a critical safety requirement to prevent hazardous hydrocarbon vapors from entering the fire main.

27. How do you operate a portable CO2 fire extinguisher?

  • A. Break the rupture disc
  • B. Point the horn down
  • C. Turn the cylinder upside-down
  • D. Pull pin, squeeze grip
Answer: D — Pull pin, squeeze grip
The standard procedure for operating a CO2 extinguisher is 'PASS': Pull the safety pin, Aim the nozzle at the base of the fire, Squeeze the operating handle, and Sweep from side to side.

28. All portable fire extinguishers must be capable of being

  • A. Recharged in the field
  • B. Carried or rolled to a fire
  • C. Carried by hand to a fire
  • D. Used on class HB" fires
Answer: C — Carried by hand to a fire
Portable fire extinguishers are designed to be mobile so they can be immediately brought to the site of an incipient fire. Their size and weight are constrained by regulations to ensure a single crew member can transport and operate them.

29. Recharging a previously used cartridge-operated dry chemical fire extinguisher is accomplished by

  • A. Authorized fire equipment servicing personnel only
  • B. Puncturing the cartridge seal after installation
  • C. Recharging the cartridge and refilling it with powder
  • D. Replacing the propellant cartridge and refilling it with powder
Answer: D — Replacing the propellant cartridge and refilling it with powder
For cartridge-operated extinguishers, the propellant charge (cartridge) and the fire-extinguishing powder are stored separately. After discharge, the cartridge must be replaced and the vessel must be refilled with the specified amount of powder to ensure it functions correctly.

30. Multiple fire pumps may be used for other purposes provided that one pump is

  • A. Capable of being connected to the fire main
  • B. Kept available for use on the fire main at all times
  • C. On line to the fire main
  • D. Rated at or above 125 psi
Answer: B — Kept available for use on the fire main at all times
While fire pumps can be used for other essential duties like ballast or general service, at least one pump must always remain on standby or be immediately connectable to the fire main to ensure instantaneous readiness during an emergency.

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