Tanker Familiarization Tanker Safety Systems 2 — Questions and Answers
Question 1: What is the primary purpose of an inert gas system on a tanker?
- To cool the cargo during transit
- To prevent flammable mixtures from forming in cargo tanks (Correct answer)
- To pressurize the cargo for faster discharge
- To remove water vapor from the tanks
Correct answer: To prevent flammable mixtures from forming in cargo tanks
Inert gas systems replace oxygen in cargo tanks with non-flammable gas (typically flue gas or nitrogen) to prevent explosive mixtures from forming.
Question 2: Which atmosphere condition in a cargo tank is considered the safest when inert gas is being used?
- Oxygen content above 21%
- Oxygen content below 8% by volume (Correct answer)
- Oxygen content between 10-15%
- Oxygen content exactly 11%
Correct answer: Oxygen content below 8% by volume
Maintaining oxygen content below 8% by volume ensures the atmosphere cannot support combustion, keeping the tank in a safe inert condition.
Question 3: What does a high-level alarm on a cargo tank indicate?
- The tank temperature has exceeded safe limits
- The tank is approaching its maximum safe filling capacity (Correct answer)
- The inert gas pressure has dropped
- The cargo pump has failed
Correct answer: The tank is approaching its maximum safe filling capacity
A high-level alarm warns crew that the cargo level is nearing the tank's maximum allowable capacity to prevent overflow and structural damage.
Question 4: What is the function of a pressure/vacuum (P/V) valve on a tanker cargo tank?
- To measure the exact pressure inside the tank
- To prevent excessive pressure buildup or dangerous vacuum from developing (Correct answer)
- To allow cargo vapors to be recovered for sale
- To regulate the flow rate of the inert gas system
Correct answer: To prevent excessive pressure buildup or dangerous vacuum from developing
P/V valves automatically open to relieve excess pressure or vacuum, protecting the tank structure from damage due to pressure differentials.
Question 5: Emergency Shutdown (ESD) systems on tankers are designed to:
- Automatically restart pumps after a power failure
- Rapidly stop cargo operations in the event of an emergency (Correct answer)
- Increase cargo transfer speed during port operations
- Switch between inert gas sources automatically
Correct answer: Rapidly stop cargo operations in the event of an emergency
ESD systems are critical safety devices that quickly halt all cargo transfer operations when triggered by a detected emergency condition.
Question 6: A fixed gas detection system on a tanker continuously monitors for:
- Crew location in confined spaces
- Presence of flammable or toxic vapors in key areas (Correct answer)
- Water ingress into the engine room
- Changes in cargo temperature only
Correct answer: Presence of flammable or toxic vapors in key areas
Fixed gas detection systems provide continuous monitoring of flammable and toxic gas concentrations in pump rooms, cargo areas, and other critical locations.
Question 7: What should crew members do FIRST when a gas detector alarm sounds in the pump room?
- Enter the pump room to identify the source
- Ignore it if it has sounded before without incident
- Stop operations, ventilate the space, and investigate from a safe location (Correct answer)
- Restart the ventilation system from inside the pump room
Correct answer: Stop operations, ventilate the space, and investigate from a safe location
When a gas alarm sounds, crew must immediately stop operations and assess the situation safely before any entry, as the space may be immediately dangerous.
Tanker Familiarization Tanker Safety Systems 2
What is the primary purpose of an inert gas system on a tanker?