Tanker Safety Systems Flashcards
7 cards from real Tanker Familiarization practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Tanker Safety Systems flashcards as text
What does the term 'Lower Explosive Limit' (LEL) mean in tanker operations?
Answer: The minimum concentration of vapor in air that can sustain an explosion
LEL is the lowest concentration of flammable vapor in air that can propagate an explosion; below LEL, the mixture is too lean to ignite.
A cargo tank atmosphere is described as 'in the explosive range' when:
Answer: Hydrocarbon vapor concentration is between the LEL and UEL
When vapor concentration falls between the Lower Explosive Limit and Upper Explosive Limit, the atmosphere is flammable and any ignition source can cause an explosion.
What is the main purpose of a cargo tank washing system (crude oil washing or water washing)?
Answer: To remove cargo residues and sludge from tank surfaces
Tank washing removes cargo residues, reducing the risk of contamination, improving vapor control, and preparing tanks for inspection or different cargo.
During crude oil washing (COW), which gas must be carefully managed to prevent an explosive atmosphere?
Answer: Hydrocarbon vapors released during the washing process
COW releases large amounts of hydrocarbon vapors; the inert gas system must maintain tank atmosphere below the LEL throughout the entire washing process.
What safety precaution is required before any personnel enter a recently cleaned cargo tank?
Answer: The tank must be tested and certified as gas-free and oxygen-sufficient
Before entry, a confined space entry permit is required, and the tank must be confirmed gas-free (no toxic/flammable vapors) and have sufficient oxygen (>20.9%).
What is the role of a pressure surge protector in a tanker's cargo loading system?
Answer: It absorbs sudden pressure spikes to prevent damage to pipelines and valves
Pressure surge protectors (surge drums or relief valves) absorb hydraulic shock from sudden valve closures or pump trips that could rupture pipelines.
Which class of tanker typically requires the most stringent safety systems due to its highly flammable, low flash-point cargo?
Answer: LPG/LNG gas carriers
LPG and LNG carriers transport cryogenic or pressurized gases that are extremely flammable at ambient temperatures, requiring the most advanced containment and safety systems.