Free Tanker Familiarization Cargo Properties and Hazards Questions and Answers — Questions and Answers
Question 1: Which of the following properties is a primary indicator of a liquid cargo's volatility and its tendency to produce flammable vapors at a given temperature?
- Viscosity
- Reid Vapour Pressure (RVP) (Correct answer)
- Specific Gravity
- Pour Point
Correct answer: Reid Vapour Pressure (RVP)
Reid Vapour Pressure (RVP) is a standardized measure of the volatility of petroleum products. It represents the absolute vapor pressure exerted by a liquid at 100°F (37.8°C). A higher RVP indicates a more volatile liquid that evaporates more easily, thus having a greater tendency to form flammable atmospheres.
Question 2: A vessel is scheduled to load a cargo of Styrene Monomer, which is susceptible to polymerization. What is the primary hazard associated with an uncontrolled polymerization reaction in a cargo tank?
- A significant decrease in the cargo's temperature.
- A rapid, exothermic reaction generating intense heat and pressure. (Correct answer)
- The cargo becoming highly corrosive to the tank structure.
- The release of oxygen, creating a fire-risk atmosphere.
Correct answer: A rapid, exothermic reaction generating intense heat and pressure.
Polymerization is a chemical reaction that can be rapid and exothermic, meaning it releases a significant amount of heat. If uncontrolled, this 'run-off' polymerization can lead to a dangerous build-up of heat and pressure inside the cargo tank, potentially causing a tank rupture or explosion.
Question 3: The 'Flashpoint' of a liquid cargo is the:
- Temperature at which the liquid will auto-ignite without an external ignition source.
- Temperature at which the liquid boils under standard atmospheric pressure.
- Lowest temperature at which the liquid gives off enough vapor to form an ignitable mixture with air. (Correct answer)
- Maximum temperature to which a cargo can be heated before it becomes unstable.
Correct answer: Lowest temperature at which the liquid gives off enough vapor to form an ignitable mixture with air.
The flashpoint is a critical safety parameter that indicates the minimum temperature required for a liquid to produce sufficient flammable vapor to be ignited by an external source, like a spark or flame. It is a primary measure of fire hazard.
Question 4: During cargo operations, the build-up of static electricity presents a significant hazard, especially with non-conductive petroleum products. Which of the following is the most immediate danger posed by an electrostatic discharge inside a cargo tank?
- Corrosion of the tank's internal coatings.
- Over-pressurization of the tank.
- Ignition of flammable vapors. (Correct answer)
- Contamination of the cargo.
Correct answer: Ignition of flammable vapors.
The primary danger of static electricity in a tanker is that a sudden discharge (a spark) can release enough energy to ignite a flammable vapor-air mixture within the tank, leading to a fire or catastrophic explosion.
Question 5: A Safety Data Sheet (SDS) for a chemical cargo indicates that it is highly toxic. What is the most likely primary route of entry that poses a significant health risk to crew members during cargo handling?
- Auditory absorption through the ears.
- Inhalation of vapors or contact with the skin. (Correct answer)
- Radiation exposure.
- Physical impact from the liquid.
Correct answer: Inhalation of vapors or contact with the skin.
For toxic liquid cargoes, the most common and dangerous routes of exposure for crew are inhaling the vapors or direct absorption of the liquid through the skin. Both can cause severe damage to living tissue, impair the central nervous system, or lead to other serious health effects.
Question 6: A tanker is carrying a cargo classified as highly corrosive. Which of the following represents the main hazard associated with this property?
- The cargo will spontaneously heat up during the voyage.
- The cargo can cause rapid destruction of human tissue and damage to the ship's structure. (Correct answer)
- The cargo vapors will displace oxygen, creating an asphyxiation risk.
- The cargo is prone to freezing at ambient temperatures.
Correct answer: The cargo can cause rapid destruction of human tissue and damage to the ship's structure.
Corrosive substances, such as certain acids and alkalis, pose a dual threat on tankers. They can cause severe chemical burns and irreparable damage to human tissue upon contact and can also corrode the ship's steel construction materials, compromising structural integrity.
Free Tanker Familiarization Cargo Properties and Hazards Questions and Answers
Which of the following properties is a primary indicator of a liquid cargo's volatility and its tendency to produce flammable vapors at a given temperature?