Tanker Familiarization Cargo Properties and Hazards Questions and Answers

Question 1

A cargo's Reid Vapour Pressure (RVP) is a standardized measure of what property?

Accepted Answer

Its volatility at a standard temperature of 100°F (37.8°C)

Answer

Reid Vapour Pressure (RVP) is a common measure of the volatility of petroleum products. It is specifically defined as the absolute vapor pressure exerted by a liquid at 37.8°C (100°F) under specific test conditions. A higher RVP indicates a more volatile cargo that will vaporize more easily.

Question 2

A gas detector in a cargo tank reads a hydrocarbon concentration well above the Upper Flammable Limit (UFL). What is the primary hazard associated with this atmosphere?

Accepted Answer

The atmosphere is too rich to burn, but the introduction of air can bring it into the flammable range.

Answer

An atmosphere with a hydrocarbon concentration above the Upper Flammable Limit (UFL), also called the Upper Explosive Limit (UEL), is considered 'too rich' to burn because there is insufficient oxygen for combustion. The primary danger is that if air is introduced into the tank (e.g., during ventilation), the mixture can be diluted into the flammable range (between the LFL and UFL), creating a significant explosion hazard if an ignition source is present.

Question 3

What does the Threshold Limit Value - Time-Weighted Average (TLV-TWA) for a chemical cargo represent?

Accepted Answer

The average airborne concentration to which nearly all workers may be repeatedly exposed over a lifetime without adverse effect.

Answer

The TLV-TWA is the time-weighted average concentration for a conventional 8-hour workday and 40-hour workweek, to which it is believed that nearly all workers may be repeatedly exposed, day after day, for a working lifetime without adverse health effects. The 15-minute limit is the STEL, the immediate danger is the IDLH, and the absolute ceiling is the TLV-C.

Question 4

Which of the following cargoes presents a significant hazard due to its tendency to polymerize, a reaction that can be accelerated by heat and generate more heat in a dangerous feedback loop?

Accepted Answer

Styrene Monomer

Answer

Styrene Monomer is a well-known example of a cargo that can self-react through polymerization. This process is exothermic (releases heat), and the increased temperature can accelerate the reaction rate, potentially leading to a 'runaway polymerization' that generates large amounts of heat and gas, which can over-pressurize and rupture a cargo tank. To prevent this, such cargoes are carried with an inhibitor and their temperature is carefully monitored.

Question 5

During a pre-transfer conference, you are informed that the cargo to be loaded has a specific gravity of 1.05. What is the most important operational consideration based on this property in the event of a spill into the water?

Accepted Answer

The cargo is heavier than water and will sink, making containment and recovery difficult.

Answer

Specific gravity is the ratio of a substance's density to the density of a reference substance, typically water. Water has a specific gravity of 1. A cargo with a specific gravity greater than 1, like 1.05, is denser than water and will sink if spilled. This makes traditional spill response methods like booming and skimming ineffective.

Tanker Familiarization Practice Test

Tanker Familiarization Practice Test

Tanker Familiarization Cargo Properties and Hazards Questions and Answers