A tank car designed to carry flammable liquids, combustible liquids, Class B poisons, and liquid food products with vapor pressures up to 3 psi is which type?

A tank car designed to carry flammable liquids, combustible liquids, Class B poisons, and liquid food products with vapor pressures up to 3 psi is which type?

• A. MC 306 / DOT 406
• B. MC 307 / DOT 407
• C. MC 312 / DOT 312
• D. MC 331 / DOT 331

Answer: (D)

Understanding tank car design helps you match the car type to the way a product must be contained. Tank cars are built for different service pressures: non-pressurized cars rely on atmospheric pressure, low-pressure cars maintain a modest internal pressure, and high-pressure cars are designed to withstand much higher pressures for liquids that must be kept under pressure to stay in the liquid state or to safely transport hazardous materials. The high-pressure cargo tank, designated as MC 331 / DOT 331, is the model used for carrying flammable and other hazardous liquids that require a pressurized containment, including certain Class B poisons and some liquid foods that have relatively low vapor pressures. This design provides the strength and safety features needed to move a broad range of hazardous liquids under pressure, which aligns with the scenario described where the cargo has vapor pressures up to about 3 psi. In contrast, non-pressurized cars (MC 306 / DOT 406) are meant for liquids at ambient pressure, and low-pressure cars (MC 307 / DOT 407) are intended for lighter pressurization and do not match the higher-containment needs described. The other high-pressure designation (MC 312 / DOT 312) refers to a different category of pressurized tanks used for other applications, not the same combination of contents in the scenario. So, MC 331 / DOT 331 is the best match for a tank car designed to carry those liquids under the specified pressure conditions.

Understanding tank car design helps you match the car type to the way a product must be contained. Tank cars are built for different service pressures: non-pressurized cars rely on atmospheric pressure, low-pressure cars maintain a modest internal pressure, and high-pressure cars are designed to withstand much higher pressures for liquids that must be kept under pressure to stay in the liquid state or to safely transport hazardous materials.

The high-pressure cargo tank, designated as MC 331 / DOT 331, is the model used for carrying flammable and other hazardous liquids that require a pressurized containment, including certain Class B poisons and some liquid foods that have relatively low vapor pressures. This design provides the strength and safety features needed to move a broad range of hazardous liquids under pressure, which aligns with the scenario described where the cargo has vapor pressures up to about 3 psi. In contrast, non-pressurized cars (MC 306 / DOT 406) are meant for liquids at ambient pressure, and low-pressure cars (MC 307 / DOT 407) are intended for lighter pressurization and do not match the higher-containment needs described. The other high-pressure designation (MC 312 / DOT 312) refers to a different category of pressurized tanks used for other applications, not the same combination of contents in the scenario.

So, MC 331 / DOT 331 is the best match for a tank car designed to carry those liquids under the specified pressure conditions.