Which designation is used for cryogenic liquid tank trucks?

Which designation is used for cryogenic liquid tank trucks?

• A. MC 331
• B. MC 312
• C. MC 307 / DOT 407
• D. MC 338

Answer: (D)

Cryogenic liquid tank trucks are designated MC-338. This label identifies vehicles built to transport extremely cold liquids, such as liquid oxygen or nitrogen. They use double-walled, vacuum-insulated tanks to minimize heat transfer and keep the contents at cryogenic temperatures. A venting system is essential here to safely release boil-off gas as the liquid warms, preventing pressure buildup. Materials are chosen for low-temperature service, typically stainless steel or aluminum, and the design includes safety relief devices and careful vent routing. The other designations refer to different types of cargo and pressure ranges. For example, high‑pressure tanks carry gases at elevated pressures, while low‑pressure tanks for flammable liquids and corrosives have different construction and containment requirements. Each designation signals the specific construction features needed to safely transport that category of content, which is why MC-338 is the correct one for cryogenic liquids.

Cryogenic liquid tank trucks are designated MC-338. This label identifies vehicles built to transport extremely cold liquids, such as liquid oxygen or nitrogen. They use double-walled, vacuum-insulated tanks to minimize heat transfer and keep the contents at cryogenic temperatures. A venting system is essential here to safely release boil-off gas as the liquid warms, preventing pressure buildup. Materials are chosen for low-temperature service, typically stainless steel or aluminum, and the design includes safety relief devices and careful vent routing.

The other designations refer to different types of cargo and pressure ranges. For example, high‑pressure tanks carry gases at elevated pressures, while low‑pressure tanks for flammable liquids and corrosives have different construction and containment requirements. Each designation signals the specific construction features needed to safely transport that category of content, which is why MC-338 is the correct one for cryogenic liquids.