DOT defines cryogenic liquids at temperatures starting at __________.

DOT defines cryogenic liquids at temperatures starting at __________.

• A. -130 F @ 14.7 psi
• B. -50 C
• C. 0 F @ 1 atm
• D. -200 C

Answer: (A)

Cryogenic liquids are defined by their extremely low boiling points at standard atmospheric pressure. The DOT sets the cutoff at a boiling point of -130 F (-90 C) at 14.7 psi. Any liquid at or below that temperature qualifies as cryogenic under hazmat rules. This is why -130 F @ 14.7 psi is the correct definition. The other options don’t match the DOT specification: -50 C is -58 F, which is not low enough; 0 F at 1 atm is -18 C, also not low enough; -200 C is colder than the threshold but the starting point used in the standard is -130 F (-90 C).

Cryogenic liquids are defined by their extremely low boiling points at standard atmospheric pressure. The DOT sets the cutoff at a boiling point of -130 F (-90 C) at 14.7 psi. Any liquid at or below that temperature qualifies as cryogenic under hazmat rules. This is why -130 F @ 14.7 psi is the correct definition. The other options don’t match the DOT specification: -50 C is -58 F, which is not low enough; 0 F at 1 atm is -18 C, also not low enough; -200 C is colder than the threshold but the starting point used in the standard is -130 F (-90 C).