At what temperature are cryogenic liquids typically stored?

• A. -130F or -90C
• B. -196C
• C. -80C
• D. -90F

Answer: (A)

Cryogenic liquids must be kept at extremely low temperatures to stay in liquid form and minimize boil-off. In practice, a very common storage temperature is around -196 C, which is the boiling point of liquid nitrogen and serves as a practical standard for many cryogenic liquids. At this level of cold, the liquids remain stable in storage dewars and vaporize much more slowly, reducing pressure build-up and losses. The other temperatures listed are much warmer than typical cryogenic storage needs; for example, -130F (-90C) is not cold enough for most cryogens, so it would lead to rapid boil-off. Similarly, -80C and -90F (about -68C) are not cold enough to safely and reliably store most cryogenic liquids. So the standard storage temperature is around -196 C.