A large production and research facility has multiple uses for cryogenic liquid cylinders and keeps an inventory of DOT 4L-100, 4L-200 and 4L-292 vessels on site. The 4L-100s are set with 22psi reliefs and installed in labs and a few other locations where they are used strictly for liquid withdrawal. The 4L-200 “medium pressure” vessels are the most commonly used liquid cylinders throughout the facility and are fitted with standard 230psi reliefs. There are also some higher pressure applications at the site where 4L-292 vessels fitted with 350psi reliefs are needed.
Liquid nitrogen, oxygen and argon vessels are normally delivered to this site every Thursday. Mid-morning one Tuesday, they empty a 4L-200 oxygen liquid cylinder at a location that has a maximum feed pressure of 260psi. On arrival at the inventory area they find that their supply of 4L-200 (230psi relief) liquid oxygen cylinders has been exhausted. There are, though, a few 4L-292 (350psi relief) liquid cylinders still on hand. They call to find out if they can take a 230psi relief off an exhausted 4L-200 and put it on a 4L-292 in order to use the 4L-292 at the process area that cannot exceed 260psi.
What is the answer?
Why?
Are there any other questions or considerations that need to be reviewed related to this answer?
Tune in next time…….
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