Liquid Oxygen Transfilling Operation

Q: I have portable liquid O2 canisters that need to be refilled from the portable storage dewar. Are there any directions for me to follow in the process to refill these canisters?

A: Yes… There are very restrictive directions that you must follow when transfilling liquid oxygen from one container to another. It is very dangerous work, because if liquid oxygen were to be spilled onto a combustible surface, it would lower the flame point of that material to room temperature and actually burst into flames. Even floors like PVC tile are a danger, because they are combustible.

Sections 18/ of the 2012 LSC require compliance with NFPA 99 (2012 edition) on all issues of medical gas. Section of NFPA 99 discusses the requirements to follow for the transferring liquid oxygen (transfilling) from one container to another. Here is a summary:

  • Transfilling must be accomplished at a specifically designated location
  • The location must be separated from patient care and treatment areas by 1-hour fire rated construction
  • The location must be mechanically ventilated
  • The location must be sprinklered
  • The location must have ceramic flooring or concrete flooring
  • The location must be posted with signs identifying transfilling is occurring
  • The location must be posted with signs that says No Smoking
  • Transfilling must be accomplished utilizing equipment complying with CGA pamphlet P-2.6
  • The use and operation of small portable liquid oxygen systems must comply with CGA pamphlet P-2.7

My advice is to get the transfilling operation out of the hospital, and contain it to a special location that is not contiguous to the facility, such as a warehouse. If you haven’t already done so, you need to purchase the P-2.6 and P-2.7 pamphlets from the CGA (

If you are currently not complying with any of the above listed requirements, I strongly recommend that you stop the transfilling process until you can correct what is non-compliant; it is that dangerous.