Jan 22 2012

Liquid Oxygen Transfilling

Category: BlogBKeyes @ 11:59 pm

Ever see any of these devices in your hospital? If so, special needs and precautions are required to continue to use them.

These devices contain liquid oxygen  and they are specifically used to transfer liquid oxygen from this reservoir to portable hand-held canisters that would be used for individuals. That process is referred to as ‘transfilling’ and is highly regulated.

Liquid oxygen is a very dangerous material and the storage and use of liquid oxygen needs to be clearly defined in your hazardous materials management plan.

Liquid oxygen by itself is not flammable, but an oxygen enriched atmosphere makes all the other materials around it much more combustible. These reservoirs are not pressurized in the sense compressed gas is pressurized at 2,000 psi. The liquid oxygen reservoirs are constantly venting gaseous oxygen into the room where they are stored. Above its critical temperature of -118 degress F, liquid oxygen will only exist as a gas. When it expands from a liquid to a gas, it occupies 860 times more volume as a gas than it did as a liquid.

The reason liquid oxygen is so dangerous, is if it were to be spilled, then any combustible material it comes into contact with will immediately ignite. Liquid oxygen boils at -297 degrees F (at standard atmospheric pressure), and it brings the ignition temperature of anything it comes into contact with down to the point where the material will ignite at room temperature. That is why the transfer of liquid oxygen is not permitted on a surface that has combustible materials, such as carpet, vinyl tile and even asphalt. It can only be transferred on concrete or ceramic surfaces.

Section of the 2000 edition of the Life Safety Code requieres compliance with the 1999 edition of NFPA 99 Standard for Health Care Facilities on issues involving medical gas. Section 8- of NFPA 99 requires compliance with the Compressed Gas Association (CGA) Pamphlets P-2.6 and P-2.7 on liquid oxygen transfilling and storage. In addition to the CGA requirements, NFPA 99 also requires the actual transferring of liquid oxygen to be separated from any portion of a facility where patients are housed, examined or treated by a 1-hour fire rated barrier. The transfilling area must be well ventilated, protected aith automatic sprinklers, and have ceramic or concrete flooring.