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Technical Support Document

Recommended Steps To Be Included in a Procedure for Removal and Insertion of Valves in Medical Oxygen Cylinders

June 5, 2009


Oxygen is one of the three components necessary for combustion. Great care must always be taken when performing any operation in an oxygen-enriched environment. Catalina Cylinders recommends the following steps be included in any procedure for the valve removal from, and the insertion in, oxygen cylinders.

Valve Removal

  1. Always perform the valve removal operation in a well-ventilated and clean (oil-free) area.


  2. Make sure there are no possible sources of ignition (i.e. lit cigarettes, open flames, welding equipment, etc.) in the well ventilated area in which the valve removal form the oxygen cylinders will be performed.


  3. Always use clean (oil-free) tools.


  4. Verify the cylinder is an oxygen cylinder by the Oxygen USP Warning label on the sidewall of the cylinder and the O2 or O with a 2 inside it stamping in the crown marking on the top of the cylinder. Do not remove the valve from a cylinder of which the contents of the cylinder is unknown.


  5. Open the valve slightly and verify the cylinder is free of oxygen charge.


  6. Do not remove the valve from cylinders containing any charge (pressure).


  7. Secure the cylinder, use a wrench that fits the valve body and manually supply enough force to break the valve free from the cylinder.


  8. Stop and listen (for hissing) for loss of contents. If heard discontinue any efforts to remove the valve from the cylinder.


  9. If there is no evidence of loss of contents after breaking the valve free, continue to remove the valve.


  10. If the valve binds (sticks) in the threads during removal, do not use an oil-based release agent to assist in the removal of the valve.


  11. After removal of a valve that was stuck in a cylinder, evaluate the threads of the valve and cylinder before ire-inserting the valve into the cylinder.


  12. Discard the Teflon o-ring. It cannot be reused.



Valve Insertion

  1. Always perform valve insertion operation in clean (oil-free) area.


  2. Always use clean (oil-free) tools.


  3. Verify the cylinder is an oxygen cylinder by the Oxygen USP Warning label on the sidewall of the cylinder and the O2 or O with a 2 inside it stamping in the crown marking on the top of the cylinder.


  4. Verify the valve is the correct valve to be used in oxygen service. For DOT-3AL cylinders the valves are CGA 870 or CGA 540 valves with straight threads.


  5. Verify the valve and cylinder threads are free of all oil-based products (i.e. lubricants). Never use products containing oil in the valve insertion process in oxygen cylinders.


  6. Inspect the inlet and outlet connection of the valve and the threads and o-ring gland of the cylinder for damage to the threads and o-ring area. If either the valve or cylinder has damage to the threads or the o-ring area, do not insert the valve into the cylinder.


  7. Always use a new Teflon o-ring every time the valve is re-installed. Verify that the new Teflon o-ring is free of lubricants and damage.

    Cylinder Valve Teflon
    Thread Designation Designation O-ring Size
    .750 - 16 UNF CGA 870 210
    1.125 - 12 UNF CGA 540 216

  8. Never use Teflon tape or any other sealing compound to seal a leaking valve/cylinder assembly.


  9. Teflon o-rings are easily damaged. Be careful when putting the o-ring onto the valve. Contact the valve manufacturer for their recommended technique to install a Teflon o-ring on a valve.


  10. Tighten the valve hand tight.


  11. If you feel the valve binding in the cylinder while inserting the valve, stop immediately, remove the valve, check the threads of the valve and cylinder for apparent damage, inspect the cylinder internally for contamination.

    Remove from service a valve and/or cylinder with damaged threads.

    If contaminates are visible inside a cylinder, remove all contaminates and re-inspect the inside of the cylinder verifying the cylinder is free of contaminates before inserting a valve into the cylinder.

    Caution: If using compressed air to remove (blowout) contaminates form a cylinder, make sure the air is oil free. The compressed air system should have in-line oil filters. Many standard compressed air systems do not have in-line oil filters.


  12. Final tightening of the valve should be done with a clean calibrated torque wrench to the recommended torque values noted below:

    Thread Catalina Cylinders
    Designation Recommended Torque
    .750 - 16 UNF 80 lbf - ft   -   85 lbf - ft
    1.125 - 12 UNF 95 lbf - ft   -   100 lbf - ft

  13. When torquing is complete, there should be no gap between the bottom of the flange of the valve and the top of the cylinder. For oversized o-rings, a slightly higher amount of torque may be required to seat vavles completely.

  14. Close the valve with no more than 1 lbf - ft torque.


  15. Do not tamper with the safety device of the valve. The safety device of the valve should be rated at the test pressure of the cylinder.


  16. Whenever replacing the safety device of a valve, Catalina Cylinders recommends that you always replace the safety device with a complete new safety device assembly.





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