OXYGEN POLICY AND STANDARDS FOR ENRICHED AIR NITROX (EANx) CYLINDER HANDLING AND INSPECTION
Cylinders and valves intended for Enriched Air Nitrox (EANx) service require special cleaning and inspection procedures. This standard addresses the handling, inspection and cleaning of EANx Cylinders. It does not address the important ramifications of handling or transporting high oxygen concentrations.
1. OXYGEN POLICY
A. PSI/PCI, Inc. adheres to Compressed Gas Association (CGA) recommendations concerning oxygen service. These recommendations establish that cylinders containing 23.5% oxygen content, or greater, shall be cleaned and serviced in accordance with CGA pamphlet G-4.1 part 11.2.6.
B. As gas blending is a common method by which EANx cylinders are filled, the oxygen content in any EANx cylinder may reasonably be expected to, at some time, exceed the 23.5% threshold. Therefore, it is PSI, Inc., policy that all EANx cylinders must be cleaned for oxygen service.
2. EANx CYLINDER HANDLING
A. Normal compressed air shall not be introduced into any cylinder marked for EANx service.
1) Any EANx cylinder receiving normal compressed air shall either have its EANx marking removed or be set aside for a formal inspection and oxygen cleaning prior to filling with EANx.
B. Normal scuba cylinders shall not be filled with EANx unless they have been properly prepared for EANx use. This includes:
1) A new formal visual inspection
2) Oxygen cleaning and servicing of the valve
3) Oxygen cleaning of the cylinder
4) Marking the cylinder for EANx service
C. EANx cylinders shall be secured for transportation to minimize cylinder damage.
D. For prolonged storage, EANx cylinders shall be drained to no more than 50 psig and secured in a vertical position.
E. EANx cylinders must be conspicuously marked as to the specific gas mix (oxygen percentage) inside.
3. CYLINDER INSPECTIONS
A. INFORMAL INSPECTION OF EANX CYLINDERS:
1) All EANx cylinders shall receive an informal inspection prior to filling. This informal inspection consists of:
a) Cylinder is within 5 year hydrostatic test/retest period.
b) Cylinder is within maximum 1 year formal visual inspection period.
c) Cylinder codes are valid.
d) Cylinder is examined for external signs of damage. Any found damage is within CGA and PSI limits.
e) Cylinder is properly marked as having been cleaned for EANx use.
2) Cylinders which fail to comply with any part of 3A 1) above shall be drained, valve closed, and set aside for a formal inspection by a trained visual cylinder inspector.
B. FORMAL INSPECTION OF EANX CYLINDERS:
1) A formal visual cylinder inspection constitutes a complete examination in accordance with the PSI, Inc. 18 Step Protocol for the visual inspection of compressed air cylinders, with the following modifications:
2) When discharging pressure from EANx cylinders, keep all combustible materials, including grease, oil and other hydrocarbons away.
3) Do not allow clothing to become saturated with the contents of the discharging cylinder.
4) Probes or other objects inserted into the cylinder shall be free of contaminants, petroleum products and body oils.
5) Cylinder valves shall be lubricated with a small amount of oxygen compatible lubricant, such as Crytox or Crystolube MCG111 to the lower valve threads. Dow Corning 111 (or similar product) and petroleum based lubricants SHALL NOT be applied to the valve.
6) The valve o-ring shall be of a material intended for oxygen service, such as Viton A.
7) Cylinder shall be oxygen cleaned in accordance with CGA pamphlet G-4.1 prior to reassembly and filling.
8) In addition to normal visual inspection procedures using a bright white light, an EANx cylinder shall also be visually inspected with an ultraviolet (black) light to determine the presence of unacceptable hydrocarbons. Repeatedly oxygen-clean the cylinder until no hydrocarbons are detected.
9) Cylinder shall be conspicuously marked as to its intended service and content.
Please email omnidive@omnidivers.com if you are interested or want additional information.
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