Service Pressure - 3000 psi
True Capacity - 40 cu feet
Buoyance - Full - -0.7 lbs
Buoyancy (500 psi) - +1.8 lbs
Weight Empty - 15.3 lbs
Outside Diameter - 5.25"'
Cylinder Length - 24.6'
The use of oxygen and oxygen-enriched gas blends is growing in popularity among sport and recreational divers around the world, especially in the United States. Judging from the questions that Luxfer has received, a good deal of confusion exists within the recreational diving community about safely using Luxfer aluminum scuba cylinders in oxygen-enriched and oxygen service. This document answers the most frequently asked questions and provides references for further research about this important subject. This page contains Luxfer’s recommendations only for Luxfer scuba cylinders manufactured in the U.S. and may not be applicable for other countries.
1. Question: What are the differences among the terms oxygen service, oxygen mixture, nitrox , enriched-air nitrox (EAN) and oxygen-enriched air?
Answer: The term oxygen service generally means using pure oxygen (oxygen concentrations of 95% to 100%), but the term is sometimes used more broadly to refer to any gas mixture containing more oxygen than air. The 'standard air' we breathe is composed of 20.95% oxygen, 78.05% nitrogen and 1% of trace amounts of other gases, including argon, carbon dioxide, neon, helium, krypton and xenon (the amounts vary depending upon your geographical location, altitude, etc.). For practical purposes, most technical literature rounds off these percentages and defines 'standard air' as 21% oxygen and 79% nitrogen.
Oxygen mixture generally refers to gas blends containing between 50% and 95% oxygen.
Oxygen - enriched air, nitrox , and enriched-air nitrox (EAN) are generally used synonymously in the diving industry since all refer to pressurized diving gas mixtures containing various oxygen concentrations greater than standard air. For example, two common mixtures used by divers are EAN 32 (32% oxygen) and EAN 36 (36% oxygen). However, in the gas industry, oxygen-enriched air is sometimes defined more specifically as gas mixtures containing more oxygen than found in standard air, but no more than 50% oxygen.
To avoid confusion, Luxfer prefers using the term oxygen service to refer only to pure oxygen usage and enriched-air nitrox (EAN) to refer to oxygen-enriched breathing mixtures used for diving.
Whatever term you choose, the main thing to remember concerning Luxfer scuba cylinders is that when you fill a cylinder with an oxygen concentration of 23.5% or more, that cylinder must be specially cleaned for oxygen service as though it contained 100% oxygen.
2. Question: Can I fill my Luxfer aluminum scuba cylinder with pure oxygen so that I can use it for decompression?
Answer: Yes, if you follow the Luxfer requirements listed below, which must be met both for pure oxygen and gas mixtures containing more than 23.5% oxygen:
The cylinder must have been properly cleaned, tested for cleanliness and maintained in a proper state of cleanliness for oxygen service in strict accordance with the Code of Federal Regulations (CFR), specifically U.S. Department of Transportation (DOT) CFR49 173.302(b).
The cylinder must be equipped with an oxygen-compatible valve and be filled only by oxygen-clean, properly maintained filling equipment dedicated to oxygen service.
The cylinder must never be fast-filled or over-pressurized.
Proper safety procedures for handling and dispensing oxygen prescribed by the DOT and U.S. Compressed Gas Association (CGA) must be followed at all times. In fact, Luxfer further recommends that anyone in the scuba industry who handles pure oxygen in a Luxfer cylinder become familiar with and follow current guidelines concerning cleanliness, filling, storage, usage and maintenance of oxygen cylinders provided by the U.S. Food and Drug Administration (FDA). As the world’s largest manufacturer of aluminum and composite medical oxygen cylinders, Luxfer has a great deal of experience with cylinders in pure oxygen service and with the FDA guidelines that promote safe oxygen usage. Luxfer’s experience has shown that following FDA guidelines is a practical and effective way of preventing oxygen-related accidents.
3. Question: Why is it necessary to clean scuba tanks for oxygen service?
Answer: To remove contaminants that can become the fuel for an oxygen-fed fire.
Oxygen, an oxidizing gas, does not burn, but it supports combustion and causes other materials to burn. In the presence of pressurized oxygen concentrations exceeding that in standard air, most materials become progressively more flammable and ignitable as the oxygen concentration and pressure increase. Even materials that would not easily catch fire in standard air under normal atmospheric pressure will ignite and burn furiously in a pressurized oxygen-enriched environment. It cannot be overemphasized that rising pressure increases the risk of ignition.
For an oxygen-fed fire to occur, three things must be present: oxygen, fuel (something to burn), and heat (an ignition source)—this is the classic “fire triangle.” When dealing with pressurized oxygen or EAN in a scuba cylinder, remember this important variation on the classic three factors needed for a fire:
Oxygen or gas containing oxygen, under pressure (higher concentrations of oxygen and significant pressure greatly increase the need for oxygen cleanliness and diligent safety practices).
An ignition (flame, spark, heat source, etc., including impact from dropping or striking a pressurized cylinder).
A contaminant (i.e., fuel—but the reason the term “contaminant” is preferred in this case is that in an properly cleaned oxygen system, no fuel is present. If fuelis present, it is contaminating the system and making it no longer safe for use with oxygen). Common contaminants include:
Machining oils (including residual oil film)
Hydrocarbon-based grease and lubricants (including compressor oil)
Some soaps, detergents, solvents and cleaning solutions, especially those that contain organic compounds
Skin lotions and emollients and cosmetics
Sun-tanning oils and lotions
Human skin oil and bodily fluids
Insects and insect body parts
Paint, wax, and marking crayons
Carbon dust from filtration systems
Metal fines, filings, scale and burrs
Chrome chips (usually from valves and other chrome-plated parts)
Rust particles and dust
Metallic oxides in general
Airborne soot and dust
Pipe thread sealants
Residue from soapy water and leak-detection fluids used to check for leaks
Lint from cloths used in cleaning
Any other material containing organic compounds and hydrocarbons
Any of these contaminants—many of which are very difficult to detect—can be the initial fuel for an ignition event, the technical term for starting a fire. Once an oxygen-fed fire gets going, even metal components—including a scuba cylinder itself—can burn vigorously. Aluminum melts at 1,220 degrees F (660 degrees C); after an oxygen-related cylinder fire, it is not unusual to find large areas of melted aluminum—which shows just how hot and energetic such a fire can be.
That’s why it’s so essential to remove contaminants and to keep the oxygen system clean. Proper oxygen cleaning need not be excessively costly or time-consuming, but it does need to be effective. Removing contaminants and keeping equipment oxygen-clean is the best way to make sure that an oxygen-fed fire never starts.
A number of agencies and organizations in the United States provide certification courses in oxygen cleaning. For examp