What is Nitrox?
- Nitrox is any mix of Nitrogen and Air.
- Normoxic Nitrox is normal air. (21% Oxygen and 79% Nitrogen)
- Hyperoxic Nitrox is a mix with more than 21% Oxygen
– Hyperoxic mixes are known as Enriched Air or Enriched Air Nitrox
What is Nitrox?
- EANx X is the % of Oxygen
- Safe Air (Refers to a mix between 22% and 50%)
- EAN 28 This is 28% Oxygen
- EAN 32 This is 32% Oxygen
- EAN 36 This is 36% Oxygen
- EAN 40 This is 40% Oxygen
• How long has it been around ?
- Some experiments done in the 1870’s
- 1910/1912 various tests done using Nitrox while riding a bike
- Lots of work done during the war (lots of progress)
- Started to be used as a sports gas in the 1970’s
- How do you name a mix ?
- – Oxygen content always named first
- EAN32 is 32% Oxygen and therefore 68% Nitrogen.
- EAN40 would be 40% Oxygen and 60% Nitrogen.
|Note both figures must add up to 100%. |
• Air is a Nitrox Mix.
- Air is 21% O2 and 79% Nitrogen.
- All mixes for the Nitrox diver are just air enriched with Oxygen
• Why Use Nitrox?
- Nitrox is safer than air if used correctly.
- Nitrox reduces the chances of illnesses which are associated with diving.
- Nitrox increases the time that can be safely spent underwater.
• Each mix has a Maximum Operating Depth (MOD)
- 28% 40 Metres MOD
- 32% 33 Metres MOD
- 36% 28 Metres MOD
- 40% 25 Metres MOD
- Equipment Differences
- You must only use Oxygen in Service cylinders
– Oxygen Clean plus Oxygen Compatible makes equipment in Oxygen Service.
- Oxygen Compatible means suitable for use with pure oxygen.
- Oxygen Clean refers to equipment which has been cleaned for use with pure oxygen.
• Current Cylinder markings for Europe are Black, but tend to be any colour with a “Nitrox Sticker” in black.
- All mixes “MUST” be tested prior to use.
- Mixes are tested using a Gas Analyser
- Calibrate the Analyser and connect to the cylinder to be tested.
- Turn on valve and allow a gentle flow of the gas to pass the analyser for about 15 seconds. Log the percentage reading
- More Oxygen than Air for Nitrox used in Diving
- Less Nitrogen, so safer for shallow dives
- Tried and tested over a long period
- Naming mixes by the percentage of Oxygen
- Shallow diving gas
- To Dive without an Instructor using Nitrox you must take a Nitrox Diver course, ask your DO for details