You must hold the appropriate qualifications before you are allowed to dive with nitrox or to mix it.
- A nitrox diving qualification allows you to dive with nitrox
- A gas blending qualification allows you to mix nitrox (fill cylinders)
The two are distinct: a gas blending qualification does not allow you to dive nitrox and a nitrox diving qualification does not allow you to mix nitrox.
Nitrox Diving Qualifications – What Mix Can I Dive with?
Only those qualified to use nitrox may dive with it. BS-AC recently made nitrox part of the Ocean Diver and Sports Diver training syllabus so those trained under the new system are now qualified to use nitrox as a back gas (i.e. they are not qualified to carry different gas mixes) with various restrictions. Divers trained in the old system, where nitrox was not part of the syllabus, are not qualified to use nitrox unless:
- they have attended a nitrox workshop, or;
- they hold some other BS-AC nitrox qualification, or;
- they hold a nitrox qualification with another agency and have approval from the Diving Officer to dive nitrox.
There are more advanced nitrox grades attainable by completing skill development courses.
Those Trained under the Old System (where Nitrox was not part of the Syllabus)
|Grade||Completed OD Nitrox Workshop||Completed SD Nitrox Workshop||Gas Mixes Allowed||Notes|
|Trainee||No||N/A||Not qualified to use nitrox.|
|Trainee||Yes||N/A||Nitrox 32 and 36 only (nothing in between)||Must use air tables, or dive with computer set to air.|
|Ocean Diver||No||No||Not qualified to use nitrox.|
|Ocean Diver||Yes||N/A||Nitrox 32 and 36 only (nothing in between)||Must use air tables, or dive with computer set to air.|
|Sports Diver / Dive Leader / Advanced Diver||No||No||Not qualified to use nitrox.|
|Sports Diver / Dive Leader / Advanced Diver||Yes||No||Nitrox 32 and 36 only (nothing in between)||Must use air tables, or dive with computer set to air.|
|Sports Diver / Dive Leader / Advanced Diver||Yes||Yes||Nitrox mixes up to 36%|
Those Trained under the New System (where Nitrox is part of the Syllabus)
|Grade||Gas Mixes Allowed||Notes|
|Trainee||Nitrox 32 and 36 only (nothing in between).||Must use air tables, or dive with computer set to air.|
|Ocean Diver||Nitrox 32 and 36 only (nothing in between).||Must use air tables, or dive with computer set to air.|
|Sports Diver||Nitrox mixes up to 36%|
|Dive Leader||Nitrox mixes up to 36%|
|Advanced Diver||Nitrox mixes up to 36%|
Nitrox Filling Qualifications
Only qualified nitrox and mixed gas blenders are allowed to fill cylinders with nitrox. If you are qualified to dive with nitrox, but not to mix it then you can ask somebody else to fill it for you.
The club has 10 designated nitrox bottles. These have the word NITROX spray painted in green on them. These bottles are not in oxygen service but are for use with the nitrox panel. When using a club bottle for nitrox please use one of these if available. For these and all other club bottles, ALWAYS analyse before filling (even if filling with air) as the bottle may have some residual nitrox in it which will affect your fill.
If you’re not using one of the club nitrox bottles but filling a personal bottle, you’ll have to make sure it’s in oxygen service if you are filling using partial pressure blending. For mixes up to 40% using the panel your bottle does not need to be in oxygen service.
Nitrox Blending Equipment
The club has a partial pressure blending Nitrox station in clubrooms. This is only for use by certified Nitrox blenders. The club regularly runs the BS-AC gas blending course for anyone looking to get certified.
A new addition is the MPS T-Mix blending panel which is plumbed in between the compressor air intake and the Coltri compressor in club rooms. This has the ability to produce Nitrox and Trimix with a 40% oxygen content.
Nitrox fills are no longer charged on the basis of the number of litres of oxygen used: instead there are two flat rates; one for fills using partial pressure and one for fills using the nitrox panel. The blender, regardless of whether the fill is for him or someone else, is responsible for paying immediately.
- Partial pressure fills cost €5
- Nitrox panel fills cost €2
If you’re not a blender then whoever the blender is will be responsible for collecting the money from you.
Analysing Nitrox fills
Fills must be analysed at the time of filling, and the percentage of oxygen and the MOD must be marked on the bottle. Duck tape and permanent markers are provided.
If you’re not a blender, then you should really be there when your bottle is being filled. If not, the blender will lock it in the cage until you can pick it up, and at that point the fill must be analysed in front of you.
Finally, the fill must be analysed one last time at the dive site in front of your dive buddy and the dive marshall.