BSAC Nitrox Cert

[RobS]

I'm in the process of completing my Sports Diver cert and am a little confused with regards to the 'new' nitrox component of the new courses.

I've dived with 32% during sea dives whilst doing my OD and I understand that ODs have to use air tables or computer settings whilst using nitrox. How does this change when I'm an SD considering the extra nitrox theory that's included?

Also the club are going to run a basic nitrox workshop which I believe qualifies me to use up to 40%, is this correct? And does this mean that I can in the future go straight to the Advanced Nitrox and Deco Procedures combined?

Cheers

Rob

[Chris Cherrington]

Advanced Nitrox and Deco is a TDI course and yes the BSAC Basic Nitrox is Ok as a pre-requisite (in respect of the nitrox part only) to start it. BSAC Advanced Nitrox is also OK from basic.

OD is nitrox on air profiles, SD is nitrox on nitrox profiles. Your instructor will clear up what you can do depending on at what point you began the new sylabus and which parts of it you have completed.

Chris

[RobS]

Cheers Chris,

I think the confusion came in when I looked on the BSAC website and there was section regarding additional nitrox training for people who had completed the 'old' SD course.

[NickBCotswold]

Hi Rob

I did basic nitrox as part of the OD course, yes did 32 and 36 only, and when dived still used air tables and 21% setting on computer.

Nearly completed SD training and still only used UPTO 36%, but also looked at other mixes, like 27% etc in use with nitrox tables.

Will now use appropriate nitrox setting on computor on the dives but Dont think it takes us upto 40% tho.....think thats advanced nitrox course (?)

[Chris Cherrington]

....Dont think it takes us upto 40% tho.....think thats advanced nitrox course (?)

Basic Nitrox (all agencies) is 40% Advanced is 50% (except TDI which is 100%)

Mixes above 32% are of little use as back gasses as most users will have run out of gas long before they run out of bottom time. 50%+ is used to accelerate decompression by reducing N2 intake in the deco part of the dive (BSAC ERD)

40% is an arbitrary figure which reflects the (also arbitrary) view of the scuba industry that gasses below 40% oxygen are "safe" to use with scuba equipment that has not been specifically cleaned for high oxygen mixtures - "oxygen service" (as I'm sure you recall from your EAN lectures...)

Oxygen toxicity is far more likely to kill you than nitrogen narcosis or DCI.

Chris

[NickBCotswold]

Basic Nitrox (all agencies) is 40% Advanced is 50% (except TDI which is 100%) Chris


thanks chris, wasnt 100% sure - just recall covering uoto 36% but then looking at the nitrox tables in far more depth

[Chris Cherrington]

The BSAC centre round two standard gasses EAN 32 and EAN 36 (NOAA 1 and NOAA 2) These are the two gasses for which we publish tables. If the bottle monkey blends at another %age you have to use your judgement or ask for a reblend. With a nitrox computer you can set the computer to whatever blend you have.

Faffing about with a percentage or two is rarely worth the bother and any blend other than 32 is also rarely worth the bother to be honest.

Chris

[JamesW]

If the bottle monkey blends at another %age you have to use your judgement or ask for a reblend.Chris

Thats why BSAC should have EAD within it. Better be careful what I say!!!! :D

[graham nurse]

[QUOTE=Chris Cherrington]Basic Nitrox (all agencies) is 40% Advanced is 50% (except TDI which is 100%) Chris Quote]



IANTD now teach up to 100% in there advanced course

[Gareth]

Thats why BSAC should have EAD within it. Better be careful what I say!!!! :D

James

EAD (Equivelent Air Depth) canculations can't be applied to Hennesey tables (BSAC88's), this is according to the man himself, Hennesey.
This is why new tables where cut for 27%, 32% & 36%.


Bill Hamilton himself once said EAD 'should't work' (when applied to Bhulmann tables). However he then followed that up with the statement that we've done millions of hours of dives using EAD & Bhulmann & not had any significant DCI incidents, as such it can be said that in practice it actually works.

When a man of Bill Hamilton's expertise states that something should't work but inpractice has been found to be acceptable (when applied to a specific table), then you get a better understanding of how little we actually know of the physiology of decompression!!

Gareth

[JamesW]

James

EAD (Equivelent Air Depth) canculations can't be applied to Hennesey tables (BSAC88's), this is according to the man himself, Hennesey.
This is why new tables where cut for 27%, 32% & 36%.


Bill Hamilton himself once said EAD 'should't work' (when applied to Bhulmann tables). However he then followed that up with the statement that we've done millions of hours of dives using EAD & Bhulmann & not had any significant DCI incidents, as such it can be said that in practice it actually works.

When a man of Bill Hamilton's expertise states that something should't work but inpractice has been found to be acceptable (when applied to a specific table), then you get a better understanding of how little we actually know of the physiology of decompression!!

Gareth


Thanks Gareth

[Chris Cherrington]

IANTD now teach up to 100% in there advanced course

OOoops - yes Graham you are quite right - bit slow off the mark today.

Chris