HSE advice on independent air supply

[Kevin Swindin]

I am just about to prepare for my TIE and I have AAS as the topic of my lesson. I recall some advice from the HSE (I think it was) that recreational divers should not operate with two second stages from a single first stage and that best practice was a completely separate air source. I can't find the reference to this. Can anyone help?

thanks

Kevin

[John Williams]

I am just about to prepare for my TIE and I have AAS as the topic of my lesson. I recall some advice from the HSE (I think it was) that recreational divers should not operate with two second stages from a single first stage and that best practice was a completely separate air source. I can't find the reference to this. Can anyone help?

thanks

Kevin


Yep!
Don't go there!
for a TIE it is simply too "in depth" and "controversial"

Just talk about the various options and give some pro's/con's for each one (including a price) and suggest people look around their own club and try each underwater before they buy!

If you can take an example of each with you to use as a visual aid.

Keep them hidden til you use them (and hide them again once used) - otherwise they become a distraction!

John
TIE Examiner!

[Nigel Hewitt]

I am just about to prepare for my TIE and I have AAS as the topic of my lesson. I recall some advice from the HSE (I think it was) that recreational divers should not operate with two second stages from a single first stage and that best practice was a completely separate air source. I can't find the reference to this. Can anyone help?It was that a minimum specification first stage could not deliver the gas to provide for two heavily used second stages if both parties inhaled simultaniously. As John says this is way OTT to even mention on an exam lesson.

It's a mathematical glitch in the specs only. In the real world with normal spec equipment it isn't a problem.

[Andy Wade]

I am just about to prepare for my TIE and I have AAS as the topic of my lesson. I recall some advice from the HSE (I think it was) that recreational divers should not operate with two second stages from a single first stage and that best practice was a completely separate air source. I can't find the reference to this. Can anyone help?

thanks

Kevin

Nigel and John are quite correct.
The only time you might hear this one come up is if your examiner wanted to discuss the subject a bit further, (just in conversation of course) I doubt if they would even raise it as a question after your lesson, which would be a little unfair IMO.
Nice to know about it though.
John's advice is great for the exam.
Remember KISS, it applies to lots of things including lesson preparation, and especially for examinations.

[Kevin Swindin]

OK, OK!;)

Thanks for all the common advice - I really wanted it as backup in case the examiner asked the question and cos it is interesting to think widely about the lesson before working out what is the must knows!

So - can anyone provide the link to a reference?

Kevin

[Adrian Kelland]

OK, OK!;)

Thanks for all the common advice - I really wanted it as backup in case the examiner asked the question and cos it is interesting to think widely about the lesson before working out what is the must knows!

So - can anyone provide the link to a reference?

Kevin
http://www.hse.gov.uk/diving/ in there somewhere - probably :)

[Edward]

So - can anyone provide the link to a reference?

http://www.bsac.org/etalk/etalk0805a.html

A starting point

Edward

[Rick]

I am just about to prepare for my TIE and I have AAS as the topic of my lesson. I recall some advice from the HSE (I think it was) that recreational divers should not operate with two second stages from a single first stage and that best practice was a completely separate air source. I can't find the reference to this. Can anyone help?

thanks

Kevin

on the IFC I was on over last weekend in London this was mentioned by Jeff Read (our trainer and I think head of BSAC Technical Group) when someone in my group had to give a theory presentation on AAS. If I recall correctly he said it could be mentioned as part of the 'Technically correct and up to date bit'

Mind you he did say that we couldnt be expected to know as guidance hasnt yet been issued by BSAC. I got the impression that this was in hand and would be released at some stage in the future; our club training officer had told us about this anyway during one of my lectures.

[Philip Smith]

I recall some advice from the HSE (I think it was) that recreational divers should not operate with two second stages from a single first stage and that best practice was a completely separate air source. I can't find the reference to this. Can anyone help?


The research report "Breathing performance of ‘Octopus’ demand diving regulator systems" can be downloaded from here:
http://www.hse.gov.uk/research/rrhtm/rr341.htm

The gist of it is that octopus systems made up from a cheap first stage and an old or cheap second stage do not perform adequately under some realistic conditions of depth, breathing rate and synchronisation of divers' breathing. In particular, some octopus systems function adequately when the divers are breathing out of phase, but fail when divers breathe in phase (i.e. inhale at the same time). The report recommended that if an octopus system is to be used, it should be based on a high performance first stage and modern second stages of similar performance, but that a completely independent system is preferred.

Phil S

[John Williams]

:eek: You GITS!

He's trying to prepare for an exam...and you shove him into the maze called HSE!:confused:

He'll get lost in there and never get out in time!:(

Don't go there!
...it's just a ploy placed there by the powers that be to confuse and bamboozle ordinary mortals like most divers
(Obviously I discount Edward from that cohort!:D ) into submission (and dribbling lunacy!):mad:

Good luck with your exam though!

John

[John Williams]

The research report "Breathing performance of ‘Octopus’ demand diving regulator systems" can be downloaded from here:
http://www.hse.gov.uk/research/rrhtm/rr341.htm

The gist of it is that octopus systems made up from a cheap first stage and an old or cheap second stage do not perform adequately under some realistic conditions of depth, breathing rate and synchronisation of divers' breathing. In particular, some octopus systems function adequately when the divers are breathing out of phase, but fail when divers breathe in phase (i.e. inhale at the same time). The report recommended that if an octopus system is to be used, it should be based on a high performance first stage and modern second stages of similar performance, but that a completely independent system is preferred.

Phil S

Much kinder..he'll be able to drop into the maze and get out again with what he wants (but does not need ...havn't we ALL been there?) with surgical precision!

Have some greens for being so helpfully accurate!
Incoming!

All the best

John

[Philip Smith]

Have some greens for being so helpfully accurate!

Glad to be of service. I meant to say, contrary to the title of this thread, the recommendations were by the authors of the research report and are not necessarily the official HSE view. The HSE press release (http://www.hse.gov.uk/press/2005/e05057.htm) on the report gives another summary of it and their view on what constitutes a suitable secondary gas supply.

Phil.

[Kevin Swindin]

Edward,

thanks, just what I was after.

Kevin

[Kevin Swindin]

Thanks to all - I do feel better able to answer the question about this if some examiner chooses to ask about this topic.

Kevin

[Edward]

Edward,

thanks, just what I was after.

Kevin

Do I get a greeny

Edward