DL - new failure modes?

jmdiver

Here goes.

It has been said that you can't out-engineer stupidity or lack of proper knowledge/training, and that an idiot will always find new levels of idiocy at his disposal.

Since I'm a newbie, I fall into the most clueless category by default. Ergo, I may be in a unique position to humbly offer something to the safety discussion!

I thought I give this a try and have a shot at the free whisky Alex has offered!

I read the DL doc FMECA Vol 6 Top down faults regarding failure modes. Did not see the following. I suppose they have already been considered but has not reached the doc yet:

a) Inability to reach manual injection

b) CO2 monitor failure

c) Wrong deco profile due to wrong mix when changing mixes. (If related to Rebreather electronics)

d) Flawed mods. (maybe to general)

e) Half fill a scrubber or pack granules in the EAC scrubber (you should see this coming )

best,
jm

Ferg3333

If anyone was to do this they need banning from diving ccr. If any mo fo teaches it they need drowning. But then the internet has enlightened the world.

AD_ward9

On the failure modes:
1. Failure to reach manual injection. It is on your mouth: the ADV is integrated into the mouthpiece and acts as a combined ADV and BOV.

2. CO2 monitor failure. This is backed up with scrubber monitoring and the CO2 sensor fails safe anyway: i.e. when it fails it shows a CO2 warning.

3. Wrong deco is in the hazards listed.

4. Flawed mods: which ones?

5. Filling the EAC can with granules. We have deliberately made it almost impossible to do that. There is nothing to keep the granules in.

Keep hunting though ...

Cheers,

Alex

onfloat

Stuff the opening(s) with cotton balls.

jmdiver

... but is the cotton CE approved??

koputai

When the ADV activates, is the addition upstream or downstream of the diver? ie: Does the diver breath the dil straight in?
If it's upstream, then in the case of a hypoxic diluent, the diver will take a lung full of hypoxic gas before it has been through the loop and had at least *some* more O2 added to it.
If it's downstream, at least the machine can add some O2, or the diver can stand on the manual O2 add. (Hmm, can't remember if the machine has a manual O2 add?)

Cheers,
Jason.

__________________
Subsea Systems - Displays, HUDs and electronics for your rebreather.

kybrt

could you have an mccr w/o a manual add?? <honest question>,

__________________
Marv


Fidelis Ad Mortem
www.diveboatkaren.com

Underwaterbear

No manual add for what? Dil? Yes if the ADV always works. O2? You have to have a mechanism for adding O2 otherwise you are diving a SCR by definition.

AD_ward9

It is designed specifically to stop people plumbing gas into their ADV that they cannot breathe. This is a very bad practice, that has contributory factor in the deaths of a number of divers.

What you plumb into your ADV, you have to be able to breathe at the depth you are using your ADV. The same gas is your bail out.

Alex

Wol

Alex

Just thought of one new failure mode - not sure if this is covered?

Assuming the unit has been in a shed for a year or so and both batteries are dead is there anything to stop someone tinkering with their new rebreather in the garden shed and popping it on their back and breathing on it not realising that the O2 is not on? (with an EAC in the unit)

One of the lessons we learn early is not to put a unit on your back until it is switched on and tested - the scenario I am thinking of could include - kids in dads shed. Untrained user - or just a rebreather diver tinkering (adjusting kit etc) and not thinking especially after a season off diving + hangover etc

I guess some kind of safety measure could be to somehow mechanically force OC if O2 was off???