Can CCR's be safe?

[CHartmann]

I have been doing a bit of research into getting an eCCR and training soon but with all of the deaths that have been going on lately and the likes of Wes Skiles (among other equally experienced divers) winding up dead while on rebreathers, I have been rethinking this.

My questions are what needs to be done beyond certification to ensure that a CCR dive is safe? Are there flaws with the typical unit? What additional safety equipment is necessary to make them safe? What additional protocols should be practiced to prevent mishaps? Are current training standards adequate or with every unit having its own course is there too much leeway?

[PfcAJ]

Define "safe".

[bl6394]

What's the standard for safe?

A CCR is a mechanical device subject to failure - or if poorly operated and maintained - LIKELY to fail. Failure means a breathing gas that causes hypoxia, hyperoxia, or hypercapnia.

From my point of view - if I'm current, follow the checklists, and maintain the unit properly, and don't get complacent - there is a reasonable risk associated with using it. It may fail - but I've got an excellent chance of noticing the failure (High / Low PO2) or Cell Errors. CO2 is tougher... My Evolution's temp stick MAY give me a scrubber failure warning, but a failed mushroom valve or scrubber o-ring leak might result in an unexpected CO2 hit. CO2 monitors exist and may be a solution - but I'm not sure how reliably they perform in the moist environment one finds in a loop.

I feel the risk (in my assessment for myself) is reasonable. I'm not sure what more could be done to make the technology safer than it already is.

[lv2dive]

The fact is, the typical rebreather diver is going to be older than the typical OC diver. All things being equal, it is also fair to assume that more advanced age brings an increased likelihood for medical issues. There are of course exceptions to this but every rebreather diver was an OC diver first so age is not a factor to be discounted.

Are rebreathers more complex? Yes. Can the related risks be mitigated? That is a question each must answer for themselves. I believe the benefits outweigh the risks.

[EngelenD]

Is a Porsche 911 safe ????
Depends how you handle it!!! It fur sure is fun !


Sent by my rEvo scrubber using a shearwater Nerd

[Germie]

Rebreathers are tools to help you in your diving. 1 of the big advantages is that you use less gas. But this can be one of the disadvantages. It is easy to go far in a cave, or go deep. You don't have to do gasswitches if the unit works (I don't speak about diluent switches). So in this way ccr diving is easy. But when something goes wrong ccr diving can be more complicated. Too less oxygen, you don't feel because of the CO2 is absorbed by the scrubber. So then you will die without warning. That is why you have to check your PO2. PO2 too high can be a problem too. CO2 can be a big big problem.
And then handling bailout. Never take too less. In case of problems a ccr is more complex than oc diving. But you will learn all things in a good course and if you practise it is possible to learn.
If you know all the possible dangers, then you can dive a ccr. Never get lazy. A lazy oc diver is dangerous, but a lazy ccr diver more. Not all cells working? No dive. Take a new scrubber on every complicated cavedive (or cave diving day, depending on what you are doing, 2 90 minutes dives to 30m depth can be done on 1 scrubberfill. But if you have done a 70m dive of 2hours, then take a new one for the next dive). And so on. Be a thinking diver.

[FW]

Is cave diving safe? Is open water diving safe? Is driving safe?

We all enter activities that have some risk involved. We all have to do what we can to mitigate the risks.

Rebreathers are more complex than open circuit, but can be dived safely if care is taken. There are two distinct times in a rebreather divers career that he/she is most at risk. New rebreather divers are at risk, because everything is new to them. However if you have a lot of rebreather hours, and get complacent, they can, and will, kill you. MCCR types are somewhat safer, because they force you to monitor your PPO2, however it is still possible to get distracted.

Bottom line, if you get complacent doing ANYTHING, you are at greater risk for having an accident.

[Kelly Jessop]

The fact is, the typical rebreather diver is going to be older than the typical OC diver. All things being equal, it is also fair to assume that more advanced age brings an increased likelihood for medical issues. There are of course exceptions to this but every rebreather diver was an OC diver first so age is not a factor to be discounted.

.

The first recreational rebreather fatality I recall was at the Wakulla 2 project with a Nobel Peace prize winner in shallow water. Although advanced in age, this as I recall wasn't a mitigating factor. But, it would be interesting to see demographics and median age for rebreather divers, as well as causes of accidents to support this thesis statement.

[kensuf]

Everything underwater involves some risk. I'd start with "What type of diving are you doing that makes you want a rebreather?" and then go from there to see whether or not you really need one.

[Dsix36]

1 - A diligent CCR diver is safer than a OC diver. I say this because they also carry a complete set of OC gas in addition to their CCR.

2 - Complacency in CCR divng = Dead CCR diver.