Pros & Cons of Using a Full Face Mask

[rjack321]

Deeper diving resulting in reduced scrubber affectiveness, and possible heavier workloads in wrecks or currents leading to higher exertionand C02 breakthrough is just one issue. There are other factors.

The site I posted above discusses the issues further.

A FFM mask really does nothing to solve CO2 breakthru.

 

[rjack321]

Hypoxia, hyperoxia and hypercapnia. All can result in undesirable effects. A full face mask will afford some opportunity for survival that may not be available with a bite mouthpiece DSV.

Hypoxia due to what? Doesn't really solve insufficient O2 carried / empty tank issues. Could help if you are diving a mCCR under high workloads and don't add enough gas, or your set points low, I suppose.

I don't see a FFM solving hypercapnia issues. Once you have breakthru you better be getting to OC.

Hyperoxia is the only real issue where I see a FFM solving a problem.

 

[Solitude Diver]

A FFM mask really does nothing to solve CO2 breakthru.

Well I don't think anyone is saying that it does solve it.

It does however prevent drowning in the event of unconsciousness due to high co2 (or for whatever reason), and with a little luck an attentive buddy can switch your bailout valve and get you onto another gas source. Not fool proof. Just another edge.

Similarly it does not prevent o2 poisoning, but I would sure want it if I took a hit and went into convulsions. Might not solve the initial problem, but could prevent death by drowning.

Again, my post was to direct anyone interested in other points of views to another site in which others had different perspectives and thoughts. It was in line with the OP.


Cheers.

 

[rjack321]

I certainly agree that RBW is a better place to discuss RBs in general and FFM use with them too :d

 

[Solitude Diver]

Whatever sport.

We're talking pros and cons of FFM. There were some thought provoking points of views that were not all rebreather specific on that thread. You seem pretty focused on debating something here. (Whatever that may be).

The OP wanted pros and cons and received a variety of opinions, etc. You do not have to read further if you don't want. This was just another point of view.

Now move on (dismissive)

(back at ya)

 

[rjack321]

Seriously the M48 looks pretty nice and solves alot of FFM cons. Although I have not seen one outside the pics and wonder about the availability of the RB attachment (since the website says military sales only).

The AGA is a lousy choice, all con no pro for that unit. Really wish the aquarium would ditch the danged things, just not worth the hassle for 18ft of water. Although not having a hooka would be a plus as well and maybe make up for the AGAs shortcomings.

 

[mntdiver]

Hypoxia due to what? Doesn't really solve insufficient O2 carried / empty tank issues. Could help if you are diving a mCCR under high workloads and don't add enough gas, or your set points low, I suppose.

I don't see a FFM solving hypercapnia issues. Once you have breakthru you better be getting to OC.

Hyperoxia is the only real issue where I see a FFM solving a problem.

I'm guessing your experience with rebreathers is limited. A full face mask is not a solution to anything, it's a safety device. As seat belts don't, for the most part, prevent accidents. Regardless of what the failure of a specific system, be it channeling/breakthrough, a clogged orifice or sensor/electronics failure resulting in hypoxia or hyperoxia, use of a full face mask is a choice of some as a safety issue. For WHATEVER reason you might go unconscious underwater (or convulse-hyperoxia) a full face mask will increase any chance of survival you might have. It may make the difference of us reading about you under the "Passings" thread or "Accidents and Incidents". Add communications and you may even be able to tell someone you're having a problem or ask for assistance.

 

[mntdiver]

Seriously the M48 looks pretty nice and solves alot of FFM cons. Although I have not seen one outside the pics and wonder about the availability of the RB attachment (since the website says military sales only).

The AGA is a lousy choice, all con no pro for that unit. Really wish the aquarium would ditch the danged things, just not worth the hassle for 18ft of water. Although not having a hooka would be a plus as well and maybe make up for the AGAs shortcomings.

What specific problem do you have with the AGA mask and which mask would you suggest be used for the interactive diver program at the aquarium?

 

[116fire]

Knee deep in nit wits...On an mCCR if you pass out from Hypoxia, you should still have your "leaky valve" feed which should be approx your resting O2 consumption, and certainly better than breathing water. The AGA's I use at work are pos pressure and self clear almost violently. We do not share ffms you donate an alternate second stage. In addition to switch blocks you can use quick connects attatched to the first stage of stage/bailout bottles.

 

[rjack321]

What specific problem do you have with the AGA mask and which mask would you suggest be used for the interactive diver program at the aquarium?

Skip FFMs which need to fit a huge variety of faces - they don't. The AGA has a backwards hose feed which creates alot of gear cross-compatility issues. It's also big, hard to clear when flooded for noobs and esp hard to clear ones ears if the noseblock doesn't fit well (like on my nose although I am only one of many who have this issue). They are also very expensive and replacing the skirts which volunteers rip fairly frequently is a big hit on the budget.

They do have one "lower face pod" which is essentially a pocket mask like thing covering only the mouth with a mic inside. I have never seen another like it and don't know the manufacturer. It has a USdivers octo 2nd stage attached to it right now and tends to sit in a box.

If I were the god of aquarium interpretation I would use those. Much simpler, nothing to impede normal mask usage and fitting. You have the needed mic/comms without all the funky FFM fitting on various faces, water clearing, nose block, special hoods, swivel failure points, expensive fragile skirts, oh and cleaning/disinfection off all the nooks and crannys. Just a simple pocket mask sized "mouthpiece" on a reg which volunteers could use their own masks + hoods with.

But like I said earlier I have ~40-45 dives with the AGA its quirks may be an aquired taste I suppose