Full face mask with a GAS SWITCH BLOCK..

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I think for sidemount it is a horrible idea negating some benefits (see UTD discussions).
btw: I do not really believe you will not drown in a full face mask when you experience a seizure.
When facial muscles move uncontrollably a full face mask will fill with water.
 
Hi Razorista.

I agree with you about the full face mask and the benefits in a seizure situation, but again about the introduction of a new LP failure point...I don't see any difference in that point with the high criticized UTD isolatable manifold.

What do you think about this LP failure point in this full face mask with gas switch block?


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What do you think about this LP failure point in this full face mask with gas switch block?
Never tried to use a ffm with anything else but single tank myself.

As you said, little difference compared to the UTD sidemount manifold solution, only UTD already has an idea on how to use it.
Introducing a complication like that in sidemount training would be a challenge.

I do not know the international perspective but I do not think full face masks will ever have much appeal to technical divers who like practicing without any mask at all so much.

---------- Post added December 18th, 2014 at 04:05 PM ----------

btw: those who really need the benefits of full face masks here in Europe seem to be already using them, but those are very rare cases.
I would not expect many sidemount divers to actually need one and the cost comparable to buying a second drysuit is very discouraging.
 
the FFM's shouldn't flood in a seizure if they are fitted properly....

They are very useful tools for certain types of team based diving. I use one pretty regularly, mainly for the com systems. The issues with the UTD manifold are very different than those on switch blocks. I have no issues at all with a quality switch block, and most rebreather divers have some sort of manifold distribution block on their units.

I've used them with switch blocks in independent doubles and decompression situations but haven't in sidemount. No issues at all with using them as long as you have a quality block. Issue with that is they are a few hundred bucks each *$350 for the omniswivel, $200 for the input*, so a bit cost prohibitive for most people. The important part of this is to have QD's on both the FFM which you should have anyway, and on each of the tanks so if the block fails for whatever reason you can plug the tank directly into the mask.
 
...The issues with the UTD manifold are very different than those on switch blocks. ...
Can you tell us why you think so?
The UTD manifold is used for gas switches essentially and would work well with a full face mask.
 
May be the idea of using a gas switch block for gas management, the same regulator all the time and the other for backup is not a bad idea after all.

Side blocks have been standard equipment on commercial masks and helmets for decades. I have never heard of a failure with this system yet. The switch block is the same thing except it is not attached to the side of the mask. The Kirby Morgan EXO-BR Mask uses a switch block to switch from surface supply air to a bailout bottle but there is no reason why it cannot be used to switch from one tank to another.
 
there is a big difference in a complete manifold block that is behind your back that you can't see and has all of the low pressure outlets, vs. one that is only outputting to the face mask. In sidemount using a switch block you still have your inflator hoses, can run a dedicated normal second stage out of each bottle and just put a third breathing hose on the first stage and have that go to the block.

Alternative to the second stage on each bottle for sidemount, is to put a QD second stage on a suicide strap and a long hose and have that come from a Y on the output of the switch block, that way your secondary is always coming from the same bottle that you are breathing on and if it is done with a QD, in a block failure you can plug the secondary on one side and mask on the other.

Either way you have to add failure points, the point of the masks are to allow communication or protection from exposure. Saying that you shouldn't do it because of added failure points is BS because it is a calculated risk for a larger reward. Do we have to use ball swivels in sidemount, no. Does it add an extra failure point, yes, I've had one. Do I still dive with it because the added comfort is worth the benefit of having the added failure point, absolutely. CCR's have many more failure points than OC, but the added benefit is worth the potential risk, same with the isolation manifold in traditional doubles over a nonisolation manifold or independent doubles. We add a few extra failure points with an SPG instead of a J-valve but it is worth the risk, same with an octo instead of buddy breathing, or a drysuit instead of a wetsuit. Balance it for yourself but there are many benefits to certain tools, FFM's aren't for every day diving, but go ask Matthew Johnston if it is worth the added risk, or any of the hazmat divers and survey/videography teams that use them.
 
there is a big difference in a complete manifold block...
I agree that there are differences in detail, but there are none in principle.
You add a few o-rings and pressed hose fittings, a few threads to watch.
At the same time you remove independent redundant elements to replace them with single points of failure.

It's not a question of a measurably higher risk or even perceived risk of failure it just violates the minimalism principle.
From my very limited experience with diving this always proves to be a mistake after a while.
KISS is an essential part of most sidemount developments that proved successful.
 
I'm an OPPONENT of FFMs and an opponent of any sort of switch block. HOWEVER, if you HAVE to run comms and HAVE to run in sidemount.....then a switchblock is one of the best options.
 
https://www.shearwater.com/products/perdix-ai/

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