Mouth Venting

Deep Smeg · 28th August 2009, 10:20

Hello all FFM Users

A question if you'll indulge me:

Is it easy to vent your loop from around your lips while using a FFM or does the face seal create to much of a back pressure?

Thanks in advance

Seb

paulraymaekers · 28th August 2009, 10:30

Quote: (Originally Posted by Pelagian)

Hello all FFM Users

A question if you'll indulge me:

Is it easy to vent your loop from around your lips while using a FFM or does the face seal create to much of a back pressure?

Thanks in advance

Seb

Seb, with a correct CCR FFM, mouth and nose are separate in the mask

and a FFM has an OPV also,

free-flow by the lips to flush does not work with a FFM, as there is always some overpressure in the mask

so to vent, I nose exhale, agains the pressure of the FFMOPV, (of wich I reduced the cracking pressure : drager panorama)

paul

Deep Smeg · 28th August 2009, 10:51

Quote: (Originally Posted by paulraymaekers)

Seb, with a correct CCR FFM, mouth and nose are separate in the mask

and a FFM has an OPV also,

free-flow by the lips to flush does not work with a FFM, as there is always some overpressure in the mask

so to vent, I nose exhale, agains the pressure of the FFMOPV, (of wich I reduced the cracking pressure : drager panorama)

paul

Hey Paul

The thing I don't understand is with the rebreather version of the Panorama there is no oro-nasal mask just the bite mouthpiece, so your lips and nose are in the same cavity as the resto of your face.

Why would you be able to vent with your nose but not your lips?

Seb

**kwinter** · 28th August 2009, 12:25

I use an AGA rather than a Panorama, but I think the same problem would be experienced by any FFM other than the MK-48. Nose and mouth are in the same space, and the mask should be fairly well sealed to the face with some positive pressure. This makes venting through the nose or around the mouthpiece ineffective.

IMHO, a full mask should not be used without a BOV. So the easy way to vent is to inhale from the loop, switch the BOV to OC, exhale, then switch it back to the loop.

Ken

mountain diver · 28th August 2009, 12:48

Quote: (Originally Posted by Pelagian)

Hello all FFM Users

A question if you'll indulge me:

Is it easy to vent your loop from around your lips while using a FFM or does the face seal create to much of a back pressure?

Thanks in advance

Seb

Yes, easy to vent loop around mouth piece as the nasal cavity and mouth
piece are separate, I use a KM-48 mask.

paulraymaekers · 28th August 2009, 12:53

Quote: (Originally Posted by Pelagian)

Hey Paul

The thing I don't understand is with the rebreather version of the Panorama there is no oro-nasal mask just the bite mouthpiece, so your lips and nose are in the same cavity as the resto of your face.

Why would you be able to vent with your nose but not your lips?

Seb

no, the bite-piece isolates completely nose and mouth, and that's the way it should be
it also allows you to breath OC gas with your nose, while you mouth is on CC
(if you have an OC connected side of the FFM)

if you vent with your lips...nothing vents as the pressure buildup in the mask is higher then the resistance in the breather, so you just blow in the unit..
if you exhale by nose, you blow against the overpressure in the mask and open the FFMOPV, but this method does not allow freeflow venting, only venting by forced exhaling trough nose

ChemicalDiver · 28th August 2009, 13:04

Quote: (Originally Posted by kwinter)

I use an AGA rather than a Panorama, but I think the same problem would be experienced by any FFM other than the MK-48. Nose and mouth are in the same space, and the mask should be fairly well sealed to the face with some positive pressure. This makes venting through the nose or around the mouthpiece ineffective.

IMHO, a full mask should not be used without a BOV. So the easy way to vent is to inhale from the loop, switch the BOV to OC, exhale, then switch it back to the loop.

Ken

Quote: (Originally Posted by kwinter)

I use an AGA rather than a Panorama, but I think the same problem would be experienced by any FFM other than the MK-48. Nose and mouth are in the same space, and the mask should be fairly well sealed to the face with some positive pressure. This makes venting through the nose or around the mouthpiece ineffective.

IMHO, a full mask should not be used without a BOV. So the easy way to vent is to inhale from the loop, switch the BOV to OC, exhale, then switch it back to the loop.

Ken

I don't get this. The mask also vents when you ascend, due to the gas volume in the mask. I presume the mask is able to vent and does not require you to breathe in through the nose and vent this through the BOV too?

So what is different than exhaling through the nose?
If you have a bailout (nasal) reg attached to the side port, you can exhale through the reg exhaust with your nose.
Venting on ascent via always switching back and forth with the BOV seems ultra complicated to me and needs a hand (and venting surely should be possible without hands) and might also strain the BOV and might make it fail more.
Or am I missing something?
BR,
Alex

paulraymaekers · 28th August 2009, 14:54

Quote: (Originally Posted by ChemicalDiver)

If you have a bailout (nasal) reg attached to the side port, you can exhale through the reg exhaust with your nose.
Alex

that is something I don't like, after a few dives I blocked that exhaust valve of that second stage, and I only use the incorporated FFMOPV
the exhaust valve on the second stage does not allow any overpressurisation of the mask, and I feel that as uncomfortable: even with that reg on my right side, tilting head right side up, you must concentrate to not let gas get out of that valve and this way spoiling gas unwanted

being able of slightly overpressurising the mask feels more better

Jorma · 28th August 2009, 21:43

Back to the original question; I use Nova with a JJ BOV, and venting is quite easy by lips facing up, if your do not have mask straps too tight.
Venting is faster through the face seal than mask outlet valve, which has a bit more back pressure.
If the straps are tight, you have to blow by nose, which is is ok if you like to make it instead of lifting head a bit up to use automatic loose lip...
If concentrated on deco-gauges or your buddy and have to look down and coming up at same time, then blowing by nose is natural.
Good luck finding your favourite way.
BR, Jorma

Deep Smeg · 1st September 2009, 16:14

Thank you for all your replies.

I'm gonna try a few different things to see what's most comfortable.

Cheers

Seb

28th August 2009, 10:20	#1 (permalink)
Deep Smeg Sebastian Chander Deep Smeg Megalodon Join Date: Feb 2005 Location: Leeds, England Posts: 498	Mouth Venting Hello all FFM Users A question if you'll indulge me: Is it easy to vent your loop from around your lips while using a FFM or does the face seal create to much of a back pressure? Thanks in advance Seb
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28th August 2009, 10:30	#2 (permalink)
paulraymaekers rEvo's daddy rEvo Join Date: May 2005 Location: belgium Posts: 3,407	Re: Mouth Venting Quote: (Originally Posted by Pelagian) Hello all FFM Users A question if you'll indulge me: Is it easy to vent your loop from around your lips while using a FFM or does the face seal create to much of a back pressure? Thanks in advance Seb Seb, with a correct CCR FFM, mouth and nose are separate in the mask and a FFM has an OPV also, free-flow by the lips to flush does not work with a FFM, as there is always some overpressure in the mask so to vent, I nose exhale, agains the pressure of the FFMOPV, (of wich I reduced the cracking pressure : drager panorama) paul __________________ www.rEvo-rebreathers.com .... the earth is flat and Elvis is alive.... .... radial scrubbers give longer dwell time than axials .... to get more accurate CO2 injection in the breathing machine we put 2 mass flow controllers in series ...
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28th August 2009, 10:51	#3 (permalink)
Deep Smeg Sebastian Chander Deep Smeg Megalodon Join Date: Feb 2005 Location: Leeds, England Posts: 498	Re: Mouth Venting Quote: (Originally Posted by paulraymaekers) Seb, with a correct CCR FFM, mouth and nose are separate in the mask and a FFM has an OPV also, free-flow by the lips to flush does not work with a FFM, as there is always some overpressure in the mask so to vent, I nose exhale, agains the pressure of the FFMOPV, (of wich I reduced the cracking pressure : drager panorama) paul Hey Paul The thing I don't understand is with the rebreather version of the Panorama there is no oro-nasal mask just the bite mouthpiece, so your lips and nose are in the same cavity as the resto of your face. Why would you be able to vent with your nose but not your lips? Seb
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28th August 2009, 12:25	#4 (permalink)
kwinter Down to no good Optima GEM Join Date: Sep 2005 Location: NJ - USA Posts: 1,294	Re: Mouth Venting I use an AGA rather than a Panorama, but I think the same problem would be experienced by any FFM other than the MK-48. Nose and mouth are in the same space, and the mask should be fairly well sealed to the face with some positive pressure. This makes venting through the nose or around the mouthpiece ineffective. IMHO, a full mask should not be used without a BOV. So the easy way to vent is to inhale from the loop, switch the BOV to OC, exhale, then switch it back to the loop. Ken
(Online)

28th August 2009, 12:48	#5 (permalink)
mountain diver Silent Lucidity Megalodon Join Date: Mar 2006 Location: Alberta, Canada Posts: 544	Re: Mouth Venting Quote: (Originally Posted by Pelagian) Hello all FFM Users A question if you'll indulge me: Is it easy to vent your loop from around your lips while using a FFM or does the face seal create to much of a back pressure? Thanks in advance Seb Yes, easy to vent loop around mouth piece as the nasal cavity and mouth piece are separate, I use a KM-48 mask.
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28th August 2009, 12:53	#6 (permalink)
paulraymaekers rEvo's daddy rEvo Join Date: May 2005 Location: belgium Posts: 3,407	Re: Mouth Venting Quote: (Originally Posted by Pelagian) Hey Paul The thing I don't understand is with the rebreather version of the Panorama there is no oro-nasal mask just the bite mouthpiece, so your lips and nose are in the same cavity as the resto of your face. Why would you be able to vent with your nose but not your lips? Seb no, the bite-piece isolates completely nose and mouth, and that's the way it should be it also allows you to breath OC gas with your nose, while you mouth is on CC (if you have an OC connected side of the FFM) if you vent with your lips...nothing vents as the pressure buildup in the mask is higher then the resistance in the breather, so you just blow in the unit.. if you exhale by nose, you blow against the overpressure in the mask and open the FFMOPV, but this method does not allow freeflow venting, only venting by forced exhaling trough nose __________________ www.rEvo-rebreathers.com .... the earth is flat and Elvis is alive.... .... radial scrubbers give longer dwell time than axials .... to get more accurate CO2 injection in the breathing machine we put 2 mass flow controllers in series ... Last edited by paulraymaekers; 28th August 2009 at 12:56..
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28th August 2009, 13:04	#7 (permalink)
ChemicalDiver RBW Member Join Date: Dec 2006 Location: Switzerland Posts: 187	Re: Mouth Venting Quote: (Originally Posted by kwinter) I use an AGA rather than a Panorama, but I think the same problem would be experienced by any FFM other than the MK-48. Nose and mouth are in the same space, and the mask should be fairly well sealed to the face with some positive pressure. This makes venting through the nose or around the mouthpiece ineffective. IMHO, a full mask should not be used without a BOV. So the easy way to vent is to inhale from the loop, switch the BOV to OC, exhale, then switch it back to the loop. Ken Quote: (Originally Posted by kwinter) I use an AGA rather than a Panorama, but I think the same problem would be experienced by any FFM other than the MK-48. Nose and mouth are in the same space, and the mask should be fairly well sealed to the face with some positive pressure. This makes venting through the nose or around the mouthpiece ineffective. IMHO, a full mask should not be used without a BOV. So the easy way to vent is to inhale from the loop, switch the BOV to OC, exhale, then switch it back to the loop. Ken I don't get this. The mask also vents when you ascend, due to the gas volume in the mask. I presume the mask is able to vent and does not require you to breathe in through the nose and vent this through the BOV too? So what is different than exhaling through the nose? If you have a bailout (nasal) reg attached to the side port, you can exhale through the reg exhaust with your nose. Venting on ascent via always switching back and forth with the BOV seems ultra complicated to me and needs a hand (and venting surely should be possible without hands) and might also strain the BOV and might make it fail more. Or am I missing something? BR, Alex
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28th August 2009, 14:54	#8 (permalink)
paulraymaekers rEvo's daddy rEvo Join Date: May 2005 Location: belgium Posts: 3,407	Re: Mouth Venting Quote: (Originally Posted by ChemicalDiver) If you have a bailout (nasal) reg attached to the side port, you can exhale through the reg exhaust with your nose. Alex that is something I don't like, after a few dives I blocked that exhaust valve of that second stage, and I only use the incorporated FFMOPV the exhaust valve on the second stage does not allow any overpressurisation of the mask, and I feel that as uncomfortable: even with that reg on my right side, tilting head right side up, you must concentrate to not let gas get out of that valve and this way spoiling gas unwanted being able of slightly overpressurising the mask feels more better __________________ www.rEvo-rebreathers.com .... the earth is flat and Elvis is alive.... .... radial scrubbers give longer dwell time than axials .... to get more accurate CO2 injection in the breathing machine we put 2 mass flow controllers in series ...
(Offline)

28th August 2009, 21:43	#9 (permalink)
Jorma RBW Member Join Date: Nov 2007 Location: Finland, Inkoo Posts: 24	Re: Mouth Venting Back to the original question; I use Nova with a JJ BOV, and venting is quite easy by lips facing up, if your do not have mask straps too tight. Venting is faster through the face seal than mask outlet valve, which has a bit more back pressure. If the straps are tight, you have to blow by nose, which is is ok if you like to make it instead of lifting head a bit up to use automatic loose lip... If concentrated on deco-gauges or your buddy and have to look down and coming up at same time, then blowing by nose is natural. Good luck finding your favourite way. BR, Jorma
(Offline)

1st September 2009, 16:14	#10 (permalink)
Deep Smeg Sebastian Chander Deep Smeg Megalodon Join Date: Feb 2005 Location: Leeds, England Posts: 498	Re: Mouth Venting Thank you for all your replies. I'm gonna try a few different things to see what's most comfortable. Cheers Seb
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