How to make a fullface snorkelmask safe by Achim Schlöffel

[lowwall]

I'm going to keep posting this when these threads come up in the hope they will end up in the search results for people looking into the safety of these things before using them.

by @Dr Simon Mitchell
...Full face snorkel masks have been raised in this thread several times. You may be interested in a study we recently published exploring their propensity for generating hypoxia or hypercapnia in comparison to a normal snorkel. See attached or Full-face snorkel masks increase the incidence of hypoxaemia and hypercapnia during simulated snorkelling compared to conventional snorkels ...

by @lowwall
Thanks for the article which is further evidence of the unsuitability of full face snorkel masks. If nothing else, it puts to rest the claim that the inclusion of one way valves completely prevents rebreathing of exhaled gases. Further, your test may well be a best case scenario for these things in that your subjects were experienced snorkelers, the testing was done in the dry so anxiety induced shortened breathing cycles were not an issue, and the testing was cut off as soon as subjects hit a threshold oxygenation level which prevented discovery of just how bad things could get. Even so, the increase in CO2 and decrease in blood O2 saturation when using these masks was alarming.

And this would just be the triggering effect in an incident. What happens next is what I feel is the real culprit. People using standard snorkels normally respond to breathing or O2/CO2 issues like shortness of breath by removing the snorkel. This is trivially simple with a snorkel, you just spit it out. But it can be a major undertaking with a snorkel mask, requiring at least one hand and typically two. Worse, a major reason people chose these masks is they are afraid of immersing their faces in water. These people are going to be loathe to even attempt removal until it's too late.

IMO, these full face masks are dangerous and defective by design.

https://scubaboard.com/community/attachments/ffsm-study-pdf.842544/

 

[ofg-1]

"How to make a fullface snorkelmask safe?"

Repeated vigorous application of this:

 

[Rob9876]

Interesting. I have 2 family members who use full face snorkels because they have jaw issues that preclude the use of traditional mouth snorkels. They've used them for years now with no issues.

I'm wondering what percent of people have problems with these, as I see other people using them everywhere. Also, it's worth noting that some users of the regular snorkels had issues also -- about half as much as full face, but still a somewhat significant portion of the experiment participants (we here tend to not talk about that aspect much).

For my family members, we do have them wear snorkel vests too, so if there's a problem they can get upright and adjust the mask. Doesn't seem that hard, and they definitely pop back up more often than those of us using standard snorkels it seems (not necessarily from any certain reason).

 

[David Wilson]

FFSM users may just crave the option to nose-breathe, dispensing with the intrusive constant gag-triggering oral presence of a mouthpiece while they swim or float on the surface for extended periods watching the sealife below them. In which case, the following mouth-excluding snorkel-mask configuration may offer a non-invasive alternative solution:

 

[John C. Ratliff]

‘Love it! Well, I have one other thing to add to this discussion.

I have worn full face masks for decades, but in the workplace to not breath hazardous chemicals in vapor/dust form. I am looking at the design of the snorkel mask, and have three more things to discuss.

—First, the snorkel mask has a divergent pathway for air to enter the snorkel, go into the mask, then into the inner mask for inhalation. Each of these pathways increases the resistance for breathing. One of our Scubaboard contributors was talking about small exhalation valves in early single hose regulators, and how dangerous they were because they increased the exhalation resistance physiologically for the diver. I don’t see this being addressed in discussions on these masks. Both inhalation and exhalation resistance would be increased by small openings for the mushroom valves, the divergent pathways, and the volume of the tubing/mask.

—Second, for industrial use of respiratory protection, the fullface respirators need to be “fit tested,” to ensure the seal around the face. Around the face is not much of a problem with snorkel masks, but the inner mask is a problem, as there is no way to ensure a tight seal of the inner mask, which is what reduces the CO2 buildup inside the mask. If that component doesn’t seal, then rebreathing of exhaled air in inevitable.

—Third, these are marketed as being able to allow “normal breathing.” I have emphasized in other posts on similar threads that “normal breathing” is shallow, and not sufficient to allow fresh air into the mask. But there is not mention, no training materials, and no instruction in how to use these snorkel masks. That is a significant oversight by the manufacturer. Normal breathing passes only about 1l2 a liter (tidal volume on the graph below, about 16 ounces in volume). This is not enough to get "good air," from outside the mask. The breathing must be deep, to bring in outside air.

Because of these deficiencies, the proposed solution shown in the video is about the only way to keep these masks safe—by destroying them.

SeaRat

 

[Nemrod]

I guess it is a matter of style but I prefer using such items for target practice.

I do not think these things can be made safe. There was a study from Hawaii University, it is here somewhere. Worse is that the intended market is, let's face it, people who are basically non-swimmers and who are not comfortable getting their faces wet. And are prone to panic when water gets up their nose or in their eyes. The opportunities for varied mayhem and all the elements are there for a fatality, CO2 retention, high inspiration effort and fluid in the lungs, inability to quickly remove. I am really surprised as litigious as it is now that they are still on the market.

 

[dcvf2]

Hi Scuba divers
I’m sorry to say : don’t worry, the FFSM adepts, they don’t read your comments… They aren’t interested in.
It’s what I often read on TripAdvisor, like : I love my FFSM , never had any issue, etc
Full Face Masks- questions - Maldives Forum - Tripadvisor

They don't care about the accumulated CO2... they are rather very quiet surface snorkelers, not at all sporty.

They chose the FFSM to find a solution to the fogging that they could not resolve with their classic mask and/or because they could not stand the snorkel in their mouth.

I’m Freediver (AIDA 3* and not FFSM adept). I gave propositions (*) Oct 1, 2021 on my #10
(*) Suggestions that I posted to them on different forums… no reaction from them… they are allergic to all forms of preventive exercises even for their safety