Atomic users

[scubadada]

This is the way Scubalab tests all regs, obviously NOT all regs perform the same.

• 37.5 RMV @ 132 fsw: This represents the maximum recreational depth at a somewhat aggressive breathing rate.
• 75 RMV @ 132 fsw: This simulates the potential demand at maximum recreational depth for a diver at an extremely heavy work rate, or loosely simulates two divers buddy breathing at a somewhat aggressive rate.
• 62.5 RMV @ 165 fsw: This represents the European conformance standard EN250. This is also the depth and breathing rate commonly used by manufacturers when determining a regulator’s performance.
• 62.5 RMV @ 198 fsw: This is the U.S. Navy’s Class A test depth and breathing rate (although the Navy uses a higher supply pressure).

The ANSTI simulator testing of regulators uses 4 standard conditions for testing. BPM=breaths per minute at 2.5 liters per breath

1) 15 BPM, RMV 37.5 L/min or 1.32 cu ft/min, 132 fsw/5 atm.

2) 30 BPM, RMV 75 L/min or 2.65 cu ft/min, 132 fsw/5 atm.

3) 25 BPM, RMV 62.5 L/min or 2.21 cu ft/min, 165 fsw/6 atm.

4) 25 BPM, RMV 62.5 L/min or 2.21 cu ft/min, 198 fsw/7 atm.

It is said that the volume of a normal breath (tidal volume) is about 500 mL, 0.5 L. The normal respiratory rate is about 12 breaths/min. So, increase the volume of a breath 5 times and increase the rate 25-150%, that's a lot of breathing. The RMV in cu ft/min will give those who use imperial units an idea of how much breathing. Condition 1 is about 3.7 x my average RMV.

Condition 1 would empty an AL80 from full to 200 psi in a little under 11 minutes, condition 2 in half that time! Keep in mind that the density of gas will have also increased 5X, to 6.0 g/L

ScubaLab rates regulators by the work of breathing in Joules/Liter during each of the 4 conditions with 5-excellent <1.05 J/L, 4-very good 1.06-1.55 J/L, 3-good 1.56-2.25 J/L, 2-fair 2.26-3.0 J/L the EN 250 limit.

The Scubapro MK2/R195 was tested in 2015 and scored 5-4-4-4. The Scubapro MK25 EVO/S620 Ti was tested in 2017 and scored 5-5-5-5. It has previously been mentioned that it would be preferable to give the actual WOB rather than the categorical ranges. It is said that a diver may be able to tell a WOB difference as low as about 0.5 J/L.

...I'd like to learn more about these tests, as I just stated I'd love to have an objective means for performing comparisons.

Maybe we start a separate thread? This is a topic that interests me greatly.

There was a relatively long thread on this topic about 5 years ago Latest ScubaLabs reg test - huh? You can also find other posts by searching on ANSTI

 

[scubadada]

Yes, I said it myself previously.

Here you can see my ANSTI machine tests.

The Mk25 breathes so slightly better and perhaps the biggest difference and the one I 'feel' is the effort to inhale that is considerably less than the Mk17.

Hi @El Diablo

Under what conditions were these run, sorry, I can't tell from the figures?

 

[Centrals]

Air flow rate for 1st and 2nd stages

I was wondering if anybody has estimations for the followings based on experience or access to technical data from manufacturers? General air flow rates for 1st and 2nd stages (separately): 1) High end regulators 2) Mid end regulators 3) Entry level regulators Another question to pick...

scubaboard.com

 

[El Diablo]

I'd really like to know how that is measured, as I wish there was some industry standard to compare performance between regs. There is too much nonsense of "this breathes better" that is really personal bias.

I'd like to learn more about these tests, as I just stated I'd love to have an objective means for performing comparisons.

Maybe we start a separate thread? This is a topic that interests me greatly.

That's a good idea for a thread.

I believe the regulations in EU are standard (25 BPM @ 165 fsw) in order to get the certification (EN250:2014).

There's of course bias but there's also personal experience. In my case, I own both regs, love them both, payed for both so I have absolutely no reason to favor one or the other. I know their strengths and weaknesses and they both breathe marvelously. I prefer my Mk25 for recreational diving as there are no for spare parts for the original S600 anymore (purge cover) so I baby it more and the Mk17 was used for the fish farm work as there are many sediments and critters floating around when working with nets.

 

[El Diablo]

Hi @El Diablo

Under what conditions were these run, sorry, I can't tell from the figures?

Hi Scubadada, according to the dive store, equivalent to 40m.

These test can differ from store to store depending on the antiquity and state of their testing machines, I asked them because both my regs where usually below 1 J/L when I service them previously.

 

[El Diablo]

The ANSTI simulator testing of regulators uses 4 standard conditions for testing. BPM=breaths per minute at 2.5 liters per breath

1) 15 BPM, RMV 37.5 L/min or 1.32 cu ft/min, 132 fsw/5 atm.

2) 30 BPM, RMV 75 L/min or 2.65 cu ft/min, 132 fsw/5 atm.

3) 25 BPM, RMV 62.5 L/min or 2.21 cu ft/min, 165 fsw/6 atm.

4) 25 BPM, RMV 62.5 L/min or 2.21 cu ft/min, 198 fsw/7 atm.

It is said that the volume of a normal breath (tidal volume) is about 500 mL, 0.5 L. The normal respiratory rate is about 12 breaths/min. So, increase the volume of a breath 5 times and increase the rate 25-150%, that's a lot of breathing. The RMV in cu ft/min will give those who use imperial units an idea of how much breathing. Condition 1 is about 3.7 x my average RMV.

Condition 1 would empty an AL80 from full to 200 psi in a little under 11 minutes, condition 2 in half that time! Keep in mind that the density of gas will have also increased 5X, to 6.0 g/L

ScubaLab rates regulators by the work of breathing in Joules/Liter during each of the 4 conditions with 5-excellent <1.05 J/L, 4-very good 1.06-1.55 J/L, 3-good 1.56-2.25 J/L, 2-fair 2.26-3.0 J/L the EN 250 limit.

The Scubapro MK2/R195 was tested in 2015 and scored 5-4-4-4. The Scubapro MK25 EVO/S620 Ti was tested in 2017 and scored 5-5-5-5. It has previously been mentioned that it would be preferable to give the actual WOB rather than the categorical ranges. It is said that a diver may be able to tell a WOB difference as low as about 0.5 J/L.

There was a relatively long thread on this topic about 5 years ago Latest ScubaLabs reg test - huh? You can also find other posts by searching on ANSTI

Just to add some figures to this very valuable information.

Mind that the 'slow and deep' breathing that we are teached and normally use UW effectively uses more air than the normal tidal breathing at the surface. I read somewhere that Males tend to fill their lungs with around 800ml and Females 600ml.

This is also a good reference point for couples diving together as the female will almost always surface with more air. Smaller lung capacity, smaller lungs, less muscle mass, smaller volume needed.

 

[El Diablo]

At what depth does the performance of the Mk17 degrade as to be not usable under heavy load as compared with the Mk25? You keep on throwing in so many variables with piston/diaphragm, balanced/unbalanced, test rig/depth, different second stages that it is difficult to follow your logic. I am not doubting that the piston regulator has a theoretical advantage due to it's having a larger orifice, but outside vague declarations of "feels ever so slightly better" what are the real world results?
I dive both piston and diaphragm first stages in recreational settings and as far as I'm concerned there are no differences in performance. They are interchangeable. Any difference in breathing characteristics is due to the second stage in my rigs.

PS: The MK17 is a balanced regulator. The Mk11 is also balanced. The Mk2 is not. The Mk2 may be old, but it is still in the catalog. The cash cow of first stages.

I don't know why you went to the extreme talking about "At what depth does the performance of the Mk17 degrade as to be not usable under heavy load "... I never stated that the differences are so great that the Mk17 is bad, quite the opposite in fact: It is an EXCELLENT regulator and that's why I bought it.
However, the Mk25 is slightly better. That's all. It is Scubapro's flagship reg for a reason.

The real world results is that 'it feels ever so slightly better' at depth and under load as I already mentioned. My original position remains. It needs less effort to breathe as it is reflected on the tests I posted just to confirm what I am feeling when inhaling. I don't understand why this statement is threatening anyone's beliefs. Some folks are more sensitive than others, some folks will feel these small differences, other won't feel a thing. Some divers prefer diaphragms, some pistons. However, facts are facts. Piston regulators allow more air to pass through due to their internal construction.
The same way a sports car with a V6 cylinder engine feels different than a V8 or a V10 / V12 and the same way you don't need a 500ps muscle car in US with your 60mph limits. Any 700cc Smart car would do.

Both regs are high-end. The 2nd stage will only affect the breathing performance at depth and low air, otherwise any differences are negligible. I've also switched the 2nd stages and the feeling was the same. The Mk25 needed slightly less effort to inhale. That's it. VERY happy with both.

 

[scubadada]

Hi Scubadada, according to the dive store, equivalent to 40m.

These test can differ from store to store depending on the antiquity and state of their testing machines, I asked them because both my regs where usually below 1 J/L when I service them previously.

Do you know the BPM, breath volume, and RMV?

I don't know of any facilities in the US that generate WOB loops and supply them to the customer after service. Of course, I have only sampled a small number, but have used a couple of very busy, well known shops.

Just to add some figures to this very valuable information.

Mind that the 'slow and deep' breathing that we are teached and normally use UW effectively uses more air than the normal tidal breathing at the surface. I read somewhere that Males tend to fill their lungs with around 800ml and Females 600ml.

This is also a good reference point for couples diving together as the female will almost always surface with more air. Smaller lung capacity, smaller lungs, less muscle mass, smaller volume needed.

Our breath volume is significantly larger than usual tidal volume, but our breath rate is also well below the usual normal when we dive.

In the ANSTI test, the breath volume is 2,500 ml and the rate is between 15 and 30 BPM

 

[El Diablo]

Do you know the BPM, breath volume, and RMV?

I don't know of any facilities in the US that generate WOB loops and supply them to the customer after service. Of course, I have only sampled a small number, but have used a couple of very busy, well known shops.

Our breath volume is significantly larger than usual tidal volume, but our breath rate is also well below the usual normal when we dive.

In the ANSTI test, the breath volume is 2,500 ml and the rate is between 15 and 30 BPM

Unfortunately not, I don't have any additional data. You can check them on their website, small shop but quite professional.

That's correct, under normal load, we breathe at a decreased rate but still air is compressed and we inhale more of it. I need to find the article explaining all of the above and post it here. It was quite revealing.

 

[scubadada]

Unfortunately not, I don't have any additional data. You can check them on their website, small shop but quite professional...

Hi @El Diablo

That was a good idea, some interesting reading. The dive shop can be found at DCP - Dive Center Paradise - ALLES FÜRS TAUCHEN

With some searching, I found that they use a bench testing system made by pressureguard PressureGuard – precision for breathing

It is a dry test. If one wanted to do it under pressure, it appears you would also need a pressure chamber, perhaps the shop has one. The breath volume is adjustable, default 2,500 ml. The breathing rate is also adjustable, default 25 BPM. It would appear to comply to the European conformance standard if pressurized to 6 atm. I don't know what PCTUV/CE is in the last bullet, perhaps that is a pressure chamber.

Very interesting