Latest ScubaLabs reg test - huh?

[Akimbo]

I'm not sure this is the most current procedure but I believe that the Navy test procedure is still with the second stage immersed:
http://archive.rubicon-foundation.o...le/123456789/3371/NEDU_1973_23.pdf?sequence=1

 

[tbone1004]

I'm not sure this is the most current procedure but I believe that the Navy test procedure is still with the second stage immersed:
http://archive.rubicon-foundation.o...le/123456789/3371/NEDU_1973_23.pdf?sequence=1

all of those ansti values should be immersed

 

[scubadada]

all of those ansti values should be immersed

The Dive Lab testing is described as an ANSTI wet breathing simulator, I assume it is. @Akimbo appears to know more about the facility.

 

[Akimbo]

... @Akimbo appears to know more about the facility.

That is probably an overstatement, but thanks. I have a recollection that the USN test is (was?) wet but can't recall exactly why. That link to the spec I posted is pretty old so may not be current or my interpretation correct. Trust but verify... emphasis on the verify.

 

[tbone1004]

That is probably an overstatement, but thanks. I have a recollection that the USN test is (was?) wet but can't recall exactly why. That link to the spec I posted is pretty old so may not be current or my interpretation correct. Trust but verify... emphasis on the verify.

as mentioned all are conducted wet. The pressure differential across the case heavily influences work of breathing due to venturi and the extra pressure to move the water through any case holes. It is one thing to measure cracking pressure dry, but to measure real work of breathing would be effectively impossible due to how the water interacts with the wet side of the diaphragms

 

[Akimbo]

... I have a recollection that the USN test is (was?) wet but can't recall exactly why. ...

as mentioned all are conducted wet. ...

I concur and understand why. I should have written that I don't recall exactly why I have that recollection. Like you, I see the logical that the test would be wet but I can't be sure that that ins't influencing my memory of the testing spec. I was hoping that someone would post links to the latest USN spec (if this one is out of date) and the EU testing procedure.

 

[tbone1004]

@Akimbo

USN spec was withdrawn relatively recently but did not require wet or dry. Most did wet only, or both wet and dry because the performance degraded when wet
http://www.dtic.mil/dtic/tr/fulltext/u2/a002726.pdf

The EN250 requirements are what the third test in scubalab is done to. 62.5rmv at 50m. USN was same RMV but at 60m and was done for 30 mins instead of 5. Their cold water test was also done at -2c vs 4c for the CE testing. That difference actually causes a lot of CE regs to fail the USN tests. Their limit for total WoB was also 1.4j/l and the Poseidon's all passed but Scubalab had them at 3star which is over 1.55j/l so who knows.

The Norsok test is also pretty brutal and the Xstream beat that one and allowed it to be certified to 200m depth for use. CE only allows up to 50m
http://www.standard.no/PageFiles/980/U-101.pdf

Jetstreams also passed the NEDU tests which were done immersed in salt water at -2c. If you look at their test profile there may be a difference in the first stage supply pressure at the high end of the breathing rates as they passed at 500psi supply, but not at 1500psi supply on the high RMV tests
http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/4105/ADA313945.pdf?sequence=1


For me? I dive Poseidon Odins as outlined in the NEDU study above. They approved it for water far colder, far deeper on air, and with a much higher workload than I ever anticipate diving so I'm OK with that. Scubalab didn't like that regulator when they tested it, but the NAVY does, so I'll stick with that

 

[ams511]

What I want to know is how much variation is there among production regulators. If we take 100 regulators is each one going to give the same result? Will the be within 5% of each other? 10%? more? I would have to think that the regulators submitted for the review would be either special built or specially selected before being sent.

A related issue is how accurate is the testing method? If I test the same regulator 100 times will it give the same results each time?

 

[buddhasummer]

The black tec Mk25/A700 tested lower than the non black version, go figure.

 

[halocline]

These test machines give a very poor picture of what a regulator actually feels like while diving. They really are there for marketing purposes more than anything else. I would take them with a very large grain of salt.

We humans have a great ability to perceive very small differences in pressure, temperature, etc, in our mouths and breathing passages. Of course this is primarily subjective, which is why there are so many different 'best' regulators for different divers.

The bottom line, most important characteristic of any regulator is reliability. If you're not confident in it, you won't enjoy diving.