Info Lack of OC WOB data for BOVs

[Brad_Horn]

In the 1990’s John Bantin et al in DIVER magazine openly published for the first time the comparative WOB data for a range of common 2nd stages tested at 50m. This caused quite some controversy because no longer was subjective simply good enough a judge of performance. Some regulators that were thought to be good just weren’t and didn’t even meet the mark or minimum expected. Minimum now set by the likes of EN250; which for a BOV, when using the bailout feature in anger, at least provides a GO/no go for its suitability during the pre-dive equipment selection phase of the dive.

For some more recent consideration of regulator performance also see You are being redirected...
"So now, we are back to what constitutes a great breathing regulator. It’s our opinion based on current regulator technology, the regulator should be capable of WOB under 2 J/L or less at 62.5 RMV down to the recreational depth limit of 130 fsw or the depth the user intends to use it to. For the “techi” people making deep air dives, it would be wise to use a regulator that is capable of below 2 J/L performance at 62.5 RMV to the maximum depth of the intended dive. Keep in mind regulator performance has gotten really good and this increase in performance makes diving safer and easier. Even a “hairy chested” deep sea diver in excellent condition diving to depths where WOB approaches 3 J/L leaves little reserve should things go side ways and heavy physical activity is encountered. Those diving into the ”outer limits” should go for the top performance regulators. In general, there is no excuse for the avid scuba diver not to have a good performing regulator, and not just one that squeaks in under the 3 Joule WOB limit.”

Why this post?
Currently there is one (1) BOV on the market with both its OC and CC WOB published. Which ~25 years after BOVs were first introduced to the market is pretty shocking.
This is the Open Safety ALVBOV. For ALVBOV read Bail Out Valve with an integral Automatic Demand and Manual Diluent Add Valve. Open Safety only offer one BOV option, rate it for use to 350m in OC and CC modes, CE’d in 2011 to 100m in CC and OC modes; only produced in Right to Left gas flow.
https://www.opensafetyglobal.com/Safety_files/DV_DL_ALVBOV_Breathing_Params_A3_100318.pdf
EN 250 respiratory performance measurements of the ALVBOV with Apeks and Apollo first stage regulators, and comparison with the Apeks TX100 as the industry performance benchmark. European limit for WOB is 2.5J/L in EN 250:2000, and 3J/L in Appendix A1:2006. Measured WOB for the ALVBOV is 0.89 J/L, similar to the benchmark.

ALVBOV CC WOB 0.57J/L on Air at 40m at 75lpm at 4’C https://www.opensafety.eu/datasheets/ALVBOV_40m_75lpm_air_081014.pdf
This is important because you can retrofit the ALVBOV to ANY rebreather on the market and lower that units measured WOB….

The importance of getting the above performance is why Open Safety engineered our own hyperbaric test lab; which we now sell to industry clients in the know https://www.opensafetyglobal.com/documents/Datasheet-iBreathe-MkIV-190605.pdf

However if you’re not interested in or don’t have the resources for 350m+ hyperbaric testing equipment, I notice and this is the crux of the post that JFD are promoting the really nifty little ANSTI Computerised Surface Test Facility bench top test system suitable for dive shop use for measuring WOB of regulators to EN250 standards.
JFD | Ansti Computerised Surface Test Facility (CSTF)
Once this testing ability gets out in the wider realm, I expect there could be the same controversy or at least interesting debate, over the lack of performance in certain BOVs; just as DIVER observed 30 years ago with OC regulators.

BUT divers having a greater range of safer BOVs to bail out onto in anger can only be a good thing!

It's also not just the BOV but how many have added a flow stop to their already badly performing BOV...

 

[Whitrzac]

Opened the thread with hope of a decent discussion, scrolled down reading, then back to look at the name.


Please take the advertisements for your non existing rebreather elsewhere.

 

[boriss]

Why this post?

Every time I read Brad's posts I'm reminded of the Simpsons...

Brad, I find it shocking that the most decorated veterans in rebreather diving, people with access to any equipment money can buy, who rely on this equipment to keep them alive, somehow choose products you don't manufacture despite your many manufactured PDFs. Why is that?

It seems to me there are companies which are good at producing products and others who are better at producing slithery FUD. Anyone with Google can look up Brad Horn, Alex Deas and OSEL.

I know the regulars are well aware of this snake, but in case anyone new or ignorant reads this... do your research. Please.

 

[flymolo]

I noticed the information you posted mentions WOB when diving on air so I wonder how relevant it is. Does any of your testing incorporate mixes containing helium?

Also, your website's SSL cert appears to be invalid or expired.

 

[Dr Simon Mitchell]

Hmmm, Brad, maybe you have a good BOV product, but as you can see from the first few responses to this thread, people are disinclined to believe anything you say; with good reason.

For the generation of divers who have no idea why Brad's post has received the negative response it has, here is a very quick summary.

Brad represents a company that in the mid 2000s claimed to be building a cheap yet extraordinarily safe rebreather with multiple unique monitoring and safety intervention systems. They aggressively denied the opinions (and attempted to trash the reputation) of multiple experts (including me) who pointed out that some of these systems would not work as designed. They began taking deposits for this rebreather in 2008 with a promise of a 16 week delivery time.

That was fourteen (14) years ago.

This rebreather is still nowhere to be seen, almost certainly because those experts were right and it simply doesn't work adequately.

Worse, they leveraged the 'reputation' associated with the promise of this rebreather and the hypothetical safety standard it represented to insert themselves as expert witnesses into multiple lawsuits or coroners investigations against other rebreather manufacturers (e.g., here), in all of which the side they represented lost. However the stress and financial fallout for parties on both sides of these lawsuits was devastating, and the legally fraught environment created around rebreathers was probably the reason for our community having the manufacturer of one of the most reliable oxygen cells withdraw from our market sector.

For the avoidance of doubt about the claims about when this rebreather (the so-called intervention closed circuit rebreather / iCCR) would ship, a video of Brad at DEMA 2009 claiming that 'customer spec' units would ship soon can be found here.

Simon M

 

[MoBro]

Wow - looks like there is some history here! As a new rebreather diver I have not heard of the iCCR and out of sheer curiosity would like to know: what did it promise and why didn't it work?

 

[Vicko]

I for one am thankful to Brad for his rebreather fatality list, where he blamed a manufacturing flaw for a number of deaths where the user was a Darwin award winner.
That list ,along with other open safety materials were used when the EU decided on the CE safety standards.

 

[cathal]

Wow - looks like there is some history here! As a new rebreather diver I have not heard of the iCCR and out of sheer curiosity would like to know: what did it promise and why didn't it work?

Just Google the search terms as advised in an earlier post

 

[cathal]

I for one am thankful to Brad for his rebreather fatality list, where he blamed a manufacturing flaw for a number of deaths where the user was a Darwin award winner.
That list was along with other open safety materials were used when the EU decided on the CE safety standards.

That list was not used for setting EU CE standards relevant to CCR’s as it was an un-substantiated, wildly inaccurate, commercially driven hack job on established CCR manufacturers.

 

[Vicko]

That list was not used for setting EU CE standards relevant to CCR’s as it was an un-substantiated, wildly inaccurate, commercially driven hack job on established CCR manufacturers.

I know, and yet when I was doing my research on what reb to get IANTD and TDI representatives for eastern europe sent me that list along with the other open safety garbage, the same package of data was used in the CE materials when the recreational agencies were asked for their opinion on how to set the CE standard, as for some reason OS is (or i hope, was) considered unbiased.
In my previous comment I was being sarcastic. I'm just glad that the non CE rebs were not completely banned.