Controversial Issues in Diving
ฝัง
- เผยแพร่เมื่อ 15 ต.ค. 2024
- There are many controversial topics in diving, and having open and honest discussions about them can help divers and dive operators learn and grow.
• Is oxygen cleaning required only for mixes with more than 40% oxygen, or should air cylinders be cleaned as well?
• Should cylinder valves be opened all the way, or should divers turn them back a quarter turn?
• Is there a difference between an SMB and a DSMB?
• Should every cylinder be analyzed every time, or only when they contain mixed gas?
• What’s the difference between a diver who is certified and a diver who is qualified?
These are just a few of the notable controversies in the industry, and we invite you to join DAN Safety Services as we present some facts and expert opinions about each. Keep an open mind, and bring your questions - we look forward to addressing these issues and more!
![เปิดใจ "อาจารย์เบียร์ คนตื่นธรรม" อดีตเคยสุดทุกทาง ถ้าใช้หนี้หมดไปบวชแน่ l [Nickynachat]](http://i.ytimg.com/vi/IxeE0xVhy08/mqdefault.jpg)
good video. but media team should put bookmarks in the video or something, to ease searching for data
Thank you for the excellent discussion. Regarding closed captioning, it is available by clicking the CC icon to the left of the settings button on the lower screen of the video on TH-cam.
I have never heard the 25% rule before. It has always been 40. So you’re saying mixtures greater than 25% must be oxygen cleaned. How is this going to apply to continuous blending systems where 02 is introduced into the compressor?
Thank you for the question. In short, yes. Science has shown that above 25%, the burn rate changes drastically. The second basis for the 25% figure is because this is the lowest nitrox mixture that exists (even though not used much anymore). So, while the CGA states that oxygen-enriched gas contains more than 23.5%, this is not a mixture we would produce.
Please also note that we are addressing the oxygen-enrichment for the purposes of establishing when equipment needs to be oxygen-cleaned. We are not speaking about the design and manufacture of the equipment - although this will follow the same rules.
It is incorrect when the industry states that OHSA (meaning the CFR or code of federal regulations in the USA) rules that oxygen-cleaning is only needed above 40%. Firstly, the CFR only addresses commercial diving in this regard. Secondly, it applies to surface supply to helmets and full-face masks. This implies usage at a much lower pressure.
Then also, please note that we only addressed the cylinder, cylinder valve, and first stage regulator. Compressors are a different issue - referring to continuous blending and then boosting the pressure to fill a cylinder. This is of concern, but we have not addressed it in this webinar.
Europe considers any mix above 21% as oxygen-enriched. However, for oxygen-cleaning purposes, they specifically state that any parts or equipment that is in contact with more than 25% must be oxygen-cleaned.
I’m a 1/4 turn back and it comes from helping teach in the 90s. Still today when I tender or checking my buddy, before they go in the water I check their tank valve.
I’ve caught it several times that a diver charged the regulator and shut their valve back off. So turning the valve and returning it did open the valve and didn’t make any noise.
Excellent discussion- we need them more often, congratulations
Regarding full open or 1/4 closed on tank values. There was a comment about what to do if you do not agree with the choice used by a dive operator. I have an additional perspective, you will compromise safety if you do not follow the standard of the dive operator. Any safety related deviation from their standard will put one or more divers at risk. If everyone is trained to expect one thing and an exception is made by a diver, it can cause a problem. This does not mean their way is right or wrong, only that if there is a standard it should be followed until everyone is trained on a new standard.
What is the right application for splint fins?
There really isn’t a “right” application for split fins. It is absolutely subjective to the diver. The purpose behind the design is to create a vortex in the water to propel divers and improve speed with less effort. This seems to help those with knee problems to ease the stress on lower joints. They do require a slightly different finning technique which, like anything else, takes time to perfect.
@@DiversAlertNetworkTV Thanks for the response.
Just wanted to clarify what I though I heard. Do you O2 Clean your second stages?
Well done Team to providing informed answers to some controversial topics.
One consideration regarding the 1/4 turn back discussion. I experienced a nearly fatal accident on OC Technical Diving by "Opening " my Isolation valve but actually closing it. So I never fully open any cylinders but return it 1.5 turns back. This assures that the cylinder is open and will give me gas under any circumstances. Once pressure drops the REV Counter Effect on SPG's will alert me to my mistake.
Errm did you listen to this forum's answer on the 1/4 turn fallacy?
As a TDI Tec IT .... the cylinder valve is all the way on or all the way off. Check your gauge while giving your reg a quick purge before you enter and remember "righty tighty, lefty loosey" when looking end on at the valve spindle.
I have my own analyzer and never use it when a get an "air" fill. GREAT IDEA TO USE IT ALL OF THE TIME. As far as the "1/4 turn" is this really a controversy?
I have both type of fins (US DIVER Jet Fins, which I bought 50 years ago, & Scuba Pro split fins purchased about 10 y ago) I"m an older diver now with 2 artificial knees
and the split fins are easier on my knees. I might not swim as fast as I once did, but slow and steady is now my pace.
Hi, quick question regarding oxygen cleaning regs and tank valves for Nitrox:
I was always told that once you clean the regs and valves for oxygen, you should only use it for Enriched Air. If the reg and or tank is used with again, one should clean it again to use with EANx. What's the science behind it?
Thank you for the question. Your information is correct in that the cylinder, cylinder valve, and first stage regulators need to be cleaned for use with any recognized nitrox mix.
As long as you only used it with enriched air, it would remain clean until you service the valve and hydrotest the cylinder. If you fill it with air again, you are essentially and potentially adding oil and other combustible particulates into the cylinder and in the flow paths of the valve and regulator. If you use oxygen-compatible air, then this is not a problem.
Although the contamination is a gradual process - it won’t be a problem after the first few fills as it is an accumulative effect, but there is no control over this.
One last point: if the air you are using to fill the cylinder has been analyzed and shown to have zero oil (we refer to this as undetectable oil) and is considered clean.
recently on a dive trip and Phuket Thailand and there was a diving instructor in the group who on an 85 ft wreck freaked out fully inflated his PC and rocketed to the surface certification is no substitute for experience
19:15 so in blatant clear English is DAN saying if we use EAN25 (25% O2 enriched gas) or higher we are recommended to have O2 clean cylinders, tank valves and first stage regulators? Most dive shops I have been to only charge a few bucks more for a Nitrox sticker on the outside of the cylinder stating Nitrox up to 40% not O2 clean. I am sure as s$%^ they didn't do a O2 cleaning on my gear during the inspection.
There is a huge disconnect on these topics especially when just few years (less than three) a Hawaiian dive charter told one his holiday dive clients that everyone on the boat dives Nitrox. She told him she was not a Nitrox certified diver and his response was that it was OK that Nitrox simply allow for longer bottom time and provide a safety margin. She got high pressured into proceeding the the dive with no Nitrox certification and there was absolutely no gas analyzation taking place. Shame on me for witnessing this whole s&*# show and not stepping up and at least asking the dive operator to produce the boats analyzer and demanding all cylinders under use to be tested! If for nothing else it would have made more of a point if they did not have an analyzer on the boat for the safety report I should have placed for this bad practice in the industry to just push divers though like cattle with very low concern for proper dive safety checks. The dive industry still have a lot of growing up to do is what this tells me. Sure we have come a long way but a lot of work ahead of us.
I have since mitigated my own dive practice and have several gas analyzers on hand now.
Good safety tips
I have a trivia: if you have 2 different readings of a tank from 2 different analyzer, let's say EAN 30 vs EAN 34....which EAN setting would you put in your dive computer, is it EAN 30 or EAN 34? :)
Personally, I would put 30% in for deco purposes, but use 34% for calculating MOD - this way you use the more conservative values
Awesome!! @@jakeman1397
Recalibrate both analyser one is probably off
I'm a tec diver and still use split fins on vacation. Nice show, well done.
The valve issue is nothing more than the agencies conforming to bad divers and lack of accountability for divers. The 1/4 turn is still best practice for valves used with high pressure water or gases to protect the vavle from wear and tear, and seizing. The industry changed this rule to protect the dumb diver that doesn't know if his valve is open or closed.
A controversial issue you didn’t cover was your "service" nearly killing one of your highest paying members and forcing him to pay out of pocket to save his own life. Why don't we chst about that? Or, better yet, you lose everything =)
I think we all pay the same, but nice try. Plus this presentation is from before woody's accident
Brilliant - very much enjoyed it and learnt! What are the correct applications for split fin opposed to solid ( not a spear chucker…😳🤿🏴).