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View Full Version : Air breaks
andibk March 10th, 2003, 08:36 AM When using oxygen for decompression it is recommended to take air breaks every 20 minutes. Is it sufficient to do your air breaks on another deco gas such as a 50% or should you do a air break on your bottom mix? Bruce WreckWriter March 10th, 2003, 08:39 AM I do it on bottom mix. 12 mininutes is recommended by some, 12 on 5 off. WW WYDT March 10th, 2003, 11:04 AM WreckWriter once bubbled... I do it on bottom mix. 12 mininutes is recommended by some, 12 on 5 off. WW Ditto, lowest PO2 gas for breaks and 12 on 5 off. dmdalton March 10th, 2003, 12:17 PM WYDT once bubbled... Ditto, lowest PO2 gas for breaks and 12 on 5 off. Ditto again! If doing multiple deco gases ie 50/50 from 70 ft to 20 ft, then O2 at 20 be sure to do 3 -5 min at 30 ft on backgas so you go into the 20 ft stop @ 1.6 ppo2 clean. Dave D Uncle Pug March 10th, 2003, 12:39 PM I think BRW has a different position concerning this. Check out this thread (http://www.scubaboard.com/showthread.php?s=&threadid=20261) As relates to going from EANx back to Helium based backgas. WYDT March 10th, 2003, 02:48 PM Uncle Pug once bubbled... I think BRW has a different position concerning this. Check out this thread (http://www.scubaboard.com/showthread.php?s=&threadid=20261) As relates to going from EANx back to Helium based backgas. That's interesting UP but I know that's not how wkpp does it and I haven't heard of any problems from them... and they definitely have some long bottom times on high He mixes and do backgas breaks while on O2..... in fact GI encourages breaks to He based mixes..... I certainly don't have the credentials to question BW but this is the first I've heard of this... :confused: dmdalton March 10th, 2003, 06:44 PM We (NOVA Tech) had Bruce W in for a seminar last September and I don't recall this issue being raised. Most of what he spoke about were the differences between the disolved gas / VPM / RGBM models and (naturaly) the advantages of the RGBM. I've got his book and will read over the referenced section. What I'm doing I've gleaned from phone/personal conversations with GI as well as studying the e-mails he's put out on Techdiver and Quest. One thing I am sure of is that there is still a lot of art (as opposed to science) in practical decompression. UP, what are you doing withregard to breaks? Dave D http://home.earthlink.net/~toddclagett/NovaTech/ WreckWriter March 10th, 2003, 06:51 PM dmdalton once bubbled... What I'm doing I've gleaned from phone/personal conversations with GI as well as studying the e-mails he's put out on Techdiver and Quest. I'm also working off G3's theories/findings. As I understand it when you go off deco gas for an air break the PPO2 in your body naturally lowers. You then receive the benefit of a O2 higher gradient when you go back on. Maybe Rob, Heather, Mike, or someone will catch this thread and explain what I'm trying to say more plainly.... WW Bottomfeeder March 10th, 2003, 10:03 PM WreckWriter once bubbled... I'm also working off G3's theories/findings. As I understand it when you go off deco gas for an air break the PPO2 in your body naturally lowers. You then receive the benefit of a O2 higher gradient when you go back on. Maybe Rob, Heather, Mike, or someone will catch this thread and explain what I'm trying to say more plainly.... I'm not Rob, Heather or Mike but might be able to help. Did you ever notice oxygen boogers? When you deco on O2, your airway (including lungs) builds up a protective coating of mucus (AKA snot). This impedes the gas exchange in the lungs. Breaks to lower O2 break down this coating pretty quickly, and restore the lungs to good exchange efficiency. You can actually feel this as you deco if you toggle the gas. It is simple on that level. As BH has said, "What works, works". The CNS toxicity issue is also addressed by this toggling. The idea is to prevent instead of treat the problem.
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