https://padlet.com/sferrar/gne2ww6dfjxa Helium penalty in diving, is it a thing of the past? en-us 2018-10-13 17:35:52 UTC 2025-12-11 11:06:38 UTC hello@padlet.com sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/292445587 -Keywords: Trimix, Technical Diving, decompression

-Summary: This article summarizes a multi-country experiment that is on going due to the rising cost of helium. The argument is that trimix may be safer to use in deep decompression than Heliox(HeO2). The study does show that there is a decreased risk in decompression sickness when diving trimix vs. heliox using the same schedule. 

-Opinions: This is a good study that is being done but there are some misconceptions that have been taken from it and people are adjusting their decompression schedules based on those misconceptions. The algorithms that are used by the U.S Military for decompression are less conservative than most dive computer algorithms that are available on the market so the data doesn't translate over to the civilian Technical diving side like everyone would like it to. Also these experiments are very very controlled which when you are on your own in open water or in a cave you do not have the same amount of control over your dive that NEDU has over the divers in the experiment.
 
-Reliability: Shearwater research is one of the top computer manufacturers for technical diving. They have been in the industry since 2004. The author is a 25 year veteran of reporting on diving and diving technology and he also coined the term "technical diving" and helped integrate technical diving in to the mainstream diving community in the 90's.]]> 2018-10-13 17:47:19 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/292445587 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/292447223

-Keywords: Technical Diving, Mixed Gas

-Summary:This article explains what technical diving and the types of gasses used in diving and technical diving. It also touches a little on surface supplied diving.  It talks a little bit about the reason we use helium in technical diving but is focused more on heliox(HeO2) more than Nitrox(a Nitrogen Oxygen mix).

Opinions: This is great to get some basic back ground information on diving, deep diving, and what technical diving actually is. It talks about the basic limitations of open circuit scuba and it talks about how technical divers exceed these depths and time limits.

-Reliability: NOAA is a leader in ocean exploration and research.]]> 2018-10-13 18:04:35 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/292447223 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/292447238 -Keywords: Mixed gas, HeO2, Diving Medicine, Decompression

-Summary:These are in depth multi chapter volumes of the U.S Navy dive manual. They talk about diving medicine, give decompression schedules for different mixes of HeO2. It also gives protocols for divers operating for the military using the equipment that is authorized by the navy.

-Opinions: This doesn't cross over directly in to technical diving but it is a great place to start to look at the difference in the algorithms used by the best in the world vs. the algorithms available to technical divers on their computers.

-Reliability: The U.S Navy dive manual is the governing document on all military diving operations. It is revised when needed based on studies done by NEDU (Navy Experimental Diving Unit)]]> 2018-10-13 18:04:48 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/292447238 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/298786068 - Keywords: Helium, Nitrogen, Compartments

-Summary: This is a very in depth journal of a study done on sheep altering gas mixtures and measuring the on-gas and off-gas of each compartment and comparing those values to expected values.

-Opinions: This is an interesting study. The only thing that gets me is the typo in the title. The other interesting thing is their are some anomaly's that happen to the human body under water under pressure breathing a pressurized gas, so this being at atmospheric pressure it has to be taken as what it is. the likely-hood of the gasses acting extremely different in the human body under pressure are slim but still there.

-Reliability: There is a typo in the title of a published journal? Other than that this information is very reliable Dr. Doolette has published more than just this journal when it comes to diving. He was worked with the navy experimental diving unit on studies. He is very well known and respected in the diving community.]]> 2018-10-30 23:34:04 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/298786068 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/298811946 -Keywords: heliox, Trimix, NEDU, DCS

-Summary: This article exams the work that is done at Navy Experimental Diving Unit in Panama City Fl. It goes through a few experiments that they have been working on. 

-Opinions: Although the helium penalty is not directly mentioned this shows a interesting aspect in diving that the average diver does not typically think about. Although there is no real governing body, only certifying agencies in diving, most of the practices that are used by civilians are taken from governments military studies and adapted to be useful to the recreational diver.

-Reliability: Alert diver is a world renowned diving magazine that overseen by DAN, Divers Alert Network, who is an insurance provider and a leader in safety practices in the civilian diving community.]]> 2018-10-31 01:45:27 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/298811946 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/310064312 -Keywords: N2, He, half life, Buehlmann model, diffusion, tissue compartments. 

-Summary: In this blog post the use of the buehlmann model to plan decompression using nitrogen and helium mixes is explained in great detail. There are graphs and diagrams that are used to show that the tissue compartments that are used to calculate gas diffusion are theoretical compartments and do not actually correspond to actual tissues in the human body. He argues that since the compartments are theoretical the way decompression is calculated based on the buehlmann model is unnecessarily biased towards the helium penalty.

-Opinions: This is one of the best objective blog posts I have had the opportunity to read. The data and graphs that show how the tissue compartments work in the blog are awesome representations of the buehlmann model and can be used to better explain how the algorithm works when using multiple gases. There is a lot that can be gained from articles from authors like Robert Helling

-Reliability: Robert Helling is a theoretical physicist that has an interest in diving. Even though this is a blog post and not a published journal it can be taken as very reliable. Mr. Helling has a better understanding of the theories involved in gas diffusion and decompression than most people. He used data points, graphs, and his understanding of physics to back up his arguments and present them in an easy to read blog post.]]> 2018-12-01 14:43:05 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/310064312 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/310082503 -Keywords: Trimix, Heliox, Decompression, Oxygen, Helium, Nitrogen, Narcosis

-Summary: This article is written about the three main thoughts of selecting the proper gas mixture when planning a deep dive. The selection of the gas mixture is very important because it can literally make or break a dive and potentially causing catastrophic events to the diver. The three main schools of thought are, selecting a gas mixture from a set of standardized mixes that are designed to work within certain depth ranges. The second is choosing a custom mix for every dive to attempt to maximize the benefits of the gasses that play a roll in diving and to minimize the risks each gas plays. The third school of thought is to use both of the previous two thoughts depending on the depth and length of the dive. There are benefits to both thoughts because a standard mix can be very beneficial to a diver when you are planning a somewhat shallow dive of less than about 85 meters. The standard mixes do not fair as well when you go much deeper than that which is where the custom mixes come in to play. This article also goes in to pretty good detail about the three main gasses that are breathed by recreational divers while touching on the other gasses that commercial and military divers use. 

-Opinion: This article is important to technical divers. If you read this article with an open mind you can get a better idea of why making the correct gas selection when planning a deep dive is very important. If you make the wrong choice when selecting a gas it can have dire consequences and I believe that is the point the author was trying to make. Although there are three schools of thought when selecting a breathing mix there really is a right and a wrong way. This article does not directly talk about the helium penalty but you definitely have to have the penalty in the back of your mind when you are selecting your gas mixes when planning a deep dive. 

-Reliability: The reliability of this blog is a little bit conflicting. On one hand there is no bad information within it and it is posted on a very prominent diving certification agencies web-page. On the other hand it is just and opinionated blog, it is not the same as getting information out of a published journal or a diving manual.]]> 2018-12-01 17:46:11 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/310082503 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/310110436 -Keywords: Hedium, Trimix, Heliox, Enriched Air, No decompression limits, Haldane model, Deep Stops, Woodville Karst Plain Project

-Summary: This article is part 9 of a RGBM Technical Series. It starts with the basics of deep stops in diving discusing why they are relevant and then it talks about the history of deep stops and the Haldane algorithm that originally thought deep stops were only sometimes necessary. It then moves in to the Woodville Karst Plain Project (WKPP) which was a cave exploration. While doing their explorations and mappings they made huge advances with deep stops and limited decompression times by making these deep stops. It dives in to the science behind decompression theory. It also talks about the different algorithms used in diving and how they work with the deep stop. Testing and validation was referenced and written out so we can understand the tests that were completed to come up with these algorithms and theories. The paper dives in to helium misfacts and it discusses the Hans Keller incident from 1962 which led to misconceptions on isobaric switches from light to heavy gases while diving. The paper goes in to detail about helium properties using comparative tables to show the benefits of different gas mixes at different depths. The paper discusses how divers that breath HeN2O2 mixes generally feel better after a dive compared to a dive on enriched air(nitrox) or air. All of the references that were used to write the paper are listed and there is explanations about who the authors are.

-Opinion: This is a very well planned and thought out paper. It might actually be one of the best that i have read making comparisons of decompression tables and schedules. There is a lot to it and it has to be read more than once to actually understand the principles that are talked about. The data points and tables in the paper are awesome and they it is nice to have those visuals. 

-Reliability: There are 86 sources listed for this paper which means Mr. Wienke and Mr. O'Leary did not just rely on their diving expertise but they reached out and studied and got valuable resources and information before releasing this document. Bruce Wienke is a program manager in the Nuclear Weapons Technology/Simulation and Computing Office at Los Alamos National Laboritory. He has written over 200 technical journal articles. Wienke is a former dive shop owner who presently works for Divers Alert Network (DAN) on applications of high performance computing and communications to diving.]]> 2018-12-01 23:15:41 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/310110436 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/310110612 -Keywords: closed circuit rebreather,  gas effeciency, Diluent, bailout, isobaric counter diffusion

-Summary: This article goes through the steps of selecting the appropriate bailout gas for closed-circuit rebreather (CCR) divers. It talks about the issues of isobaric counter diffusion and how right now the densities of gases play a roll in which gas you select as a bailout. It also talks about minimizing risks by selecting the correct volume of bailout gas for your dive. It weighs out if narcosis is a bigger risk to the diver than isobaric counter diffusion when bailing out from their rebreather.

-Opinion: Although this does not directly talk about the helium penalty it is an important thing to think about when talking about eliminating the helium penalty. What happens when you bail out to a secondary gas that may contain helium in it with a lower nitrogen and oxygen content, is that you lose the benefits of the optimized partial pressure at depth that the rebreather gives you. So in that case decompression schedules could become muddled and difficult to follow creating a hazard to the diver.

-Reliability: BSAC is a UK diving agency that provides training for all skill levels. This blog is found on their web page. Although i don't have any experience with this particular agency they seem to play the same roll in the UK that SDI/TDI plays here in the united states. Providing training and resources to all levels of divers.]]> 2018-12-01 23:18:33 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/310110612 sferrar https://padlet.com/sferrar/gne2ww6dfjxa/wish/310110655 -Keywords: Decompression sickness (DCS), PFO, Decompression, Dive computers, unearned hit vs. unexplained hit

-Summary: This is a blog post written by John Chatterton himself. It talks about unearned vs. unexplained cases of DCS. The health of the diver and the amount of decompression that was completed by the diver for the specific dive plays a huge roll when you are talking about decompression. What John Chatterton is saying is that there is no such thing as an unearned hit but it is really just an unexplained hit. An unearned hit is usually used to describe a case of DCS that occurs when the diver has followed all of the rules according to the dive tables that they are using of their dive computer. But it should only be called an unexplained hit because there are factors that come in to play like fatigue, dehydration, and overall health play that even if you do follow the rules DCS can still occur because your body is not functioning optimally.

-Opinion: I absolutely love this article. It ties in to the helium penalty because when we are talking about using helium in diving you are almost certainly talking about dives that are deep and will require decompression. These dives are inherently more dangerous than an open water dive within the recreational limits and bullheaded divers that get bent like to prove that they followed all of the rules to the T and that the case of decompression sickness was unearned. Following the procedures and dive plan is really only half of the battle when you are talking about these deep technical dives.

-Reliability: John Chatterton is a world renowned diver and explorer. He has been at the forefront when it comes to deep technical diving. This is a very factual opinionated blog post that if read with an open mind some common misconceptions about unearned hits can be cleared up.]]> 2018-12-01 23:19:22 UTC https://padlet.com/sferrar/gne2ww6dfjxa/wish/310110655