Tag: Sweden

Hydrogen Diving: The Good, The Bad, the Ugly

In the preceding blog post, I reminded the reader that the Earth’s supply of helium is limited. It is not a renewable resource.

Being a diving professional, I am not concerned about the consequence of a helium shortage on party balloons. But I am thinking about the potential consequences on diving.

So, knowing that hydrogen has both good and bad traits, it would be prudent to begin thinking about whether or not there is a way to safely substitute hydrogen for helium in technical, scientific, commercial and military diving.

Perhaps the word “bad” is too much of an understatement. Perhaps “horrible” would be a better descriptor for something like the Hindenburg disaster.

With that sobering reminder of what can happen, we now cautiously move on to the science.

First, we begin with the explosion hazard of hydrogen in binary mixtures of hydrogen and oxygen.

For diving in the 10 to 20 bar range, 326 to 653 fsw range, the upper explosion limit is 94.2 molar percent. So that means that if a binary gas mixture contains 96% hydrogen and 4% oxygen, it should not explode when ignited.

Those underlined words are important. An explosive mixture of hydrogen and oxygen will not explode without an ignition source. Proof of that is exhibited in many college introductory chemistry lectures, and documented in the following YouTube video.

Arne Zetterström

As a forecast of our potential future, during World War II, Sweden was deprived of a ready source of helium coming from the U.S. and elsewhere. So, the clever and industrious Arne Zetterström conducted a series of experimental deep, hard hat dives from 1943 to 1945 using a mixture of 96% hydrogen and 4% oxygen on dives ranging from 12 to 17 bar.

Once at depth, Zetterström switched from a non-hydrox gas mixture to the “hydrox” gas mixture. His initial test dive was to 111 msw (362 fsw, 12 bar), progressing through six dives to a maximum depth of 160 msw (522 fsw, 17 bar).

That dive series was successful. Unfortunately, on the last dive on 7 August 1945, Zetterström died tragically when his dive tenders mistakenly pulled him directly to the surface from the bottom depth of 522 fsw. He died from fulminant decompression sickness.

From the above table we see that modern measurements confirm that Zetterström chose his gas mixes wisely. At a 96 mol% of hydrogen, he was above the upper explosion limit. If there had been an unexpected ignition event, his breathing gas mixture would not have exploded.

I have confirmed the oxygen partial pressure for Zetterström’s dives using PTC Mathcad Express 3.1 and will share the process.

First, I show pressure conversions familiar to Navy divers and diving scientists, but not known to most others.

For Zetterström’s 111 msw (362 fsw) dive, the partial pressure of oxygen (PO2) would have been 0.478 atm, at the top end of the target range (0.4 to 0.48) for U.S. Navy chamber oxygen atmosphere during saturation diving. A PO2 of 0.48 is believed to be the highest PO2 tolerated for extended periods. Saturation dives sometimes last over a month.

For Zetterström’s 6th and last dive, to 160 msw (522 fsw), the oxygen partial pressure was 0.7 ata, about half of what it normally is in modern electronic rebreathers with fixed PO2.

A far more detailed story of the Zetterström Hydrox dive series can be found in this book.

Arne Zetterström Memorial Dive

In 2012, the Swedish Historical Diving Society and the Royal Institute of Technology (KTH) Diving Club, Stockholm, conducted an Arne Zetterström Memorial dive to a relatively shallow depth of 40 msw or 131 fsw. The original 96% – 4% ratio of hydrogen and oxygen was maintained, resulting in a gas mixture with a PO2 of 0.20 atm.

As reported in the KTH Dive Club’s Dykloggen (dive log) report of July 2012, the team lead was Ola Lindh, Project Leader and Diver. Åke Larsson, another diver, contributed the following information about that dive.

The Hydrox divers used open circuit scuba, with back mounted air, and for decompression, bottles of hydrox and oxygen.

The Swedish divers did not go deeper than 131 feet because they were just above the mud at that depth in a quarry. Plus, they did not yet have details of Zetterström’s decompression plan for deeper diving.

Today, they do possess the wartime hydrogen decompression plan, so deeper hydrogen dives may be forthcoming.

Three gas mixtures – hydrogen, and air (nitrogen and oxygen)

When you mix an inert gas like nitrogen (or perhaps helium?) with hydrogen and oxygen mixtures, that greatly reduces the explosion hazard. But as this video shows, sooner or later the ratios might change enough to become explosive.

Naval Medical Research Institute

I spent 12 years working as a diving biomedical researcher at the Naval Medical Research Institute (NMRI) in Bethesda, MD.

Main entrance to the Albert R. Behnke Diving Medicine Research Center, at NMRI.

My laboratory was in the Behnke Diving Medicine Research Center building, but the hyperbaric hydrogen facility was situated a safe distance behind the main building. In the unlikely event of an explosion, the main Behnke facility and its hyperbaric chamber complex would be preserved.  

The hyperbaric hydrogen facility was used to test the effects of high-pressure hydrogen and biochemical decompression on pigs, rather than risk human divers. And all of that was done safely, thanks to the professionalism of Navy divers and scientists.

Dr. Susan Kayar checking on the hydrogen diving pigs.

Kayar, a member of the Women Divers Hall of Fame, used at 230 msw (751 fsw) a gas mixture of 88% hydrogen, 2% oxygen, balance helium with a slight amount of nitrogen. That 88% hydrogen mixture put the gas mixture well above the 71.3% upper explosion limit for three gas components at 24 bar pressure. The resulting PO2 was 0.5 ata.

Compagnie Maritime d’Expertises (COMEX)

COMEX and their human-rated hyperbaric chambers are located in Marseilles, France.

When it came to manned hydrogen diving, the effect of hydrogen narcosis forced COMEX to operate below the upper explosion limit during its long series of experimental hydrogen dives.

In 1985, COMEX’s Hydra V was the first manned hydrogen dive to 450 msw. Hydrogen fraction was 54%, helium fraction was 45%, and oxygen fraction 1%. PO2 was a nominal 0.45 atm, the same partial pressure used by the U.S. Navy for saturation dives.

In 1988 during Hydra VIII, the first open water hydrogen dive, the depth was 534 msw, or 1752 fsw. Hydrogen fraction was 49%, helium fraction was 50%, and oxygen fraction 1%. The resulting oxygen partial pressure was 0.54 atmospheres.

The following video documents the record-breaking Hydra VIII dive.

The 534 msw Hydra VIII depth record was broken by Hydra X, a 701 msw, 2300 fsw chamber dive. The gas mixture was the same as in Hydra VIII, hydrogen fraction 49%, helium 50%, and oxygen percentage 1%. Due to the increase in depth, PO2 rose to 0.7 atm, an oxygen partial pressure frequently used in older U.S. Navy rebreathers.

The head of the Diving Medicine Department at NMRI, CAPT Ed Flynn, M.D. (glasses and grey hair sitting on the right side of the console), was performing physiological studies on both Hydra VI and VIII. In essence he was the Patron Saint of the NMRI Hydrogen Research Facility.

Shallow Hydrogen Diving

What have the previous studies taught us? Well, for one thing, the Swedes showed in their Arne Zetterström Memorial dive that you can get away with oxygen concentrations close to normoxia, PO2~0.21 ata. The disadvantage of normal atmospheric partial pressures of oxygen, compared to higher pressures, is related to decompression time. There is a decompression advantage when breathing oxygen pressures of 1.3 to 1.45 ata. Virtually all modern electronic rebreathers use those oxygen pressures for that reason. But as the KTH Dive Club showed, hydrogen decompression can be safely handled at relatively shallow depths.

For recreational divers, there is an economic advantage for reducing helium usage by substituting nitrogen. We don’t yet know what the economic and safety comparison would be when using helium diluted hydrogen versus pure hydrogen.

Hydrogen, helium, and oxygen were the standard gases used by COMEX. But they were likely chosen to lessen hydrogen toxicity. Hydrogen toxicity would not be a problem at shallow depth. And in fact, the KTH Dive Club reported no toxicity problems.

Retrospection

As proud as I have been of the record-breaking COMEX hydrogen research program, and of the highly imaginative U.S. Navy hydrogen research program, it has not been lost on me that the first deep human hydrogen dives were conducted by an undoubtedly low-cost program led by a single Swedish Naval Officer, Arne Zetterström.

Now, I find it remarkable that the people testing hydrogen diving at relatively shallow depths, would also be Swedish. Unlike the COMEX and NMRI projects described above, I suspect the KTH Dive club was not sponsored by multimillion dollar programs.

You have to admire the Swedish chutzpah.

Disclaimer: The author is no longer employed by the Navy or Department of Defense. All opinions are my own, and not those of any government agency. This document is posted purely for historical and educational interest. At risk of violent death, under no circumstances should the reader be tempted to explore the production, storage, or use of hydrogen without thorough and certified safety training.

Hydrogen Diving – A Very Good Year for Fiction

Susan R. Kayar

It is incredibly unlikely that two scientist colleagues, Susan Kayar and myself, separated by large amounts of time and distance, would independently publish two novels about deep hydrogen saturation diving, in the same year. Unlikely or not, it happened in 2017. Neither author was aware of the other’s intentions, or even their whereabouts.

Some things are inexplicable.

Hydrogen diving is, to use an over-used analogy, a double edged sword. On the one hand it makes truly deep diving possible, yet it can cause bizarre mental effects on some deep hydrogen divers. And that dichotomy is grist for any novelist’s mill.

I had previously written  about hydrogen diving and the pioneering role a Swede named Arne Zetterström had in developing it. Unfortunately, perhaps because he was a bold diver, he did not survive to become an old diver. Ironically, his death while diving wasn’t the fault of the hydrogen, but of his inattentive tenders. But as they say, that’s another story.

Once the remarkable, serendipitous co-publication of these two hydrogen diving novels became known, Kayar and I decided to post reviews, each about the other’s book. After all, if we didn’t, no one else would.

Quoting from Dr. Kayar’s biography listed on her Goodreads site, “Susan R. Kayar holds a doctorate in biology from the University of Miami. Her research career in comparative respiratory physiology spanned more than twenty years. She was the head of a research project in hydrogen diving and hydrogen biochemical decompression in animal models at the Naval Medical Research Institute, Bethesda, Maryland. She currently resides in Santa Fe, New Mexico, with her husband Erich; they met when they were both performing research at NMRI. Dr. Kayar was inducted into the Women Divers Hall of Fame in 2001 for her contributions to the study of diving physiology and decompression sickness.”

As for me, my bio is included in the About page of this blog.

My review of her book, Operation SECOND STARFISH: A Tale of Submarine Rescue, Science, and Friendship, is repeated here, and her review of mine is at the bottom of this post.

“Submarine deep sea “black ops” can be risky business even when everything goes well. But when things go badly, submariners’ lives are in peril, and everyone is praying for a miracle, and a savior. This well written novel drops you into the middle of such a desperate situation, and the potential savior, or potential scapegoat, is an unexpected protagonist, a female civilian scientist who knows the Navy way, knows how to motivate Navy divers, and unconsciously toys with their affections. This is a sensitively written account with a focus as much on interpersonal relations as on the technical aspects of hydrogen diving and biological decompression, or “Biodec.” Some of the greatest themes in this story are of the personal heroism of divers willing to risk their lives in the cold, foreboding darkness of the deep sea in an improbable effort to save fellow sailors.

The story may be fictional, but the science is not. In fact, for all the reader knows, everything written could have happened, or perhaps will, the next time the Navy has a submarine stranded on the bottom. The author, Susan Kayar, Ph.D. has pursued with Navy funding the very technology exposed in this story.

Amazingly, this is one of two novels published independently by scientists in the same year concerning record breaking deep hydrogen dives conducted on super-secret national security missions. That is a rare coincidence indeed, since to my knowledge no other novels about deep hydrogen diving have ever been written.

The other book is a sci fi techno-thriller called Triangle: A Novel, the second volume of a trilogy published by one of Kayar’s fellow scientists and colleagues, this reviewer. In both books, the hazards of deep diving are very real, and the tension is palpable. If you want to learn of the possibilities and perils of deep hydrogen diving, and experience the heroism of exceptional men and women in extraordinary circumstances, you now have two books to both entertain and painlessly inform you.

Kayar’s book will leave you wishing you could ride along with Doc Stella as she rides off into the sunset on her Indian motorcycle. What a ride it is.”

 

Kayar’s review of my novel, Triangle, the second in the Jason Parker Series of science fiction thrillers, follows.

“I thoroughly enjoyed Triangle, the second novel in the Jason Parker Trilogy by John Clarke. It is a fun and engaging mash-up of diving science and science fiction. John and I worked together in diving research for the Navy in Maryland years ago. He continues to this day to perform diving research for the Navy in Florida (while I moved on to other activities and then retired). As one would expect, his details in diving science and Navy jargon are impeccable. But it is impressive that his characters are well drawn and his plot twists are creative and bold.

My favorite part of Triangle has to be the ultra-deep hydrogen dive sequence for admittedly personal reasons. John and I, friendly colleagues though we were, had not been in contact with each other for a couple of decades or more. And yet my own diving novel, Operation SECOND STARFISH, was published in the same year as Triangle, and also contains an ultra-deep hydrogen dive sequence. Mutual friends had to tell us that the other had published a book for us to re-establish contact. I would imagine that our two books are the only novels ever to describe a hydrogen dive, which is a huge technical and physiological challenge, as readers will discover. John’s hydrogen dive works out (if I dare say so without revealing too much of his excellent plot) about as well as such a dangerous scenario ever will. My hydrogen dive is a lot rougher, in keeping with the more aggressive compression rate chosen to respond to the disabled submarine rescue that forms the basis of my story.

Any readers truly interested in dives well beyond 1000 feet of seawater will find a lot to learn and marvel over in Triangle. Readers just along for the exciting sci-fi ride will be equally happy to have spent time in John Clarke’s imaginative world. I look forward to his predicted December release of the third novel in this series.”

 

Anyway you look at it, these two fun novels contain a cram course in the rarest type of diving there is, diving with hydrogen as a breathing gas.