DOCSLIB.ORG

Deep Hydreliox Diving Seminar

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Deep Hydreliox Diving Seminar NUI Diving Seminar 2017 – Evolution session 2017 Deep Hydreliox Diving Seminar Gareth Kerr Diving Fathom Systems Ltd. Aberdeen, UK International Bergen The Summary of presentation • A Brief History of Hydreliox Diving2017 • Benefits to the diver – Hydreliox vs Heliox Seminar • Obstacles to commercialisation of Hydreliox Diving • Hydrogen acceptance & use in current times • Technology enhancements in commercial diving • Justification for usingInternational Hydreliox? • Safety & risk concernsBergen and mitigation • Thoughts forThe the future... Apologies & acknowledgements 2017 Dr. Jean-Yves Massimelli – UDS Seminar (ex-Comex diving doctor for HYDRA Project) Diving Théo Mavrostomos – ex Comex (deepest man in the world – HYDRA 10 Project – 701m) International Ben SharplesBergen – JFD (BusinessThe Execution Director) a brief history of hydreliox diving Comex ‘HYDRA’ Research Programme2017 Started in 1968 with HYDRA 1Seminar and continued for 28 years to HYDRA 12 Divingin 1996 International Bergen Comex founder (1961) The Henri Germain Delauze a brief history of hydreliox diving HYDRA objectives were to study alternative2017 breathing gases for deep divingSeminar – especially hydrogen Diving International Bergen Comex headquartersThe Marseille France a brief history of hydreliox diving It was hoped that hydrogen would2017 help alleviate the physiological effectsSeminar of deep diving – including: Diving • High pressure nervous syndrome (HPNS) • Respiratory comfortInternational / work of breathing • Diver cognitive & physical capabilities Bergen • Sleep patternsThe & appetite a brief history of hydreliox diving Deep diving trials using Heliox concluded2017 that there were real depth limits toSeminar this technique Diving International Bergen Comex Sagittaire – 1974 The (610MSW - 50 hours bottom time) a brief history of hydreliox diving Gas density effects, thermal balance, insomnia,2017 communications issues, psychological issues and HPNS Seminar Diving International Bergen National Hyperbaric Centre Aurora ’93 trials 1993 (450 / The 470MSW for 33 days) a brief history of hydreliox diving Trials with nitrogen as an ‘additive’2017 to the breathing mix to alleviate theSeminar ‘anxiety’ at 150m Diving International Bergen The Comex Janus IV - Phase B (1977 - 501MSW in water) a brief history of hydreliox diving Comex demonstrated Ultra-deep diving2017 both in chamber and in the water using HeN2O2 but significant challenges were present.Seminar Diving In 1981 Duke University (USA) conducted trials using HeN2O2 to 686MSW inInternational the chamber where divers experienced difficulty and suffered trembling and memory lapses. Bergen The 2017 Seminar a brief history of hydreliox diving Diving HYDRA experimental chamber dives led to open water dives to 534MSW from Orelia in 1988 (HYDRA 8) International Bergen The a brief history of hydreliox diving Orelia was not designed for Hydreliox –2017so had to be adapted to support operations using hydrogen: Seminar Diving International • Chamber room purged with nitrogen • Tenders used closed circuitBergen re-breathers • Bell umbilical stored onThe deck • H2 gas storage & gas handling on deck a brief history of hydreliox diving HYDRA 10 – deepest chamber dive to 701MSW2017 - 1992 Seminar Diving International Bergen The Théo Mavrostomos World record holder a brief history of hydreliox diving HYDRA 10 – dive profile (42 days) 2017 • Normal blowdown to Seminar 200m on HeO2 • Continue blowdown to Diving 400m adding only H2 • Return to HeO2 for 400m to 700m International • Linear bleed to 420m • Remove H2 to reduce Bergen depth to 280m • Normal deco to surface The a brief history of hydreliox diving Comex developed new equipment and2017 techniques: • Hydrogen removal unit Seminar (‘de-hydrogenator’) • Laboratory Diving instrumentation and monitoring • Closed-circuit rebreather for diver’s bail-out International • Mass-spectrometer & GC based gas analysis Bergen • Advanced medical / clinical monitoring of The divers In-chamber a brief history of hydreliox diving Hydra 12 investigated ‘Helium IN – Hydrogen2017 OUT’ • Chamber & Bell atmosphere was conventional HeO2 • Divers’ lock-out gas was Hydreliox – to avoidSeminar hydrogen in the chambers • Issues experienced with vestibular bends due to high gas-gradients Diving during transition IN – OUT – IN even at 210m • Technique proved successful Internationalapart from gas gradient issues • Similar diver performance to previous Hydreliox trials Bergen The In-water Benefits to the diver – Hydreliox vs Heliox HYDRA results showed significant benefits2017 of Hydreliox: • Improved cognitive abilities of divers Seminar • Ventilatory comfort (less breathing effort & stress) • Physical comfort (absence of jointDiving & muscular pain) • Absence of significant clinical & para-clinical disorders, including HPNS, anxietyInternational & narcosis • Improved sleep patterns & appetite Bergen The Benefits to the diver – Hydreliox vs Heliox Other important considerations identified:2017 • Careful selection & training of divers is required (physical & psychological) Seminar • Importance of comfort, ergonomics and environment in chambers • Optimised compression & decompressionDiving profiles developed • Maximum ppH2 = 20 bars • HPNS & narcosis monitoring of divers required • Importance of decompressionInternational monitoring • General medical clinical and para-clinical monitoring (before, during and after hyperbaric exposure) Bergen • Hydrogen not flammable below 4% O2 The Obstacles to commercialisation of Hydreliox Why has Hydreliox not been commercialised?2017 • Flammability / explosive nature of hydrogen – If hydrogen was not flammable, it would beSeminar the diving gas of choice and Comex would have further developed Hydreliox rather than He in H out. • Much of the commercial saturationDiving diving carried out today is shallower than 180MSW • Deeper diving operations are feasible on Heliox to 350m+ with increasing difficulty and Internationalreduced diver capability with depth • Commercial drivers have not existed to develop the technology • ROV and remote interventionBergen techniques have improved The 2017 Seminar Hydrogen acceptance & use in current times Diving Hydrogen is becoming more readily accepted due to: • Its use as a green fuel for cars International Bergen The Hydrogen stored at 350 bars Hydrogen acceptance & use in current times Hydrogen is becoming more readily accepted2017 due to: • Its use as a green fuel for buses Seminar Diving International H2 Stored at 700 bars Bergen The Hydrogen acceptance & use in current times Hydrogen is becoming more readily accepted2017 due to: • Consumer safety through system design Seminar Diving International Bergen The 350 bar H2 refuelling 2017 Seminar Hydrogen acceptance & use in current times Diving Hydrogen vehicles (FCEV) will increase International Bergen The Scandinavian H 2 refuelling station 2017 Seminar Hydrogen acceptance & use in current times Diving Fuel Cell technology has advanced significantly International Bergen The Automotive fuel -cell stack 2017 Seminar Hydrogen acceptance & use in current times Diving Hydrogen production from electrolysers International Bergen The Alkali liquid electrolyser PEM electrolyser Hydrogen acceptance & use in current times Hydrogen compressors 2017 Seminar Diving International Bergen 3-stage diaphragm compressorThe Ionic liquid compressor (950 bar output) Hydrogen acceptance & use in current times Hydrogen in marine environments 2017 Seminar Diving International • Norway leading the way with Hydrogen fuelled vessels Bergen • September 2017 – Viking Cruises announce first H2 powered cruise ship • Significant experienceThe within DNV-GL and LR Norway for H2 systems • Erna Solberg is promoting hydrogen research for maritime & automotive uses Technology enhancements in commercial diving Fully automated diving systems (since 20172009): • Deep Arctic (Divex HMCS) Seminar • Seven Atlantic (Divex HMCS) • Seven Falcon (Drager) Diving • Deep Explorer (JFD HMCS) • Seven Kestrel (Drass ISAT) International Safety PLC systems complyBergen with IEC61508 The Technology enhancements in commercial diving PLC / SCADA control of chamber parameters2017 Gas-free control rooms Seminar Diving International Bergen Chamber control roomThe Dive control room 2017 Seminar Technology enhancements in commercial diving Diving Remotely controlled / automated gas distribution & control to chambers & SDCs International Bergen The Technology enhancements in commercial diving Improved chamber ergonomics & diver2017 comfort • Seminar Private sleeping compartments Diving • Mood lighting • In-chamber entertainment systems • Improved diver voice International communications • Private telephone calls Bergen from divers to shore The • Internet & email access Technology enhancements in commercial diving Improved diver monitoring & instrumentation2017 Seminar Diving International • IMCA & NORSOK diver exposure monitoring • Bergen High accuracy environmental sensors The • Medical monitoring 2017 Seminar Technology enhancements in commercial diving Diving Recent developments in diver bail International Bergen The -out systems Justification for using Hydreliox? The Ethical view... 2017 Why do we need to dive deeper than 180MSW? • In some regions this is uncommon (UKCS, Norway)Seminar • In other areas diving is regularly carried out to 300MSW Diving • There are situations where unplanned deeper intervention would be beneficial Is diving >180MSW safe enoughInternational with impaired diver capabilities and increased stress
Load more

Recommended publications
  • Download Transcript
    SCIENTIFIC AMERICAN FRONTIERS PROGRAM #1503 "Going Deep" AIRDATE: February 2, 2005 ALAN ALDA Hello and welcome to Scientific American Frontiers. I'm Alan Alda. It's said that the oceans, which cover more than two thirds of the earth's surface, are less familiar to us than the surface of the moon. If you consider the volume of the oceans, it's actually more than ninety percent of the habitable part of the earth that we don't know too much about. The main reason for our relative ignorance is simply that the deep ocean is an absolutely forbidding environment. It's pitch dark, extremely cold and with pressures that are like having a 3,000-foot column of lead pressing down on every square inch -- which does sound pretty uncomfortable. In this program we're going to see how people finally made it to the ocean floor, and we'll find out about the scientific revolutions they brought back with them. We're going to go diving in the Alvin, the little submarine that did so much of the work. And we're going to glimpse the future, as Alvin's successor takes shape in a small seaside town on Cape Cod. That's coming up in tonight's episode, Going Deep. INTO THE DEEP ALAN ALDA (NARRATION) Woods Hole, Massachusetts. It's one of the picturesque seaside towns that draw the tourists to Cape Cod each year. But few seaside towns have what Woods Hole has. For 70 years it's been home to the Woods Hole Oceanographic Institution — an organization that does nothing but study the world's oceans.
    [Show full text]
  • Exploration of the Deep Gulf of Mexico Slope Using DSV Alvin: Site Selection and Geologic Character
    Exploration of the Deep Gulf of Mexico Slope Using DSV Alvin: Site Selection and Geologic Character Harry H. Roberts1, Chuck R. Fisher2, Jim M. Brooks3, Bernie Bernard3, Robert S. Carney4, Erik Cordes5, William Shedd6, Jesse Hunt, Jr.6, Samantha Joye7, Ian R. MacDonald8, 9 and Cheryl Morrison 1Coastal Studies Institute, Louisiana State University, Baton Rouge, Louisiana 70803 2Department of Biology, Penn State University, University Park, Pennsylvania 16802-5301 3TDI Brooks International, Inc., 1902 Pinon Dr., College Station, Texas 77845 4Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, Louisiana 70803 5Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, Massachusetts 02138 6Minerals Management Service, Office of Resource Evaluation, New Orleans, Louisiana 70123-2394 7Department of Geology, University of Georgia, Athens, Georgia 30602 8Department of Physical and Environmental Sciences, Texas A&M – Corpus Christi, Corpus Christi, Texas 78412 9U.S. Geological Survey, 11649 Leetown Rd., Keameysville, West Virginia 25430 ABSTRACT The Gulf of Mexico is well known for its hydrocarbon seeps, associated chemosyn- thetic communities, and gas hydrates. However, most direct observations and samplings of seep sites have been concentrated above water depths of approximately 3000 ft (1000 m) because of the scarcity of deep diving manned submersibles. In the summer of 2006, Minerals Management Service (MMS) and National Oceanic and Atmospheric Admini- stration (NOAA) supported 24 days of DSV Alvin dives on the deep continental slope. Site selection for these dives was accomplished through surface reflectivity analysis of the MMS slope-wide 3D seismic database followed by a photo reconnaissance cruise. From 80 potential sites, 20 were studied by photo reconnaissance from which 10 sites were selected for Alvin dives.
    [Show full text]
  • Challenges of Diving to Depth
    background sheet Challenges of diving to depth Photo by Jess © Australian Antarctic Division To harvest rich food resources of oceans, air- oxygen is stored in blood and muscle of diving mammals, breathing animals not only need to swim, they need and 35-60% in diving birds. to dive. Unlike fish, which have gills, air-breathing Reptiles are ectotherms, with much lower metabolic rates animals can’t extract oxygen from water. Instead than endotherms. Research into oxygen storage capacities these animals must regularly come to the surface to of reptiles is limited, influenced by the fact that some species breathe. are capable of cutaneous respiration (respiration through skin), enabling direct uptake of oxygen from water. Oxygen storage in the respiratory system Many deep-diving animals have lung capacities similar to terrestrial animals, indicating that their respiratory systems are not the predominant oxygen store. In many species, particularly whales, decreased lung volume correlates with increased dive depth. Some terrestrial diving animals, including sea otters and diving rodents, have large lungs that provide an important oxygen store. Sea otters store 55% of their oxygen in their lungs. Diving to depth with a large respiratory oxygen store can cause hyperbaric problems such as decompression sickness. However, sea otters are not deep divers, routinely diving to only a few metres. Oxygen storage in blood Diving animals store a significant proportion of oxygen in their blood. Oxygen storage in blood depends on an oxygen-binding protein, haemoglobin. Haemoglobin carries oxygen from the lungs to the rest of the body. The more haemoglobin present in blood, the more oxygen is bound and delivered to the body.
    [Show full text]
  • WOODS HOLE OCEANOGRAPHIC INSTITUTION Deep-Diving
    NEWSLETTER WOODS HOLE OCEANOGRAPHIC INSTITUTION AUGUST-SEPTEMBER 1995 Deep-Diving Submersible ALVIN WHOI Names Paul Clemente Sets Another Dive Record Chief Financial Officer The nation's first research submarine, the Deep Submergence Paul CI~mente, Jr., a resident of Hingham Vehicle (DSV) Alvin. passed another milestone in its long career and former Associate Vice President for September 20 when it made its 3,OOOth dive to the ocean floor, a Financial Affairs at Boston University, as· record no other deep-diving sub has achieved. Alvin is one of only sumed his duties as Associate Director for seven deep-diving (10,000 feet or more) manned submersibles in the Finance and Administration at WHOI on world and is considered by far the most active of the group, making October 2. between 150 and 200 dives to depths up to nearly 15,000 feet each In his new position Clemente is respon· year for scientific and engineering research . sible for directing all business and financial The 23-1001, three-person submersible has been operated by operations of the Institution, with specifIC Woods Hole Oceanographic Institution since 1964 for the U.S. ocean resp:>nsibility for accounting and finance, research community. It is owned by the OffICe of Naval Research facilities, human resources, commercial and supported by the Navy. the National Science Foundation and the affairs and procurement operations. WHOI, National Oceanic and Atmospheric Administration (NOAA). Alvin the largest private non· profit marine research and its support vessel, the 21 0-100t Research Vessel Atlantis II, are organization in the U.S., has an annual on an extended voyage in the Pacific which began in January 1995 operating budget of nearly $90 million and a with departure from Woods Hole.
    [Show full text]
  • DEEP STOPS and DEEP HELIUM RGBM Technical Series 9 Bruce R
    DEEP STOPS AND DEEP HELIUM RGBM Technical Series 9 Bruce R. Wienke and Timothy R. O’Leary NAUI Technical Diving Operations Tampa, Florida 33619 BASICS Deep stops – what are they? Actually, just what the name suggests. Deep stops are decompression stops made at deeper depths than those traditionally dictated by classical (Haldane) dive tables or algorithms. They are fairly recent (last 15 years) protocols, suggested by modern decompression theory, but backed up by extensive diver practicum with success in the mixed gas and decompression arenas - so called technical diving. Tech diving encompasses scientific, military, commercial, and exploration underwater activities. The impact of deep stops has been a revolution in diving circles. So have slower ascent rates across recreational and technical diving. In quantifiable terms, slower ascent rates are very much akin to deep stops, though not as pronounced as decompression stops. Deep stops plus slow ascent rates work together. And they work together safely and efficiently. Many regard deep stops as a most significant development in modern diving. Here’s why. Deep stops usually reduce overall decompression time (hang time) too. And when coupled to the use of helium in the breathing mixture (trimix) to reduce narcotic effects of nitrogen, technical divers report feeling much better physically today when they leave the water. The reduction in hang time ranges from 10% to as high as 50%, depending on diver, mix, depth, and exposure time. Feeling better while decompressing for shorter periods of time is certainly a win-win situation that would have been thought an impossibility not too long ago.
    [Show full text]
  • SCUBA DRILLS Snorkeling Gear Prep, Entry, Snorkel Clear, Kicks Gear Prep: Mask (Ant Fogged) –Fins, Gloves, Boots, Ready by Entry Point Access
    (616) 364-5991 SCUBA DRILLS WWW.MOBYSDIVE.COM Snorkeling Gear Prep, Entry, Snorkel clear, Kicks Gear prep: Mask (ant fogged) –fins, gloves, boots, ready by entry point access. (it is crucial that the mask-fins-boots are properly designed and fitted before the aquatic session to prevent delays in training due to gear malfunction ) Equipment nicely assembled by entry point for easy donning and water access ENABLED EQUIPMENT NICELY ASSEMBLED – BUDDY CHECK – LOGBOOK CHECK – ENTRY – DRILL REVIEW Equipment Nicely Assembled: (Each Diver needs to develop the practice of properly assembling their scuba gear by themselves) Full tank secured until ready for gear assembly. Tank upright, BCD tank band straps are loosened as to allow easy placement of strap around the tank. NOTE: Hard pack BCD’s usually have ONE tank band, Soft pack BCD’s usually have TWO tank bands. Most bands have a buckle / cam strap and need to be weaved a particular way to stay secured. Ensure the BCD’s placement on the tank so the tank valve is level with where the diver’s neck will be and that the front part of the valve (where the air is released) is facing the back of the diver. Secure the strap or straps so they are tight enough to pick up the BCD and tank and not slip while shaking. Regulator placement: The First stage (dust cap removed) is placed over the tank valve so the intake of the 1st stage covers the o-ring on the tank valve, (o-ring should be in place – if not, lack of seal will cause air leak).
    [Show full text]
  • Deep-Diving Foraging Behaviour of Sperm Whales 75, 814–825 (Physeter Macrocephalus)
    Journal of Animal Blackwell Publishing Ltd Ecology 2006 Deep-diving foraging behaviour of sperm whales 75, 814–825 (Physeter macrocephalus) STEPHANIE L. WATWOOD*, PATRICK J. O. MILLER†, MARK JOHNSON‡, PETER T. MADSEN*¶ and PETER L. TYACK* Departments of *Biology and ‡Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole MA 02543, USA; and †NERC Sea Mammal Research Unit, School of Biology, University of St Andrews, St Andrews KY 16 9QQ, UK Summary 1. Digital tags were used to describe diving and vocal behaviour of sperm whales during 198 complete and partial foraging dives made by 37 individual sperm whales in the Atlantic Ocean, the Gulf of Mexico and the Ligurian Sea. 2. The maximum depth of dive averaged by individual differed across the three regions and was 985 m (SD = 124·3), 644 m (123·4) and 827 m (60·3), respectively. An average dive cycle consisted of a 45 min (6·3) dive with a 9 min (3·0) surface interval, with no significant differences among regions. On average, whales spent greater than 72% of their time in foraging dive cycles. 3. Whales produced regular clicks for 81% (4·1) of a dive and 64% (14·6) of the descent phase. The occurrence of buzz vocalizations (also called ‘creaks’) as an indicator of the foraging phase of a dive showed no difference in mean prey capture attempts per dive between regions [18 buzzes/dive (7·6)]. Sperm whales descended a mean of 392 m (144) from the start of regular clicking to the first buzz, which supports the hypothesis that regular clicks function as a long-range biosonar.
    [Show full text]
  • Extreme Recreational Diving Pushing the Limits Assoc
    1 | 65 National Center for Hyperbaric Medicine in Gdynia Medical University of Gdansk, Poland Extreme recreational diving Pushing the limits Assoc. Prof. Jacek Kot, MD, PhD Bühlmann Symposium Zürich Switzerland 2019 2 | 65 Disclaimer • I declare no real or potential conflict of interest. • Any views or opinions presented in this presentation are solely those of the author and do not necessarily represent those of any organization that author belongs to, including EUBS and ECHM. • All pictures are presented here either by the courtesy of their authors or taken from public websites for non-commercial use. Assoc. Prof. Jacek Kot, MD, PhD Head of National Center for Hyperbaric Medicine of Poland President of the EUBS General Secretary of the ECHM Medical Consultant of DAN Europe Extreme recreational diving Bühlmann Symposium Jacek Kot, 2018 Zürich Switzerland 2019 3 | 65 Professor A A Bühlmann → and Hans Keller → Hans Keller planted the Swiss flag at 1000 feet off California From - TAUCH MEDIZIN Springer-Verlag 1983 ▬▬▬▬ Extreme recreational diving Bühlmann Symposium Jacek Kot, 2018 Zürich Switzerland 2019 4 | 65 Deepest underwater cave in the world Krzysztof Starnawski _ National Geographic _ 2017 Courtesy of Krzysztof Starnawski (Poland) Extreme recreational diving Bühlmann Symposium Jacek Kot, 2018 Zürich Switzerland 2019 5 | 65 Types of recreational diving Safe Increased risk High risk (“technical”) • Up to 30 m • Between 30 and 50 m • Compressed air in open • With basic breathing Over 50 m (down to 300 circuit • mixtures (nitrox and
    [Show full text]
  • The Effect of Sonar on Human Hearing
    11 The Effect of Sonar on Human Hearing Renzo Mora, Sara Penco and Luca Guastini ENT Department, University of Genoa Italy 1. Introduction Human use of the Earth’s oceans has steadily increased over the last century resulting in an increase in anthropogenically produced noise. This noise stems from a variety of sources including commercial shipping, oil drilling and exploration, scientific research and naval sonar. Sonar (for sound navigation and ranging) is a technique that uses sound propagation (usually underwater) to navigate, communicate or to localize: sonar may be used as a means of acoustic location (acoustic location in air was used before the introduction of radar). The term sonar is also used for the equipment used to generate and receive the sound. The range of frequencies used in sonar systems vary from infrasonic to ultrasonic. Sonar uses frequencies which are too much high-pitched (up to 120,000 cycles per second) for human ears to hear. Although there is a growing concern among the public that human generated sounds in the marine environment could have deleterious impacts on aquatic organisms, only few studies address this concern on the effects of these sounds on the human auditory system. The effects of sound on the human auditory system have been the subject of several studies, but one question needs to be resolved yet: the effects caused by the naval sonar. For these reasons this chapter wants to show the effects of active middle frequency sonar on human. Published data from humans under water in literature are scarce and sometimes use different terminology with regard to sound levels.
    [Show full text]
  • De L'helium a L'hydrogene, L'intervention Humaine a Grande
    DE L’HELIUM A L’HYDROGENE, L’INTERVENTION HUMAINE A GRANDE PROFONDEUR (EXPERIENCE COMEX) B. Gardette, C. Gortan, H.-G. Delauze GARDETTE Bernard, Docteur es Sciences, Directeur Scientifique COMEX SA, Marseille, FRANCE GORTAN Claude, Directeur du Centre d’Essais Hyperbares COMEX, Marseille, FRANCE DELAUZE Henri Germain, Président du groupe COMEX, Marseille, FRANCE THE DEEP HUMAN UNDERWATER INTERVENTION : COMEX EXPERIENCE Since 40 years, 43 experimental dives (deeper than 200 msw) were performed with heliox (oxygen/helium), trimix (oxygen/nitrogen/helium), hydrox (oxygen/hydrogen) or hydreliox (oxygen/hydrogen/helium) breathing gas mixtures. In 1988, six Comex and French Navy divers worked at a record depth of 534 msw with hydreliox and in 1992, a world record onshore dive at 701 msw was performed by Comex in Marseilles. These dives showed the efficiency of hydrogen diving at very deep depth (150 – 650 msw). -3 - 1. L’HELIUM La plongée à l’air comprimé comporte des limites. L’essoufflement, la toxicité de l’oxygène (2) et les effets de la narcose à l’azote, imposent au plongeur de ne pas dépasser les 50/60 mètres de profondeur (1-3-4). Dans les années 1930, des expériences ont été entreprises par la Marine américaine pour alimenter le plongeur non plus en air comprimé, mais en mélange respiratoire synthétique dans lequel l'azote est remplacé par un autre gaz inerte, diluant de l'oxygène, l'hélium. Ce dernier, très inerte sur le plan biochimique, d'une densité sept fois inférieure à celle de l'azote, permet de meilleures performances en supprimant les effets de la narcose et de l'essoufflement.
    [Show full text]
  • Diving Physics and "Fizzyology"
    Phys Diving Physics and "Fizzyology" Introduction Like all animals, human beings need oxygen in order to survive. When we breathe, we extract oxygen from the air, and use that oxygen for metabolism, which is how we convert the food we eat into useable energy to do the things that we do. One of the by-products of metabolism is carbon dioxide; whenever we exhale, we are getting rid of the carbon dioxide that our bodies produce. The main purpose of breathing, therefore, is to provide our bodies with oxygen, and rid our bodies of carbon dioxide. We humans are terrestrial (land-dwelling) mammals, and as such, our lungs are designed to breathe gas. Unlike fishes, we have no gills, so we cannot breathe water. Therefore, the first problem we must overcome to explore the underwater realm is a means to provide breathing gas. However, if this were the only barrier humans must overcome to enter the sea, we would have long-ago discovered most of the mysteries of the ocean. All we would need to remain underwater indefinitely would be a long tube going to the surface -- a huge snorkel -- through which we could breathe. Unfortunately, there is another problem we must over come when descending to the depths -- a problem with far more complex and difficult consequences. That problem is pressure. Pressure Have you ever wondered why nobody makes snorkels that are ten, or twenty, or a hundred feet long? The answer becomes obvious as soon as you try to breathe through a snorkel when your body is more than two or three feet (~1 meter) beneath the surface of the water.
    [Show full text]
  • Tiedemann's Advanced Programs
    Enriched Air Nitrox Do you want a better safety margin when it comes to Decompression Sickness? Longer bottom times? A clearer head when diving? Nitrox can be helpful in all these areas. Certification as a Nitrox Diver allows you to use Nitrox when diving. Here are few benefits that you may not know about: Since Nitrox contains less nitrogen, you will get longer dive times. As an example, the time limit for an air dive to 70 feet is only 40 minutes. With a Nitrox mix of 36 (36% oxygen and 64% nitrogen) the time limit is 70 minutes. If you think 40 minutes is enough time for a dive to 70 feet consider this... If you make the dive on air and go for 40 minutes you are right at the limit - no margin for safety. You are using 100% of the time allowed. If you make the dive on Nitrox 36 for 40 minutes you are only using about 60% of the time allowed - that is a great safety margin. Since Nitrox contains less nitrogen, the effects of Nitrogen Narcosis are lessened. Less Narcosis means clearer head while diving. Less likely to make a mistake. Safer diving. Since Nitrox contains less nitrogen, you will get longer dive times. Many people think Nitrox is for deep diving. Nitrox does not work in deep diving - you will learn this in the Nitrox course. Nitrox can be dangerous in deep water - that’s why you need to be certified to use it. The course consists of one/two academic review sessions - which are done on Long Island, two dives using Nitrox done at Dutch Springs (fills and tanks provided), registration in the SSI online Nitrox program (a $80 value) and a physical certification card (a $25 value).
    [Show full text]