Nitrox Diving Course Phuket SSI Enriched Air - FULL ENG

welcome to the specialty enriched air nitrox [Music] if you're interested in more longer bottom times and shorter surface intervals or more safety than nitrox is for you as you will learn in this program enriched air nitrox can provide many benefits for recreational divers whatever you decide we hope you enjoy learning all about enriched air nitrox of all the advances in recreational sport diving perhaps none generates more excitement than the use of enriched air nitrox the term EA NX has been shortened to nitrox yes nitrox sounds like voodoo gas but it's quite the contrary the major benefit of diving with nitrox is the gas that limits our depth and time nitrogen simply stated nitrox is any mixture of oxygen and nitrogen for example the air you are breathing right now is one form of nitrox we will use the term nitrox and the acronym EA NX solely to refer to mixtures with oxygen concentrations fo twos of 22 percent or more EA NX is an acronym for enriched air nitrox in which the X is a variable standing for the fo2 value thus EA n 32 for example represents a nitrox mixture with an fo 2 of 32 percent the terms richer and leaner are often used to compare nitrox mixtures with differing FO 2's the two most commonly used nitrox mixtures are EA + 32 + EA n 36 these mixes are also known as nitrox 1 and nitrox 2 [Music] however as one approaches the recommended depth limit for recreational diving the higher concentration of oxygen in EA and 36 puts recreational divers and greater risk of o2 toxicity than ei + 32 does nitrox has the potential to benefit divers in at least two significant ways diving nitrox exposes your body to less nitrogen then diving air does at the same depth therefore it has the potential to provide longer no decompression limits shorter surface intervals and longer repetitive dives if you dive nitrox within the same depth and time limitations as you normally do air you can add more safety to your dive by reducing the risk of decompression sickness [Music] in choosing to dive nitrox you must decide which of these benefits is more important for you if your objective is to maximize dive time you can still be as safe as you are when diving air within common-sense limits if you choose to use nitrox within the more conservative limits for diving air you can increase this safety margin even further a common misconception is that nitrox enables divers to go deeper than they can on air while nitrox has benefits it also has limitations a complete understanding of the benefits and limitations will help you decide whether to dive nitrox or air you are taking the first important step in becoming an enriched air nitrox diver this program trains you to use nitrox mixtures up to 40% of oxygen the use of nitrox above EA and 40 is beyond recreational sport diving if you are interested in going beyond the sports diving limits ask your SSI dive professional about enrolling in the SSI extended range program [Music] when you first learn to dive you may have been told that breathing pure oxygen is toxic at depth the degree to which oxygen is toxic under water depends on factors such as the quantity of oxygen to which you are exposed and the length of that exposure remember breathing nitrox exposes us to considerably more oxygen than air does for example EA 1032 contains over 50 percent more oxygen than air this means that while oxygen toxicity is not a concern when diving air at normal recreational deaths the same may not be true of nitrox the best way to compare the levels of oxygen found in nitrox and air is through partial pressure of oxygen abbreviated PP o-- two or simply po2 what is po2 simply stated it's a numerical value you obtained by multiplying ambient pressure expressed as depth in bar or atmospheres by the fraction of oxygen fo2 found in breathing gas for example air consists of 79% nitrogen and 21% oxygen at one bar or atmosphere the partial pressure of each gas found in air adds up to one bar or an atmosphere as well in this example the partial pressure of nitrogen is zero point seven nine and the partial pressure of oxygen is zero point two one bar or atmospheres the risk of CNS oxygen toxicity becomes more substantial above a po2 of one point four bar or atmospheres increasingly experts recommend a limiting po2 of one point four bar or atmospheres for all divers central nervous system oxygen toxicity is the main concern for the nitrox diver this is because once CN so2 toxicity symptoms develop they may progress rapidly to compulsions the threshold for CNS oxygen toxicity appears to be 1.1 bar or atmospheres however total exposure can range from one point one to one point four bar or atmospheres as long as you are within the time limits the risk of CNS oxygen toxicity becomes more substantial above a po2 of 1.4 bar or atmospheres po2 s increase by diving deeper and by examining these numbers you will see that lean nitrox mixtures carry a reduced risk of oxygen toxicity this table also helps illustrate why ei and 32 is the recommended nitrox mixture for most recreational dives by using a mixture no richer than EI + 32 you can dive as deep as the maximum depth limit for recreational diving of 40 meters or 130 feet several factors may contribute to CNS oxygen toxicity obviously exceeding recommended limiting po2 s is one such factor another factor is length of exposure the greater your total oxygen dose as determined by a combination of depth and time the greater the likelihood of a CNS hit another factor that may contribute to CNS oxygen toxicity is elevated carbon dioxide levels this may result from exertion or from using an inadequate or poorly maintained regulator you must be able to recognize the warning signs and symptoms both in yourself and others and respond appropriately signs of oxygen toxicity to look for in your body are convulsions inability to stop whatever he or she is doing unresponsiveness or irritability signs of CNS oxygen toxicity you may notice in yourself include visual distortion or tunnel vision ringing ears nausea muscle spasms irritability dizziness any manifestation of the signs and symptoms of CNS oxygen toxicity requires an immediate response the focus of that response should be reducing the affected divers exposure to oxygen by ascending if you notice these symptoms in yourself signal your body and begin an immediate but controlled ascent if CNS oxygen toxicity manifests itself in compulsions there may not be much the convulsing diver can do about it at this point the affected diver will be dependent on the prompt and appropriate response by an observant dive buddy regardless of what actions the situation dictates be sure to alert responding emergency medical system personnel and the emergency room physician that the affected diver may have had a reaction to elevated partial pressures of oxygen [Music] the best way to deal with CNS oxygen toxicity is to prevent it steps that may help you to do so include establishing and remaining within maximum operating depth limits limiting total Oh to exposure to safe values reducing co2 levels let's examine each of these steps in more detail every time you dive nitrox you should first establish a maximum operating depth or mo D exactly what this mo D will be will depend on the concentration of oxygen in the gas you will breathe and the limiting po2 you choose to remain within your exposure to elevated po2 s must not only stay within safe levels of maximum 1.4 bar or atmospheres they must also not exceed safe time limits the shallower you remain the less risk there is of oxygen toxicity plan your dive so that it requires the least possible exertion avoid strong currents and loan travel distances use only adequate well maintained regulators the easier your regulator breathes the less co2 build-up you will experience be sure to discuss the suitability of any regulators you currently own or are considering purchasing for nitrox diving with your SSI dive Center much remains to be discovered regarding the exact causes of CNS oxygen toxicity susceptibility to o2 toxicity may vary from individual to individual and from day-to-day staying within a particular limiting po2 and taking additional precautions may still not prevent you from suffering CNS oxygen toxicity which can cause serious personal injury or death by drowning or other causes [Music] because of the risks of both CNS oxygen toxicity and decompression sickness it is vital you personally confirm the oxygen concentration present in every cylinder you dive if you have not been able to maintain personal control over the nitric cylinder you plan to use do not assume its contents decal necessarily reflects what is now in the cylinder do not use any night truck's mixture unless you have either personally analyzed or witnessed the analysis of its fo2 content to properly analyze cylinder o to content you will need an o2 analyzer a flow meter and whatever hardware is required to connect them to the nitric cylinder you will be analyzing you will also need a gas source containing either pure oxygen air or a nitrox mixture whose fraction of oxygen has been established unequivocally to calibrate your o2 analyzer prior to its use we will cover the basic procedures needed to analyze cylinder content as part of your nitrox diver training you will practice these procedures under the direct supervision of your ssi instructor the only pieces of dive equipment with which we need to concern ourselves in regard to nitrox are those that come into direct contact with the gas these items include scuba cylinders and valves first and second stage regulators and any attached components the chief concerns regarding these items are increased oxidation and the risk of fire or explosion the o-rings seals and other components used in many pieces of scuba equipment are subject to oxidation over time substances such as neoprene combined with oxygen and deteriorate the presence of high concentrations of oxygen greatly facilitates the process of spontaneous combustion and thus increases the risk of fire or explosion you must follow the manufacturer's specifications for use of your dive equipment rather than try to discern what these are on your own your better choice is to consult your local SSI dive Center the term Oh too clean means that all components of a scuba cylinder the health first and second stage regulator or other equipment items have undergone a special cleaning process designed to remove any trace of hydrocarbon build-up as well as any trace of grease or other non oxygen compatible contaminant the term Oh to service rated means that an item has not only been completely disassembled and subjected to the o2 cleaning process but also that it has been reassembled using only oxygen compatible lubricants a rings and other components any scuba cylinder that may contain gases other than air must be labeled as such were a diver to use an unmarked cylinder containing night rocks mistakenly thinking it was air he or she would risk unanticipated CNS oxygen toxicity Blanc wise were a nitrox diver to use a cylinder containing air mistakenly thinking it was EA and X he or she might increase his or her risk of decompression sickness ssize recommended nitric cylinder decal spells out more clearly what the encircling band does and does not mean it also provides some basic warnings regarding nitrox use more importantly it reminds divers of the vital importance of personally analyzing or witnessing the analysis of the F o2 level of the gas contained in the cylinder prior to using it [Music] this information may also be incorporated into the cylinders visual inspection decal if it is not a separate visual inspection decal is required [Music] [Music] the way in which planning nitrox dives differs most from planning air dives is that when diving EAN eggs you must also manage your exposure to oxygen fortunately for nitrox divers who remain within normal recreational diving limits this can be a very simple and straightforward procedure although diving nitrox reduces your exposure to nitrogen it does not eliminate it even though you use one or more of the accepted methods for planning nitrox dives correctly you may still suffer decompression sickness one means of controlling your exposure to nitrogen when diving nitrox is to simply continue to use the same dive computer that you do when diving air the chief drawback of this approach is that you will not gain increased bottom time shorter surface intervals or longer repetitive dives which are among the chief reasons many people dive nitrox in the first place remember that even though you may use a computer or an air based dive table when diving nitrox you must still take steps to ensure your exposure to oxygen does not exceed acceptable levels nitrox programmable dive computers make diving easy they track both nitrogen and oxygen exposure the simplest way to manage your exposure to oxygen is to dive with a computer that tracks your o2 exposure analyze your gas set the fo2 value in your computer and observe any limits or warnings it displays this method also provides all of the other benefits you gain from diving with the computer which include tracking nitrogen absorption maximizing your bottom time and the ability to accurately monitor your ascent rate an alternative simple approach to managing your exposure to oxygen is for you to remain within the maximum po2 of 1.4 bar or atmospheres and make certain that your total bottom time for all dives on a 24-hour period does not exceed 180 minutes you must also make certain that you do not overdose by exceeding 150 minutes on any single dive within the day if you are targeting more safety a common way to plan nitrox dives is to use the concept of equivalent air depth in conjunction with the same computer settings or tables divers normally use on air dives [Music] many nitrox divers like to use the fact that EA NX contains less nitrogen than air to gain an additional safety margin while treating nitrox as though it were air may somewhat reduce the risk of decompression sickness it does not eliminate it divers who treat nitrox as air must still keep their exposure to elevated partial pressures of oxygen within acceptable limits remember whether you are seeking additional bottom time or reduced risk of decompression sickness appropriate ascent rates should be maintained with so many planning tools and options available it should be clear that diving nitrox is as much a decision-making process as it is a planning process for your own safety always remain within a limiting po2 of 1.4 bar or atmospheres and keep total accumulated dive time for any 24-hour period within 180 minutes diving nitrox opens the door to opportunities that are not available to recreational divers using air it can require a somewhat greater expenditure of resources then diving air does but if you pull those divers who have discovered the world of EA and X diving the general consensus would be it's worth it [Music] you

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Keywords: scuba diving, scuba diving phuket

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Length: 22min 20sec (1340 seconds)

Published: Wed Oct 31 2018