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1. Accessories Dive slate Animal guide Pencil Dive buoy Surface signalling device Reel Main torch Spare torch Strobe light Position indicator light Snap hook Anti fog spray liquid Equipment lanyard Spare gear O ring Cylinders Weights Straps Tool kit Wet suit repair kit Special equipment Underwater camera Lens and zooms Flash Films Video camera Housing Tapes Video lights Batteries Battery charger Wiring and connector Notes 55 PO Table and O exposition limits for Dives with NITROX as per NOAA rules G Reba Oceanic amp Atmospheric Administration Single Multiple EAN 36 EAN 32 CNS exposure exposure 1 dive more dives meter meter fi t or minute within 24 hours within 24 hours 2 22 150 25 27 m2 ov 20 2 ao a fa foe j o j 7 a w os s0_ _3 5 e o 028 560 s0 Conversion table from meters to foot 1 meter 3 28 foot ia TABLE CONVERSION MEASURES OF PRESSURE 1 PSI pound x square inch 0 073 kg x cm2 1 kg x cm 14 223 PSI 1 atm 1 033 kg x cm 1 atm 14 696 PSI 56 Pg Partial pressure of a gas to a certain depth Fg Fraction of the gas or partial pressure of the gas in surface in meter depth 10 10 x Fg Pg in foot depth 33 33 x Fg Pg EAD equivalent depth in air in meter FN2 x depth 10 0 79 10 EAD in foot FN2 x depth 33 0 79 33 EAD MOD Maximum op
2. 12 stantially different 2 37 BAR vs 1 92 BAR the diver who breaths Nitrox absorbs the same amount of nitrogen of a diver that breaths air at the same depth in a longer time When you breath Nitrox at a given depth it is as if you were breathing air shallower such shallower depth is called Equivalent Air Depth EAD You can find the EAD s for EAN32 ed EAN36 in the AIR column of the ESA EANx Table 1 or calcu late them with a simple mathematical operation F N2 x Profondit 10 diviso 0 79 10 This formula can be used to calculate the EAD for any Nitrox mix all you need to do is use the pro per FN2 and the desired depth For instance 0 64 times 30 divided 0 79 and redu ced by 10 14 3 metres that is the EAD equiva lent for 20 metres with EAN36 Diving at 20 metres breathing Nitrox 39 is equivalent to diving at 14 3 metres with air indeed the ppN2 at 20 metres with Nitrox 36 is the same of that at 14 3 metres with air Note all these operations and the following ones are considering that the ambient pressure in salt water increases by 1 BAR every 10 metres The modern computers behave the same more or less you need to set the correct percentage of 02 measured in the mix you are going to use and the computers calculate the no decompression limits based upon the EAD You will plan your dives many time during your course both with ESA EAN 36 EAN 32 Air Dive Tables and computer if avai
3. ching the PO2 limit set before diving We will talk about computer shortly 13 Minitest 1 The Nitrogen pp PN2 to 30 meters EAN brea thing 36 is a 1 92 bar b 2 56 bar c 2 72 bar 2 The EAD for an immer sion to 30 meters EAN 32 breathing is a 22 4 meter b 15 8 meter c 24 4 meter 3 3 Considering the limits of the course ESA Nitrox Diver the MOD for EAN 32 are while for EAN 36 correspond to a 40 meter 34 meter b 36 meter 31 meter c 31 meter 36 meter QE 9 Z q T SIaMSUY Planning Plan your dives as always done making arrange ments with a dive mate that is not less qualified than you Note Instructors must be specifically trained to dive with Nitrox too Make sure the equipment is suitable for Nitrox and analyse the cylinder The ESA Instructor will teach you how to do it concentrate and try as many times as possible don t hesitate to ask que stions if you don t feel confident Analysing the cylinder is mandatory for each dive with Nitrox and is the first thing to do when pre paring and planning your dives The preceding paragraph explained that all you need to do is concentrating on the percentage of oxygen in the cylinder you will use You will have to analyse it personally sign a specific register and declare that you are aware of what you are about to use and how to use it You will find this procedure really simple after having applied a few times and yo
4. 3 times before proceeding with the analysis Anyhow a flowmeter is preferable Should you not use the instrument for long remove the batteries and disconnect the sensor before putting it away the sensor must be stored in its specific container You must put everything in a place with no humi dity away from sunlight and extre me temperature Respect all instructions related to the sensor substitution You must know that the life of the sensor depends on its exposition to oxygen irrespective from the fact that it is connected to the analyser You will have understood that the oxygen analysis is the most impor tant part of the preparation for the dives with Nitrox therefore you must get skilled in analysing your cylinder Anyhow as already stated it is not a complex operation fur thermore remember that the new analysers provide reliable results if the instructions provided by the manufacturers are respected Natch OUT The sensor contains a liquid that can be harmful it avoids to touch it if you notice los ses of liquid both that you deal with a sensor in use or that you deal with a new sen sor in this case it is advisable to avoid to open the wrapping that contains it usually transparent If the sensor introduces signs of usury and loss of liquid it must be replaced in any case it is had to try to mend its hull with glue or other In case of accidental contact with the liquid it is necessary to wash abundantly
5. Medicines The same considerations for dives with air apply to dives with Nitrox avoid taking congestion relief medicines before diving should you be taking medicines ask the doctor to get informa tion As you know alcohol and drugs must be avoided before diving as well Carbon dioxide As demonstrated by some analysis there is a close connection between carbon dioxide concen tration in the organism and oxygen intoxication For this reason remember to respect the rules you have learned during the ESA Open Water Diver Course breathe slowly deeply and conti nuously Avoid holding your breath to save air the most probable result would be a higher air consumption and carbon dioxide accumulation The latter exposes you to fatigue decompression sickness nitrogen narcosis and oxygen intoxica tion Considering the limits for recreational dives using EAN32 and EAN36 monitoring carbon dioxide is not needed Anyhow as accumulating carbon dio xide is subjective should you usually have heada che after diving get in touch with a doctor aware of scuba diving related issues reduce the exposi tion to oxygen limiting the maximum PO2 to 1 4 BAR and avoid holding your breath while diving Decompression sickness arterial gaseous embo lism and narcosis As far as decompression sickness is concerned all that you have already learned during the ESA Open Diver Course and subsequent still applies breathing Nitrox reduces nitrogen absor
6. dive down to 40 metres cannot reach this depth nei ther with EAN36 nor with EAN32 Oxygen toxicity to the human organism mainly for lunges can be controlled respecting the expo sition time indicated in the NOAA tables i e 120 minutes for a single dive and 180 for the repetiti ve ones Finding a balance is the only way to enjoy the advantages of Nitrox to do this take in due account the type of dive and the objective to reach Probably diving on a wall with the compu ter following a multilevel path you don t need to use Nitrox as this kind of dives let you stay under water considerably long You know that should you want to explore an area between 23 and 27 metres to look for a specific organism or to enjoy the spectacular gorgonias the no decompression limit is 25 minutes with air and 40 minutes with EAN 36 equivalent air depth 21 metres you may dive at the maximum depth for about 26 37 minu tes maintaining a good safety margin and being more concentrated Considering that when you breath Nitrox the nitrogen absorption is reduced you can decide to use it even if a specific dive don t let you enjoy the advantages of extending the no decompres sion limits As already said you will have to take into account Nitrox availability but there is another factor to be considered cold Sometimes enjoying the advantages of Nitrox is difficult because of cold water limiting the dive duration Another issue could be the a
7. or the ESA EAN 36 EAN 32 Air Dive Tables specifically desi gned to plan dives with the most diffused Nitrox mixes and if needed with air Just like the ESA Dive Tables the ESA EAN 36 EAN 32 Air Dive Tables contains three table that enables you to plan single dives and provide pres sure groups after the dive EANx Table 1 find the new pressure group after a specific surface inter The ESA val EANx Table 2 and plan the repetitive dive Nino beel f EANx Table 3 table used The ESA EANx Table 1 includes three columns for for Nitrox EAN36 EAN32 and AIR respectively The three 36 and 32 columns show the actual depths related to each point out specific mix using this table you don t need to in 120 calculate the EAD to plan you dives minutes the maxi What is the EAD To answer this questions let s mum time refresh the partial pressure of gasses of single As you will remember the effect of a gas on the immersion organism is dependent upon its partial pressu re During your ESA EAN 36 EAN 32 AIR DIVE TABLES Open Water Diver cour Vetere eni peroni peke av oiia se you learned that a small quantity of car bon monoxide may be Gruppo di Appartenenza Pressure Group tolerable at the sea level but can be toxic eo under water because of 95 its increasing partial 5 pressure 40 30 30 The effects of nitrogen are due to its partial Tea aoma
8. the boat they are discus sing it with Robert the Diveleader who escorted them One only regret It s a pity the dive was so short Several minutes later while the three divers are still talking ano ther group of divers emerge They are guided by Lucy the other Diveleader that works at the diving centre After the divers are onboard Karen asks Lucy why they dived for longer and if a decompress stop was needed Lucy explains that according to the rules of the diving centre dives exceeding the no decompression limits are forbidden and that she and the other divers could stay lon ger because they used a gas mix similar to air but with less nitrogen and more oxygen Nitrox Karen and Denise happy for chance to dive longer ask Robert to use Nitrox during the second dive so that they could visit the bow of the boat that is surrounded by many fish such as corvinas and groopers Robert tells them that is not possible to dive with Nitrox because there are not enough cylinders and they need to be trained to use it The most greater time granted by the Nitrox allows a more accu rate explora tion Needless to say that after noting that they must finish their second dive before than the other divers that are using Nitrox the two friends deci de go get informed the ESA Nitrox Diver course Getting the ESA Nitrox Diver license is really easy this manual and your ESA Nitrox Diver Instructor will prov
9. the oxygen percentage may seem to request extra efforts but as stated several times a bit of experience makes it become a very simple procedure that doesn t take too long fur thermore you will feel safer and will enjoy your dive more if you analyse your own Nitrox cylinder Should you have doubts on the data provided by the oxygen analyser if the diving centre is serious and relia ble you can decide to plan your dive in order to limit the depth to the highest oxygen percentage measu red and the no decompression limit to the lowest value You will be sure to avoid both decompression sick ness and oxygen intoxication to your CNS Oxygen toxicity for the CNS is extremely serious as it can affect the divers health anyhow to prevent any related problems respect the PO2 limit of 1 5 bar and the maxi mum exposition to oxygen that is commonly agreed by many scientists doctors physiologists and resear chers As you know there are limits to be respected also when you dive with air while the disadvantage of diving with Nitrox is that such limits are more stringent they are justified by the longer dive time and that anyway maintains the exposition to oxygen within safe and acceptable levels Planning dives bearing in mind the morphology of the seabed is advisa ble this avoids exceeding the maxi mum depth and helps in taking the most from Nitrox The recreational diver that thanks to the ESA Deep Diver course can
10. the potentiality of Nitrox you should dive where the tempe rature of the water is higher than 22 C during the warm sea son when it is hot or using a dry suit The dry suit reduces the heat exchange wit water thanks to the air between the suit and the skin of the diver Remember that to use a dry suit safely you should be trained Ask your instructor about the ESA Dry Diver Course Using a dry suit is not difficult but it takes the right training and experience on the other end it gives you the possibility to extend the dive time in cold water The newest diving equipment is both more and more reliable and comfortable it gives divers the possibility to enjoy diving thoroughly The next paragraph deals with equipment and how they relate to oxygen enriched mixes The outcome of the analysis per next paragraph is that using Nitrox is always the best choice it extends the no decompression limits the chance to suffer of decompression sickness is reduced thanks to the fact that you breath less nitrogen you can be more concentrated and last but not least you will be less tired also after some repetitive dives Equipment The oxygen oxidizing features as well as the com bustion supporting power depends on its concen tration Warnings and procedures related to equipment to dive with Nitrox are based on such features In addition to taking into account all the precau tions with equipment and related maintenance you lea
11. 7 minutes b 70 minutes c 53 minutes 4 The cylinders for Nitrox must be properly mar ked a to avoid wasting time b to prevent accidents c so that the end users don t need to analyse it Nitrox is produced removing nitrogen from the air adding oxygen to the air both a and b Oooo ui 6 Combustions caused by a high concentration of oxygen depend on Minitest 1 Nitrox breathing a removes the possibility to have the MDD b the MDD can equally be revealed c you cannot verify an over lung pressure 2 The treatment for MDD and EGA also foresees a the administration of pure oxygen b a physician s interven tion c aand b are exact 3 A datum volume of Nitrox in a flexible contai ner during ascending it to it is unchanged b it increases c it decreases qJ E Z QT siamsuy 43 Minitest 1 You can learn the techni ques for managing an emer gency during the course a ESA Prevention amp Rescue Diver b ESA Advanced Diver c ESA Ecodiver 2 The term PDD means a Pathologies from Decom pressure b Personal Diving Device c Pathologies from Descent 3 In case of emergency it is important a to get as soon as possi ble help physician b to establish the causes of the accident c to guess exactly the name of the pathology D fb Z D T slamsuy 44 a type of oxygen b hydrocarbons and lubricants not compatible with oxygen
12. NITROX DIVER MANUAL PESA ESA WorldWide No part of this book may be reproduced in any form Product n M0011 Editor Mauro Bertolini Formative project development consulting and revision Mauro Bertolini Mario Romor Miho Tsuruoka Egidio Trainito Maria Laura Careddu Text and photos Mario Romor Illustrations Stefano Trainito Jacopo Pasqualotto Index Chapter One New chances What will You learn Nitrox Definitions Calculations Planning Diving Analysing O Congratulation What have You learn RI Two What will you learn Miscellaneous Equipment Recharging Oxigen CNS oxygen clock Managing emergencies Congratulation What have You learn Chapter Three 47 51 Open Water dives 1 and 2 9 rules for diving with Nitrox ee ESA 9 Suggestions to preserve the aquatic environment Not to be left at home NOAA dive table of O exposition and conversion tables Formulas ESA EAN 36 EAN 32 AIR DIVE TABLES O analisys Chapter One New chances It s a beautiful day the sky is clear the sea is calm and the temperature is warm outside and in the water as well These are the perfect conditions to dive on the KT one of the most inte resting and well kept wrecks of the Mediterranean Sea Karen and Denise two ESA Wreck Diver licensed divers are enthu siast the good weather conditions and the favourable sea state let them have a great dive and now back on
13. ake you more familiar with the underwater environment Should and exercise not be clear or you want to do it again don t hesitate asking the Staff Ascent and safety stop Ascend slowly not faster than 10 metres per minute using a fixed point of reference and stop at 5 metres for 3 minutes Ascending slowly and complete the safety stop is important for all kind of dives included those with Nitrox This enables you to improve safety and diving techniques The Instructor will provide the needed information 49 Getting out of the water Do it using the technique suggested by the Instructor Disassembling the equipment and taking care of it It is important and needed to keep your equip ment including the instruments needed for orienteering efficient Whenever possible rinse it with fresh water even before disassembling it then put it into your sack to wash it when sugge sted by the Staff Debriefing Listen to the comments the Instructor will have This is another way of improving Don t do any thing else but listen to the Instructor during the briefing He will have useful comments on you performance suggestions and recommendations Take the opportunity to improve further and don t hesitate to ask questions Registering your dive Fill in your logbook and ask your Instructor to sign it This is needed to confirm your open water trai ning Register all parameters such as the CNS oxygen clock the
14. alification of ESA Point The deno minated structures ESA IC Point can promote to organize and to conduct the courses of formation for the Preliminary ESAs The esa intends to also characterize him through a particular facing appointment the populariza tion of the knowledges on the environment to improve the quality of the immersions and to create in the subacqueis a greater awareness toward the submerged space The professionals ESAs in fact effect their formative run also receiving a solid preparation on the knowledges related to the environment the whole formative activity of the ESA is firmly connected to objecti ve of safeguard of the aquatic environments 53 54 9 Suggestions to preserve the aquatic environment If you follow these simple rules you will give a great con tribution to the preservation of the aquatic environ ment 1 Control your buoyancy at all times If you are neu trally buoyant you will avoid damages to the sea floor and its inhabitants If you don t wear gloves you will be less inclined to touch and feel about the sea floor cau sing possible damages 2 When you approach the bottom don t flap your hands and fins around If you have to rest on the bot tom make sure your knees and fins don t cause any damage 3 Avoid tunnels and caverns by touching their ceiling you could damage the life living on them besides you bubbles could not escape and turn the top of a cave into a submerge
15. and that respect all the instruction provided by the equipment manufac turer to have problems are very low Anyhow considering that people are not all the same neither learning methods nor tables can guarantee that problems are warded off Furthermore you could see an accident happe ning by chance and being helpful is important Therefore continuing your training you may have already done it attending the ESA First Aid is important this course can be attended by any body This course trains you to help people who don t feel well or victims of accidents The ESA Prevention amp Rescue Diver is a more complete course and is specific to scuba diving the prere quisites for this course are having the ESA Advanced Diver or similar licence have at least 20 dives registered in your log book Learning techniques to held divers specially providing oxy gen in case of decompression diseases and to those people who have risked to drown is of paramount importance Breathes slowly deeply and 3 continually A avoids with P i care to effect R of K he tra 41 Minitest 1 The due greatest danger to the elevated concentra tion of the oxygen breathed during dive is a the nitrogen narcosis b the poisoning from oxy gen to pulmonary level c the poisoning from oxy gen to the CNS 2 To prevent hiperoxya a respect the limits of oxy gen s exposure b to respect the limi
16. arly displayed on the instruments you use during the dive you will not find it on the table therefore you will have to consider the next higher availa ble value For the EAN32 column this value is 22 metres equivalent to 18 metres EAD in the AIR column The no decompression limits 50 is the same at 24 metres with EAN36 at 22 metres with EAN32 and at 18 metres with air Based upon the duration of the dive the same applies to the pressure group The procedure for repetitive dives with air applies also to repetitive dives with Nitrox Once you decide the maximum depth of the new dive look for it in the EANx Table 3 in the column related to the Nitrox mix you intend to use Intercept the line related to depth with the column related to the pressure group and complete planning your dive as you already know For instance assume you have dived at 20 metres for 39 minutes using EAN32 during the first dive your pressure group is G After 1 30 hour surface interval the pres sure group is E see the EANx Table 2 and you decide to dive at 15 metres using EAN32 Identify the line of the EANx Table 3 related to the chosen depth and intersect if with the column related to the pressure group E you will find the Residual Nitrogen Time of 49 yellow cell and the No Decompression Limit of 81 green cell You should not dive more than three times using Nitrox during the same day indeed should you
17. c flames 7 Oxygen intoxication to the whole body a is rare if the recreational divers respect the exposure limits b is mainly due to breathing oxygen high concen tration for long c both a and b 8 According to the NOAA tables PO2 1 5 maxi mum the exposure to oxygen limits over 24 hours rolling are a 120 for a single dive o 180 for repetitive dives b 180 for a single dive o 120 for repetitive dives c 100 for a single dive o 120 for repetitive dives If you use a computer for Nitrox dives read the instruction carefully don t exceed 90 CNS exposure to O2 over 24 hours rolling c both a and b ow o 10 Oxygen intoxication to CNS can be caused by a the position of the diver during the dive b a regulator that provides Nitrox too easily c an excessive CO2 accumulation 11 In case of decompression sickness after a Nitrox dive look for medical help check brea thing and heart beat and a provide pure oxygen b don t provide pure oxygen c both a and b 12 Among the symptoms of oxygen intoxication to CNS you can find a visual and auditory alterations tremors of lips b pain itchiness tiredness c high temperature paleness swelling 13 Hyperoxia susceptibility a changes from person to person b for the same person depends on the specific moment c both a and b 14 Convulsions are dangerous while diving as the victim a can hurt because of blunt inst
18. ceptibility to oxygen intoxication changes from diver to diver and from time to time One important point is that the symptoms may reduce while diver is ascending but they can start without any premonitory and proper signs therefore the diver is taken by surprise and should he be victim of convulsions he risks to drown Many serious accidents happened diving really deep with air were ori ginated by oxygen intoxication to the CNS this is another good reason to respect the limits CNS Oxygen Clock This is a procedure used to monitor the CNS exposure to oxygen it was established by the NOAA The CNS exposure to oxygen can determined thanks to the limits established in the NOAA table oxygen exposure limits per dive either using the maximum PO2 or analytically using other tables that provides a percentage of exposure as a function of the time spent for each PO2 during the dive CNS Safety is improved thanks to the indication provi 37 Minitest 1 The recharge for partial pressures is particularly delicate because a the operator interacts with pure oxygen at high pressure b the pure oxygen passes through the compressor and the tank valve c a and b are exact 2 The components of the recharge station that uses pure oxygen necessarily have to be a new b oil free c painted to yellow and green strips 3 To produce the Nitrox a it can be used any type of oxygen b it is had
19. choose to dive three times it is advisable to dive using air within 18 metres the third time You can plan to have repetitive dives using diffe rent Nitrox mixes and air Be careful when using the dive planner specifically when looking for the 1 Before use remembers to always analyze the air mixture 15 Profondit Immersioni Consecutive The EANx Table 3 point out the nitro gen residue and the new limit of not decompres sion for the consecutive immersions Ripetitive Dive Depth 16 aly N w la alp w depth and the column related to Nitrox or pressu re group should you make any mistakes you may be subject to Decompression Disease or hypero xia For the same reason remember to set the correct oxygen percentage before diving with the computer Let s consider the following example Andrew and Michael are going to dive at 27 metres using EAN32 what is the maximum operative depth for this Nitrox mix considering a limit PO2 of 1 5 BAR 36 metres therefore they made the right choice To plan the dive they look for the depth in the EAN32 column of the EANx Table 1 as 27 metres is not included in the table they must consider 29 metres They read the Equivalent Air Depth in the AIR column 24 metres then the no decompression limit 30 choose the duration of the dive and identify the related pressure group The two friend decide to dive at 27 metres for 25 minut
20. course in order to extend your depth limit to 30 metres always within the no decompression limits The ESA Nitrox Diver program can be carried out during other courses such as ESA Open Water Diver and ESA Advanced Diver ask your instruc tor what you need to do to get the two licenses during two integrated training programs What will you learn Knowing the composition of Nitrox its effects how planning dives correctly and getting ready for them makes the divers fully use the potentia lities of hyper oxygenated gas mixes or with reduced amount of nitrogen without exposing themselves to risks What is Nitrox What are the associated risks What do need to do to plan dives with Nitrox How can prepare my dive at the best How should behave while diving How will analyze the gas mix and check the oxygen percentage You will find the answers to the above and other questions in this chapter The information you will get will be useful already during the first dive should you have any doubts or additional questions don t hesitate to ask your ESA Nitrox Diver Instructor Nitrox The word Nitrox is com posed by two words nitrogen and oxygen the two main gasses that constitute the air you breath everyday The air can be conside red to be a Nitrox mix with 21 of oxygen that is the normal percentage of oxygen contained in the air Such a mix with 21 of oxygen and 79 of nitrogen is called air while t
21. d desert 4 Don t hold on to sea turtles large fishes and sea mammals just swim with them but don t chase the ani mals they might not enjoy it as much as you 5 Try not to touch animals you don t know You might get hurt or remove their protective mucus making them more vulnerable 6 Do not remove anything from the bottom shells nei ther dead nor alive algae covered objects or archaeo logical finds 7 Do not buy souvenirs made with shells or other mate rials coming from the sea It a way to discourage their collection or fishing 8 Do not litter the sea Use the rubbish bins 9 Carry on your training and extend your knowledge of the marine environment you will discover that every location deserves a dive and that every environment has amazing discoveries to unveil All the inhabitants and the visitors of the underwater spaces thank you in advance for your effort Not to be left at home Miscellaneous ID s Dive Licence Log book Reservations tickets Emergency contacts Swim suit Sun screen Sun glasses Hat Wind breaker Towel Bath robe Sandals Goggles and bathing cap Spare clothing Food and drinks Medicines Equipment Bag Fins mask and snorkel Wet suit Thermals Hood Gloves Booties Weights BCD Full cylinder Main regulator Spare regulator Pressure gauge BCD pipe Dry suit pipe Knife Instruments Dive computer Depth gauge Timer Compass Thermometer Dive tables
22. depth for the analysed Nitrox The same rule applicable to computers apply to analysers you must read the instruction in the user manual and respect them Your ESA Nitrox Diver Instructor will teach you maybe he has already done it to use one or more analyser models Pay attention to his lessons and don t hesitate to ask questions try the procedure until you feel you have learned perfectly Should you buy or use an analyser different from what you have used during your training ask information to the dealer or the operator that is supplying it Anyway some procedures are always the same no matter the analyser model make sure you deal with professional and relia ble diving centres read the user manual check that it is fit and that the batteries are charged or perfectly connected to the electric line verify that the sensor is properly working and not expired read the terms related to its substi tution provided by the manufactured connect the cable to the computer and to the sensor correctly its operability can be compromise by extreme temperatures altitude and pressure variations humidity and condensate see the instructions I avoid holding the sensor and your hand palm Example of 02 turn on the analyser and check the analyser display and wait that the numbers it shows stabilise to fixed values set the instruments using air 21 02 and possible with pure oxygen 99 02
23. done by the Nitrox Instructor c must be done by the end user 13 In case of signs of oxygen intoxication a ascend a bit and continue the dive b emerge and get out of the water c emerge get out our of the water and don t dive for 24 hours 14 For a more accurate oxygen analysis a you should use a flow regulator b you should keep the sensor on you hand palm c you should set the instrument in order to read 79 on the display 15 To avoid damages during the oxygen analysis the sensor must be substituted a every 4 years b in accordance with the indications of the manufacturer c every 6 years I declare that have reviewed all the wrong answers with the ESA Instructor and that have understood the related explanation Signature date 25 26 Chapter Two What will you learn The preceding chapter provided the information you need to plan your dives with Nitrox maybe you have already used such information for your first dive with such a mix As anticipated there other important information that can help you in making you more aware about diving with Nitrox this will help you improving your safety and conti nuing your diving career This chapter will answer questions such as is more convenient using air or Nitrox Which are the advantages of Nitrox Which are the related complications and disadvantages Do need to change my equipment to use Nitrox How are Nitrox cylinders identified How are t
24. e to help you putting it on when you and your mate are both ready check each other equipment As you usually do you can assemble BCD and regulators on the cylinder and then verify that it is charged The best way to put the equipment on may depend on the specific dive should you be on a boat you may decide to do it in the water the instructor will provide the needed information As you know checking the equipment before diving is the best way to avoid equipment related problems so do it carefully Should you discover any problem inform the Instructor or the Staff or your mate Check that the oxygen percentage is properly set in the computer N B should the weather conditions and your experience be enough at the discretion of the Instructor you could check the equipment after you have jumped into the water Getting into the water The Instructor and the Staff will provide you the information for the best way of getting into the water based upon the boat and the dive site Be sure you are positively trimmed and wait toge ther with your mate indications from the Staff on when starting to dive and on the exercises to be carried out at the sea level Checking the correct quantity of ballast This is an important check and must be done before starting to dive Checking the correct quantity of ballast is important to be trimmed as needed being perfectly trimmed is important while diving in to be more relaxed and to avid probl
25. ems to the environment Furthermore you will be able to respect the established depth limit Get used to making this check to prevent problems due to an incorrect quantity of ballast Descent Use a rope or the seabed as a reference point and don t exceed the depth planned by the Instructor This phase is really important remember the MOD Specifically remember to descend together with your mate slowly and checking either the computer or the depth gauge All information about the best way to descend will be provided by the Instructor during the briefing Diving respecting both plan and safety parame ters Check depth time and manometer frequently and exchange the information with the mate Dive one meter shallower than planned You must take extreme care of depth when diving with oxygen enriched mixes in order to avoid oxy gen toxicity related problems As you can dive longer remember to check the time and the manometer You should exchange information about the pressure in the cylinder with your mate every 20 30 bars Exercised for other ESA courses Should you attend the ESA Nitrox Diver course in conjunction with other ESA courses practice the exercises for such other courses as explained by the Instructor during the briefing This doesn t apply in case the ESA Nitrox Diver course is atten ded as a stand alone course Repetitions and experience Repeat the exercises under the supervision of the Staff This will m
26. engine So checking your instruments while diving and making sure your dive mate does it as well you avoid exceeding the depth limits in order to pre vent nitrogen narcosis or oxygen intoxication and make sure you don t exceed the no decompres sion limits reducing the chances to get decom pression sickness you avoid running out of air or Nitrox in order to prevent sudden and uncontrol led ascends Being perfectly trimmed helps in exceeding the limits so that you can be more relaxed while diving and concentrate on what you are doing Considering how dangerous the effects of oxygen can be should you feel and symptoms imputable to this gas ascend and get out of water without wasting time and don t dive for 24 for hours as a minimum Minitest 1 In the immersions with Nitrox the analysis of the oxygen from who uses it is a considere procedure a obligatory b useless c optional 2 To plan an Nitrox dive with the ESA table is neces sary to know a the EAD b the MOD c a and b are exact 3 Using the underwater computer when we chan ges type of mixture it is important a to vary the percentage of O2 on the tool b to wait for 24 hours bet ween an immersion and the other c a and bare exact D E IZ D SJaMSUY 19 b b Minitest 1 In the Nitrox dives a it needs to foresee to ascend with at least 100 bar in the cylinder b it behaves us as in the other immersions monito ri
27. environmental conditions and the exercises plus your personal comments Remember to ask the Instructor to sign 9 rules for diving with Nitrox 1 Use proper and efficient equipment make sure it is regularly maintained 2 Analyse the oxygen personally 3 Make sure the oxygen analyser works properly respect the instruction provided by the manufac turer and make several trials with air pure oxy gen if available and then the Nitrox mix 4 Respect the Maximum Operative Depth don t exceed 31 metres with EAN 36 and 36 metres with EAN 32 5 Set correctly the oxygen percentage in the com puter or choose the right column in the table ESA EAN 36 EAN 32 AIR DIVE TABLES the wrong oxygen percentage can cause decompression sick ness or iperoxia 6 Make sure the computer is properly set before each dive get used to check both and your mate instrument before diving 7 Respect the limit of 120 minutes for a single dive and 180 minutes for repetitive dives over 24 hours rolling Don t dive more than 3 times a day with Nitrox this simple rule helps you in preven ting helps you in preventing oxygen intoxications Should you get close to the limits don t dive for 12 hours at least 8 Breath continuously without holding your breath and prevent breathlessness carbon dioxi de accumulation can cause hypoxia So avoid hol ding your breath while diving try not to get weary and use a good performance regulat
28. erational depth with limit PO2 to 1 5 in meter 1 5 x 10 FO2 10 MOD in foot 1 5 x 33 FO2 33 MOD Here are the Formulas They are more Simple g than it seems Test o apply its EAN 36 EAN 32 AIR DIVE TABLES EANx No Decompression and O Exposure Limits Repetitive Group Designation Tables for No Decompression Dives TABLE 1 the waterworld crew Profondit Profondit Profondit Gruppo di Appartenenza Pressure Group Depth Depth Depth EAN 36 EAN 32 AIR m m m A B Cc D E l F m G Single dive maximum time with EAN x 120 minutes Tempo massimo per immersione singola con EAN x 120 minuti 58 Ripetitive Group at the Beginning of the Surface Interval TABLE 2 Gruppo di Appartenenza all inizio dell inter vallo di superficie DC RE E NE E E EI EANx Esse Zi ea ea TABLE 3 Warning These tables must be used by certified divers or under the direct control of a _ __ ii certified scuba instructor Residual Nitrogen Time Minutes Adjusted No Decompression Time Limit ere totale massimo per immersioni consecutive nelle 24 h 180 minuti Maximum total time for ripetitive dives within 24 hours 180 minutes Profondita Immersioni Consecutive Ripetitive Dive Depth Product N A0039 59 O analysis Switch on the tool and waits for some minutes that the sensor environments
29. es the pressure group at then of the five is F They plan a repetitive dive on a rocky seabed close to Butterfly Head they have to sail for about 2 hours and 30 minutes a good surface time that makes the F pressure group turn to C The maximum depth for the second dive is 20 metres and they will use EAN36 After having checked with the analyser that the oxygen per centage stated on the card attached on the cylin der is correct they use the EANx Table 3 They look for the chosen depth in the EAN35 column and intersect the related line with the column specific to the C pressure group The Residual Nitrogen Time is 21 yellow cell and the new No Decompression Limit is 49 green column The place is really nice but they dive for 45 minu tes only Adding the actual duration of the dive with the Residual Nitrogen Time they can use the pressure group at the end of the second dive 45 21 66 minutes corresponding to the pressu re group As you see things change if you compare dives with air to dives with Nitrox You must take care of the oxygen percentage identify the related maximum operative depth and make sure you never dive deeper You must make sure you will never exceed the allowed exposition to oxygen although this is almost automatically respected if you respect all parameters related to recreational dives Avoid diving more than three times or to dive for more than 120 minutes for a single dive or 180 m
30. es the needs of storing pure oxygen The disadvantage is that producing different types of Nitrox is difficult this system is more productive when preparing one specific type of Nitrox These are the main procedures used to produce Nitrox Remember that to apply them you must become a trained and qualified blender The ESA Nitrox Diver course doesn t enable you to do it this is done by specific qualifying agencies Furthermore the recreational divers finds the perfect equilibrium between safety and recrea tion respecting the rules and procuring Nitrox from professional diving centres able to produce the most diffused and standard mixes EAN 32 and EAN 36 One very important feature of the oxygen used for Nitrox is that it is medical oxygen it purer and is specifically produced to be breathed Oxygen for welding is forbidden Usually the diving centres that recharge Nitrox ask the divers to show the Nitrox Diver licence to analyse the mix and to sign a register it seems there are too many procedures to respect but they are all aimed at your safety and demonstra te the people you are dealing with are professio nals Therefore try to be collaborative and don t trust those who underestimate these procedures To avoid chances of contamination the Nitrox recharge stations as well as those for air should be equipped with special filters and be regularly maintained with extreme care and seriousness These are some of the feature
31. ess or because of high oxy gen concentration Flames and sparks as well as traces of hydrocar bons in the cylinder and lubricants used can cause explosions because of the high oxygen con centration Air recharge stations can push small quantity of hydrocarbons inside the cylinders Furthermore the valves for air cylinders don t use materials suitable for oxygen specifically seals and lubri cants Usually reliable and professional recharge sta tions respect all the safety procedure Therefore you don t need to worry too much concentrate on choosing the services offered by qualified and professional personnel instead One point must be duly taken into account and respected by Nitrox divers the cylinders for compresses gasses must be used for the type of gas they were pre pared for tested and certified Recharging a cylin der with a different gas is dangerous as it can cause explosions therefore don t charge a Nitrox cylinder with any other gas and vice versa Recharging Although an enormous number of people drive their car everyday very few of them know the procedures used by a refinery to produce the fuel they use In the same way Nitrox divers don t need to know the procedures used to obtain Nitrox perfectly Therefore we will not provide too many details but some basic information is useful to better understand Nitrox Furthermore should you choose to become a professional diver these notions will constit
32. gs Not everybody knows it can become dan gerous You have already learned during the ESA Open Water Diver course that too low hypoxia and too high hyperoxia oxygen partial pressures can cause serious conditions that can put life in danger The oxygen partial pressure can become too low during a long free dive or while ascending from a free dive after a too long hyperventilation making the diver faint These are all problems treated during the pre vious courses hypoxia can also be caused by a too low quantity of oxygen in the gas mix and can be prevented analysing it before diving Considering the high oxygen partial pressure in Nitrox mixes we take a closer look at the problems caused by hyperoxia specifically oxygen intoxication to whole body and lungs and intoxication to the central nervous system CNS Intoxication to whole body and lungs Recreational divers can hardly suffer of this problem Indeed it is a pro blem that may affect those divers subject to long exposure to oxygen partial pressure greater than 0 5 BAR Usually depth and no decom pression limits as well as those rela ted to air consumption and cold heat exchange with water avoid the recreational divers from being exposed to oxygen long enough to feel the symptoms Such kind of pro blems instead can be suffered by those divers who work under water considerably long even in shallow water These problems must be taken into account by technical d
33. he EANx mixes prepared Who can recharge Nitrox cylin ders Who must analyse the oxygen percentage What are the effects of carbon dioxide Does Nitrox eliminate Decompression Sickness and Narcosis What should do if see an accident How can bring help All the subjects answering the above questions will be treated in accordance with the recreatio nal dives philosophy simplifying the most difficult concepts without forgetting the information that improve your safety and the advantages of dives with Nitrox Miscellaneous If you add oxygen to air the percentages of oxy gen and nitrogen change the first increases and the second decreases The same happens if you remove nitrogen from air Let s have a look at advantages and disadvantages of Nitrox As you already know the main advantage is the exten sion of the no decompression limits this feature is more appreciated when diving between 15 and 30 metres Thanks to Nitrox you will be able to explore a site for longer without exceeding the no decompression limits You may think that diving with hyper oxygenated mixes respecting the no decompression limits for air causes safety improvements This is partially true if you consider that comparing to dives at the same depth for the same time one with Nitrox and one with air the nitrogen absorption is reduced with diving with Nitrox Anyhow under a mere statistic point of view the degree of occurrence of decompression sick
34. he word Nitrox is specially used to indi cate an oxygen enri ched air mix By Nitrox we intend all those breathable mixes with more oxygen and less nitrogen You can easily understand that in order to main tain the overall equilibrium and pressure of a given amount of air you need to increase the quantity of oxygen when reducing the amount of nitrogen The Nitrox certifica tion that you will receive is essential to participate to immer sions with the Nitrox Minitest 1 True or False The gas mixture prepara tion must be performed by recreative divers 2 The word Nitrox is composed from the names of a Nitrogen and oxygen b Oxygen and dioxide of carbon c Nitrogen and helium 3 The denominated mixture NOAA Nitrox 1 are essentially compo sed from a 21 oxygen and 79 nitrogen b 32 oxygen and 68 nitrogen c 36 oxygen and 64 nitrogen q D Z aS D4 T J40MSUY How does it happen You will find the answer in the next chapter which deals with preparation of Nitrox Please note that Nitrox can be prepared by qualified people only Any mix containing a percentage of oxygen higher than 21 can be called Nitrox or Enriched Air the oxygen percentage in mixes used for recreational dives ranges between 21 and 40 For safety and practical reasons the ESA Nitrox Diver course deals mainly with the two most tested diffused and convenient ones NOAA Nitrox e NOAA Nitro
35. helium and oxygen helium nitrogen and oxygen loom re The two most diffused Nitrox mixes are EAN 37 e EAN 25 NOAA Nitrox IV and NOAA Nitrox V NOAA Nitrox and NOAA Nitrox II OTCON The reduced quantity of nitrogen extend the no decompression limits reduces the effects of nitrogen narcosis both a and b are correct OTCLVWwW a The nitrogen partial pressure in the Nitrox 36 mix at the sea level is a 1 bar b 0 36 bar c 0 64 bar 5 The EAD for a dive at 19 m with EAN 32 is a 14 97 m b 24 97 m c 13 49 m 6 The no decompression limit for a dive at 27 metres with EAN 36 in the ESA Tables is a 25 minutes b 40 minutes c 30 minutes 7 The no decompression limit for a dive at 27 metres with air in the ESA Tables is a 25 minutes b 40 minutes c 30 minutes 8 The maximum PO2 limit to take into account when planning dives with Nitrox is a 1 8 bar b 1 5 bar c 0 5 bar 9 The divers that use a computer before diving with Nitrox must a read the instructions provided by the manufacturer b set the O2 percentage correctly c both a and b are correct 10 MOD means a minimum operative depth b maximum operative depth c the ascend procedure after dives with Nitrox 11 The depth limit using EAN 30 is a 30 metres b 40 metres c 38 metres 12 The analysis of oxygen a can be done only by the operators what recharge the cylinders b can be
36. ide all the information needed to diver longer without exceeding the no decom pression limits using properly the two most com mon Nitrox mixes NOAA Nitrox 1 and NOAA Nitrox 2 i e Nitrox with 32 and 36 of oxygen respectively You will learn to analyse the gas mix what you will use to plan your dives and to monitor expo sure to oxygen During your course the ESA Nitrox Diver Instructor will show how to perform all needed actions and will give suggestions on the best usage of the hyper oxygenated gas mixes in order to take advantages from their potentiality avoiding any potential problems Read and answer the questions you find in the miniquiz and the What have you learned questionnaires start this new adventure and add your new important license to your collection The ESA Nitrox Diver license enables you to recharge and hire Nitrox cylinders dive with Nitrox and satisfy the need to have it as a prere quisite for other courses This manual deals with the new limits establis hed for recreational dives with Nitrox anyhow your new license does not authorize you to go beyond the limits of your main license For instance the limits for an ESA Open Water Diver or similar license released from other organisa tions is 18 metres without exceeding the no decompression limits If you have not done it already in order to better use the potentiality if Nitrox you may think to attend the ESA Advanced Diver
37. ifically they will take care of seals rubber components and lubricants Should you have to buy a new piece of equip ment consider the possibility to buy components designed to withstand Nitrox for instance as buying a good regulator improves safety you A Nitrox dedicatd regulator 31 It s funda mental to make the cylindersNit rox reco gnizable 32 should buy one that is designed to be used at oxy gen high concentrations This will make your dives safer and you will enjoy the more All the other recommendations you received during your ESA Open Water Diver course and subsequent ones apply to dives with Nitrox as well of course your equipment must include BCD manometer emergency regulator and instruments needed to measure depth and time Cylinders As you know the cylinders must comply with rules and regulations of a specific the country You will remember that you can find the data stamped close to the neck of the cylinder this data is related to the gas that can be contained in the cylinder its capacity the nominal pressure and the hydrostatic one as well as the date the next hydrostatic test will have to be performed Cylinders for Nitrox have the same data the difference is that instead of specifying air as the usable gas the stamped data shows EAN Sometimes you could find air cylinders charged with Nitrox In this case the oxygen percentage will be less than 40 and a
38. inutes for repetitive dives over 24 hours Some computers calculate the exposition to oxy gen based on the percentage of the maximum tolerable quantity make sure you don t exceed 90 over 24 hours indeed make sure you main tain well under this limit You will see that diving cautiously you will enjoy your dives more With the computer Should you wish to dive with a computer make sure it can calculate dives with Nitrox Check carefully the oxygen percentage set for instance the display must show that the it is set to 36 in case you dive with EAN36 Remember there are several models of computers able to plan dives with gas mixes other than air read the user manual carefully to be sure you use your compu ter correctly and safely Dive applying the techniques you learned during your ESA OWD course and as stated in the ESA Advanced Diver manual and ESA Computer Diver manual Remember that you must respect the maximum depth related to the PO2 and that you always must verify the percentage of oxygen set spe cially when changing mixes from one dive to the other Try to imagine the consequences of diving with first time with EAN36 setting the oxygen percentage at 36 and the second time with air without changing the computer set tings You would believe that you have not exceeded the no decom pression limits while you have already exceeded them you would ascend unsafely and be subject to the decompression disease As y
39. ir or Nitrox consumption These issues can be solved using bigger cylinders and diving either in warm seas or with a dry suit Calculating your air Nitrox con sumption Consider that a person breath about 20 litres of air per minute in regular conditions at sea level as you lear ned during the ESA OWD course the consumption must be related to the specific depth you are diving Thus at 30 metres 4 ATA the consump tion is 80 litres per minute 20 litres x 4 ATA As you know a 15 litre cylinder char ged at 200 bas contains 3000 litres of gas air or Nitrox 15 litres x 200 bars The cylinder duration ad 30 metres can be estimated diving 3000 by 80 3000 litres 80 litres per minu te 37 5 minutes The gas consumption changes from diver to diver and depends about specific conditions breathlessness and cold as well as fatigue can drastically increase the gas consump The safety stop for 3 minutes to 5m must also be effec ted in the Nitrox dives 29 Control system of oxigen filling 30 tion Therefore this calculation can only help you in understanding if the capacity of a specific cylinder can support the no decompression limits extended by diving with Nitrox Although this cal culation is based on conservative assumptions you must check your manometer frequently and remember to emerge when the cylinder pressure is 50 bars Heat dispersion To prevent excessive heat dispersions and enjoy
40. itself and correctly measure the percentage of ox Note all the connections must be completely taghtin up included the attacks to the sensor and to the tool Example of system for Op analysis Body of the sensor Plastic T join Terminal of the sensor Co UO ee ee ee ce ce ce Sene fe ee ce ee ce ee ee ee Flow regulator for DIN valve 1 Connection of tbe regu lator of flow to the DIN valve Zi Graft of the link to T on the regula tor of flow 3 Is impor tant to screw well the ferrule of connec tion of the sensor to the cable of the tool 4 Insertion of the sensor in the spe cial lodging in the link TOT 5 The proce dure must be made first ona cylinder with air setting I orchestrate him it on 21 6 The proce dure repeats bim on the cylin der with th Nitrox The reading does effec ted when the datum stabilizes him 61
41. ivers as well the usage of high oxy gen concentration mixes during decompression stops reduces signifi cantly the duration but increases the exposition to oxygen which must be carefully monitored Medical oxygen used for therapeutic purposes can cause intoxication as well There are two measures for exposure to oxygen the Oxygen Toxicity Unit OTU and the Unit Pulmonary Toxicity Dose UPTD Specific tables let you calculate these measures for given PO2 and dive duration they are then used to calcula te the exposure percentage which must not go beyond the limits established in special tables to avoid risks According to the outcomes of the workshop on Nitrox cited at Chapter 1 the divers that respect the limits recreational dives don t need to measu re the exposure for the whole body They need to take into consideration the central nervous systems CNS exposure to oxygen instead Oxygen intoxication to the central nervous systems CNS Oxygen intoxication to the CNS is caused by high oxygen partial pressure and or a long exposure Particular Long exposures can be dangerous starting from a filters can PO2 of 1 3 BAR Therefore respecting the limits improve established by the NOAA is really important PO2 notably 1 5 BAR duration of a single dive 120 minutes the purity of overall duration of repetitive dives 180 minutes the air every rolling 24 hours 3 maximum dives with during the Nitrox in one day recharge Sus
42. lable You will have understood why Nitrox provides extended no decompression limits anyhow as usually happens you have advantages and disad vantages In our case the latter is due to the increased quantity of oxygen and is constituted by a limitation in the maximum depth As you have already learned during your ESA Open Water Diver course the oxygen is needed for living but when its partial pressure exceeds a given amount it becomes toxic the maximum partial pressure of 02 PO2 that can be tolerated is set to 1 6 BAR This is a very critical limit and to guarantee safety you should not exceed 1 4 BAR PO2 when diving This gives you a safety margin in case you should inadvertently dive deeper or longer than you should Air that contains 21 of oxygen cannot cause troubles due to oxygen toxicity hyperoxia diving not deeper than 56 metres if such limit is respec ted As the limit for recreational dives is set to 40 metres all breathing air divers that respect it are far away from suffering any oxygen intoxication Be careful The maximum depth is not constant when breathing Nitrox it changes with the quan tity of oxygen therefore you must carefully analy se the mix contained in your cylinders Maximum Operative Depth MOD A workshop arranged to evaluate the conditions the Decompression physiologists researchers equip ment manufacturers and technicians attended it lt was appraised that diving
43. n understan ding principles and plan dives with Nitrox maxi mising amusement and making sure safety is fully guaranteed Planning dives is one of the most important acti vities when you use Nitrox Planning has a funda mental role for safety and to better use the potentiality offered by Nitrox You have already learned to plan dives with air during your diving courses Planning dives with Nitrox is based on the same steps and care but in addition to this you need to take in due account the different gas percentages While a smaller quantity of nitrogen extend the no decompression limits the higher quantity of oxy gen reduces the maximum depth you can reach and increases the exposition to oxygen rate Furthermore in relation to the breathed gas you will have to take into consideration the equip ment you use more information will follow in the next chapter Extended no decompression limits imply a longer dive for which you must consider Nitrox con sumption breathing and temperature of the water you may be cold How can you calculate the extended no decom pression limits when using Nitrox You will use dive planners similar to those used for air that takes into account the reduced quantity of nitro gen you can also use special computers specifi cally designed to dive with Nitrox You can use the ESA Dive Tables for air and find the no decompression limits using the Equivalent Air Depth EAD defined shortly
44. ness is really small also for dives with air therefore Nitrox cannot be conside red 100 safer than air Nitrox reduces the affects of nitrogen narcosis nevertheless high pressu re oxygen can cause simi lar effects Therefore admitting that Nitrox eli minates completely the effects of narcosis is not correct Many divers state that after dives with Nitrox they are less weary than they are after dives with air and that under water they are much more con centrated indeed it is often used on cruises boats and by guides who dive many times everyday Planning dives with Nitrox is not so different from doing it with air You have to take into considera tions some specific fac tors availability of Nitrox need to check the oxygen percentage limits depth and time related to oxy gen toxicity to the central nervous system CNS and for the whole organism mainly to lunges Although Nitrox is still hardly available in some cases it is getting more and more diffused Should you participate to diving cruises with people that dive exclusively with Nitrox on a boat equipped to produce it why not using it Thanks to new technologies and impro ved systems to produce oxygen enriched air Nitrox recharge stations are more and more diffu sed in many diving centres of the most famous 27 The Nitrox helps to reduce the effects narcotics of the nitrogen 28 locations for dives The analysis of
45. ng with attention depth time and manometer c variations of depth can not be effected 2 To respect the time and depth limits is important for a to prevent the MDD and the oxygen poisoning b to avoid excessive loss of heat c to prevent the MDD 3 If imputable symptoms to oxygen poisoning are manifested a ascent for 1 meter and continue the dive b immediately ascent on surface to go out of the water and not to effect dives for at least 24 hours c stop on the bottom and to restore the control of the respiraton qe 27 D TiSA MSUY 20 Analysing oxygen As you have read you must analyse Nitrox cylin ders to check the oxygen percentage before using them This procedure is one of the few things that change from diving with air It may look a bit com plicated at the beginning but you will find it easier and easier as you get experienced the most important things is that the oxygen analyser must be correctly set This component was origi nally developed for health purposes and is widely used in hospitals to monitor the percentage of oxygen supplied to patients Specific oxygen analysers have been developed since when diffe rent gas mixes are used for diving Usually the analyser consists of a sensor a transducer a coaxial cable a computer with liquid crystal dis play buttons to switch it on and set its functions and parameters Some analysers can provide maximum operative depth and equivalent air
46. ng your computer with you you will not need to make any conversions Diving Diving with Nitrox is just like diving with air you only need to take care of all the parameters and don t exceed the maximum planned depth Oxygen intoxication can affect the Central Nervous System and have no premonitory symptoms therefore respecting the maximum operative depth is mandatory For instance should the limit be 31 metres pre pare yourself mentally and physically in order not to exceed 29 30 metres this gives you a good safety margin in case of distractions If you are supervised by a Diveleader dive shallower than him and plan your dives in sites where exceeding the maximum operative depth is not that easy To avoid problems due to oxygen intoxication remember to respect the limits established for the global exposition to oxygen over 24 hours Your ESA Instructor and the dives included in the course will teach you to control these two impor tant parameters and avoid problems By the way the depth limits are established also for dives with air therefore we can barely state that diving with Nitrox doesn t introduce anything new either way a good diver must be able to control all the instruments to monitor all parameters and respect all limits You do the same when you drive your car you monitor the speed to avoid to exceed the limits and check any warning lights This helps in avoiding fines running out of petrol or damaging the
47. ocedure you learned during the ESA OWD course ascend without wai ting any longer but slowly to 5 metres and have a long safety stop as far as the left quantity of Nitrox you have enables you to do it The usage of computers for dives with Nitrox is quite similar to that for air and the rules to be respected are the same Once again read care fully the user manual supplied by the manufactu rer Should you wish to improve your knowledge on computers you can attend the ESA Computer Diver course Be cautious As you know thanks to its capability to calculate the nitrogen absorption the compu ter let you dive longer if you dive starting deeper and then ascend to shallower depths in order to reduce the nitrogen absorption rate You will be able to dive even longer using Nitrox so plan your dives in order to start to ascend well in advance of getting close to the no decompression limit respect the maximum operative depth and take into account the exposition to oxygen British system Some countries use the British system For instan ce if you dive in the Caribbean Sea and hire your equipment you will use instruments that measu re depth in feet Therefore you will have to con vert measures Remember that 10 metres corre spond to 10 feet and that 1 BAR is 14 7 PSI The appendix to this manual will provide conversion tables and formulas to calculate maximum opera tive depth equivalent air depth and partial pres sures If you bri
48. or 9 Respect your license and local rules depth limit the ESA Nitrox Diver license doesn t enable you to dive deeper You must comply with the limitations of your preceding license i e ESA OWD 18 metres Remember to consider the limitations cause by PO2 The CNS value per minute must be multi plied by the minutes spent at a certain depth 51 52 Appendix ESA ESA is a didactic agency and his her principal objective it is that to form the scuba divers from the initial level up to the attainment of the pro fessional levels as Diveleader and Instructor To do this the ESA is established to jointly apply the most evolved operational standards to an eleva ted safety degree and to promote the underwa ter activity in his her various forms The formative runs of the ESA foresee the infor mation integration divulged by the instructor with the materials of support that accompany the various levels of brevet Initial practical formation happens with the development of the underwater abilities in swim ming pool or delimited basin subsequently you apply and you improve in free waters For every program or raced ESA it is anticipated a verification of the learning from the instructor that will have to preserve a test of the happened evaluation The scuba divers can receive from the ESA the initial formation to progress toward taller levels of brevet to specialize himself herself themsel ves in different areas tied
49. ou have read in the previous paragraph the computer provides the exposure to oxygen percentage showing num bers or graphically Should you exceed the 50 of the tolerable exposure wait at least for an hour before diving again this should be done anyway make sure you don t exceed 90 over 24 hours or any other value indicated the computer manu facturer Whenever you should exceed such Always veri fies perso nally with the O2 analyser that the per centage of O2 pointed out on the label is exact 17 A computer for the immersions Nitrox that visualizes the nitrogen absorption and the exposure to the oxygen max depth URINE RR limit don t dive for 12 hours at least At this stage you may be asking yourself if you can dive with Nitrox when the oxygen percentage is set to 21 air in the computer Yes you can do it indeed the no decompression limits with are more stringent than those for Nitrox so you would be safer Some divers use this procedure to increase the safety margins in case of repetitive dives Anyhow you must remember to analyse the gas mix you are about use for your dive and not to exceed the maximum operative depth rela ted to the oxygen percentage in order not to be subject to PO2 beyond 1 5 BAR the computers for air don t provide any alarm in case you exceed it so you must respect it Should the computer fail while diving react in accordance with the pr
50. ption as well as the decompression sickness risk anyhow a reduced risk still exists To prevent the decompression sickness you need to plan your dives carefully to respect the no decompression limits check the manometer fre quently analyse the Nitrox mix to check the oxygen percentage before each dive set the computer properly and respect all that you have learned As you know should a diver have signs and symptoms specific to decompression sick ness look for a doctor check if he breaths and that his heart beats and make him breathe pure oxygen if available until the medical staff is available The decompression sickness can be treated only in hyperbaric chambers by qualified personnel As far as volume variations with depth and pres sure are concerned Nitrox and air behave the same way it decreases when going deep and increases ascending The arterial gaseous embolism is due to lungs overstretching to avoid it remember to apply the The full face mask can pre vent the flood of the aerial streets in case of convulsions 39 max PO 1 5 most important rule you learned during your first course don t hold your breath when scuba diving The procedures in case of decompression sickness apply to arterial gaseous embolism as well Nitrogen narcosis risk is reduced when diving with Nitrox but oxygen has narcotic effects too Therefore should you feel a bit exuberant remember it can be narco
51. rgan Wells who is know for having managed the Nitrox program at NOAA The standardisation was needed to optimise the use of Nitrox having regards to the maximum level of safety It is thanks to his colleague Dick Rutkowksi that Nitrox started to be used in sportive dives in the eighties and subsequently in the recreational dives It will happen that you will listen about de azoti sed air this is due to the fact that you can pro duce Nitrox by subtracting nitrogen from air Indeed we can refer to Nitrox also in relation to the fact that the percentage of nitrogen is redu ced instead of talking about the higher quantity of oxygen Anyhow considering the effect that the latter has while diving the Nitrox mixes are defined on the base of the quantity of oxygen they contain Gas percentages are often called fraction of a Always gas Fg for instance fraction of 02 or FO2 address to a that indicates the quantity of oxygen and specialized Fraction N2 or FN2 for nitrogen Remember center that by subtracting FO2 to 100 you calculate FN2 The effect of a gas on the organism is dependent upon its partial pres sure usually indicated with pp or Pg For instance PO2 indicates the oxygen partial pressure and PN2 the nitrogen one RIC At sea level where the ambient CLAN TN pressure is 1 BAR or 1 ATM you ARICA can easily calculate the partial pressure of the two gasses it is the 21 of 1 BAR for o
52. rned during your previous courses you need to consider that some materials such as rubber get worn faster if exposed to high oxygen concentration This may cause some malfunc tions Furthermore remember that grease hydrocar bon for instance mixed with oxygen causes com bustions as well as flames or sparks due to elec trical discharges Sudden combustions can cause explosions which put in danger people animals and things The outcome of the workshop about Nitrox diving held in 2000 referred to in the first chapter is that the standard equipment can be used with gas mixes containing up to 40 of oxygen unless otherwise specified by the manufacturer Luckily the recreational divers use enriched air mix with a 40 maximum percenta ge of oxygen furthermore the most two common Nitrox mixes EAN32 and EAN36 contribute to making the equipment exposed to lower percentages Very good news You don t need to change your equipment to start this new exiting adventure Be careful although The above doesn t apply to cylinders and val ves which need to be specifically approved for oxygen enriched mixes we will treat this topic in a while Although you can dive with the equipment you usually use for dives with air you should think about using oxygen compatible compo nents Every time you have to overhaul your equipment inform the technicians that you are using Nitrox and ask them to add the improvements needed spec
53. ruments b cannot be trimmed c can drown 15 To avoid oxygen intoxication to the CNS a apply all rules for recreational dives in a strict way b respect depth and exposure to oxygen limits c both a and b I declare that have reviewed all the wrong answers with the ESA Instructor and that have understood the related explanation Signature date Device to check the flow of Nitrox on the sensor of the analyser KOO SSSI So O IR eno et e 45 46 Open Waters 1 and 2 Briefing Listen to the explanation from the Instructor and don t hesitate to ask questions in case you need clarifications Open Waters briefings are specifically important as ascending to clarify something is not conve nient for many reasons listening to the briefing and have enough time to dive and practice the exercises and repeating them is much more profi table The Instructor will explain all you have to do how and when therefore putting on hold any other activity during the briefing and concen trating on it only is of paramount importance Again should you need any clarifications don t hesitate to ask questions either the Instructor or the Diveleader will help you Nitrox analysis You will analyse the chosen mix together with your mate and under the supervision of your Instructor this is needed to verify that the oxy gen percentage indicated by the blender and is correct and compatible with the dive
54. s 20 pressure for this rea Le son nitrogen narcosis and nitrogen absorp tion increase with depth It is easy to understand that the higher the nitro gen partial pressure the smaller the no decom pression limits there are to ways of increasing them or reducing the nitrogen narcotic effect 1 reducing depth and therefore the nitrogen par tial pressure 2 reducing the quantity of nitrogen in the gas mix so that at the same depth the partial pressure is less For instance the quantity of nitrogen in an air cylinder breathed at 20 metres as a partial pres sure of 2 37 BAR 0 79 BAR x 3 ATA while the ppN2 for the EAN36 at the same depth is 1 92 BAR F N2 x ATA at 20 metres salt water 0 64 bar x 3 bar 1 92 bar As you can see the two partial pressures are sub 11 b b Minitest 1 The smaller nitrogen quantity in the Nitrox a It allows times of per manence longer than with the air b It forces the scuba diver to long standstills of decompression c lt reduces the times of permanence within the limits of not decompres sion 2 The EAD a It is to point out the Equivalent Air Depth equivalent depth with the air b It serves for planning the immersions with the Nitrox c a and b are exact 3 The effects of the gases are due a To their partial pressure b To the temperature of the underwater environ ment c To the partial pressure of another gas DE 9 Z 0 T slamsuy
55. s to be taken into account when evaluating professionalism and quality of a recharge station e request to show the licence e order and cleanness of the recharge area e type of oxygen used e well identified cylinders e usage of the card or sticker with the informa tion about the cylinder e filling in and signing the register e request to analyse the 02 Ask for information about the recharge stations of your town to your ESA Instructor or to an ESA Point www esaweb net Oxygen Everybody knows how oxygen is important for Minitest 1 The use of oxygen in high concentrations over 40 a it asks for particular attentions for it s ele vated inflammability b it doesn t foresee some type of precaution c improve the dura tion of the equipment 2 With EAN 32 and EAN 36 the scuba diver can use a only Nitrox devoted equipment b also the normal equip ment for the air if otherwi se specified not from the manufacturing house c only equipment compa tible oxygen 3 The cylinders for the air can contain Nitrox a provided that the oxygen that comes into contact with the tank doesn t over come 40 b only if the recharge hap pens with particular systems and the cylinders are identifiable however c a and bare exact 2 Q Z D T suamsuy 35 Through the transparent plastic hose a flow arri ves assem bled of 02 that is mixed with the air inhaled by the presser 36 livin
56. sis Indeed check your and your mate lucidity often In case of any unu sual behave ascend a bit and signs and symptoms will disappear Managing emergencies Having accident while diving is really difficult if your respect all the proce dures and rules conscientiously this applies also to Nitrox diving Should Remember an accident happen this shall be managed as established in the ESA First Aid Open Water Diver Advanced Diver and Prevention amp Rescue Diver manuals Anyhow should you see a diver faint maximum time while diving and should divers more qualified than you be not around try For single dive is LO to help him without risking your minutes safety Ascend with him try to hold the regulator in his mouth but should he lose it don t waste time trying putting it back Ascend e 8O minutes in he respecting the maximum speed limit without hesitation Once at the sea LY hours E You are level trim him positively open his airways and if needed try to resu making multiple dives scitate him look for help without 40 stopping checking that he breaths and that his heart beats and if necessary without stopping the resuscitation Should a diver have problems after having ascen ded look for medical help and should he faint apply the above Once again it is statistically demonstrated that the chances for a diver that applies conscientiously all the rules he learned during the courses
57. specific adhesive label must be attached to the cylinder A recent European rule established that the dome of the cylinder must be painted with colours specific to the gas contained So air cylinders have black and white segments oxygen cylinders are all white Nitrox cylinders are blue helium ones are brown Other regulations and procedures establish that Nitrox cylinders must be clearly marked with a horizontal yellow band with Nitrox or Enriched Air or EANx printed in green the two colours can be exchanged between them Each cylinder must be equipped with card or stic ker with the following information type of the gas mix contained and when it was recharged results of the O2 analysis performed by the blen der and the name of the blender itself the MOD maximum operative depth based upon the maxi mum PO2 and the oxygen percentage measure by the end user In some cases you can find Nitrox cylinders what looks like those used for air in this case make sure that at least the card or sticker with the above data attached to it remember avoid dea ling with operators who don t respect those pro cedures useful for prevention Remember that Nitrox cylinders must clearly state the type of gas contained and the type of gas they were manu factured for this is important for the two follo wing main reasons 1 risk of explosion due to the high oxygen concentration 2 risk of suffering of decompression sickn
58. t must be carried out by highly professional blenders with oil free equipment to avoid explosions Specific tables tell the blenders the quantity of oxygen to be added to air or other known mixes with oxygen to obtain the chosen typo of Nitrox Getting the desired mix with a good accuracy is quite difficult with this procedure Continuous flow mix A specific equipment add oxygen in a controlled way to the air that before it flows through the com pressor this way the blender can analyse the mix and change the oxy gen flow rate until the oxygen per centage is the needed one This procedure avoids the pure oxygen from flowing through compressor valves and cylinders reducing con siderably the changes to have explosions Anyhow using oxygen compatible equipment are strongly recommen ded and usually requested by law Nitrogen removal from air This procedure was conceived considering the method used by the agriculture industry to pro duce nitrogen needed for fertilizers thanks to filters capable of letting the nitrogen flow and blocking the oxygen Changing the setting of these filters it is possible to remove form the air the proper quantity of nitrogen and obtain the chosen Nitrox This procedure avoids contacts between pure oxygen and the equipment used Anyhow considering the high concentration of oxygen and the high pressure using oil free mate rials and lubricants is preferable Furthermore this procedure eliminat
59. the stricken area with current sweet water and to look for medical intervention C ongratulations Now you can plan together with your ESA Nitrox Diver Instructor your first dives with Nitrox You will be exited and curious of trying it You have already established the basis to become a skilled ESA Nitrox Diver you know what Nitrox is you know the basic terminology you know why it extends the no decompression limits You can calculate the partial pressure of the gasses at the various depths the maximum operative depth and the equivalent air depth for the two main Nitrox mixes You have used the mathematical formulas to plan your dives and to better understand how to use Nitrox and know the fundamental steps for analysing it Analyse the cylinder you will use together with your Instructor plan your dive and enjoy your first expe rience with Nitrox Next chapter will provide detailed information on other important features of diving with Nitrox 23 24 What have You learned This exercise will let your review all the most important information contained in this unit so that you can improve your preparation and be ready for your next appointment with your instructor Answer the questions choosing the right questions among the listed ones Check you answers with your Instructors in case of any inaccuracy he will provide all the needed explanations The Nitrox is a gas mix composed of oxygen and nitrogen
60. to the underwater activity as the sea biology the photo the under water archaeology etc Reached adjust her credential the scuba divers can participate in the programs for the forma tion type professional within the underwater activity The esa establishes elevated standards for the formation of his her own affiliate they is under water professionals in possession of a brevet ESA Diveleader or of taller degree The preliminary ESAs are formed from the ESAs IC Director prepared and qualified people ade quately to transmit the techniques of teaching to the preliminary future The formation of the instructor is complete and foresees the acquisition of information on the theory of the immersion on the procedures ESA notions of psychology and marketing the deve lopment of the abilities of management of the single scuba divers or in group of management of the problems of safeguard of the environment and other The validations of the brevets ESAs are issued from the central center and from the offices ESA officially authorized The department ESA that deals him with the for mation informs the affiliate ESAs on the varia tions of the existing procedures and on the intro duction of new procedures You they can also join to the ESA qualified struc tures that operate in the field of the recreational underwater activity Immersion centers underwater club and you negotiate subacquei they are able in fact to acquire the qu
61. to use medical oxygen c it is not had to use medi claoxygen q q Z 2 T slamsuy 38 ded by the NOAA for the maximum P0O2 the analytical procedures are more useful for techni cal divers that breathe different oxygen concen trations for pre assigned periods The most recent computers used for dives with Nitrox cal culate the oxygen exposure percentage based upon the various depths at which the divers remain during the dives and display it to the divers usually with the CNS symbol You can decide to trust your computer of course but you have to read carefully the instructions and should you reach 50 CNS exposure during 24 hours rolling wait at 1 hour at least before diving again Never exceed 90 CNS exposure during 24 hours rolling Should it happen don t dive for 12 hours at least Signs and symptoms low heart beats palpita tions depression anxiousness false visual effects darkness flashes tunnel effect hearing the bells or other auditory hallucinations verti gos irregular breathing nausea tremors and contraction of lips cheeks nose eyelids blac kout and convulsions with serious risk of drow ning Should you feel any of these symptoms ascend without waiting exit from the water and don t dive for 24 hours as a minimum Concurrent elements Other elements can cause oxygen intoxication to CNS symptoms such as medicines tiredness car bon dioxide accumulation in the organism
62. ts of depth and PO c aand b are exact 3 The CNS Oxygen Clock it is a a particular analogical tool for the Nitrox dives b a system of monitoring the exposure to the oxygen of the CNS c the clock used by the scuba divers professionals 4 The acronym CONVUTIV is used to remember a a particular procedure of equipment s control b the symptoms of the oxygen poisoning of the CNS c the formulas to plan the Nitrox dives Ov QEI9Z 9 T sIamMsuy 42 What have you learned This exercise will let your review all the most important information contained in this unit so that you can improve your preparation and be ready for your next appointment with your instructor Answer the questions choosing the right questions among the listed ones Check your answers with your Instructors in case of any inac curacy he will provide all the needed explana tions 1 If compared with air Nitrox a extends the no decompression limits b doubles the no decompression limits c enables you to ignore the no decompression limits 2 Diving with Nitrox and respecting the no decompression limits applicable for diving with air 21 O2 79 N2 a you avoid the decompression sickness b you absorb less nitrogen c nitrogen narcosis is more likely to happen 3 How long can a 15 litre cylinder charged at 20 BAR provide air at a depth of 25 metres if you breathe at a rate of 20 litres per minute at the sea level a 5
63. u will feel more confident after having checked the content of the cylinder yourself In many countries this procedu re is dictated by the existing laws and local rules get informed about them when you are planning a travel as always You can be properly assisted if you get in touch with an ESA Point or with ESA Nitrox Diver Instructor After having checked the cylinder you can plan your dive bearing in mind that a 1 tolerance is allowed this means that a mix containing a quan tity of oxygen that ranges between 31 and 33 can be considered to be EAN32 Tables Respect all the rules you learned during your ESA Open Water Diver course Set the maximum depth you want to reach and make sure it is com patible with the limit set for the specific mix you will use EAN 36 31 metres EAN 32 36 metres If the depth is compatible with such limit you can look for it in the ESA EAN 36 EAN 32 Air Dive Tables Table 1 in the column related to the mix you are about to use EAN 36 EAN 32 or AIR otherwise you can use the next higher value After you have identified the correct depth move to the right you will find the EAD in the AIR column then all times and the no decompression limit or should it not higher the Exposition to Oxygen limit 120 From this point you can proceed as if you were planning your dives with air For instance should you want to dive at 21 metres using EAN32 while this depth is cle
64. use a flow meter to make sure that the sensor is receiving the correct flow of gas this is of fundamental importance to prevent dangerous consequences due to wrong readings by the analyser make the analyses 3 times and make sure you always get the same values if appropriate make the check with air 21 02 should the instrument provide additional functions maximum ope rative depth pp 02 no decompres sion limits equivalent air depth make sure you have correctly set the right data and respect the instructions provided by the manu facturer turn off the analyser and store it adequately unless anybody else needs to use it write the oxygen percentage on the card and on the register write the MOD for the analysed depth on the card sign to confirm you have analysed the cylinder and that you know the O2 percentage in the cylin der you will use 21 Is funda When the flow meter is not available some divers mental to use to measure the oxygen percentage putting read with the sensor in a space saturated of the Nitrox mix attention the to analyse instructions You can use a plastic bag with a hole for the sen of the pro sor and another for the regulator in this case as ducer of the the sensor doesn t work well when the pressure O2 analyser increases you must avoid to inflate the bag too much Furthermore it is important to wash the bag filling it up with Nitrox and then emptying it
65. ute some of the fundaments of your knowledge As you may have already understood reading the b b Minitest 1 The principal advantage given by the use of the Nitrox is a the facility with which can be retrieved b the increase of the times of immersion within the limits of not decom pression c a greater duration in the time of the equipment 2 Another very important advantage is a the best lucidity of the scuba diver during the immersion b the total disappearance of the problems of narcosis c a and bare exact 3 Considering a consump tion of 20 liters to the minute in surface how much does a cylinder of 10 liters last x 200 bar to the depth of 10 meters a around 100 minutes b around 50 minutes c around 35 minutes q D Z Q siamsuy 33 Cylinder of oxygen used in the recharge Nitrox for partial pressures X INZIARE CHWRERE T Que COLL B su Raupa _ AP RUB Be Rappa Bone Oy APRLENT Riva z MA ALI 34 preceding paragraphs there are to main procedu res for obtaining Nitrox 1 adding oxygen to the air 2 removing nitrogen from the air Let s review them together bearing in mind that they can only be performed by specifically trained and qualified blenders Partial pressure recharge This procedure is quite dangerous because is based upon pure oxygen being pumped in a cylin der already containing air or that will be added after the oxygen It seems easy to use bu
66. within the limit of 1 6 BAR PO2 can be considered safe provided that it is strictly respected and that exposition to oxygen Many computers consider safe of dives with Nitrox held in is not excessive setting the PO2 limit at 1 5 BAR To guarantee safety you can decide to plan your dives in order to set the PO2 limit at 1 4 BAR so that you can still have a good safety margin in case you dive slightly deeper it should never happen even when diving with air provided you don t exceed 1 6 BAR The ESA EAN 36 EAN 32 Air Dive Tables provides the MOD for the two common mixes 36 metres for EAN 32 e 31 metres for EAN 36 These limits are based upon the PO2 set at 1 5 BAR You must plan and dive with Nitrox in order to never exceed such depths The operation that enables you do calculate the MOD for a given mix is the following 1 5 x 10 FO2 10 MOD EAN brea thing 36 to 31 meters the same nitrogen quantity is absorbed that to 24 meters with the air 2000 EAN 36 EAN 32 AIR DIVE TABLES No Decompression and O Exposure Limits Repetitive Group Designation Tables for No Decompression Dives Profonat Profondit Profondit Depth Dopth EAN 36 EAN 32 AIR m m m Gruppo di Appartenenza Pressure Group Computers can work for you Indeed there are computers for dives with Nitrox that provide acoustic or visual alarm to the diver when rea
67. x Il containing 32 and 36 of oxygen respectively In specific dives such as technical military explo rative scientific or during which people work under water Nitrox mixes with oxygen percentage higher than 40 can be used this is to reduce the decompression time The ESA Nitrox Diver course is for divers who want to extend the no decom pression limits respecting all safety margins Therefore this manual does not treat any of the specific dives listed herabove Definitions To avoid confusion and use the potentiality given by Nitrox to the maximum extent some defini tions are needed It may looks like things get more complex at the beginning but you will be able to remember them easily Let s start from the two main gasses as you may already know O2 is the symbol for oxygen and N2 is that for nitrogen Many divers refer to Nitrox calling it EANx that is Enriched Air Nitrox where x indicates the oxygen percentage EAN 32 and EAN 36 are the two standard mixes and are equivalent to enri ched air with 32 of O2 the former and 36 of O2 the latter The National Atmospheric and Oceanic Administration NOAA is an US organisation involved in many subjects mainly for commercial reasons Its field of application ranges from dives on ocea nic sea bed to aerospace it published the dive planner with two Nitrox mixes mentioned above in the seventies The person who standardised the two mixes was Doctor Mo
68. xygen 0 21 BAR and 79 of 1 BAR for nitrogen 0 79 BAR You will have already GORSI noted that 0 21 0 79 1 i RICARICA E RR The next paragraph will teach you to process other mathematical operations related to dives with Nitrox As already done for the ESA Open Water Diver course the pressure is indicated in BAR that cor responds to 1 atmosphere or 14 7 PSI ATA indicates absolute pressure that is the ambient pressure that is calculated adding 1 BAR the atmospheric pressure to the hydrostatic Minitest 1 EANx initials it is used for pointing out a Enriched Air Nitrox b Air Enriched of Oxygen c a and bare exact 2 The term air nitrogen free a It is reported to the fact that Nitrox can be produ ced escaping nitrogen from the air b It is to point out a mixtu re with high nitrogen con centration c It points out a composed specific mixture of 80 of oxygen and 20 of nitro gen 3 The sigles pp and Pg point out a The percentage of oxy gen b The nitrogen percentage c The partial pressure of a datum gas 9 10729 T siamsuy 10 pressure 1 BAR every 10 metres of salt water Calculations Usually mathematics helps solving problems dis covering new things and during your ESA Open Diver course to calculate how the pressure chan ges with depth Furthermore the dive planner are based upon mathematical calculations Once again mathematics will help you i
69. you have planned Remember that any time you use a gas mixes other than air oxygen percentage 21 you will have to analyse the mix using a suitable instru ment connected to a flow meter Do it with your mate each one will analyse the content of his cylinder under the supervision of both the other mate and of the Instructor Planning the Nitrox dive Use the ESA table for diving with Nitrox with your mate as indicated by the Instructor To take the most of the profits by diving with Nitrox having regards of safety planning every dive carefully is of fundamental importance Take the advantage of this exercise to improve your skill and solve any problems with your Instructor and your mate Should anything appear not too clear or in case of doubts don t hesitate to ask the Instructor to cla rify it this is important for your safety Should you use a computer for Nitrox dives verify that the oxygen percentage is correctly set CNS Oxygen Clock 47 48 Verify that you don t risk exceeding or getting too close to the established oxygen exposure limit taking into account previous dives Oxygen intoxication to the CNS is an important factor to be considered when diving with Nitrox don t exceed the exposure limit of 120 minutes over 24 hours rolling for a single dive and 180 minutes for repetitive dives Getting ready checking the equipment and put ting it on Prepare the equipment needed for the dive ask your mat

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