tdi advanced nitrox by G9Fnone

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									BorneoDream.com




                  Billy Hammond
                       #10407
     Welcome to
Advanced Nitrox Diving


      Nitrox Review




  Equipment Requirements




   Advanced Nitrox???
    •Extension of Time
    •Decompression Gas
     Physical Principals
         Of Diving


    Pressure & Pressure Effects!



        •   Equalizing
        •   Buoyancy
        •   Dive Time
        •   No Deco Limits
        •   MOD


Depth + Pressure = STRESS
      Units Of Atmosphere



1 ATA =

760 mmHg = 14.696 psi = 1.0132 bar etc




  Atmosphere vs. Atmosphere Absolute




33 fsw approximately = 10 metres = 1 BAR
         Depth Vs. Pressure


  Depth          Depth       Pressure
  (fsw)         (metres)      (BAR)
          Surface              1 BAR
    33              10         2 BAR
    66              20         3 BAR
    99              30         4 BAR
   132              40         5 BAR
   165              50         6 BAR


 Pressure (ATA) = (Depth ÷ 33 fsw) +1
Pressure (BAR) = (Depth ÷ 10 metres) +1
        Pressure Vs. Volume


        Depth             Pressure    Volume
(fsw)        (metres)       (BAR)          (size)
        Surface               1              1
 33               10          2             1/2
 66               20          3             1/3
 99               30          4             1/4
 132              40          5             1/5
 165              50          6             1/6

             Simply Stated:
“Volume is inversely related to pressure”
      Formula:         P1 × V1 = P2 × V2
                 Boyle’s Law


Problem: A Flexible container has 57 litres of air at 15
metres. How much will the volume change if it is taken to
28 metres?


Solution:
Step 1: Change depths to BAR:
               15 metres = 2.5 BAR
               28 metres = 3.8 BAR


Step 2: Re-work formula to solve for V2:
                  P1 × V1 ÷ P2 = V 2


Step 3: Solve:
     2.5 BAR × 57 litres ÷ 3.8 BAR = 37.5 litres
              Dalton’s Law


    Ptotal = Pgas1 + Pgas2 +Pgas3 … Pgas(n)

                       or

        “The whole is equal to the sum
               of all the parts”

Air =
          21% Oxygen
          78% Nitrogen
          1% Other Stuff (mostly argon)


Pressure of a gas =
                 Pg = Pt × fg
         Total pressure × fraction of gas
                                                         Dalton’s Law


Table 4 ~ Depth, Pressure and Gas Pressures Air and Nitrox

      Depth         Total             Air                    EAN32                  EAN40

                   Pressure
 fsw     metres               Nitrogen      Oxygen   Nitrogen    Oxygen     Nitrogen    Oxygen
                    (BAR)

   Surface            1        0.79          0.21     0.68           0.32    0.60           0.40

 33           10      2        1.58          0.42     1.36           0.64    1.20           0.80

 66           20      3        2.37          0.63     2.04           0.96    1.80           1.20

 99           30      4        3.15          0.84     2.72           1.28    2.40           1.60

132           40      5        3.95          1.05     3.40           1.60      --            --

165           50      6        4.74          1.26       --            --       --            --
                                                   Dalton’s Law


Table 4 ~ Depth, Pressure and Gas Pressures Air and Nitrox
      5                                     ~ EAN40, EAN60 and EAN80

   Depth         Total           Air
                                EAN40                  EAN32
                                                       EAN60                  EAN40
                                                                              EAN80

                Pressure
                Pressure
fsw
fsw    metres
       metres              Nitrogen
                           Nitrogen   Oxygen
                                      Oxygen   Nitrogen
                                               Nitrogen    Oxygen
                                                           Oxygen     Nitrogen
                                                                      Nitrogen    Oxygen
                                                                                  Oxygen
                 (BAR)
                 (BAR)

  Surface         1.0        .60         .40     .40            .60     .20            .80
  Surface          1        0.79        0.21    0.68           0.32    0.60           0.40
 10       3       1.3       0.78        0.52    0.52           0.78    0.26           1.04
 33      10        2        1.58        0.42    1.36           0.64    1.20           0.80
 20       6       1.6       0.96        0.64    0.64           0.96    0.32           1.28
 66      20        3        2.37        0.63    2.04           0.96    1.80           1.20
 33      10       2.0       1.20        0.80    0.80           1.20    0.40           1.60
 99
 55      30
        16.6       4
                 2.67       3.15
                            1.60        0.84
                                        1.07    2.72
                                                1.07           1.28
                                                               1.60    2.40
                                                                         --           1.60
                                                                                        --
132
 66        40
           20      5
                  3.0       3.95
                            1.80        1.05
                                        1.20    3.40
                                                1.20        1.60
                                                           (1.80)        --
                                                                         --            --
                                                                                       --
165
99         50
           30      6
                  4.0       4.74
                            2.40        1.26
                                        1.60      --            --       --            --
                                                      Dalton’s Law


Table 5 ~ Depth, Pressure and Gas Pressures ~ EAN40, EAN60 and EAN80
                                    Example: EAN 60 at 10 metres has corresponding
      Depth         Total           gas
                                  EAN40 pressures of:
                                                   EAN60           EAN80
                   Pressur
          metre
 fsw                  e      Nitrogen   Oxygen    Nitrogen   Oxygen   Nitrogen   Oxygen
           s
                    (ATA)
  Surface            1.0       .60       .40        .40       .60       .20       .80
 10           3      1.3      0.78       0.52      0.52       0.78     0.26       1.04
                                               Oxygen: 2 BAR × .60 = 1.20 BAR
 20           6      1.6      0.96       0.64      0.64       0.96     0.32       1.28
 33           10     2.0      1.20       0.80Nitrogen: 2 BAR × .40 = .80 BAR 1.60
                                                  0.80    1.20      0.40
 55       16.6      2.67      1.60       1.07      1.07       1.60       --        --
 66           20     3.0      1.80       1.20      1.20      (1.80)      --        --
 99           30     4.0      2.40       1.60        --        --        --        --
            Dalton’s Law



   Maximum Operating Depth
           (MOD)
   Depth is the same as Pressure so…
Pressure (Total) can be converted to Depth
                        Pg
                       Pressure of the gas
               Pt
  Pressure Total = =
                        fg
                       Fraction of the gas



               Best Mix
                         Pressure of the gas
                         Pg
                 fg
Fraction of the gas =
                         Pt Pressure Total
Dalton’s Law


 How Dose?
  Best Mix?
 What Deep?


     Pg

 =        =×
fg        Pt
        Equivalent Air Depth


Step 1: How Much Nitrogen?
                  fN2 = 1 – fO2

Step 2: How much N2 compared to air?
             Ratio = (1 – fO2) ÷ 0.79


Step 3: Convert to absolute depth!
    Absolute Depth = Actual Depth + 10 metres


Step 4: EAD “absolute”:
     EAD “absolute” = Absolute Depth × Ratio


Step 5: Calculate the “EAD”:
       EAD = EAD “absolute” - 10 metres
        EAD Formula



        EAD Formula:


        FN2
EAD =       ×(D+33) -33
        .79

        FN2
EAD =       ×(D+10) -10
        .79
                                                 Physical Principals
                                                      Review


1. What is the absolute pressure at 28 metres?
         (28 ÷ 10) + 1 = 3.8 BAR




2. What is the depth at an absolute pressure of 3.1 BAR?
         (3.1 - 1) × 10 = 21 metres


3. What is the pressure of oxygen of EAN45 at 19 metres?
         ((19 ÷ 10) + 1) × .45 = 1.3 BAR PO2
                                                 Physical Principals
                                                      Review


4. What is the pressure of nitrogen of EAN28 at 43 metres?
         ((43 ÷ 10) + 1) × (1 - .28) = 3.8 BAR




5. At what depth does the pressure of oxygen of normal air reach 1.6 BAR?


         ((1.6 ÷ .21) – 1) × 10 = 66.19 metres
                                                   Physical Principals
                                                        Review

6. What is the MOD of:
    EAN28
   ((1.6 ÷ .28) - 1) × 10 = 47.1 metres
    EAN40
    ((1.6 ÷ .4) - 1) × 10 = 30 metres
    EAN50
    ((1.6 ÷ .5) - 1) × 10 = 22 metres
   EAN60
   ((1.6 ÷ .6) - 1) × 10 = 16.6 metres

7. What is the EAD of EAN50 at 21 metres?
          ((1 - .5) ÷ .79) × (21 + 10) - 10 = 9.6 metres
 Physiological Principles
        of Diving


Physiology is exceptionally complex



  Body responds to nitrogen and
  oxygen as if they are DRUGS



      2 problems with diving:
     DCS and CNS O2 Toxicity



    Time and Dose relationship
              Nitrogen


         Properties of Nitrogen


       If anything seems wrong…
             IT IS WRONG!!!
              Surface NOW!


       Decompression Illness:
      Type I – Pain Only Bends
   Type II – Central Nervous System


Dehydration is the leading cause of DCS
              Oxygen


         Properties of Oxygen



     Hypoxia               OTUs
    Hyperoxia           CNS Toxicity
Pulmonary Toxicity     ‘Free Radicals’



             ConVENTID



      NOAA O2 Exposure Chart
Carbon Dioxide


 CO2 Convulsions




   CO2 Sources




 Deleterious Effect




 Worsens Narcosis
      CO2 Sources


     Compressor Intakes
Poor Compressor Maintenance
Improper Blending Techniques



        Problems:

Colorless, Odorless, Tasteless:
     Hemoglobin Bonding
 Unconsciousness > Death
                                               Physiological Principals
                                                       Review


1. What are the two pressure effects of nitrogen on the human body?
          Nitrogen Narcosis and Decompression Sickness

2. What should the diver do if “nitrogen narcosis” is suspected?
          Ascend or abort the dive

3. Does Nitrox eliminate the need to plan dives and the “bends”?
          Absolutely NOT

4. Is using Nitrox “safer” than using “air”?
          No, not necessarily, oxygen toxicity is a concern

5. Can the diver predict the onset of an oxygen convulsion?
          No, the diver can only plan to avoid
                                         6-10
                                              Physiological Principals
                                                      Review


6. Is diving at a pressure of oxygen of 1.3 BAR “safer” than 1.4 BAR?
          Only in the sense it may take longer to convulse, otherwise no, it is not “safer”


7. What are the two types of oxygen toxicity?
          Pulmonary and Central Nervous System
8. Which type of oxygen toxicity is of primary concern to the Nitrox diver?
          Central Nervous System – convulsions
9. List three conditions that carbon dioxide can cause or make worse:
          a. Headache
          b. Increased narcosis
          c. Increased oxygen toxicity

10. Why is carbon monoxide considered a major hazard?
          It binds with the hemoglobin of the blood and prevents oxygen from getting to the
          tissues
Dive Planning


Accident Analysis



   What If….?



 Computer Loss



   Gas Loss
Advanced Nitrox Uses


Reduced nitrogen absorption
     Shortens deco time
   Increases N2 elimination


  Planning Considerations:
     Tables / Computers
        Pony Bottles
Different gases and reasoning
Computer generated dive tables
   Multimix dive computers
        Gas Requirements


                 SAC Rate
      Surface Air Consumption Rate
     (also SCR, Surface Consumption Rate)

         Determining SAC Rate:
1. Determine bar used
2. Determine litres used
3. Determine time
4. Determine litres used per minute
5. Convert litres used per minute at depth
   (BAR) to SAC (SCR)
             Dive Tables


        Use the table of choice:
    USN, Sport, DCEIM, Buhlmann …


                3 Sections

1. No Deco Table
2. Surface Interval Table
3. Residual Nitrogen Table



       DO NOT MIX TABLES!
                          Dive Tables


 GROUP DIVE EAD (ANDEAD TIMEND USED)
SECOND LETTERS &BOTTOM (NOTE GAS USED)
    RECORD DEPTH AND DIVE LETTER TIME
     TOTAL RECORD ACTUAL DEPTH
      FINAL BOTTOM & DECO GAS DIVE
       SAFETY AND/OR NOTE INTERVAL
        DETERMINE TIME FOR 2
            TOTAL SURFACE STOP(S)
            STOP(S) START
START            SIT




AD:                AD:


EAD:               EAD:



        TBT:               ABT:
                          +RBT:
                          =TBT:
 Pitfalls of Tables


     Major Pitfall?
     … The Diver!!!



 No Multi-Level Tracking



Inaccurate Time Tracking



Inaccurate Depth Tracking
       Nitrox Tables


Based on Standard Tables & Mixes
   (Typically EAN32 & EAN36)



          Ease Of Use



      No Calculation Errors



   EAD Tables More Common
                                      EAD Table
                                      (Imperial)


 Air
        .21   .22   .23   .24   .25    .26   .27   .28   .29
Table
 30     30    30    31    32    33     34    35    36    37
 40     40    40    41    42    43     44    46    47    48
 50     50    51    52    53    54     55    56    58    59
 60     60    61    62    63    64     66    67    69    70
 70     70    71    72    74    75     76    78    80    81
 80     80    81    82    84    86     87    89    90    92
 90     90    91    93    94    96     98    100   101   103
100     100   101   103   105   107    108   110   112   114
110     110   111   113   115   117    119   121   123   126
                                      EAD Table
                                       (Metric)


 Air
        .21   .22   .23   .24   .25    .26   .27   .28   .29
Table
 9      9     9     9     10    10     10    11    11    11
 12     12    12    13    13    13     13    14    14    14
 15     15    15    16    16    16     17    17    17    18
 18     18    18    19    19    19     20    20    21    21
 21     21    21    22    22    23     23    24    24    24
 24     24    24    25    25    26     26    27    27    28
 27     27    27    28    28    29     29    30    31    31
 30     30    31    31    32    32     33    33    34    34
 33     33    34    34    35    35     36    37    37    38
                                      MOD Tables
                                       (Imperial)


 Air
        .21   .22   .23   .24   .25     .26   .27   .28   .29
Table
 30     30    30    31    32    33      34    35    36    37
 40     40    40    41    42    43      44    46    47    48




140     140   142   144   146   149    151    154   156   159
 MOD
 1.4    187   177   167   159   151    144    138   132   126
 1.6    218   207   196   187   178    170    162   155   149
                                      MOD Tables
                                       (Metric)


 Air
        .21   .22   .23   .24   .25    .26   .27   .28   .29
Table
 9      9     9     9     10    10      10   11    11    11
 12     12    12    13    13    13      13   14    14    14




 42     42    43    43    44    45      45   46    47    48
 MOD
 1.4    57    54    51    48    46      44   42    40    38
 1.6    66    63    60    57    54      52   49    47    45
                                  PO2 Table
                                  (Imperial)



PO2   O2 Time   .21   .22   .23   .24   .25    .26   .27

1.0    300      124   117   110   104   99     93    89
1.1    240      139   132   124   118   112    106   101
1.2    210      155   147   139   132   125    119   113
1.3    180      171   162   153   145   138    132   125
1.4    150      187   177   167   159   151    144   138
1.5    120      202   192   182   173   165    157   150
1.6     45      218   207   196   187   178    170   162
                                  PO2 Table
                                   (Metric)



PO2   O2 Time   .21   .22   .23   .24   .25   .26   .27

1.0    300      38    36    33    32    30    28    27
1.1    240      42    40    38    36    34    32    31
1.2    210      47    45    42    40    38    36    34
1.3    180      52    49    47    44    42    40    38
1.4    150      57    54    51    48    46    44    42
1.5    120      61    58    55    53    50    48    46
1.6     45      66    63    60    57    54    52    49
                                                              Dive Planning
                                                                 Review


1. What is the Surface Air Consumption rate of a diver that has the following data:
         Depth:                  12 metres
         Cylinder:               2830 L@227 bar
         Start PRESSURE:         145 bar
         End PRESSURE:           117 bar
         Time:                   4 minutes


         Aluminum 227 bar = 12.467 litres per bar (12.5 litre cylinder)


         Used 28 bar in 4 minutes = 7 bar / minute


         7 bar/min. × 12.467 litres/bar = 87 litres per minute


         12 metres = 2.2 BAR
         87 ÷ 2.2 = 40 litres of gas per minute (rounded for safety)
                                                     Dive Planning
                                                        Review


2. Show the Dive Plan and profile for an Air dive to 23.5 metres for 34 minutes, 3:21 Surface
   Interval, and a second dive to 16 metres for 36 minutes. Show all residual nitrogen
   categories.

        AIR                      H         3:21         C                       J




AD: 23.5metres                           AD:16metres


EAD: 23.5metres                         EAD:16metres


                   TBT :34                               ABT:         :36
                                                        +RBT:         :17
                                                        =TBT:         :53
                                                   Dive Planning
                                                      Review


3. What is the best mix for a dive to 20 metres and not exceed an oxygen pressure of 1.4 BAR.


    1.4 ÷ (20 ÷ 10 + 1) = .47 or EAN 47



                          Depth, Mix and PO2 Table (Metric)

   PO2       O2 Time      .44      .45      .46.      .47      .48       .49      .50

    1.3        180        20        19       18       18        17       17        16
    1.4        150        22        21       20       20        19       19        18
    1.5        120        24        23       23       22        21       21        20
                                                  Dive Planning
                                                     Review


4. Show the Dive Plan and profile for a Nitrox dive to 25 metres for 38 minutes, 2:18
   Surface Interval, and a second dive to 19.5 metres for 48 minutes. Choose the Best
   Mix with an oxygen pressure of 1.4 BAR at the maximum depth. Use the same mix for
   both dives. Show all residual nitrogen categories.




    a.   Using the EAD Tables, the best mix for 25 metres at 1.4 BAR oxygen exposure is
         EAN 40.


    b.   Using the EAD Tables, the EAD of EAN 40 at 25 metres is 18 metres. (note there
         may be a “rounding” difference in depths between imperial and metric EAD
         tables)
                                                     Dive Planning
                                                        Review


4c. USN Tables & USN Modified Tables (in this case using either of these tables results in
    the same answer, but note the difference using the metric tables.)


       EAN 43                   F (G)       2:18        D (E)                    I




     AD: 81 fsw                            AD: 64 fsw
      25 metres                           19.5 metres

    EAD: 50 fsw                            EAD: 40 fsw
      18 metres                              12 metres

                   TBT :38                                 ABT:        :48       :48
                                                          +RBT:        :37       :49
                                                          =TBT:        :85       :97
                                               Dive Planning
                                                  Review


4c. DCIEM Tables



                                                                          E (E)
      EAN 43                 F (E)    2:18     × 1.3 (1.4)




   AD: 81 fsw                         AD: 64 fsw
    25 metres                        19.5 metres

   EAD: 50 fsw                       EAD: 40 fsw
     18 metres                         12 metres

                   TBT :38                              ABT:       :48     :48
                                                   × modifier:   × 1.3   × 1.4
                                                       =TBT:     :62.4   :67.2
                                             Dive Planning
                                                Review


4c. Buhlmann Tables



                                                                E (E)
      EAN 43               E (E)    2:18




   AD: 81 fsw                       AD: 64 fsw
    25 metres                      19.5 metres

   EAD: 50 fsw                     EAD: 40 fsw
     18 metres                       12 metres

                 TBT :38                           ABT:   :48
                                                 + RBT:   :19
                                                  =TBT:   :67
                                                     Dive Planning
                                                        Review


5. How much gas would the diver in Question 4 require for the second dive assuming an
   average SAC rate of 25.5litres/min ?



    a.   Convert 19.5 - to BAR:

         (19.5 + 10) ÷ 10 = 2.95 BAR



    b.   Determine gas used:

         2.94 BAR × 25.5 l / min × 48 minutes = 3611 litres.
Equipment Considerations


    < EAN40       vs.     > EAN40
    (cleaning, lubricants, materials)



Oxygen doesn’t burn, FUEL burns
  (oxygen just promotes combustion)



     Adiabatic compression
     (production of toxic gasses)



 High-pressure vs. Low-pressure
         (system components)
 Equipment Markings


    Regulator Identification




       Cylinder Markings
  (Oxygen, Nitrox, Argon, Contents)




     Cylinder Certifications
(Eddy, VIP/CIP, Hydro, Oxygen Clean)
    Oxygen Analysis


   Components Of Analysis
           Fuel Cell
          Analysis Unit
    Flow Containment System

Analyzer Setup (Demonstration)
Nitrox Production


  Partial Pressure




Membrane Separation




Continuous Blending
                                         Equipment Considerations
                                                 Review


1. Oxygen cleaning means to remove what material?
         Hydrocarbon (oil/grease) contaminations


2. Oxygen cleaning is required for mixes above what percentage?
                 Above 40 percent for all equipment - Any percentage for cylinders


3. Opening a valve slowly, reduces what problem?
         Adiabatic compression – high temperatures due to sudden pressure increases – may
         cause fire or worse, produce carbon monoxide


4. What three markings are required of a Nitrox cylinder?
         Cylinder Identification, Inspection Label and Contents Label
                                          Equipment Considerations
                                                  Review


5. Who is responsible to ensure the analysis of a Nitrox cylinder?

          The DIVER!


6. Does an oxygen analyzer measure the “fraction” of oxygen or the “pressure” of
   oxygen?

          It measures PARTIAL PRESSURE (unless of course you have access to mass
          spectrometers!)



7. Name at least two methods of producing Nitrox.

          Partial Pressure Blending and it various forms, Membrane separation techniques,
          Continuous Blending
                                         Equipment Considerations
                                                 Review


8. What color is commonly used for regulator covers used with high values of Nitrox or
   oxygen?

          Nitrox second stage regulator covers tend to be yellow and Oxygen (or mixes
          above 40% in some cases) tend to be green

9. To analyze a cylinder of EAN80, what gas should be used to calibrate the oxygen analyzer


          Oxygen



10. Does a cylinder need to be oxygen cleaned to be used with EAN36?

          Of course, cylinders are the exception for the 40 Percent Rule … since they may
          be blended by the partial pressure technique
Congratulations!!!

Let’s Go Diving!!!

								
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