Transcript Slide 1

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
(fsw)
Depth
(metres)
Surface
Pressure
(BAR)
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
(fsw)
(metres)
Surface
Pressure
Volume
(BAR)
(size)
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
fsw
Total
metres
Surface
Pressure
Air
EAN32
EAN40
Nitrogen
Oxygen
Nitrogen
Oxygen
Nitrogen
Oxygen
1
0.79
0.21
0.68
0.32
0.60
0.40
(BAR)
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 5
4 ~ Depth, Pressure and Gas Pressures Air
and Nitrox
~ EAN40,
EAN60 and EAN80
Depth
fsw
fsw
Total
metres
metres
Pressure
Pressure
(BAR)
(BAR)
Air
EAN40
EAN32
EAN60
EAN40
EAN80
Nitrogen
Nitrogen
Oxygen
Oxygen
Nitrogen
Nitrogen
Oxygen
Oxygen
Nitrogen
Nitrogen
Oxygen
Oxygen
Surface
Surface
10
3
33
10
20
6
66
20
33
10
99
30
55
16.6
1.0
1
1.3
2
1.6
3
2.0
4
2.67
.60
0.79
0.78
1.58
0.96
2.37
1.20
3.15
1.60
.40
0.21
0.52
0.42
0.64
0.63
0.80
0.84
1.07
.40
0.68
0.52
1.36
0.64
2.04
0.80
2.72
1.07
.60
0.32
0.78
0.64
0.96
0.96
1.20
1.28
1.60
.20
0.60
0.26
1.20
0.32
1.80
0.40
2.40
--
.80
0.40
1.04
0.80
1.28
1.20
1.60
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
Depth
fsw
Total
metre
s
Surface
Example: EAN 60 at 10 metres has corresponding
gas pressures of:
EAN40
EAN60
EAN80
Pressur
e
(ATA)
Nitrogen
Oxygen
Nitrogen
Oxygen
Nitrogen
Oxygen
1.0
.60
.40
.40
.60
.20
.80
10
3
1.3
0.78
0.52
0.52
0.78
0.26
1.04
20
6
1.6
0.96
0.64
0.64
0.96
0.32
1.28
33
10
2.0
1.20
0.80Nitrogen:
0.80 2 BAR
1.20× .40 =0.40
.80 BAR 1.60
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
--
--
--
--
Oxygen: 2 BAR × .60 = 1.20 BAR
Dalton’s Law
Maximum Operating Depth
(MOD)
Depth is the same as Pressure so…
Pressure (Total) can be converted to Depth
Pressure TotalPt= =
Pg
Pressure
of the gas
fg
Fraction
of the gas
Best Mix
Fraction of the gas
fg =
Pg
Pressure of the gas
Pt Pressure Total
Dalton’s Law
What
How
BestDeep?
Dose?
Mix?
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:
EAD =
FN2
×(D+33) -33
.79
EAD =
FN2
×(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
Hyperoxia
Pulmonary Toxicity
OTUs
CNS 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
SECOND
GROUP
TOTAL
FINAL
LETTERS
DIVE
RECORD
BOTTOM
STOP(S)
DEPTH
&(AND
SURFACE
AND
&
TIME
START
EAD
DIVE
FOR
(NOTE
INTERVAL
LETTER
2ND GAS
DIVEUSED)
TIME
RECORD
SAFETY
DETERMINE
TOTAL
EAD
AND/OR
BOTTOM
ACTUAL
DECO
NOTE
TIME
DEPTH
GAS
STOP(S)
USED)
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
Table
.21
.22
.23
.24
.25
.26
.27
.28
.29
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
Table
.21
.22
.23
.24
.25
.26
.27
.28
.29
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
Table
.21
.22
.23
.24
.25
.26
.27
.28
.29
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
1.4
187
177
167
159
151
144
138
132
126
1.6
218
207
196
187
178
170
162
155
149
MOD
MOD Tables
(Metric)
Air
Table
.21
.22
.23
.24
.25
.26
.27
.28
.29
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
1.4
57
54
51
48
46
44
42
40
38
1.6
66
63
60
57
54
52
49
47
45
MOD
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:
Cylinder:
Start PRESSURE:
End PRESSURE:
Time:

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)
12 metres
2830 L@227 bar
145 bar
117 bar
4 minutes
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
AD: 23.5metres
AD:16metres
EAD: 23.5metres
EAD:16metres
TBT :34
C
ABT:
+RBT:
=TBT:
J
:36
:17
: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)
AD: 81 fsw
25 metres
2:18
I
D (E)
AD: 64 fsw
19.5 metres
EAD: 50 fsw
18 metres
EAD: 40 fsw
12 metres
TBT :38
ABT:
+RBT:
=TBT:
:48
:37
:85
:48
:49
:97
Dive Planning
Review
4c. DCIEM Tables
EAN 43
F (E)
2:18
AD: 81 fsw
25 metres
AD: 64 fsw
19.5 metres
EAD: 50 fsw
18 metres
EAD: 40 fsw
12 metres
TBT :38
E (E)
× 1.3 (1.4)
ABT:
× modifier:
=TBT:
:48
× 1.3
:62.4
:48
× 1.4
:67.2
Dive Planning
Review
4c. Buhlmann Tables
EAN 43
E (E)
AD: 81 fsw
25 metres
E (E)
2:18
AD: 64 fsw
19.5 metres
EAD: 50 fsw
18 metres
EAD: 40 fsw
12 metres
TBT :38
ABT:
+ RBT:
=TBT:
:48
:19
: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!!!