USN Diving Manual Revision 6USN Diving Manual Revision 6Critical Changes that Affect You

Dr. Ed FlynnyCAPT John Murray MC USN

Naval Sea Systems Command25 June 2009

1

Major ChangesMajor Changes

• New Air Decompression Tables with In• New Air Decompression Tables with In-Water Oxygen Decompression Capability

• Seamless Air/MK 16 Repetitive Diving• Seamless Air/MK 16 Repetitive Diving• Elimination of Air Surface Decompression

ProceduresProcedures• Revised Flying After Diving Limits

N R l f Ch b D l t• New Rules for Chamber Deployment• New Rules for Multi-Day Oxygen Exposure

2

New Air TablesNew Air Tables

• Why did we revise the 1957 tables?• What algorithm did we use?• What algorithm did we use?• What do the new tables look like?• How do they compare to other tables?• How did we test the tables?

3

Why Revise 1957 Tables?Why Revise 1957 Tables?

• Safety• Safety– Widespread criticism by government and

industry over many yearsindustry over many years– Ad hoc schedule jumping common in USN

M difi ti f t bl i i d t– Modification of tables common in industry– Newer tables prescribe longer decompression

Ri k f DCS i i h i i d h– Risk of DCS increases with increasing depth and bottom time.

4

Why Revise 1957 Tables?Why Revise 1957 Tables?

• Capability• Capability– SurDO2 limited to 170 fsw for 40 min

N i i d i f S DO– No repetitive group designators for SurDO2

– No capability for in-water O2 decompression– No capability to change decompression mode

on the flyAi d MK 16 i i d i– Air and MK 16 repetitive group designators not compatible

5

DCS Incidence with St d d Ai T bl 1971 96Standard Air Table 1971-96

(38,172 dives, 207 cases)

7

8

9

s

5

6

7

000

dive

s

2

3

4

Cas

es/1

0

1

Lower Third Middle Third Upper Third

6

Decompression Stress Level

Safety Concerns ExampleSt d d Ai t 150 fStandard Air at 150 fsw

ο Circles experimentalο Circles -experimental dives with no DCS

Δ Triangles-dives with150 fswg

3002%

5%

10%

1%Δ Triangles-dives with

DCS⎤ Black Triangles-dives

200

T, m

in

10%

20% ⎤ Black Triangles dives with DCS >2% with 95% certainty

100TDT

• Standard Air does not provide enough

00 20 40 60

Bottom time, min

7decompression time

,

TWA 800 SurDO2 E i 120 130 fExperience 120-130 fsw

Prescribed Schedule 5/34 14 7 %Prescribed Schedule 5/34 14.7 %Schedule + 1 Jump 1/56 1.8 %Schedule + 2 Jumps 0/303 0.0 %Schedule + 3 Jumps 2/290 0.7 %p-------------------------------------------------------

RCC Oxygen Time (min)RCC Oxygen Time (min)No Jump 3 Jumps Canada VVal-18

8120/60 32 51 53 60

VVal-18 AlgorithmVVal 18 Algorithm

• Developed by CAPT Ed Thalmann in 1983• Developed by CAPT Ed Thalmann in 1983• Features

Nine tissue compartments– Nine tissue compartments– Exponential uptake, linear washout of inert gas

Ascent controlled by VVal 18 M value matrix– Ascent controlled by VVal-18 M-value matrix• Basis of

USN MK 16 constant PO tables– USN MK 16 constant PO2 tables– Navy Decompression Computer

9

VVal-18 vs. USN 57VVal 18 vs. USN 57

300 2%

200

300

VVal-18200

TDT,

min

USN57

150 fswg

100

00 20 40 60

Bottom time, min

10

VVal-18 AlgorithmM difi dModified

• For air decompression• For air decompression– Increase bubble overpressure (PBOVP) from

0 f 10 f h i i0 fsw to 10 fsw to shorten air stop times• For oxygen decompression

– Keep bubble overpressure at 10 fsw– Reduce sat/desat ratio from 1 to 0.7 to re-

lengthen oxygen stop times. • Consistent with reduced tissue blood flow on O2

11• Modifications do not affect no-stop times

VVal-18 Mod Vs Experimental D t t 150 fData at 150 fsw

150 fsw g300Vval-18 Mod Vval-18

200

T, m

in USN 57

100TDT

00 20 40 60 80

12

0 20 40 60 80

Bottom tim e , m in

VVal-18M vs. USN 57120 f120 fsw

10

8

9

10%

)120 fswUSN 57

5

6

7

ty o

f DC

S (%

VVal-18M

2

3

4

Prob

abili

VVal-18

40 min

50 min

0

1

0 50 100 150 200 250

30 min

40 min

13Total Stop Time (min)

Reduction of TST with In-W t O 150 fWater Oxygen—150 fsw

35018M

250

300

min

)

18M Air

150

200

top

Tim

e (m

50

100

150

Tota

l St

18M Air/O2

0

50

0 10 20 30 40 50 60 70

14

Bottom Time (min)

VVal-18M vs. Experimental O D i D tOxygen Decompression Data

140

100

120

min

) 4/24

0/60

80

100

pres

sion

Tim

e (

1/60

40

60

Tota

l Dec

omp

0/23

0

20

120/50 170/40 150/55

15

DCS Risk with Air and O2120 f120 fsw

Bottom Air Air/O2Bottom Air Air/O2Time TDT Pdcs TDT Pdcs

25 12 2.20 8 1.9630 28 2.62 17 2.1740 55 4.18 31 2.7150 99 5 81 47 3 2850 99 5.81 47 3.2860 173 7.17 62 3.74

16

ORCA IIORCA II

17

18

New Air Table SetNew Air Table Set

• Air Decompression Table which gives the• Air Decompression Table which gives the decompression schedules and repetitive group designators.

• No-Decompression Table which gives the no-decompression limits and repetitive group designators for no-decompression dives.designators for no decompression dives.

• Surface Interval Credit Table

R id l Ni Ti T bl• Residual Nitrogen Time Table

• Flying After Diving Table

19

Air Decompression TableAir Decompression Table

• Contains schedules for 3 modes of ascentContains schedules for 3 modes of ascent– Air decompression in water– Air/O2 decompression in waterAir/O2 decompression in water– SurDO2

• Upon completion of 40 fsw stop• Upon completion of 40 fsw stop– Complete decompression on air at 30/20 fsw

C l d i O 30/20 f– Complete decompression on O2 at 30/20 fsw– Surface and complete decompression on O2 in

RCC20

RCC

Surface Decompression on OOxygen

• Rules identical to Surface Supplied Heliox• Rules identical to Surface-Supplied Heliox– Surface upon completion of 40 fsw stop– Surface interval not to exceed 5 min– Surface interval not to exceed 5 min– Recompress to 50 fsw. Breathe O2 for 15 min– Ascend to 40 fsw Complete remainingAscend to 40 fsw. Complete remaining

chamber O2 time at 40 fsw• Air Decompression Table gives number of p g

O2 periods required– Each O2 period 30 min long

21– 5 min air break after each O2 period

20 fsw Last Stop20 fsw Last Stop

• Choice based on operational considerations• Animal evidence supports superiority over

10 fsw during decompression on air – Hills BA, J. Appl Physiol., 1968– Hills BA, Clinical Science, 1970

I h tl i t 10 f d i• Inherently superior to 10 fsw during oxygen decompressionSt d d f ll t bl i M l t• Standard for all tables in Manual except MK 16 MOD 0, where it is optional.T bl b t d f 10 f

22• Tables can be recomputed for 10 fsw

Air Decompression Table150 f150 fsw

T t l Ch b150 fsw

Total ChamberBottom Gas Ascent O2 Repetitive

Time(min) Mix 80 70 60 50 40 30 20 Time (M:S) Periods Group

Air 0 5.00Air/O2 0 5.005 0 C

Decompression Stops (fsw)

Air 1 6.00Air/O2 4 9.00

Air 3 8.00Air/O2 5 10.00

F

15 0.5 H

10 0.5

Air 13 18.00Air/O2 10 15.00

Air 34 39.00Air/O2 21 26.00

0.5 K

1 M

20

25

Air 3 50 58.00Air/O2 5 26 36.00

Air 11 70 86.00Air/O2 9 30 49.00

Ai 4 1 99 12 00

1.5 Z

1.5 O30

35

23

Air 4 17 99 125.00Air/O2 4 13 32 59.00 2 Z40

Table SelectionTable Selection

In-Water Decompression on air > 15 Min

No Yes

Use In-Water Decompression on

AirIn-Water Air/O2 TDT > 90 Min

No Yes

U I W tUse In-Water Decompression on Air/O2 -or- Surface Decompression on

oxygen

Use Surface Decompression on

oxygen

24

VVal-18M vs. USN 57 150 f Ai Di150 fsw Air Dive

100

120m

in)

New AirTable

60

80

Sto

p Ti

me

(m

0 Jump

1 Jump

0

20

40

Tota

l

00 5 10 15 20 25 30 35 40 45

Bottom Time (min)

25

Comparison with Other Air T blTables

180

120

140

160

me

(min

) New USN

120 fsw

80

100

120

ompr

essi

on T

im

Canada

RN

20

40

60

Tota

l Dec

o

USN 57

00 10 20 30 40 50 60 70

Bottom Time (min)

26

In-Water Oxygen TimesIn Water Oxygen Times

60

70

)

50

60

2 Ti

me

(min

)

30

40

) In-

wat

er O

2

Line of Identity

10

20

VVal

-18(

M)

00 10 20 30 40 50

Canadian In Water O2 Time (min)

27

Canadian In-Water O2 Time (min)

Chamber Oxygen Time120 f S D O Di120 fsw Sur D O2 Dive

100

120

e (m

in)

CF

60

80

ygen

Tim

e

USN

RN

CF

VVal-18

20

40

mbe

r Oxy USN

00 20 40 60 80 100 120

B tt Ti ( i )

Cha

28

Bottom Time (min)

TestingTesting

No formal laboratory testingNo formal laboratory testing– Schedules felt to be inherently safer than

existing USN 57 schedulesg– Safety of in-water oxygen validated in Canada

Field testingField testing– Ulithi Atoll (USS Mississinewa oil removal)– Apra Harbor, Guamp ,– La Maddalena, Italy (Emory S. Land cleanup)

29

2003 SurDO2 Testing U S S MISSISSINEWAU.S.S. MISSISSINEWA

DEPTH BOTTOM TIME OUTCOMEDEPTH BOTTOM TIME OUTCOME(fsw) (min)83-90 46-99 0/78

91-100 44-108 0/22104-110 41-74 0/16112 114 32 53 0/6112-114 32-53 0/6

Total 0/122

30

2007 Field Test ResultsUSS E S L d ClUSS Emory S. Land Cleanup

Mode Depth Bottom Time OutcomeAi 60 120 25 80 0/26Air 60-120 25-80 0/26

Air/O2 55-120 25-110 0/133SurDO2 60-130 20-90 0/291

Total 0/450Total 0/450

31

VVal-18 vs. USN 57Sh ll N D Li it ( i )Shallow No-D Limits (min)

Depth USN 57 VVal 18Depth USN 57 VVal-1825 fsw 595 1103 30 f 405 37230 fsw 405 37235 fsw 310 232

f40 fsw 200 16450 fsw 100 9260 fsw 60 63

32

Experience with 40 fsw 200 i N D Li itmin No-D Limit

• NMRI Study (103 subjects, 3 cases of DCS)NMRI Study (103 subjects, 3 cases of DCS)– Auditory/cerebral DCS, residual memory loss

after multiple treatmentsp– Cutis marmorata, scintillating scotoma– Elbow painElbow pain

• Seaward Marine CVN hull cleaning ops11 cases of DCS 9 Type II over 20 years– 11 cases of DCS, 9 Type II over 20 years

– Dizziness, blurred vision, confusion, weakness200 i d di t i t d t d th f 37 f

33

– 200 min no-d dives restricted to depth of 37 fsw

VVal-18 vs. USN 57N D i TiNo Decompression Time

70

60

50

63

50

60(m

in)

USNVval-18

50

40

48

40

33

40

50

essi

on T

ime

(

30

25

20

33

29

2523

2020

30

No

Dec

ompr

e

15

10 10

5 5 5 5 5

1715 14

12 11 1010

N

34

060 70 80 90 100 110 120 130 140 150 160 170 180 190

Depth (fsw)

Repetitive Dive Clean TimeRepetitive Dive Clean Time

Repet Group Hr:MinRepet Group Hr:MinA 2:20D 5 23D 5:23G 8:00J 10:36L 12:21N 14:05Z 15:50

35

Allowable No-D Time at 80 f ft 80 /40 N D difsw after 80 /40 No-D dive

45

35

40

45m

e (m

in)

20

25

30

essi

on T

im

Std Air

10

15

20

Dec

ompr

e VVal-18

0

5

0 200 400 600 800

No

D

36

0 200 400 600 800

Surface Interval (min)

CNS Oxygen Toxicity RiskCNS Oxygen Toxicity Risk

6

4

5

ives

190 fsw 150 fsw

3

4

case

s/10

00 d

i

120 fsw

1

2

CN

S c

90 fsw

025 30 35 40 45 50 55 60 65

Bottom Time (min)

37

Ascent Rate and Stop TimeAscent Rate and Stop Time

• 30 fsw/min standard for all tables in Manual• 30 fsw/min standard for all tables in Manual• Ascent time between decompression stops

i l d d i h b iincluded in the subsequent stop time– Standard for all tables in Manual– Required re-computation of MK 16 Nitrogen-

Oxygen and Helium-Oxygen Tables for R i i 6Revision 6.

38

Recompression Chamber R i tRequirements

39

Required Surface Interval B f Fl i t 8 000 F tBefore Flying to 8,000 Feet

Repet Group Old Time New TimeRepet Group Old Time New TimeC 0:00 0:00D 3.28 1:45G 12:05 9:13J 17:35 14:13

M 21:37 18:00M 21:37 18:00Z 24:00 21:01

40

Multi-day Oxygen Exposure Li itLimits

• For MK 16 MOD 1 (PO2 = 1 3 atm)• For MK 16 MOD 1 (PO2 = 1.3 atm)– Maximum of 4 hours dive time per day

M i f 16 h di i k– Maximum of 16 hours dive time per week– If pulmonary or visual symptoms develop, stop

di i til t f f 24 hdiving until symptom free for 24 hours• Limits for other PO2 exposures not yet

bli h destablished

41

New USN Air TablesAd t-Advantages-

• Improves safety compared with current tablesImproves safety compared with current tables• Provides SurDO2 capability to 190 fsw• Provides repetitive dive capability after SurDO2Provides repetitive dive capability after SurDO2• Provides in-water O2 decompression

– Alternative to SurD for contaminated water– Reduces water time to acceptable level

• Allows repetitive diving between all modes of air d it di iand nitrox diving

• Repetitive group designator allows interface with VVal-18 based computers

42

VVal-18 based computers

New Air TablesDi d t-Disadvantages-

• Long decompression times on air force greater use• Long decompression times on air force greater use in-water O2 or SurD O2 options

• Logistic burden correspondingly increasedLogistic burden correspondingly increased• Small but finite risk of CNS oxygen toxicity exists

with in-water oxygen decompressionwith in water oxygen decompression• Oxygen cleanliness rules must be followed• Shorter 35-40 fsw No-D times will impact shipShorter 35-40 fsw No-D times will impact ship

husbandry dives unless computers used• Repetitive dive rules less permissive; some clean

43

Repetitive dive rules less permissive; some clean times greater than 12 hours

Summary A f di i iA new way of diving air

• Emphasis on use of oxygen for all but the h d i dishortest decompression dives– Either in-water oxygen decompression or

S DOSurDO2

– Allows a increase in safety without an increase i i t d i tiin in-water decompression time

44

AcknowledgementsAcknowledgements

Wayne GerthWayne GerthDavid DooletteKeith GaultKeith GaultDavid SoutherlandH h V LiHugh Van LiewDick Vann

h i bChris LambertsenMDV Brian Pratschner

45

46

Shallow versus Deep StopsGerth et al., 2008

170 fsw/30 min Air Dive TDT = 174 min170 fsw/30 min Air Dive, TDT = 174 minDecompression profile

70 60 50 40 30 20 10Shallow Stops: 0 0 0 9 20 52 93p

Deep Stops: 12 17 15 18 23 17 72OutcomeOutcome

– Shallow Pattern: 3 hits in 192 divesD P tt 11 hit i 198 di

47

– Deep Pattern: 11 hits in 198 dives

Dive Frequency at 120 fsw1979 19961979-1996

Bottom Time No DivesBottom Time No. Dives20 53925 57130 39040 29550 9150 9160 10

48

Oxygen Hazard Mitigation

Material Selection Evaluation System Cleanliness-Metals (Evaluate IAW ASTM G94)

-Non-Metals (Evaluate IAW ASTM G63)-System Design (Evaluate IAW ASTM G88)

y-MIL-STD-1330 (Navy Use)

-ASTM G93 Practice for Cleaning Methods and Cleanliness Levels fory g ( ) Methods and Cleanliness Levels for

Material and Equipment Used in Oxygen-Enriched Environments

Training of Personnel-Maintaining System Cleanliness

Dangers of Oxygen Systems-Dangers of Oxygen Systems-Oxygen System Operation Guidelines

A ti di f t d h d iti tiAny questions regarding oxygen safety and hazard mitigation can be addressed to Mr. Ryan Webb following this presentation.

In-water Oxygen TimesIn water Oxygen Times

70

50

60

me

(min

) VVal 18M = squaresVVal 18 = circles

40

50

wat

er O

2 Ti

m

Line of Identity

20

30

al-1

8(M

) In-

w

0

10VVa

50

0 10 20 30 40 50Canadian In-Water O2 Time (min)

2007 SurDO2 Dive Frequency120 f120 fsw

80

60

70

s

30

40

50

mbe

r of D

ives

10

20

30

Nu

030 35 40 45 50 55 60

Bottom Time (min)

51

Why not 50/50 nitrox?Why not 50/50 nitrox?

AdvantagesAdvantages– Minimal risk of CNS O2 toxicity in the water– No risk of making a mistake on composition– No risk of making a mistake on composition

DisadvantagesDid not provide enough reduction of– Did not provide enough reduction of decompression times to satisfy operators

– More difficult to obtain in remote areas– Mixing and oxygen analysis required

52

Recompression Chamber R i tRequirements

53