Mixed Gas Diving Supervisor Flashcards
Familiarize with the procedural steps of conducting a mixed gas dive as a Diving Supervisor
What stations shall be manned by formally (NDSTC) tained mixed gas diver
- Diving Officer
- Master Diver
- Diving supervisor
What stations shall be manned by formally trained (NDSTC) surface supplied diver
- Diver
- Standby Diver
- Rack operator
- Console operator
- Timekeeper/Recprder (Logs)
What positions can you use a non-diver
- Tender
- Standby Tender
- Winch Operator
When is a Diving Medico Officer (UMO) required to be on the side?
- All planned exceptional exposure dives
- Dives planned to exceed normal working limits
Is a Master Diver and Dive Medical Technition (DMT) required on dive station for mixed gas operations
Yes
What is the Surface Supplied HeO2 Diving Minimum Equipment
- MK 21 MOD 1 or KM-37NS with umbilical
- Thermal protection
- Hot water suit - Wet suit - Dry suit
- Weight belt (If required)
- Dive Knife
- Fins or boots
- EGS w/ submersible tank presure gage
- Surface supplied diving harness
What are the normal operational limit for surface supplied mixed gas
300 FSW for 30 Minutes
How much sleep do divers need before mixed gas dive
8 hours within the last 24 hours
To minimize pulonary O2 tox effects divers should take a ______ break after ______ of diving
Take a 1 day** break after **4 consecutive days of diving
Is repeative diving allowed in surface supplied helium oxygen diving
No
(Exception- dive aborted during decent shallower than 100 FSW)
Following a “No-Decompression Dive” the diver must wait ______ before making a second dive
12 Hours
Following a decompression dive, divers must wait ______ before a second dive
18 Hours
Following a no-decompression dive the diver must wait ______ before acent to altitude
12 Hours
Following a decompression dive, divers must wait ______ before ascent to altitude
24 Hours
Helium has a _____________ wich can cause rapid loss of body and respiratory heat
high thermal conductivity
Helium oxygen mixtures must be analyzed with an instument having an accuracy of _______
+/- 0.5 percent
Bottom Mixture ranging
90/10 He/O2
to
60/40 He/O2
50% He / 50% O2 used for what depth and range of mix
90 FSW to 40 FSW
49-51%
100% O2 is used at what depth
Used at in-water SurD
What mix is EGS
Same as bottom mixture (unless less than 16% O2, then use range from 15-17% O2)
What is the maximum oxygen concentration for a diver never shall exceed an O2 partial pressure of ___________ while on bottom
1.2 ata (Cut off depth)
Descending with < 16% O2
Mixed Gas
- Hat bolth divers on air on the surface
- Up/Over to 20 fsw
- Shift to pri BM, vent diver for ::20, leak check
- BT begins when divers leave 20’ or :05 at 20’
Abort Procedures < 100’ or > 100’
Mixed Gas
- Ensure divers are in No “D” status
- If BM is > 16% O2, ascend to surfaces 30 fpm
- If BM is < 16% O2, ascend to 20’ shift to air, vent bolth divers, confirm, ascend to surface
- If aborted < 100’ add BT of all dives to BT of new dive, use deepest depth to calculate T/S
- If aborted > 100’ no repet dives
Light headed or dizzy on bottom
Mixed Gas
- Have diver stop working, vent rig, verify O2 on Analox
- If bad gas suspected, shift divers/ stby to Sec BM
- If entire gas supply is suspected, shift to EGS, abort
Unconsious diver on the bottom
Mixed Gas
- Verify MMP and O2%
- Check status of other diver
- Vent affected diver
- if bad gas suspected, shift to Sec BM, vent all divers
- Check for breathing, abort dive
- Bring diver to first ‘D’ stop, if breathing continue ‘D’
Loss of Bottom Mix on the bottom
Mixed Gas
- Shift to Sec BM abort dive
- If can’t shift to Sec BM, shift to EGS, abort dive
- at 90 fsw, shift to 50/50, resume decompression
- If EGS exhausted before 90’, shift to air, shift to 50/50 at 90 fsw, resume decompression
Bottom time excess of table
Mixed Gas
- Decompress onthe :120 schedule using DD
- Shift to 100% O2 at 40 fsw, complete :30
- Sur ‘D’ up/over to 60’in chamber
- TT-6 with max extensions
Delay to First sop > :01
Mixed Gas
- Round delay up to next whole minute, add to BT
- Recompute T/S. if no changes, continue deco
- If change, preform missed stops at current depth, dont go deeper
Delay in leaving or arriving at next stop > 90’ > :01
Mixed Gas
- Round delay up, add to BT recompute
- If no change, continue decompression
- If change, pick up new schedule, ignore any missed stops/times
Delay in leaving or arriving at next stop < 90’ > :01
Mixed Gas
- Can be ignored unless between 90’ -70’
- Delays > :05 btwn 90’-70’ shift to aire, add any time on air to BT, recompute, if change in schedule, pick up new schedule at current depth, ignore any missed stops/times
Loss of 50/50
- Shift to air, continue decompression
- If fixed, shift back to 50/50, time on air counts
- If can’t be fixed continue on air to 50 fsw
- Shift to 100% O2, NTE :16 at 50 fsw
- If exceeds :16 at 50’ travel to 40’ and add remaining time to 40’ stop time, Sur ‘D’
CNS O2 Toxicity (Nonconvulsive) at 90’-60 stops
- Bring divers up 10’ shift to air
- Vent affected diver, then unaffected diver
- Remain at stop until previouse stop is made up
- Continue decompression
- At next stop, shift back to 50/50, resume decompression
CNS O2 Toxicity (Convulsive) at 90’-60’ stops
- Shift to air, vent unaffected diver, than affected
- Wait for Tonic/Clonic phase
- If breathing decompress to 50’, shift to 50/50, Sur ‘D’ at completion of 40’ Stop
- If not breathing reposition airway, if still not, launch stby to assist stricken diver to surface, treat for AGE, leave unaffected in water to complete decompression
CNS O2 Toxicity (Nonconculsive) at 50’-40’ stops
- Up 10’, shift to air, vent affected, then inaffected
- Douvle missed time if on 50/50, triple if on O2
- Sur ‘D’ after completion of time
- If Sur ‘D’ is not fesible, continue on Air or O2
- On O2, at 30’, take a :10 air break, shift to O2, resume deco
- ON Air, at 30’, tripple stop time
