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45 Cards in this Set
- Front
- Back
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Describe the oxygen off-effect? |
The off-effect may occur several minutes after the diver comes off gas or experiences a reduction of oxygen partial pressure. The off-effect is manifested by the onset or worsening of CNS oxygen toxicity symptoms.
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What are the symptoms of a chemical injury?
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Symptoms will begin with rapid breathing or headache immediately progressing to choking, gagging, foul taste, and burning of the mouth and throat ("Caustic Cocktail")
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What is the treatment for a chemical injury?
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Assume an upright position, Depress the manual bypass valve continuously and make a controlled ascent to the surface, rinse mouth out with fresh water. Do not induce vomiting and seek medical attention immediately.
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What are the symptoms of middle ear oxygen absorption?
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Pressure or mild discomfort, muffled hearing, a moist crackling sensation
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What are the normal/maximum working limits of the MK-25 Mod 2 UBA? |
Normal working limit - 25 fsw for 240 minutes
Maximum working limit - 50 fsw for 10 minutes |
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When does a diver's excursion time start and end?
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Excursion time is the time between the diver’s initial descent below 20 fsw and his return to 20 fsw or shallower at the end of the excursion.
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Define a successive oxygen dive?
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A successive oxygen dive is one that follows a previous oxygen dive after an Off-Oxygen Interval of less than 2 hours.
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According to the U.S. Navy Dive Manual how long may you leave the CO2 absorbent in an air tight MK-25 MOD 2 rig and still dive the rig?
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14 days
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How many excursions are allowed during a MK-25 MOD 2 UBA dive?
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One
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Name the NAVSEA approved CO2 absorbents?
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High Performance Sodasorb, Regular
Sofnolime 4-8 Mesh NI, Grade L Sofnolime 8-12 Mesh NI, Grade D Divesorb Pro 5-8 Mesh Refer to Table 19-2 |
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What is the maximum oxygen time permitted in a 24 hour period? |
4 hours
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How do you calculate an adjusted oxygen exposure limit for a successive oxygen dive? |
Single Depth Limit - Determine the max O2 time for the deepest exposure, then subtract the O2 time from the previous dive from the maximum O2 time
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What are the restrictions for flying after an oxygen dive? |
Fly immediately unless the O2 dive has been part of a multiple-UBA dive profile where the diver was breathing another mixture (i.e. air, N2O2, or HeO2)
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Where can I find UBA canister duration limits?
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NAVSEA 00C3 ltr 3151 ser 00C34/3160, 27 Sep 01
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What is the primary cause of hypoxia while diving the MK-25 UBA? |
Improper or inadequate purge of the UBA
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What is the difference of the fiberglass (MOD O) and molded urethane (MOD 2) CO2 canisters?
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The urethane (MOD 2) canister can be completly disassembled for cleaning
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Can you use 8-12 mesh absorbent in the fiberglass canister (MOD O)? Yes/ No |
No
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When wearing the MK-25 UBA, where is the red dot located?
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Top left
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What position is the dive/ surface valve in when on bag (oxygen)? |
Up = dive
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Is a DMT/ SOT required for MK-25 closed-circuit diving? T/F |
True (Group One instruction)
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What are the Single Depth Oxygen Exposure Limits? |
25FSW - 240 min
30FSW - 80 min
35FSW - 25 min
40 fsw - 15min
50 fsw - 10 min |
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Max Excursion Times |
21-40 fsw = 15 min
41- 50 fsw = 5 min |
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What are the 3 options for an inadvertent excursion? |
1) If the excursion exceeds the limits of max O2 time or SDL, abort dive.
2) IF the excursion is within the limits continue dive.
3) The dive may be treated as an SDL if within SDL limits. |
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What are the cause of hypercapnia? |
1) Improper packing of Soda Sorb, leading to channeling 2) Improper leak test, leading to flooding 3) Over exertion 4) Exceeding the canister duration limits 5) Skip breathing |
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Symptoms of Hypercapnia |
Increased Breathing Rate Labored Breathing Headache Confusion Unconsciousness |
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Symptoms of Hypoxia |
Confusion Loss of coordination Dizziness Convulsions |
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When is a convulsion hypoxia related vs. CNS O2 related? |
A convulsion at the beginning of a dive is hypoxia related. |
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What are the causes of CNS O2 Toxicity? |
Increased partial pressure of O2 below 25ft Time of Exposure Prolonged Immersion Stress from strenuous physical exercise Carbon dioxide buildup Cold Stress Certain Thyroid or Adrenal Disorders |
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What are the temperature operational limits? |
35F - 99F |
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When using 8-12 Mesh D-Grade Sofnolime within what timeframe shall the canister be packed? |
Same day as the dive |
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When using 4-8 mesh what is the time frame for packing the canisters? |
2 weeks |
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A dive is aborted when the O2 pressure reaches what pressure? |
50 bar or 725 PSIG |
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Use of a Neoprene canister sleeve is recommended at what temperatures, and mandatory below what? |
40 - 60 F
Below 40 F it's mandatory |
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Water Temperature of 40 degrees F limits the duration of the canister to how many minutes? |
91 min |
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What mesh is used for the MOD 0 canister? |
4-8 only |
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What is the temperature operational limit of the MOD 0 canister? |
40 - 90 Degrees F |
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What is the maximum O2 time allowed in a 24 hour period? |
240 minutes |
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Warm water working operation limits |
88 - 94 F - Limited to canister/O2 bottle duration 94 - 97F - Limited to 3 hours based on physiological limits 97 - 99F - Limited to 1 hour based on physiological limits |
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Warm water resting diver limits |
88 - 94 F - Limited to canister/O2 bottle duration 94 - 97 F - Limited to canister/O2 bottle duration 97 - 99 F Limited to 2 hours based on physiological limits |
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Divers should hydrate with how much water how long before a dive? |
500ml, 2 hours before the dive |
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What type of fluids should be drank immediately following a dive? |
Electrolyte beverages |
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Dive Manual limitations for oxygen exposure are for what type of operations? |
Training and exercise scenario's |
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What are the limitations of O2 diving at altitude? |
None, no changes to durations or depths are needed. |
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What is the normal gas consumption for a MK25 diver at a .8 knot pace? |
15-17 psi/min |
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When is hypoxia most likely to occur? |
On surface, and less likely at depth due to partial pressure allow enough O2 in the mix. |
