1. What are the 6 tables used for air decompression? 1) No-Decompression limits & Reptet Group Designatoin Table for No"D" Air Dives. 2) Air Decompression Table. 3)Residual Nitrogen. Timetables for Repet Air Dives. 4)Sea Level Equivalent Depth Table. 5)Repet Groups Associated w/ Initial Ascent to Altitude Table. 6) Required Surface Interval Before Ascent to Altitude After Diving.
2. What are the 3 modes of the Air Decompression Tables? (1) In-water decompression using air. (2) In-water decompression using on air & O2. (3) Surface decompression on O2.
3. True or False; The Repet Group Designator for air decompression and air/O2 decompression are the same?
True, they are the same for both.
4. What is required to dive a second dive team when you have divers decompressing in the chamber?
The chamber and surface-supplied diving system must have separate air supplies.
5. What is your course of action if you decide to Sur"D" your diver while he is at his 30'or 20' O2 stop in-water decompression stop?
Multiply all remaining in-water O2 time 1.1, divide the total by 30, then round up the results to the next highest half period. (:15)
6. What are the benefits of using oxygen during decompression?
The use of oxygen helps accelerate elimination of excess nitrogen from the body.
7. What two things directly effect nitrogen absorption in the body?
Depth and time at depth.
8. During a Sur ‘D’ O2 dive in the chamber, you and green diver are breathing oxygen (BIBs). While whining about how cold it is, lying to green about how all the women at the bar wanted you last night and sharpshooting what the Dive Supervisor could have done better, green diver starts to convulse. State the proper course of action that needs to be taken.
Remove the mask. After all symptoms have completely subsided, decompress 10 feet at a rate of 1fsw/min. For a convulsion, begin travel when the patient is fully relaxed and breathing normally. Resume oxygen breathing at the shallower depth at the point of schedule interruption.
10. List 4 advantages to decompressing a diver in a chamber rather than in the water.
1) Shorter exposure time in the water. 2) Inside the chamber the divers can be maintained at a constant pressure, unaffected by the surface conditions of the sea. 3) Once divers have been recovered into the chamber another dive team can begin descent.
11. State the RNT exception rule.
In some cases, the residual nitrogen time may be longer than needed to provide adequate decompression on the repetitive dive. This situation is most likely to occur when the surface interval between the dives is short. After determining the decompression requirement for the repetitive dive the diver should recalculate the requirement by summing the bottom times of the two dives and taking the deepest depth. If the resultant table and schedule produces a longer no-decompression time or a shorter decompression time, the table and schedule with the lesser decompression obligation may be used.
12. Explain the “Safe Way Out” procedure.
If a diver is not able to reach 50 fsw in the chamber because of difficulty equalizing middle ear pressure. Compress the diver to the deepest depth he can attain initially. This will usually be less than 20 fsw Begin oxygen breathing at that depth. Continue attempts to gradually compress the diver deeper. Double the number of chamber oxygen periods indicated in the table and have the diver take these periods at whatever depth he is able to attain. Oxygen time starts when the diver initially goes on oxygen. Interrupt oxygen breathing every 60 minutes with a 15 minute air break. The air break does not count toward the total oxygen time. Upon completion of the oxygen breathing periods, surface the diver at 30 fsw/min. Carefully observe the diver post-dive for the onset of decompression sickness.
13. Explain the protocol for a surface decompression dive in which the surface interval exceeds 7 minutes.
If the surface interval is greater than 7 minutes, continue compression to a depth of 60 fsw. Treat the divers on a Treatment Table 5 if the original schedule required 2 or fewer oxygen periods in the chamber. Treat the divers on Treatment Table 6 f the original schedule required 2.5 or more oxygen periods in the chamber.
14. What is the procedure when your divers reach their first stop in 3::16, and they were supposed to get there in 1::14 and their time to 50’ was under a minute late?
Add :03 to first stop time
15. What is the procedure when your divers take 1::47 to get to their 20’ stop from their 30’ stop on an air/O2 dive?
Count that time to the 20’ stop time.
16. Commercial airplanes are pressurized to what altitude?
8000’
17. If your decompression stop in the water is 35 minutes, do you take an air break?
No
18. At what depth do symptoms of hypercapnia usually become apparent?
