Follow on Sat situation Flashcards
USE FOLLOWING VALUES
Questions 1 to 9 — Mobilise a job where the work is at two different depths, the following information must be used for these questions.
Divers Gas Consumption:-
35 L/min, 1.25ft3/min
Divers Gas consumption from a bail out bottle in an emergency:-
40L/min, 1.5ft/min
Metabolic oxygen consumption in chambers:-
0.72m3/day or 0.5L/min per diver or
25ft3/day or 0.018ft3/min per diver
SYSTEM:- 1 SDC (Bell) = FV 5m3 2 DDC of equal FV which is unknown, but prior to sat it required 672m3 of gas to blowdown DDC’s and TL’s to 120msw 2 TL’s = FV 10m3 each 3 teams of 2 divers
WORK SCHEDULE:- Team 1 to carry out a total of 6 lockout hours per day at 35msw, between 0001hrs and 0700hrs using DDC 1 and TL 1, storage is 30msw assume bell is deployed to work depth. Team 2 and 3 are to carryout a total of 14 lockout hours per day at a depth of 160msw between 0800hrs and 2400hrs using
DDC 2 and TL 2, storage is 150 msw. Assume the bell is deployed to working depth.
GAS :
Mix 1 = 140 bar 10/90
Mix 2 = 165 bar 3/97
Mix 3 = 190 bar 2/98
DURATION:-
Team 1 = 7 days Saturation with 3 days decompression
Team 2 and 3 = 5 days saturation with 5 days decompression
COMPANY POLICY:- 100% Gas reserves for DDC’s, TL’s, SDC and Diving.
- What is the F.V. of a single chamber without the TL ?
(a) 16.25m3
(b) 17 m3
(c) 18 m3
(d) 23 m3
2. What is the total volume of gas required to pressurise DDC 1 and TL to 30msw and DDC 2 and TL 2 to 150msw ? (a) 504 m3 (b) 525 m3 (c) 540 m3 (d) 594 m3
- Which of the following is the total gas required for diver lockout per day for
teams 2 and 3, assuming a consumption rate of 35 litres per minute?
(a) 6720 litres
(b) 7140 litres
(c) 470400 litres
(d) 499800 litres - Ignoring diver lockout but including decompression, what is the total volume
of metabolic oxygen consumed by the 6 divers during their saturation?
(a) 1800 litres
(b) 43200 litres
(c) 86400 litres
(d) 65000 litres - To supply the correct PPO2 the company tables require a 4% oxygen mix on a
dive to 160msw, what oxygen % will be required at 35msw?
(a) 14.2%
(b) 15.1%
(c) 18.3%
(d) 19.4% - How much gas is used to pressurise the bell between the hours of 0001 hours
and 2400 hours when all three teams are diving? (ie 1 day of normal diving operations after the first day)
(a) 60 m3
(b) 65 m3
(c) 72.5 m3
(d) 87.5 m3
- If one of the TL’s is leaking 17 m3 of gas per day while isolated from the DDC
due to leaks. How many m3/hour does this equate to?
(a) 0.29m3/hr
(b) 0.71m3/hr
(c) 1.25m3/hr
(d) 1.7m3/hr - During decompression of teams 2 and 3 at what depth should the 12% BIBS
mix be changed to prevent the PPO2 from dropping below 1.5 bar?
(a) 90msw
(b) 105msw
(c) 115msw
(d) 125msw
9.From the gas mixes available a mix of 200 bar of 5% is required. What are the
options?
a. 165 bar of 3% & 35 bar of 2% OR 125 bar of 2% & 75 bar of 10%
b. 143 bar of 3% & 57 bar of 10% OR 125 bar of 2% & 75 bar of 10%
c. 143 bar of 3% & 57 bar of 10% OR 140 bar of 2% & 60 bar of 3%
d. 130 bar of 3% & 70 bar of 10% OR 110 bar of 2% & 90 bar of 10%
- C
672/12 = 56m3 both chamber.
56/2 = 28m3 each chamber.
28 -10 = 18m3 chamber without the TL.
- A
DD1 = 28 x 3 = 84m3 DD2 = 28 x 15 = 420m3
Total = 504m3
- D
17(depth) x 14(h) x 60(min) x 35(l/m) =
499800litres or 499.8m3
- B
10days x 6divers x 0.72m3/day =
43.2m3 or 43200l of O2
- B
17 x 4% = 0.68bar ppo2
companies table.
- 68/4.5 = 15.1% at 35m
- C
Team 1 = 30m to 35m so
0.5 x 5 = 2.5m3
Ps: After lockout return to 30m to lock the team back to system.
Team 2 = 30m to 150m to 160m so….
13 x 5 = 65m3
Ps: After lockout return to 150m to lock the team back to system.
Team 3 = 150m to 160m so…
1 x 5 = 5m3
Than…
- 5 + 65 + 5 = 72.5m3 total.
- B
17/24 = 0.71m3/hr
- C
1.5/12% = 12.5 - 1 = 11.5 x 10 =
115m
- B
200 x (5 -2)/(10 - 2) =
75bar of 10%
so…
200 - 75 = 125bar of 2%
or triangle
200/7 = 28.5 comum factor
5 x 28.5 = 143bar of 3%
2 x 28.5 = 57bar of 10%
PS: If you read the answers carefully REMEMBER you cannot make 5% using 2% and 3% !!!!
You are mobilising a DSV and the system consists of 1 bell (FV 6m3), 2 DDC’s (FV unknown) and 2 E/L’s (FV 8m3 each). The FV of the DDC’s is not known but on a previous sat blowdown to 90 msw, 500 m3 of gas was used for the DDC’s and the E/L’s.
There are 3 dive teams (each 2 man) and they share the same bell. Team 1 will live at 40 msw and work at 50 msw diving for 7 hours a day. Teams 2 and 3 will live at 170 msw working at 185 msw. Both teams dive for 7 hours each day.
a) What is the volume of a DDC?
b) What is the amount of gas used to pressurise Teams 2 and 3 in DDC 1 and E/L 1 to living depth?
c) DDC 1 and E/L 1 were pressurised from 0-3 msw on 16%. What was theppO2 at 3 msw? From 3 to 170 msw on 2% what was the ppO2 at 170 msw?
d) What was the initial depth blowing down on 20% and then on 2% for DDC 2 and E/L 2 to 40 msw to give a PO2 of 430 mb?
e) What is the amount of gas used by Teams 2 and 3 per day diving? (using 35 l/min)
f) What % O2 are the divers using at dive depth with a ppO2 of 700 mb?
g) What is the metabolic O2 consumption for all 3 teams over 10 days?
a. FV = FGV 500 = 55.5
PRESS 9 - 16 = 39.5 / 2 = 19.75
b. 420 m3 20 + 8 = 28 x 17 = 476m3
c. 258 mb 3.3 % 592mb
d. 7.8 msw on 20%
32. 2 msw on 2%
e. 655.2 m3
f. 3.6%
g. 42m3
A saturation system consists of two 24m3 living chamber, an 8m3 transfer chamber and two 6m3 bells. The storage depth of the system will be 85 msw, with a working depth of 95 msw.
Lockout partial pressures of O2 will be 600 to 800 mbars. Twelve divers will dive in teams of three with two divers locking out for a period of 6 hours each and each team will carry out 1 dive a day for a 12 day sat, followed by a 4 day decompression. Work out the following:
a) The amount of gas used to pressurise the system to living depth
b) The amount of gas used by the divers for the entire saturation if the divers reclaim system is working (assume rate as 5 lts/min)
c) The amount of gas used if on freeflow for a one off 6hr dive(assume 35lts/min)
d) The % O2 range for the dive depth
e) The amount of gas used to pressurise the bells in a 24 hour period (4 bell runs a day with the bells going to work depth, do not include the initial blowdown to storage depth.)
f) The metabolic O2 usage for 16 days
g) The O2 partial pressure of the storage depth if the O2% is 3.7%
A) 68m3 x 8.5 BAR(G) = 578m3
B) 12 days x 24hrs x 2 divers x 5 ltrs x 60 mins x 10.5 BAR(A)
= 1814400lts = 1814m3
C) 6 hrs x 2 divers x 35 ltrs x 10 BAR(A)
X 60 mins = 264600lts = 264.6m3
D) 5.7 % - 7.6 %
E) 24 m3
F) 134.4m3 (using 0.7m3/Day) 138.2m3 (30 lts / Hr)
G) 352 mb
