Condensed D022 Exam Flashcards
40F to Celsius
5/9 x (F-32)
.556 x (8)
= 4.4 Celsius
40C to Fahrenheit
= (9/5 x C) + 32
= (1.8 x 40) + 32
= 104 Fahrenheit
40C to Kelvin
C+ 273
= 313 Kelvin
40F to Rankin
F + 460
=500 Rankin
Healthy Reminders
25% is 25/100 or 0.25
250ppm is 250/1,000,000 or 0.00025
ppm to decimal move it back 6 places or / 1,000,000
ppm to % move it back 4 places or / 10,000
ppm to mb / 1000
400ppm is 0.0004
650ppm is 0.065%
Fun Fact
*useless info
Gas reclaim systems have an average loss of 5 liters/min
Normal gas consumption at 140m
35lpm x 15b
=525liters or 0.525m3
Normal gas consumption at 120fsw
120/33 +1= 4.64ata
1.25ft3/min x 4.64 =
= 5.8ft3/min
64bottle quad charges to 200bar, 50L cylinders.
How much gas is available?
64 x 50 x 200 = 640,000L
=640m3
Note: total volume don’t mean shit, available gas does
Re: a quad charged to 200bar
- you still need to overcome bottom pressure, ex 140m dive requires 15bar
- still need 10bar to drive the reg
-plus a safety factor
Looking at changing quads around 40bar.
You can go lower with shallow surface dives
16 x 50L quad charged to 180bar
To be changed over at 40bar
Diver is working at 100msw
How long can the Diver work for?
180bar - 40bar =140bar
140bar x 50L x 16 = 112,000L
Diver 35Lpm x 11 = 385Lpm
112,000/385 = 290.9
290.9/60 = 4.85
0.85 x 60 = 51min
4hrs 51min
Imperial
A quad contains 22,400ft3 @ 3000psi
Gauge now reads 2400psi, change the quad over at 500psi.
How much gas is available?
FGV= vol when full x (available pressure/pressure when full)
22,400 x (1900/3000)
22,400 x 0.63
=14,186.7 ft3
Or
22,400 / 3000 x 1,900
Suitable compressor?
-LP comp supplies 8ft3/min @250psi
-2divers @ 80fsw
Pressure Required:
80fsw/33+1= 3.42ata
+10ata for reg
=13.42ata
13.42ata x 14.7psi
=197.27psi (All Good)
Volume Required
3.42ata x 1.25ft3 x 2divers = 8.56ft3/min
(No Joy)
Compressor can’t supply enough volume
Bailout endurance
Diver working at 180msw and has a 12L bottle charged to 180bar
How long will it last in an emergency?
40Lpm metric 1.5ft3 imperial
2180bar -10reg -19bar depth = 151bar available
151bar x 12L = 1812L
19 x 40Lpm = 760Lpm
1812/760 = 2.38 (0.38x60)=22.8
=2min 23secs
What is the breathing rate for BIBS?
Imp and metric
0.7ft3/min
20L/min
In sat you should have enough gas to provide 4hrs breathing on BIBS per Diver for each mix.
Give me the formula for Final pressure after temperature corrections
Final Pressure = Initial Pressure x Final Temp (R or K)
—————————————————
Initial Temperature (R or K)
Make sure you convert to temperature absolute.
