calculations

Question 1

A diver is down for 20 mins at 30m doing light work. What cylinder size?

WP= 232 Bar

Answer 1

30m = 4 bar
consumption rate = 4 bar x 25 for light work = 100 litres/ min
total consumption for job = 100 x 20 = 2000 litres
reserve air = 500 litres
total air = 2500 litres

cylinder size = total air (air for job + reserve)        2500
                        -----------------------------------------     =  ---------    = 10.77 litres = 12 litre cylinder. 
                       working pressure (WP)                     232

Question 2

air available calc

Answer 2

WP x cylinder size

Question 3

air for job calc

Answer 3

breathing rate at depth x time for dive

Question 4

50 bar reserve
10l cylinder at 200 bar
10m and light work

how much time to dive

Answer 4

air available for job= (200-50) x 10 = 1500 litres

breathing rate at depth =. 2 x 25 = 50 litres a min

1500/ 50 = 30 mins

Question 5

1cm3 = ? ml

Answer 5

1ml

Question 6

1m3 = ?litres

Answer 6

1000 l

Question 7

1 bar = ? kg per cm2

Answer 7

1 kg/ 1 cm2

Question 8

fresh water density

Answer 8

1000 kg / m3

Question 9

salt water density

Answer 9

1030 kg/ m3

Question 10

daltons triangle

Answer 10

                                | fraction of the gas.    |      absolute pressure 
                               |

Question 11

what is the partial pressure of o2 at 24m using nitrox 36?

Answer 11

percentage of o2 = 36% = 0.36
absolute pressure = 3.4 bar

po2 = o2 (as decimal!!!!!) x bar
4.4 x 0.36 = 1.22 bar

Question 12

standard breathing rate (SBR) for

light work

Answer 12

25 litres per min

Question 13

standard breathing rate (SBR) for

moderate work

Answer 13

40 litres per min

Question 14

standard breathing rate (SBR) for

hard work

Answer 14

70 litres per mim

Question 15

breathing a mix containing 40% o2 at 21m. what is the equivalent air depth?

Answer 15

equivalent air depth =
n2% (decimal) x (D+10)
———————————– - 10
0.79 *

0.6 x (21+10)
—————— - 10
0.79
= 23.54- 10
=13.54 m

Question 16

equivalent air depth calculation (metric)

Answer 16

n2% (decimal) x absolute depth (D+10)

• ——————————————————– - 10
  0. 79 *

*standard n2 % as dec

Question 17

calculate max depth for nitrox32

hint scuba pressure limit is 1.4 bar

Answer 17

absolute pressure = pO2/ gas frac.

1.4 / 0.32 = 4.38 bar = 33.8 m

Question 18

calculate max depth for nitrox36

hint scuba pressure limit is 1.4 bar

Answer 18

absolute pressure = pO2/ gas frac.

1.4 / 0.36 = 3.888888888 bar = 28.9 m

Question 19

depth calculation

Answer 19

(absolute pressure - atmospheric pressure) x 10

Question 20

absolute pressure calculation

Answer 20

depth (m)
———- + atmospheric pressure
10