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From: Andy Hall <mbhphaa@es*.ee*.ma*.ac*.uk*>
Date: Tue, 28 Nov 1995 17:08:49 GMT
To: techdiver@terra.net
Subject: RMV
For any insomniacs out there, instead of counting sheep try calculating
your RMV from your last dive instead ( read the profile back off your
computer and draw it on graph paper ).


Calculation of RMV for dive:-
(In Imperial units - Vive la difference ?)

0    5    10   15   20   25   30   35   40   45   50 Time in minutes
|    |    |    |    |    |    |    |    |    |    |   
*****************************************************- Surface _
\         |       |        |  1.6ata      |__1.3ata_/10ft _
 \        |       |        |_____________/20ft _
  \       |       |       /30ft _
   \2.5ata| 4.0ata|2.3ata/
    \     |       |     /
     \    |       |    / 60ft _
      \   |       |   /
       \  |       |  /
        \ |       | / 
         \|_______|/100ft _

Dive  Profile

Time(Mins) * Pressure(ata) = Equivalent time on surface(mins)
10	   * 2.5           = 25
 8         * 4.0	   = 32
 9	   * 2.3	   = 21		
15         * 1.6	   = 24
10	   * 1.3	   = 13
			    ____
                            115mins Equivalent surface time
			    ____	
Tank pressure in  3364 psi
-Tank pressure out 725 psi
		  _____
 		  2639 psi	
		  _____

Tank is 103 cuft at 3364psi = 0.444 cuft water capacity 

2639psi/14.5psi = 182ata air used during dive
Therefore, Volume used is 182 * 0.444 = 80.8 cuft

80.8 cuft / 115 mins = 0.702 cuft/min. !

----------------------------------------------------------
or in Metric :-

0    5    10   15   20   25   30   35   40   45   50 Time in minutes
|    |    |    |    |    |    |    |    |    |    |   
*****************************************************- Surface _
\         |       |        |  1.6bar      |__1.3bar_/3m _
 \        |       |        |_____________/6m _
  \       |       |       /10m _
   \2.5bar| 4.0bar|2.3bar/
    \     |       |     /
     \    |       |    / 20m _
      \   |       |   /
       \  |       |  /
        \ |       | / 
         \|_______|/30m _

Dive  Profile

Time(Mins) * Pressure(ata) = Equivalent time on surface(mins)
10	   * 2.5           = 25
 8         * 4.0	   = 32
 9	   * 2.3	   = 21		
15         * 1.6	   = 24
10	   * 1.3	   = 13
			    ____
                            115mins Equivalent surface time
			    ____	
Tank pressure in  232 bar
-Tank pressure out 50 bar
		  _____
 		  182 bar	
		  _____

Tank is 12L water capacity, 232 bar 

182bar air used during dive
Therefore, Volume used is 182 * 12 = 2184L

2184L / 115 mins = 19 L/min !

------------------------------------------------

And Why Not !

Cheers,
Andy.

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