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SuperLite
17B
Supply Pressure Requirements & Tables
Table 1 should be used whenever low pressure
compressors are used or when using surface control
panels that are limited to outlet pressures within the
range of 220 psig or less.
It is important to insure the required outlet pres-
sure from the table can be maintained in a stable
manner at the surface to insure adequate supply at
depth. When used with high pressure consoles that
can regulate pressures greater than 220 psig use
Appendix 3 Table 2 SuperFlow
Regulator High Pressure Regulated Source.
Diver Work Rates
The divers work rate, also known as respiratory
minute volume (RMV), is basically how hard the
diver breathes. As the diver's physical exercise
increases, so does the ventilation rate. Proper train-
ing teaches the diver to never push the work rate
beyond normal labored breathing. (This is in the
30-50 RMV range). To put things in perspective,
heavy work for a physically fit person:
Swimming at one knot is about
Running at 8 miles per hour is about 50 RMV.
Once the diver hits 55 RMV, they are entering the
extreme range. Many fit divers can do 75 RMV
for one to two minutes providing the inhalation
resistive effort of the breathing system is not much
above 1-1.3 J/L. The divers work rate should never
be so heavy that the diver cannot maintain a simple
conversation with topside.
When the work rate gets into the moderately heavy
to heavy range 40-50 RMV the diver needs to slow
down!
Working to the point of being excessively winded
should be avoided at all costs!
Working at rates greater than 58 RMV underwa-
ter is extreme, and can pose hazards that are not
present when doing extreme rates on the surface.
When underwater, inhalation and exhalation resis-
tive effort increases due to the density of the breath-
ing gas and resistive effort of the equipment. The
increase in resistive effort can cause an increase in
blood level CO
because the diver cannot ventilate
2
as freely as when breathing at the surface. When
breathing air at the deeper depths, nitrogen narcosis
164
Appendix 3
/ SuperFlow
350
®
®
38 RMV.
© ⅯⅯⅩⅡ Kirby Morgan Dive Systems, Inc. All rights reserved. Document # 120613005
can mask CO
symptoms which can then snow-
2
ball into even heavier breathing, often resulting in
confusion, panic, and in rare cases muscle spasm,
unconsciousness, sometimes resulting in death.
In some rare cases high ventilation rates has been
suspected as the cause of respiratory barotraumas,
including arterial gas embolism. The possibil-
ity of suffering a respiratory over inflation event
during high work rates while underwater could be
even greater for divers that smoke, or have previ-
ous known or unknown lung disease or respiratory
damage. The safest course for the diver is to keep
the equipment properly maintained for peak per-
formance and to know and understand the capabili-
ties and limitations of the equipment including all
breathing supply systems they use.
The output capability of the supply system includ-
ing umbilicals should be known to all that use it
and periodic tests should be done to insure flow
capability.
Use Of Low Pressure Supply Table
The low pressure supply tables were developed to
simplify calculation of supply pressure. In order to
get the required volume to the diver, you need to
have the proper supply pressure. The table starts at
90 psig and increases in 10 psig increments. The
user simply selects the lowest pressure that best rep-
resents the low cycling pressure of the compressor
being used. The table basically shows the maxi-
mum depth that can be attained while breathing at
RMV's (breathing rates in liters per minute) listed.
It is strongly recommended that divers plan for a
minimum supply pressure that will allow the diver
to work at no less that 50 - 62.5 RMV.
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