USER MANUAL ::
ENGLISH
:: 23
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BREATHING PERFORMANCE
Full regulator capacity is obtained as long as the cylinder
pressure is twice the absolute interstage pressure, given
the cylinder valve pressure drop is within EN 250 limits.
Taking into account the normal variations in interstage
pressure and adding a safety margin, the required minimum
cylinder pressure during diving is:
50 bar cylinder pressure from 0 msw to 100 msw
70 bar cylinder pressure from 101 msw to 200 msw
It is a good practise to always plan your dive according to
the “1/3-rule”, planning to use 2/3 of the cylinder capa-
city.
The diagram above show a calculated graph for Work of
Breathing in Joules/litre at Q
average
=62.5 litres/min.
The equation behind it, is extracted from hundreds of tests,
from which coefficients for gas dependency, average flow
dependency, and depth dependency is calculated.
Its maximum inaccuracy is /- 10%
The equation assumes the most dense gas possible to safely
breath is used, i.e. a maximum tolerable pO
2
, pN
2
at any
depth. Adding more Helium will lower the figures.
It is important to understand that this equation does not
apply to any other regulator, since the coefficients and cha-
racteristics are strongly dependent on the regulator cons-
truction.
Recommended limit
Min cylinder pressure
Absolute interstage pressure
EN 250 stops here
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