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> Use of Fieno Test finished ... > > > The mixed gas Fieno system (40% oxygen, 60% nitrogen) is a different > system to the usual one used for scuba diving. A diver who is used to > ...... > When using the Fieno (and doing normal diving) consumption of gas is > fixed. That is to say that underwater time is also fixed. ...... > ................ > On a > dive when the demand valve is not used you should be able to dive for > more than 50 minutes on the 1.3 litre tank (tank is 1.3 litres of > mixed gas at 200 bar). Even a dive to 30 metres should not require the > use of the demand valve. One difference between the Fieno system and > scuba is that there is a fixed limit of 5 litres per minute and this > does not vary with depth. ^^^^^^^^^^^^^^^^^^^^^^^^^^ So, the Fieno system must be a semiclosed circuit rebreather, which doesn't control partial pressure of O2, if I am correct. Because the gas flow is constant and not a demand flow, the partial pressure of O2 can variate in the air (gas) bag. Does the Fieno monitor ppO2 and diver's breathing rate ? If diver uses more than 2 liters of oxygen per minute, nitrogen will be riched into air bag. Does the Fieno system give you any warning if ppO2 would fall too low ? Moreover, because ppO2 variates, the decoplanning is difficult. If Fieno doesn't have build-in O2 analyzer and deco-computer, the use of Fieno has almost the same limitations than the old closed circuit oxygen rebreather, hasn't it ? Jouni Polkko jpolkko@vi*.hu*.fi* Finland
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