Quote: (Originally Posted by
AD_ward9)
1. The PPO2 set point is low to begin with, and the user does a fast ascent. On fast ascents, the max allowed EU injection rate of 6litres/min of O2 is not enough to keep the O2 above 0.21. That is, EN14143:2003 has a limit in it which can kill people. The solution is to put in multiple injectors where only one works at a time, until the PPO2 is outside the allowed bands. For example, on a Meg if the user sets a PPO2 of 0.4 then goes for the surface quickly, the diver can lose consciousness on the way up.
Alex
I guess my response was lost during the upgrade.. The ce is a MIN not max injection rate.. (and with the jaksa solenoid the meg is just above this)
5.7.2 Oxygen partial pressure setpoint maintenance
In apparatus with a fixed oxygen partial pressure setpoint the inspired partial pressure of oxygen shall be
maintained within
0,10 bar during constant depth phases of the dive. This at a ventilation of 40 l min-1 and
associated oxygen consumption of 1,78 l min-1 Standard Temperature and Pressure, Dry (STPD).
During the ascent phase the inspired partial pressure of oxygen may reduce to a minimum of 0,5 bar below
the set point but shall regain steady state set point within 1 min of halting an ascent.
When gas is injected into the breathing circuit the volume of oxygen added in 1 min shall be at least 6 l
(STPD).
at a low setpoint this is insuf***ient, and borderline from a high setpoint with a reasonable ascent (and little work).. Its insufficient with an emergency ascent or a working ascent.. IMHO about 12lpm should be the minimum target..