Point of no return on-the-fly calculation

AD_ward9 · 17th November 2006, 17:38

Quote: (Originally Posted by Genesis)

True, but I don't convulse doing that without some help from a PO2 that is climbing beyond safe limits!

This is true but an SCR uses add gas that can be breathed directly, and thus its safe even if you were to take a hit off the feed without any dilution.......

Its safe to say that if the OR thinks it has the PO2 under control and it does not, that this is an undocumented failure mode right?

Just seems to me that if you have all sensors down, given that the user CAN cause the unit to miscalculate a safe breathing mix (and there is no way to know if it has happened) you can't realistically advocate staying on-loop if other options are available.

We don't. When all sensors are down the loop is shut. It has a manual overide, which is why the unit still works to keep the PPO2 limit within limits.

SCRs use fairly high O2 mixes. I agree, it gives the unit a wider margin. On a CCR we do not have that luxury.

We will publish the verification information in due course, before it is sold.
This means the theory, the test plan and the actual test results.

Alex

17th November 2006, 17:38	#11 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,862	Re: Point of no return on-the-fly calculation Quote: (Originally Posted by Genesis) True, but I don't convulse doing that without some help from a PO2 that is climbing beyond safe limits! This is true but an SCR uses add gas that can be breathed directly, and thus its safe even if you were to take a hit off the feed without any dilution....... Its safe to say that if the OR thinks it has the PO2 under control and it does not, that this is an undocumented failure mode right? Just seems to me that if you have all sensors down, given that the user CAN cause the unit to miscalculate a safe breathing mix (and there is no way to know if it has happened) you can't realistically advocate staying on-loop if other options are available. We don't. When all sensors are down the loop is shut. It has a manual overide, which is why the unit still works to keep the PPO2 limit within limits. SCRs use fairly high O2 mixes. I agree, it gives the unit a wider margin. On a CCR we do not have that luxury. We will publish the verification information in due course, before it is sold. This means the theory, the test plan and the actual test results. Alex
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