[PSUBS-MAILIST] life support test

[Stephen Fordyce via Personal_Submersibles]

Hi Brian and all,
I'm just going through commissioning a new/modified rebreather which is a
bit relevant to this. I believe (sort of at odds with conventional training
manuals) that it's valuable to experience the physiological signs and
symptoms of the various gases at incorrect levels. Your other systems
should of course protect you and be highly conservative, but you never know.

To that end, after a recent long dive I continued to breather the scrubber
at home on the couch (for several hours) until the high CO2 effects were
noticeable. I've also had a controlled low oxygen experience that I
consider valuable. Both worth doing, maybe even regularly - I'd like to do
high oxygen one but that's been a bit tricky so far.

If anyone has plans to be exiting a partially flooded sub at depths below
30m/100ft then a nitrogen narcosis experience would be extremely valuable.
Especially with quick compression, your mental faculties deteriorate
rapidly. Even at that depth, and it gets worse as you go deeper. I don't
dive below 50m on air because I barely know what I'm doing.

Cheers,
Steve Fordyce

On 18 Mar 2018 2:04 pm, "Cliff Redus via Personal_Submersibles" <
personal_submersibles at psubs.org> wrote:

> See
>
> *DESIGN GUIDELINES *FOR
>
> CARBON DIOXIDE SCRUBBERS
>
> I
>
> MAY *1983*
>
> REVISED *JULY 1985*
>
> Prepared by
> M. L. NUCKOLS, A. PURER, G. A. DEASON
>
> for the philological affects of high CO2 level but if you abort the test
> if you ever exceed 5000 ppm, you should be safe.  In addition to the CO2
> issues, you should also familrrize yourself with both *Hypoxia* which
> describes levels lower than Normoxia, or percentages lower than 21% and
> *hyperoxic* breathing gas when levels rise above 22% of oxygen. Hypoxia
> would come from running out of makeup O2 or leaving the O2 supply valve
> closed by accident and hyperoic state would most likely be caused by a high
> pressure leak of O2 into the cabin caused by a loose fitting.  I would
> recommend you abort the test if O2 concentration falls outside the
> acceptable range as defined by ABS.
>
> When you go back and analyze the test, it is helpful to have data logged
> cabin atmosphere parameters including, CO2 and O2 concentrations, cabin
> pressure and temperature and relative humidity.
>
> Cliff
>
> On Sat, Mar 17, 2018 at 5:37 PM, Brian Cox via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> Hi All,
>>               Thinking about testing my life support.  Will obviously
>> have some people outside the sub watching me, and talking via radio.  But I
>> was wondering if there would be a point at which I should abort the test
>> when the CO2  gets to a certain point .   If it levels off and stays at a
>> constant but is some what elevated would it be ok to monitor that situation
>> ?   Like say it levels off at 2000 ppm and assuming my oxygen is at a
>> constant 20.8 %    ?
>>
>> Brian
>>
>>
>>
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>>
>
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