Re: [PSUBS-MAILIST] test of CO2 safety hardware - any volunteers?

[Erik Muller <emuller@naic.edu>]

Gail,
Many of the points you made are true. Let me address them one at a time:

>I'm wondering how accurate and useful a device like the one you 
describe would be.
Indeed, as am I. This is why I am calling for people with air-tight 
hulls to test the system. I am not suggesting that it be implemented on 
anyones machine before testing its efficiency and it is developed.

>With reliable professionally-made devices being available, why would 
you want to entrust something as important as life support to a $0.50 
expedient?
That is true: you need to fold in the reliability of your equipment is 
to the decisions you make in piloting and using your craft. However, to 
take this question to the (unreasonable) extreme: why would you build 
your own submarine when you can buy a perfectly operational one, 
brand-new for a few hundred thousand or million? The fun is in the 
manufacture and learning how it all works. However, care needs to be 
taken when using new systems in that they are tested properly. Perhaps 
the 50c device works well enough as a first order indicator. I dont 
know. I think it is worth finding out. I DO know that it tests positive 
for a single breath, which has more that enough oxygen remaining in it 
to be comfortable. If anything, I think this will be an 
overly-conservative indicator. I can cite the age-old 'NASA vs USSR - 
high tech gravity-proof-pen vs  ordinary pencil' example as a great case 
where cheaper is better. This might turn out to be one such case.

>From what I've learned, CO2 levels are taken care of by the scrubber, 
and it's pretty easy to verify whether or not that's working.  So this 
home made CO2 sensing device doesn't sound necessary.

Sure, but some people dont have a scrubber in your machine. Others have 
different systems to help reduce CO2 pp. Scrubbers are not part of 
everyones hardware. I have not planned for one since my dives will be short.

>Speaking for myself, I think I'd prefer the professional instrument. 
Thats fine. Then this system is not for you. Some people dont have the 
money, or want to try to make it all from the ground up (i.e. some 
people like to grow their own for the fun of it). Im not insisting that 
this system be immediatly implemented by all. Just that it is a system 
that MIGHT be useful to SOME people, and is worth testing. Nothing more. 
If tests show  that it is unusable, then we have learned something. If 
tests show that it IS useable, then we have also learned something. Its 
a win-win world in this case.

There is a commercial in australia which says: 'you will never know if 
you never go'. If its not tested, we will never know if it is useable, 
or not. People have been objecting to my suggested technique for about a 
week, yet no-one has tested it. I would really prefer that people object 
with numbers or solid data, rather than opinions. The proof is in the 
pudding. We grow by testing and learning. <insert other assorted 
feel-good anthropic cliches here>.

Anyhow. thats enough from me.
EM.