Re: Explosive decompression - how fast?

On Apr 28, 10:46=A0am, Michael Ash <m...@[EMAIL PROTECTED]
> wrote:

>> there are plenty of medical problems for which this would be
>> very much more dangerous.
>
> The altitude limit is a function of the oxygen delivery system,
> not of altitude.

I'm not certain of that. You certainly could be talking about a
significant risk for a small percentage of the population. Pressure
changes are significantly traumatic all on their own for a percentage
of the population. Another issue you might have is heating - although
with the excess power of a modern aircraft, this shouldn't be a big
problem, but it's a new one to consider. As you go up and depompress,
the temperature drops - radically. And if you heat the cabin air to
comfortable levels, you are going to be warming the air to
uncomfortable levels on the way down as the air in the cabin
recompresses. Although as discussed below, you're going to need
careful change-out and balancing of the breathing mix anyway, so
practically this isn't going to be an issue (economicly is another
matter). Sodas and other carbonated beverages might be a lot more
fun :).

>> Which means you can't go to the toilet without
>> a portable oxygen tank
>
> Yeah, that's a bit of a problem alright...

Well, if they want *really* cheap flights, give them a diaper. Or make
them provide their own. Works for the Shuttle...

> My understanding is that pure oxygen at a reasonable
> breathable pressure is essentially the same fire hazard
> as the standard atmosphere.

It's not. Not even close. the fact that 80% of the gas running through
a flame does nothing more than warm up (does not contribute energy to
the process) keeps a flame in a "normal" atmosphere significantly
cooler. If all you have is low-pressure pure O2 for an atmosphere,
there's nothing to dilute that heat flux. Among other problems. Not
the least of which is potential O2 toxicity (better watch that
breathing gas mix on the way down *very* closely). You've just turned
the "cheap" plane into a cheap plane with a very sophisticated gas-
handling system. Not easy, safe, or cheap.


 Presumably you'd have a regulator which
> keeps the partial pressure of oxygen at the same value all the way up,
so
> you'd gradually go from 20% at whatever your reference altitude is
> (8,000ft again?) up to 100% at your max altitude.
>
> --
> Michael Ash
> Rogue Amoeba Software