Fellow Sentients-
Here's another note that got munched by the hungery hungery Sunbane.
[email removed] writes:
>Subject: Misc. Questions
>All I need is the air that I breathe...
>- ---------------------------------------
>One of the hazards of space travel is going to be running out of breathable
> air. When considering a particular 'scene' for a scenario I was
> planning, I realised I had no good idea of how long it takes a person
> to use up the available air in a sealed room. So, some questions for
> the list.
>Imagine you are in a sealed room. How long does it take a person to die
> because the air gets bad - and why? Is it lack of Oxygen, or the
> presence of impurities?
Found this in my Mech Eng. Handbook so I ought to be accurate:
**** WARNING: MILDLY TECHNICAL DISCUSSION FOLLOWS!!! ****
A average person consumes 0.83 kg of oxygen and produce 1.00 kg of CO2 per day
for a give volume of air at 1 atmosphere and 25 degree C come to something
like this:
7.776 * Volume in cubic meters = hours of Oxygen for 1 person
However I am unaware of the concentration of CO2 would be toxic to human in a
sealed enviroment so this would be a ultimate limitation. Also these value
are for someone who's awake so it can be increase if these folk were asleep or
resting.
>If the room is filled not with air, but with Oxygen only:
>- - what atmospheric pressure should it be at to be safe? I believe that if
> the pressure is too high the atmosphere promotes any sort of minor
> spark into a serious fire/explosive hazard.
>- - how long before a typical human unfortunate dies from bad air in this
> scenario.
The best example of this would be the Apollo 1 tragedy. The crew capsule at
that time used a pure oxygen supply which ultimate killed the crew when it
caught on fire(fuel was in the cabin material). I would rate
the odds of a fire a MUCH greater risk then running out of O2. Assume this
scenario is played out in the presence of operating device (electrical/optical
/or mechanical) I would try the following:
To determine if a oxygen fire starts:
Average: Pressure in atmoshpere + modifiers
modifiers
+1 if mechanical device present
+1 if optical/electronic device present
+2 if High speed mechanical device present
+3 if High power electric device present
+5 if Anything sparks!
Determining on the nature of the material the fire could be a glowing amber
(low level of reactant or slow burning type) or an explodsion that engulfs the
entire room... Makes for short adventures though....:(
>Some questions on firearms...
>- -------------------------------
> .. At what tech level can you build guns out of non metallic materials?
> .. What sort of non metallic materials are possible - plastics, carbon
> fibre, or what?
The Glock series pistol and the Steyr series rifles are both examples of
existing guns with frame built of plastic. However the receiver and barrel
are both made of traditional metallic materials. So late TL-8 is when I would
expect them.
In order to make the barrel and receiver out of non metallic would be
diffcult. What is need are high temperature, high strength, and high wear
resistant materials. So far none of the non-metallic materials exibit all of
these qualities. If the goal is to pass through airport type metal detector
then you could use metal composite made of non-ferrous (i.e. iron) materials.
Materials like Carbon Titanium composite is an example. But don't expect to
see these until about TL-10
> .. At what tech level can you build caseless ammo and weapons to use it?
> And when does the result become as practical as weapons using cased
> ammo?
In FF&S it states that any non-ETC rounds after TL-10 are caseless. As to
when it becomes practical it depends on your definition of 'practical'. If
the concern is 'cook-off' that pretty much been solved. If the conern is
reloading you're out of luck. In my campaign I allow players to make their
own ammunition (within reason as to type) if they possess a ammunition mould
and press set...think of it as an injection moulding machine for ammunitions.
However it's a ship mounted device...definitely not man-portable.
Also as a side note: use of caseless ammo allows receivers to be designed
without the normal ejection cycle...thus allow a potentially higher cyclic
rate of fire.