[PSUBS-MAILIST] G.L. Rules Life Support Systems

[Alan James]

   Life support systems need to sustain you for a minimum time of 96 hrs (4 days)
beyond your intended mission time. This is for autonomous submersibles which
are untethered submersibles with a boat in support. For autonomous submersibles
like Carsten's, they require 168 hrs (7 days). 
   Depending on the rescue concept you provide, these times for autonomous sunmersibles
may be shortened.
   Food, water, and the disposal of waste & effluent facilities need to be provided for the
above times. ( the waste disposal facility needs to be able to stop the sub from stinking)
   The O2 partial pressure needs to be kept within the range 0.19 - 0.23 bar. The CO2 pressure
needs to be kept below 0.01 bar. Audible alarms are to be automatically set off if there is any 
variation outside these parameters.
   Air purifying & conditioning units are to be installed.
   Guideline notes for life support are - O2 demand: 15 l/hr (resting); 40 l/hr working.
- CO2 production 22 l/h (average). For tourist subs, 26.4 l/h
   No Smoking signs needed.
   An emergency respirator or a breathing mask which can be connected to an emergency
breathing air system is to be provided for each crew member, in addition a reserve unit
is required. They need to have gas tight eye protection & provide a minimum of one hour of air.
The crew members need to be able to reach the exit still wearing these masks.
   When travelling on the surface, the submarine is to be vented via an air mast.
The battery ventilation system is independent from other ventilation systems.
Natural venting may be OK for small battery plants.
   O2 bottles in the pressure hull are limited to containing a volume that if it escaped, wouldn't
increase the pressure by 1 atm or increase the O2 content of the air by more than 25%
by volume.
   Manually operated oxygen metering systems are to be equipped with a bottle shut off valve
& a device for controlling the flow rate with a flow rate indicator.
   If the metering device is not provided in redundant form it is to be equipped with a manually 
operated bypass. I think this means that if the meter blocks you can switch to your extra
meter, but if that isn't going to exist you need some way to bypass the meter.
   The CO2 absorption unit has to be capable of keeping the partial pressure in the range of
0.005 - 0.010 bar. At the end of your 96 hr survival time it shouldn't be more than 0.02 bar.
   The CO2 unit needs a dust filter of non combustible material.
   If development of H2 can be expected, the hydrogen content needs to be monitored
continuously in the battery spaces.
   If the hydrogen content reaches 35% of the lower explosion limit it is to be signaled audibly
& visually at the control stand.
   The life support monitoring equipment includes pressure, temperature, humidity, oxygen
partial pressure, CO2 partial pressure, H2 portion, bottle pressures, outlet pressure of pressure
reducing valves. A permanent gauge & standby indicator are required for O2 & CO2. Test tubes
may be recognized as standby indicators.
An analysis system has to be provided for determining atmospheric impurities.
I think the K250 system has got a lot going for it.
Alan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20140128/e762f36f/attachment.html>