12.1 Atmospheric systems

The standard operating environment onboard the Camelot is a class M oxygen-nitrogen atmosphere; class M being conditions approaching that of Earth. Two independent primary atmospheric plenum systems deliver temperature and humidity controlled gasses throughout the ship; a separate reserve systems provides backup.

Atmospheric processing units for the primary system are located around every 75m^3 of habitable ship volume. These devices maintain a comfortable environment, for most anyway, by removing CO2 and other waste gasses and replenishing O2 partial pressure. This is primarily down by the use of photosynthetic bioprocessing via engineered algae-like organisms in controlled ecospheres; they generate everything they need save the CO2 gas pumped in by the ships systems.

Cruise Mode operational rules specify a ninety-six hour duty cycle for processing modules, although normal time between scheduled maintenance is approximately three thousand operating hours. At the end of each 96-hour duty cycle, it is normal for the entire atmospheric processing load to be automatically switched to the alternate primary system. It is, however, possible to switch these things around manually. Atmospheric flow can be remotely switched at utilities junction nodes, so that breathable air can be rerouted to processors at other locations, adding yet another layer of redundancy.

The reserve system is a third redundant set of atmospheric processors, providing up to 62% of nominal system capacity for periods up to 36 hours, depending on system load and system damage. These are intended for use only in the event of major primary system failure. The reserve system shares the plenum network of the two primary systems, and operates by computerized system analysis, which allows any damage plenum sections or processors to be isolated and removed from service.

Additionally, emergency atmospheric supply systems provide breathing mixture to designated shelter areas for up to 24 hours in crisis situations. These systems draw on independent oxygen and power supplies, physically isolated from primary systems and each other. The emergency systems are not intended to provide complete shipwide atmosphere. The emergency atmospheric supply systems provide minimal air recycling via chemical systems, but drawing on any available supplies can significantly extend oxygen supply from the primary systems or from any unused contingency supply modules.

In case of major failure of atmospheric supply necessitating use of the emergency system, contingency atmospheric supply modules will maintain a breathable environment for 20 minutes; these modules are located at every major corridor junction. It is hoped that this will give the crew enough time to escape to wherever there IS air. Except in cases of large-scale explosive decompression, say from a few quantum torpedoes impacting on the hull directly, even a severe atmospheric supply failure is expected to permit upwards of 45 minutes for evacuation of all personnel to designated shelter areas, or just off the particular deck.

Nominal atmospheric values for Class M compatible conditions are 25 degrees C, 45% relative humidity, with pressure maintained at 101 kilopascals. Atmospheric composition is maintained at 76% nitrogen, 21% oxygen, 1% trace gases; Basically, a warm spring day on Earth. Go figure..anyway. Approximately ten percent of living space can be switched over to class H,K,L or N conditions without major hardware swapout. Vehicle-wide adaptation to such atmospheric conditions can be accomplished by major replacement of atmospheric nodes while on a starbase visit.