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High altitude breathing apparatus is used for unpressurised (ambient pressure) aeronautical and mountaineering activities where the oxygen content of the natural atmosphere is insufficient for maintaining physical activity, consciousness, or life, but the atmospheric pressure is sufficient that a pressure suit is not needed.
breathing at altitude in aviation, either in a decompression emergency, or constantly (as in unpressurized aircraft), usually in high pressure cylinders; oxygen first aid sets, in small portable high pressure cylinders [1] gas blending, for mixing breathing gases such as nitrox, trimix and heliox
A store of oxygen, usually as compressed gas in a high pressure cylinder, but sometimes as liquid oxygen, that feeds gaseous oxygen into the ambient pressure breathing volume, either continuously, or when the user operates the oxygen addition valve, or via a demand valve in an oxygen rebreather, when the volume of gas in the breathing circuit ...
[1] The scrubber canister uses potassium superoxide as both a carbon dioxide absorbent and as an oxygen source. A sodium chlorate oxygen candle in the base of the unit generates oxygen on start-up as the canister has to reach a high internal temperature before it will start generating oxygen. The circulation of exhaled air containing carbon ...
Or it can be run with one of its two absorbent canisters filled with potassium superoxide, which gives off oxygen as it absorbs carbon dioxide: 4KO 2 + 2CO 2 = 2K 2 CO 3 + 3O 2; in this mode the oxygen cylinder is a bailout, or to fill and flush the circuit at the start of the dive. [1]
The effects of high altitude on humans are mostly the consequences of reduced partial pressure of oxygen in the atmosphere. The medical problems that are direct consequence of high altitude are caused by the low inspired partial pressure of oxygen, which is caused by the reduced atmospheric pressure, and the constant gas fraction of oxygen in ...
An open circuit SCBA typically has three main components: a high-pressure gas storage cylinder, (e.g., 2,216 to 5,500 psi (15,280 to 37,920 kPa), about 150 to 374 atmospheres), a pressure regulator, and a respiratory interface, which may be a mouthpiece, half mask or full-face mask, assembled and mounted on a framed carrying harness. [2]
Most commercial aircraft that operate at high flight altitudes are pressurized at a maximum cabin altitude of approximately 8,000 feet. On most pressurized aircraft, if cabin pressurization is lost when the aircraft is flying at an altitude above 4,267 m (14,000 feet), compartments containing the oxygen masks will open automatically, either above or in front of the passenger and crew seats ...