Altitude Chambers Specifications

An altitude chamber, or hypobaric chamber, is used to simulate conditions of various elevations above sea level. As altitude increases, certain atmospheric parameters decrease, particularly the oxygen content and the ambient pressure. As this has physiological consequences, and because people in certain endeavors are obligated to confront high altitudes, having a means of familiarizing the body to high-altitude conditions without actually having to travel is essential. Altitude chambers must meet certain engineering specifications in order to do their job effectively.

  1. Size

    • The hypobaric chamber used by the University of Wisconsin's Biotron controlled-environment research facility is a cylinder 23 feet long with a diameter of just under 7 feet, yielding a volume of about 850 cubic feet. A bench 16 inches long runs the length of the chamber, which features two doors 2 feet wide and 4.5 feet high at one end on either side of an airlock 5 feet long. The floor of the chamber measures 21 feet by 4 feet. The altitude "tents" made by companies such as Hypoxico are much smaller, as these are designed to accommodate only one or two occupants.

    Pressure

    • The ambient pressure in the Biotron facility's chamber can be set to a maximum of 760 millimeters of mercury, approximating sea-level atmospheric pressure, and to a minimum of 52 mm Hg, equivalent to the pressure at about 60,000 feet above sea level -- twice the elevation of the summit of Mount Everest. The Hypoxico units, intended to be used by athletes rather than aviators or astronauts, simulate conditions found at various points on Earth's surface and can be adjusted to mimic altitude ranges between sea level and 21,000 feet.

    Other Metrics

    • Air must be constantly circulated throughout the chamber in order for hypobaric conditions to be maintained. The Biotron module has a flow rate ranging from 100 to 200 cubic feet per minute, or 2,830 to 5,660 liters per minute. The much smaller Hypoxico tents max out at under 130 liters per minute. The Biotron unit has a 115-volt, 15-amp power supply and is kept at a temperature of 20 degrees Celsius, or 68 degrees Fahrenheit. The tents are extraordinarily lightweight for their size, weighing between 9 and 20 pounds, or 4 to 9 kilograms.

    Physiology

    • The reason athletes in endurance sports, such as distance running, cycling and Nordic skiing, train or live at high altitude is because the lower oxygen content at these elevations drives a compensatory response by the body's bone marrow, where red blood cells are produced. More red blood cells means a higher oxygen-carrying capacity of the blood, so that when athletes return to sea level to compete, they enjoy an advantage other athletes achieve by illicit means -- using performance-enhancing drugs and by "blood doping."