Decompression tables

Decompression tables, also known to divers as dive tables, are tabulated data, often in the form of printed cards or booklets, that allow people to determine a decompression schedule that is acceptably safe for a given dive or other hyperbaric exposure profile and breathing gas.

Decompression tables represent procedures recommended for decompression from hyperbaric exposures in a continuum of possibilities by schedules tabulated for discrete cases of such exposures chosen for practicality and convenience of the user. They may represent data from theoretical decompression models or empirical data from series of tests on human subjects, or combinations thereof, and may be empirically adjusted to reduce risk or improve decompression efficiency. The availability of dive computers which can apply algorithms in real time to calculate the personal decompression status of a diver have to a large extent supplanted decompression tables for recreational and scientific divers, but tables remain a practical and convenient method for deciding decompression schedules for people exposed to similar but not necessarily identical pressure profiles, particularly when they are to be decompressed as a group, such as saturation divers and compressed air workers.

With decompression tables, it is generally assumed that the hyperbaric exposure, or dive profile, is a square profile, meaning that the diver descends to maximum depth immediately and stays at the same depth until resurfacing (approximating a rectangular outline when drawn in a coordinate system where one axis is depth and the other is duration). Some dive tables also assume the physical condition or acceptance of a specific level of risk from the diver. Some recreational dive tables only provide for no-stop dives at sea level sites, but the more complete tables can take into account staged decompression dives and dives performed at altitude.