Haldane's decompression model

Decompression table-I in ft and psi. "Stoppages during the ascent of a diver after ordinary limits of time from surface."

Decompression table-II in ft and psi. "Stoppages during the ascent of a diver after delay beyond the ordinary limits of time from surface."

Haldane's Decompression Tables I and II

Haldane's decompression model is a mathematical model for decompression to sea level atmospheric pressure of divers breathing compressed air at ambient pressure that was proposed in 1908 by the Scottish physiologist, John Scott Haldane (2 May 1860 – 14/15 March 1936),^[1] who was also famous for intrepid self-experimentation.

Haldane prepared the first recognized decompression table for the British Admiralty in 1908 based on extensive experiments on goats and other animals using a clinical endpoint of symptomatic decompression sickness.

Haldane observed that goats, saturated to depths of 165 feet (50 m) of sea water, did not develop decompression sickness (DCS) if subsequent decompression was limited to half the ambient pressure. Haldane constructed schedules which limited the critical supersaturation ratio to "2", in five hypothetical body tissue compartments characterized by their halftime. Halftime is also termed Half-life when linked to exponential processes such as radioactive decay. Haldane's five compartments (halftimes: 5, 10, 20, 40, 75 minutes) were used in decompression calculations and staged decompression procedures for fifty years. ^{[citation needed]}

Previous theories to Haldane worked on "uniform compression", as Paul Bert pointed in 1878 that very slow decompression could avoid the caisson disease, then Hermann von Schrötter proposed in 1895 the safe "uniform decompression" rate to be of "one atmosphere per 20 minutes". Haldane in 1907 worked on "staged decompression" – decompression using a specified relatively rapid ascent rate, interrupted by specified periods at constant depth – and proved it to be safer than "uniform decompression" at the rates then in use, and produced his decompression tables on that basis.