History of decompression theory
Key dates in decompression research, from 1878 to today.
- 1878
Paul Bert links bubbles to decompression sickness
In La Pression Barométrique, Bert shows that compressed-air illness is caused by nitrogen coming out of solution, and that a slow return to the surface prevents it. He also describes oxygen toxicity at high pressure.
Read the guide - 1908
Haldane introduces staged decompression
Boycott, Damant and Haldane publish their goat experiments for the Royal Navy. They model the body as tissues with different half-times, limit ascent to a 2:1 pressure ratio, and bring the diver up in stages.
Read the guide - 1912-1950s
Navy tables develop
Navies extend Haldane’s tables to deeper and longer dives. Oxygen decompression and surface decompression in a chamber come into use.
- 1965
Workman defines the M-value
At the US Navy Experimental Diving Unit, Robert Workman replaces the single ratio with a maximum tissue pressure for each compartment at each depth, called the M-value.
Read the guide - 1983
Bühlmann publishes ZHL-16
Albert Bühlmann in Zürich publishes a model with 16 compartments and M-values written as a and b coefficients. Its ZHL-16C version is used in most dive computers today.
Read the guide - 1983
The Orca Edge dive computer
The Orca Edge is one of the first electronic dive computers sold widely. It calculates tissue loading during the dive from a pressure sensor, so a multilevel dive is no longer treated as if it were spent entirely at its maximum depth.
Read the guide - 1988
Recreational dive tables
PADI introduces the Recreational Dive Planner and the British Sub-Aqua Club the BSAC 88 tables, both designed for no-stop and repetitive recreational diving rather than for navy work.
Read the guide - 1980s
Thalmann’s linear-exponential model
In Edward Thalmann’s model, gas leaves a supersaturated tissue more slowly than it entered. It becomes the basis of the US Navy’s air and nitrox tables.
Read the guide - 1986-2000s
Bubble models
The Varying Permeability Model and RGBM aim to limit bubble growth directly. Both put the first stops deeper.
Read the guide - 1990s
Gradient factors
Erik Baker publishes gradient factors: two settings that control how close an ascent gets to Bühlmann’s M-values, from the first stop to the surface.
Read the guide - 2011
US Navy deep-stop trial
A US Navy trial finds more decompression sickness with a deep-stop schedule than with a conventional schedule of the same total stop time. Divers move towards shallower first stops.
Read the guide - Today
Today
Dive computers and planners, including DiveLogic, use these models together with oxygen exposure, gas density and counterdiffusion checks.