Saturation diving is a diving technique used in the Marine Oil, Gas and Renewables industry that allows divers to reduce the risk of decompression sickness (“the bends”) when they work at a great depth (generally down to 350m) for long periods of time.The divers live under pressure in a Saturation system or “saturation spread”, a hyperbaric environment on the surface for the duration of the project or several days to weeks.

Saturation diving allows for greater economy of work and enhanced safety for divers. After working in the water, they rest and live in a dry pressurized habitat on or connected to a Diving Support Vessel (DSV) at approximately the same pressure as the work depth; divers will generally work for 8 hours followed by 16 hours of rest on the DSV. The diving team is compressed to the working pressure only once, at the beginning of the work period and decompressed to surface pressure once, after the entire work period. Unplanned exposure to normal atmospheric pressures will quickly result in severe sickness and death.

With thanks to the Science channel, the below video is a short summary of saturation diving.