Saturation diver life-support systems must provide adequate respiratory and
thermal protection to allow work in the water at extreme depths and temperatures.
Because of the increased stresses placed upon the diver by deep saturation dives,
this equipment must be carefully designed and tested in its operating environment.
The diver life-support system consists of two components: an underwater
breathing apparatus (UBA) and a thermal protection system. The actual in-water
time a diver can work effectively depends on the adequacy of his life-support
apparatus and his physical conditioning. Important considerations in the duration
of effective in-water time are the rate of gas consumption for the system and the
degree of thermal protection. Present U.S. Navy saturation diving UBAs are
designed to operate effectively underwater for at least 4 hours. Although a given
diving apparatus may be able to provide longer diver life support, experience has shown that cumulative dive time at deep depths will progressively reduce diver
effectiveness after a 4-hour in-water exposure.