In technical diving and nitrox diving, the maximum operating depth (MOD) of a breathing gas is the depth below which the partial pressure of oxygen (ppO2) of the gas mix exceeds a safe limit. This safe limit is somewhat arbitrary, and varies depending on the diver training agency or Code of Practice, the level of underwater exertion planned and the planned duration of the dive, but is normally in the range of 1.
maximum operating depth meaning:[Defence] The keel depth that a submarine is not to exceed during operations. This depth is determined by the submarine’s national naval authority. See also test depth.