The term Maximum Operating Depth (MOD) refers to what?

Maximum Operating Depth (MOD) specifically refers to the maximum depth at which a diver can safely breathe a specific gas mixture without exceeding safe partial pressure limits for oxygen. For Nitrox divers, it indicates the optimal depth where the partial pressure of oxygen remains within safe limits, typically set to avoid physiological effects such as oxygen toxicity.

At depths beyond the MOD, the partial pressure of oxygen in the mixture would increase to a point that could pose serious risks. This is particularly crucial when using enriched air mixtures, as they contain higher concentrations of oxygen than air, making it essential for divers to calculate their MOD to ensure their safety. Understanding and adhering to the MOD allows divers to plan dives effectively and mitigate the risks associated with breathing elevated pressures of oxygen underwater.