What does the term “MOD” stand for in Nitrox diving?

The term "MOD" stands for Maximum Operating Depth in Nitrox diving. It refers to the deepest depth at which a specific blend of Nitrox can be safely used without exceeding the maximum partial pressure of oxygen (PPO2) that is considered safe for divers, typically set at 1.4 ATA (atmospheres absolute) for recreational diving.

Understanding MOD is crucial for divers using enriched air because it helps them avoid oxygen toxicity, which can occur if the partial pressure of oxygen rises too high. Since the oxygen content in Nitrox blends is higher than that of regular air, divers must be aware of their MOD to ensure their safety while diving at various depths. This concept is essential for planning dives, especially when using different gas mixtures, to maximize safety and minimize risks associated with high oxygen levels.