What is the partial pressure of oxygen (PO2) used to compute the maximum operating depth?

The partial pressure of oxygen (PO2) is a critical factor in assessing the safe limits for diving with enriched air (Nitrox). The maximum operating depth (MOD) for a specific gas mixture is determined by the maximum safe PO2 to which divers can be exposed. For Nitrox diving, the commonly accepted maximum PO2 for recreational diving is typically 1.4 ATA.

However, when considering operational limits, some agencies, including IANTD, may allow a higher PO2 for specific circumstances. While 1.4 ATA is the standard recommendation for everyday recreational diving, the option of 1.6 ATA represents more conservative limits that some divers might use under certain conditions, providing an added margin for safety.

The chosen answer indicates that at a PO2 of 1.6 ATA, it requires additional considerations concerning any potential risks or depth limitations. Thus, when calculating the maximum operating depth using this PO2, divers must adjust their dive plan to account for the increased pressure of oxygen at deeper depths. This is why 1.6 ATA is often referenced in the context of maximum operating depth for enriched air diving.

Understanding the significance of PO2 helps divers make more informed decisions regarding their dive profiles, enhance safety, and effectively