What is the maximum allowable partial pressure of oxygen recommended for recreational diving?

The maximum allowable partial pressure of oxygen recommended for recreational diving is 1.4 ATA (atmospheres absolute). This level is established to balance the benefits of using enriched air nitrox for reduced nitrogen absorption and risk mitigation related to oxygen toxicity.

At 1.4 ATA, divers can safely take advantage of the higher oxygen content in nitrox without entering the range where oxygen toxicity becomes a significant risk during typical recreational dives. Oxygen toxicity can lead to harmful effects on the central nervous system, especially during deeper dives where partial pressures can exceed safe limits.

Limiting the partial pressure to 1.4 ATA also helps ensure that divers maintain a margin of safety, reducing the likelihood of negative physiological effects while allowing for extended bottom times and shallower ascents that nitrox provides. Therefore, for recreational dives, adhering to this guideline is crucial for diver safety and overall enjoyment of the underwater experience.