How do dive tables differ for air vs. Nitrox diving?

Dive tables for Nitrox diving differ significantly from those for air diving due to the gas mixture's composition. Nitrox is a blend of oxygen and nitrogen, typically containing a higher proportion of oxygen than air, which is about 21% oxygen and 79% nitrogen. In Nitrox diving, the reduced nitrogen load is a critical factor to consider.

Nitrox tables are specifically designed to reflect this reduced nitrogen load. Since Nitrox contains less nitrogen than air, divers using Nitrox can spend more time at certain depths without incurring the same risks of nitrogen narcosis or decompression sickness, compared to using air. The tables take this into account by adjusting bottom time limits and decompression schedules to optimize safety and extend allowable dive durations.

Understanding this fundamental difference is crucial for safe dive planning and execution when switching from air to Nitrox, as the diver must utilize the appropriate tables that align with the specific gas mixture they are using.