How does using a higher percentage of oxygen in Nitrox affect dive time?

Using a higher percentage of oxygen in Nitrox significantly reduces dive time limits due to the increased risk of oxygen toxicity. As the percentage of oxygen in the gas mixture rises, the partial pressure of oxygen experienced by the diver increases, particularly at greater depths. This is critical because oxygen becomes toxic at higher partial pressures, which can lead to serious health risks such as convulsions and other neurological effects.

To ensure diver safety, limits are set on the maximum operating depth (MOD) and the exposure time to higher levels of oxygen, leading to a reduction in allowable bottom time for dives conducted with enriched air Nitrox. The deeper the dive and the higher the oxygen content, the more critical it is to monitor and adhere to these limits to avoid the onset of oxygen toxicity.

Therefore, planning dives with higher oxygen concentrations requires careful consideration of dive tables and dive computers, as adherence to pre-established dive limits is essential for maintaining safety during the dive.