What is the maximum recommended partial pressure of oxygen for dive durations exceeding 30 minutes?

The maximum recommended partial pressure of oxygen for dive durations exceeding 30 minutes is 1.4 atm. This standard is rooted in the understanding of oxygen toxicity, which can increase with longer exposure to higher partial pressures.

When a diver breathes a mixture with a partial pressure of oxygen at or below this threshold, they reduce the risk of central nervous system toxicity and other physiological effects associated with elevated oxygen levels. The 1.4 atm limit is particularly important for dives that last longer than half an hour because the duration coupled with increased pressure can lead to increased risk of oxygen toxicity.

This guideline ensures a balance between leveraging the benefits of oxygen in a Nitrox mix for extended dive times while safeguarding the diver's health. Maintaining the maximum partial pressure at or below 1.4 atm assists divers in planning their dives more safely and effectively. Divers should always carefully monitor their dive plans to stay within these recommended limits to avoid potential dive-related injuries.