What is the common maximum operating depth (MOD) for EANx 40?

The common maximum operating depth (MOD) for Enriched Air Nitrox (EANx) 40, which contains 40% oxygen and 60% nitrogen, is set to avoid the risks associated with oxygen toxicity while maximizing the benefits of using a higher oxygen content. At this percentage, the MOD is generally recommended to be around 130 feet or 39 meters. This is based on the partial pressure of oxygen (PPO2), which should not exceed 1.4 atm for recreational diving to minimize the potential for central nervous system toxicity.

Since the partial pressure of oxygen at a depth of 130 feet is approximately 1.4 atm, it falls within the acceptable range, allowing divers to safely utilize EANx 40 for dives at this depth. Understanding the implications of using enriched air, particularly regarding the risks associated with higher oxygen concentrations at greater pressures, is crucial for safe diving practices.