How can you determine the Maximum Operating Depth (MOD) for an EANx mixture?

To determine the Maximum Operating Depth (MOD) for an Enriched Air Nitrox (EANx) mixture, you can use the formula: MOD = (PO2 max) / (mix percentage). This formula is essential as it relates the partial pressure of oxygen to the concentration of oxygen in the gas mix.

The partial pressure of oxygen (PO2) that divers can safely breathe is generally a maximum of 1.4 ATA (atmospheres absolute) for recreational diving. Therefore, by applying the desired maximum partial pressure to the oxygen percentage in the EANx mixture, the MOD can be calculated to ensure divers do not exceed safe limits while breathing oxygen at depth.

For example, if your EANx mixture is 32% oxygen, you first convert the percentage into a decimal (0.32), and then you calculate: MOD = 1.4 / 0.32, which gives you a derived depth limit.

Using this formula helps divers manage their gas mixes and plan their dives more safely, directly aligning with best practices in dive planning and safety protocols.