What is the Maximum Operating Depth calculated for EAN36 using the MOD formula?

To determine the Maximum Operating Depth (MOD) for EAN36 (Enriched Air Nitrox with 36% oxygen), the MOD is calculated using the formula:

MOD = (Maximum Partial Pressure of Oxygen) / (Fraction of Oxygen in the Mixture) - 1 atm

In diving, the standard maximum partial pressure of oxygen for recreational diving is considered to be 1.6 ATA (atmospheres absolute). This accounts for the oxygen's partial pressure and is essential to ensure safety while avoiding toxicity.

Given that EAN36 consists of 36% oxygen, the formula becomes:

MOD = (1.6 ATA) / (0.36) - 1 atm

Calculating the values, you first convert the partial pressure of oxygen into depth by considering that every additional atmosphere adds approximately 33 feet (or about 10 meters) of depth.

1 ATA is at the surface (0 feet), so we calculate:

1.6 ATA - 1 ATA = 0.6 ATA

Now convert this back into feet of seawater (fsw):

Depth increase from 1 ATA = 33 feet (as at surface = 1 atm)

Thus, for 0.6 ATA:

Depth = 0.