Question 1

What is Equivalent Air Depth (EAD)?

Accepted Answer

Equivalent Air Depth (EAD) is the depth at which breathing air would produce the same partial pressure of nitrogen as the Nitrox mix you're using at your actual depth. It's a way to calculate your no-decompression limits as if you were diving on air, making it easier to use standard air dive tables. The lower the EAD, the less nitrogen you're absorbing.

Question 2

How is EAD calculated?

Accepted Answer

The formula is: EAD = (Depth + 10) × (1 - O₂%) / 0.79 - 10. For example, at 30 meters using EAN32 (32% oxygen): EAD = 40 × 0.68 / 0.79 - 10 = 34.4 - 10 = 24.4 meters. This means diving on EAN32 at 30m is equivalent to diving on air at 24.4m in terms of nitrogen exposure.

Question 3

Why is EAD useful for Nitrox diving?

Accepted Answer

EAD allows you to use standard air decompression tables while diving with Nitrox. Most recreational divers don't carry specialized Nitrox tables, so EAD provides a simple way to adapt air tables for Nitrox dives. This helps plan safer dives with accurate no-decompression limits.

Question 4

What is the relationship between oxygen content and EAD?

Accepted Answer

Higher oxygen percentages result in lower EAD values because there's less nitrogen in the breathing mix. For instance, EAN40 has a significantly lower EAD than EAN32 at the same depth, providing more decompression safety margin. Air (21% O₂) at any depth has an EAD equal to its actual depth since it's the baseline.

Question 5

How does EAD help reduce decompression risk?

Accepted Answer

By using EAD to plan your dive, you're essentially planning for a shallower dive than you're actually doing. This provides a safety margin in your decompression calculations. The difference between your actual depth and EAD represents the nitrogen reduction benefit of using Nitrox over air.

O₂ %	18m	19m	20m	21m	22m	23m	24m	25m	26m	27m	28m	29m	30m	31m	32m	33m	34m	35m	36m	37m	38m	39m	40m
EAN22	18.4m	19.4m	20.4m	21.4m	22.4m	23.4m	24.4m	25.4m	26.5m	27.5m	28.5m	29.5m	30.5m	31.5m	32.5m	33.6m	34.6m	35.6m	36.6m	37.6m	38.6m	39.6m	40.6m	Details
EAN23	18.7m	19.8m	20.8m	21.8m	22.8m	23.9m	24.9m	25.9m	26.9m	28.0m	29.0m	30.0m	31.0m	32.1m	33.1m	34.1m	35.1m	36.2m	37.2m	38.2m	39.2m	40.3m	41.3m	Details
EAN24	19.1m	20.1m	21.2m	22.2m	23.3m	24.3m	25.3m	26.4m	27.4m	28.5m	29.5m	30.5m	31.6m	32.6m	33.7m	34.7m	35.7m	36.8m	37.8m	38.9m	39.9m	40.9m	42.0m	Details
EAN25	19.5m	20.5m	21.6m	22.7m	23.7m	24.8m	25.8m	26.9m	27.9m	29.0m	30.0m	31.1m	32.1m	33.2m	34.2m	35.3m	36.3m	37.4m	38.5m	39.5m	40.6m	41.6m	42.7m	Details
EAN26	19.9m	21.0m	22.0m	23.1m	24.2m	25.2m	26.3m	27.4m	28.4m	29.5m	30.6m	31.6m	32.7m	33.8m	34.8m	35.9m	37.0m	38.0m	39.1m	40.2m	41.2m	42.3m	43.4m	Details
EAN27	20.3m	21.4m	22.5m	23.5m	24.6m	25.7m	26.8m	27.9m	29.0m	30.0m	31.1m	32.2m	33.3m	34.4m	35.5m	36.5m	37.6m	38.7m	39.8m	40.9m	41.9m	43.0m	44.1m	Details
EAN28	20.7m	21.8m	22.9m	24.0m	25.1m	26.2m	27.3m	28.4m	29.5m	30.6m	31.7m	32.8m	33.9m	35.0m	36.1m	37.2m	38.3m	39.4m	40.5m	41.6m	42.7m	43.8m	44.9m	Details
EAN29	21.2m	22.3m	23.4m	24.5m	25.6m	26.7m	27.8m	28.9m	30.1m	31.2m	32.3m	33.4m	34.5m	35.6m	36.7m	37.8m	39.0m	40.1m	41.2m	42.3m	43.4m	44.5m	45.6m	Details
EAN30	21.6m	22.7m	23.9m	25.0m	26.1m	27.2m	28.4m	29.5m	30.6m	31.8m	32.9m	34.0m	35.1m	36.3m	37.4m	38.5m	39.7m	40.8m	41.9m	43.0m	44.2m	45.3m	46.4m	Details
EAN31	22.1m	23.2m	24.3m	25.5m	26.6m	27.8m	28.9m	30.1m	31.2m	32.4m	33.5m	34.7m	35.8m	36.9m	38.1m	39.2m	40.4m	41.5m	42.7m	43.8m	45.0m	46.1m	47.2m	Details
EAN32	22.5m	23.7m	24.9m	26.0m	27.2m	28.3m	29.5m	30.7m	31.8m	33.0m	34.1m	35.3m	36.5m	37.6m	38.8m	40.0m	41.1m	42.3m	43.4m	44.6m	45.8m	46.9m	48.1m	Details
EAN33	23.0m	24.2m	25.4m	26.6m	27.7m	28.9m	30.1m	31.3m	32.4m	33.6m	34.8m	36.0m	37.2m	38.3m	39.5m	40.7m	41.9m	43.1m	44.2m	45.4m	46.6m	47.8m	49.0m	Details
EAN34	23.5m	24.7m	25.9m	27.1m	28.3m	29.5m	30.7m	31.9m	33.1m	34.3m	35.5m	36.7m	37.9m	39.1m	40.3m	41.5m	42.7m	43.9m	45.1m	46.3m	47.5m	48.7m	49.8m	Details
EAN35	24.0m	25.2m	26.5m	27.7m	28.9m	30.1m	31.3m	32.5m	33.8m	35.0m	36.2m	37.4m	38.6m	39.8m	41.0m	42.3m	43.5m	44.7m	45.9m	47.1m	48.3m	49.6m	50.8m	Details
EAN36	24.6m	25.8m	27.0m	28.3m	29.5m	30.7m	32.0m	33.2m	34.4m	35.7m	36.9m	38.1m	39.4m	40.6m	41.8m	43.1m	44.3m	45.5m	46.8m	48.0m	49.3m	50.5m	51.7m	Details
EAN37	25.1m	26.4m	27.6m	28.9m	30.1m	31.4m	32.6m	33.9m	35.1m	36.4m	37.7m	38.9m	40.2m	41.4m	42.7m	43.9m	45.2m	46.4m	47.7m	48.9m	50.2m	51.4m	52.7m	Details
EAN38	25.7m	27.0m	28.2m	29.5m	30.8m	32.0m	33.3m	34.6m	35.9m	37.1m	38.4m	39.7m	41.0m	42.2m	43.5m	44.8m	46.1m	47.3m	48.6m	49.9m	51.2m	52.4m	53.7m	Details
EAN39	26.3m	27.6m	28.9m	30.1m	31.4m	32.7m	34.0m	35.3m	36.6m	37.9m	39.2m	40.5m	41.8m	43.1m	44.4m	45.7m	47.0m	48.3m	49.6m	50.9m	52.2m	53.5m	54.8m	Details
EAN40	26.9m	28.2m	29.5m	30.8m	32.1m	33.4m	34.8m	36.1m	37.4m	38.7m	40.0m	41.3m	42.7m	44.0m	45.3m	46.6m	47.9m	49.3m	50.6m	51.9m	53.2m	54.5m	55.8m	Details

Equivalent Air Depth Tables

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