MT2019 Tables - Professional Diving | Official French Tables 2019

Q: Who must use MT2019 tables?

Anyone performing professional hyperbaric work in France: commercial divers, construction divers, underwater inspectors.

Q: What is the maximum depth for MT2019 air dives?

75 metres. Beyond that, Heliox mixtures (Annex 2) are required.

Q: How do oxygen decompression stops work?

Pure O₂ at 6m or 12m accelerates off-gassing but requires strict monitoring against toxicity.

⚠️ Warning — Data from the decree of May 14, 2019 (Official Journal). For informational purposes only. Ascent rate: 9-12 m/min depending on depth. See MN90 vs MT2019 differences.

Official source

French decree of May 14, 2019, published May 24, 2019. Replaces MT92 tables.

Annex

Table

Depth

Understanding MT2019 Tables

The MT2019 tables, published in the French Official Journal on May 24, 2019, are the regulatory reference for professional diving in France. They replace the former GERS 65 tables and are mandatory for all professional hyperbaric operations (underwater works, inspections, subsea construction).

Annex structure

MT2019 tables are organized into three annexes: Annex 1 covers air and Nitrox dives (11 tables including no-decompression limits, air stops, pure oxygen stops, surface-supplied dives, Nitrox, multi-level, and altitude dives). Annex 2 covers Heliox dives (4 tables). Annex 3 provides emergency tables for managing decompression accidents.

Differences from MN90

Unlike MN90, MT2019 tables integrate pure oxygen decompression (O₂ stops at 6m and 12m), Nitrox mixtures with an equivalence system, and Heliox dives for deep interventions. Profiles are generally more conservative, adapted to professional constraints (physical effort, cold, stress).

FAQ — MT2019 Tables

Who must use MT2019 tables?

Anyone performing professional hyperbaric work in France must use MT2019 tables. This includes commercial divers, construction divers, underwater inspectors, and civil defense personnel. Recreational divers typically use MN90 tables or a dive computer.

What is the maximum depth for MT2019 air dives?

The standard air table (Annex 1, Table 3) covers dives up to 75 metres. Beyond that, Heliox mixtures (Annex 2) must be used to avoid nitrogen narcosis and oxygen toxicity.

How do oxygen decompression stops work?

MT2019 tables provide pure oxygen stops at 6m (Table 4) and 12m (Table 5). Pure O₂ significantly accelerates off-gassing by eliminating inspired nitrogen. Stop times are shorter than air stops, but O₂ toxicity risk (Paul Bert effect) requires strict monitoring and exposure limits.