TS EN ISO 24805

TS EN ISO 24805 focuses on the competencies a diver must gain in training for recreational rebreather diving, specifically for decompression dives that require mandatory stops. It defines requirements for training programmes that prepare divers to conduct dives using a rebreather to 40 m with a nitrox breathing mixture, or to 45 m with a trimix breathing mixture, and it sets out evaluation criteria for those competencies.

The technical significance of this standard comes from the way rebreather diving differs from open-circuit scuba. Rebreathers recirculate part of the breathing gas, so training must address oxygen control, carbon dioxide removal, gas management, emergency awareness, and disciplined decompression procedures together. These requirements apply in addition to the general rules for recreational diving service provision in ISO 24803.

How the training scope is framed

In general diving practice, nitrox means a breathing gas with an increased oxygen fraction, while trimix is a three-gas mixture of oxygen, nitrogen, and helium. At greater depths, trimix is commonly used to manage narcosis and gas density. Mandatory decompression stops indicate that ascent cannot be direct; the diver must follow a controlled ascent schedule, which makes this a more advanced training context than no-stop recreational diving.

• Training programme requirements for rebreather diving
• Dives to 40 m using nitrox
• Dives to 45 m using trimix
• Dives requiring mandatory decompression stops
• Evaluation criteria for the required competencies
• Additional requirements to ISO 24803 recreational diving service provision