ISO 24805:2022

Overview - What ISO 24805:2022 covers

ISO 24805:2022 is an international standard that defines minimum requirements for rebreather diver training for recreational decompression diving to 40 m using nitrox or 45 m using trimix, where mandatory decompression stops are required. It specifies the competencies learners must acquire, the evaluation criteria for those competencies, and the conditions under which training must be delivered. The standard complements the general recreational diving service requirements in ISO 24803.

Key technical topics and requirements

ISO 24805:2022 organizes training requirements into theoretical knowledge, practical skills, prerequisites and evaluation. Major technical topics include:

• Scope and prerequisites

  • Maximum depths: nitrox to 40 m, trimix to 45 m
  • Mandatory decompression diving techniques
  • Minimum age, required prior diving experience and health fitness criteria

• Theoretical knowledge

  • Rebreather fundamentals and types (e.g., CCR, SCR)
  • Function and operation of rebreather components
  • Breathing performance, gas density and gas mixtures
  • Gas supply and CO2 absorbent duration
  • Decompression theory and procedures for planned decompression stops
  • Risks: hypercapnia, hypoxia, hyperoxia and CO-related issues
  • Buddy system and team procedures

• Practical skills and training parameters

  • Rebreather assembly, pre-water checks and maintenance
  • Pre-dive, in-water and post-dive procedures
  • Emergency responses and malfunction management (response when breathing loop is available or not)
  • Required in-water sessions and instructor responsibilities
  • Breathing gas limits for CCR and SCR platforms

• Evaluation and certification

  • Knowledge and skill evaluation criteria for nitrox and trimix training paths
  • Proof of qualification and record keeping

Practical applications - who uses this standard

ISO 24805:2022 is intended for:

• Dive training organizations designing rebreather courses
• Scuba instructors and instructor trainers teaching advanced rebreather and decompression techniques
• Dive operators and centres that provide advanced rebreather experiences
• Certification bodies and regulators establishing minimum competency and safety criteria
• Advanced recreational divers planning training pathways for deep rebreather decompression dives

Related standards

• ISO 24803 - Recreational diving service providers (general requirements)
• ISO 24804 - Rebreather training - No-decompression diving
• ISO 11107 - Enriched Air Nitrox training (EAN)
• ISO 24801-2, ISO 24802-2 - Diver and instructor training levels

ISO 24805:2022 provides a practical, safety-focused framework to standardize advanced rebreather training, ensuring consistent competencies for decompression diving to 45 m.