Course Overview

The ADAS Closed Bell diver (Part 4) qualification is the most advanced of the commercial diving qualifications and enables the diver to work in the construction diving industry to a maximum of 300m using underwater tools, breathing apparatus and techniques including the use of closed bells and saturation systems.

The course is a progressive step from ADAS Part 3 and trains divers in the use of closed diving bells and chamber complexes as a diver or another member of the dive team to:

  • be able to dive using a closed bell and breathing artificial gas mixtures in air-range dives and dives deeper than 50 metres.
  • respond to emergencies in the water, bell or chamber when acting as a diver or another member of the diving team.

The training will culminate in the diver being placed into saturation with one dive being completed to a depth of approximately 100 metres.

Course Standards

This course meets the standards of:

  • AS2815.4 – Closed Bell Diver
  • Certificate IV in Hyperbaric Operations (Closed bell diving). National Qualification Code: 10133NAT.

Note: If you study at an ADAS training establishment outside of Australia you may not be eligible for this Australian Qualifications Framework certificate. The ADAS licence, however, is issued at all ADAS training establishments.

Student Prerequisites

Before applicants commence ADAS Closed Bell (Part 4) training, the ATE must ensure that:

  • Hold a current ADAS Part 3 diving qualification or approved equivalent for a minimum of 12 months. The date that the applicant obtained their Part 3 Certificate or recognised equivalent must be recorded on the application form submitted to ADAS for the Part 4 Certificate.
  • Have completed (in no less than 12 months and no more than 5 years) at least 100 dives for a minimum total bottom time of 100 hours working as either a Part 2 and Part 3 diver. These dives must have been recorded and in a formal diver’s daily logbook in a format in accordance with, or similar to, that required by ADAS and been certified by a qualified supervisor. Where doubt exists the ATE should confirm the validity of the above industry time with the nominated contractor/s
  • In regard to the dives required above:
    • all of the dives must have been conducted in surface supplied equipment and in open water. i.e. not in compression chambers, pools, and tanks
    • no dives undertaken as part of a training and/or assessment courses are to be counted
    • twenty (20) dives over 15m must be included in the total number of dives and bottom time
    • only bottom time is to be counted towards the fifty (50) hours, i.e. decompression stop time is not to be included
  • Hold either a recognised current Diver Medic Technician certificate or a current First Aid certificate from an accredited training organization (i.e. has been certified within 3 years of the conclusion of the proposed training program) and CPR and oxygen resuscitation skills must have been refreshed within the 12 month period prior to the conclusion of the training program. The student’s First Aid qualifications must meet the competency requirements of AS/NZS 2299.1 Occupational diving operations standard operational practice.
  • Are in possession of a valid certificate of medical fitness to dive (see AS/NZS 2299.1) issued, after examination, by a doctor trained and experienced in underwater medicine in accordance with the requirements in AS/NZS 2299.1, and that certification remains valid until the scheduled completion date of the training being undertaken. If the applicants’ health has changed significantly since the medical certificate was issued, the applicant shall seek an appropriate medical review; and
  • Unless Non-English Language (NEL) speaking course arrangements have been made with ADAS, are able to understand written and verbal communication in English, and can communicate effectively in English with other persons.
  • Is able to add, subtract, multiply and divide whole numbers, decimals and vulgar fractions; calculate percentages; and transpose and solve simple formulas, eg gas laws.


The following units of unit competency are completed:

  • ADAHYP401A Work safely in hyperbaric operations
  • ADAHYP402A Maintain effective working relationships within dive or hyperbaric operations team
  • FSKNUM14 Calculate with whole numbers and familiar fractions, decimals and percentages for work
  • BSBWHS201 Contribute to health and safety of self and others
  • ADABEL421A Carry out pre-dive preparations in closed bell diving operations
  • ADABEL422A Undertake underwater deployment in closed bell diving operations
  • ADABEL423A Implement emergency procedures in closed bell diving operations
  • ADABEL424A Conduct post-dive procedures in closed bell diving operations
  • ADABEL425A Ensure health and safety in closed bell diving in compliance with legislation and guidance
  • ADABEL476A Apply first aid within a chamber and bell
  • ADABEL477A Complete chamber surface procedures
  • ADABEL478A Maintain effective working relationships in closed bell diving operations
  • ADADIV474A Work safely in offshore diving operations
  • Elective: SISOSCB317A Complete a dive using Enriched Air Nitrox (EANx)
  • Elective: ADASSB458A Use enriched air nitrox in occupational diving operations

Delivery & Assessment

The ADAS Closed Bell course runs for three (3) weeks and includes all facets of training and assessment as a Closed Bell diver.

Before any assessments are undertaken the candidate should have a high expectation that the assessments will be safely and successfully completed. The person presenting the candidate for assessment should check and record that in their opinion the candidate has undertaken suitable and sufficient training, or has demonstrated that they have suitable and sufficient experience to be submitted for assessment. However, this does not mean that the candidate will automatically successfully complete the assessments. Share This

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