How Did RF3 Agree Those Rebreather Safety Points? by Rosemary E Lunn

RF3 Consensus

This is not one of the most riveting photos you will ever see. But it is a darn important one. It was taken during Rebreather Forum 3 – an international safety symposium held three years ago this week in Orlando. The event was hosted by the AAUS, DAN and PADI.

Pictured here is Gavin Anthony, speaking during the final session of RF3. Gavin is a much respected technical expert in diving technology, systems, safety and operations, and he provided valuable input into the consensus statements.

The two hour discussion session was chaired by Dr Simon Mitchell who achieved positive consensus on 16 safety points from the rebreather communities. How did it all happen? You can hear this historic session via this link.

What were the points agreed?

REBREATHER FORUM 3 CONSENSUS STATEMENTS

CHECKLISTS:
The forum acknowledged the overwhelming evidence demonstrating the efficacy of checklists in preventing errors in parallel fields that share similar technical complexity. Two recommendations regarding checklists were consequently agreed:

  1. CHECKLISTS
    The forum recommends that rebreather manufacturers produce carefully designed checklists, which may be written and / or electronic, for use in the pre-dive preparation  (unit assembly and immediate pre-dive) and post-dive management of their rebreathers.

– Written checklists should be provided in a weatherproof or waterproof form.

– The current version of these checklists annotated with the most recent revision date should be published on the manufacturer’s website

  1. CHECKLISTS
    The forum recommends that training agencies and their instructors embrace the crucial leadership role in fostering a safety culture in which the use of checklists by rebreather divers becomes second nature.
Checklists have been an integral part of PADI Rebreather and Tec CCR courses since their launch in 2011. PADI checklists are generic.  They should be supplemented by a unit specific manufacturer's checklist where available.

Checklists have been an integral part of PADI Rebreather and Tec CCR courses since their launch in 2011. PADI checklists are generic.
They should be supplemented by a unit specific manufacturer’s checklist where available.

TRAINING AND OPERATIONS:

  1. TRAINING AND OPERATIONS
    The forum applauds and endorses the release of pooled datadescribing numbers of rebreather certifications by training agencies, and encourages other agencies to join ANDI, IANTD, and TDI in this initiative
  2. TRAINING AND OPERATIONS
    The forum endorses the concept of making minimum rebreather training standards available in the public arena.
  3. TRAINING AND OPERATIONS
    The forum endorses the concept of a currency requirement for rebreather instructors. We recommend that training agencies give consideration to currency standards in respect of diving activity, class numbers, and unit specificity for their instructors.
  4. TRAINING AND OPERATIONS
    The forum recognizes and endorses the industry and training agency initiative to characterize “recreational” and “technical” streams of sport rebreather diver training. These groups will have different operational, training and equipment needs.

ACCIDENT INVESTIGATION

  1. ACCIDENT INVESTIGATION
    The forum recommends that training agencies provide rebreather divers  with a simple list of instructions that will mitigate common errors in evidence preservation after a serious incident or rebreather fatality.

– These instructions will be developed under the auspices of the Undersea and Hyperbaric Medical Society Diving Committee in consultation with the relevant RF3 presenters.

  1. ACCIDENT INVESTIGATION
    The forum endorses the concept of a widely notified centralized “on-call” consultation service to help investigators in avoiding errors or omissions in the early stages of a rebreather accident investigation, and to facilitate referral to expert investigative services.
  2. ACCIDENT INVESTIGATION
    The forum recommends that in investigating a rebreather fatality the principal accident investigator invite the manufacturer of the incident rebreather (or other relevant equipment) to assist with its evaluation (including the crucial task of data download) as early as is practicable.
  3. ACCIDENT INVESTIGATION
    The forum endorses the DAN worldwide initiative to provide a means of on-line incident reporting with subsequent analysis and publication of incident root causes.

RF3 logo

DESIGN AND TESTING

  1. DESIGN AND TESTING
    The forum recommends that all rebreathers incorporate data logging systems which record functional parameters relevant to the particular unit and dive data, and which allow download of these data. Diagnostic reconstruction of dives with as many relevant parameters as possible is the goal of this initiative.

– Footnote: An ideal goal would be to incorporate redundancy in data logging systems, and as much as practical, to standardize the data to be collected

  1. DESIGN AND TESTING
    The forum endorses the need for third party pre-market testing to establish that rebreathers are fit for purpose. Results of a uniform suite of practically important unmanned testing parameters such as canister duration, and work of breathing (qualified by clear statements of experimental parameters) should be reported publicly. Ideally, this testing should be to an internationally recognized standard.
  2. DESIGN AND TESTING
    The forum acknowledges recent survey dataindicating a poor understanding of rebreather operational limits in relation to depth and carbon dioxide scrubber duration among trained users, and therefore recommends:
  3. that training organizations emphasize these parameters in training courses.
  4. that manufacturers display these parameters in places of prominence in device documentation and on websites.
  5. DESIGN AND TESTING
    The forum strongly endorses industry initiatives to improve oxygen measurement technologies, and advocates consideration of potentially beneficial emerging strategies such as dynamic validation of cell readings and alternatives to galvanic fuel cells.
  6. DESIGN AND TESTING
    The forum identifies as a research question the issue of whether a mouthpiece retaining strap would provide protection of the airway in an unconscious rebreather diver.
  7. DESIGN AND TESTING
    The forum identifies as a research question the efficacy of a full face masks for use with sport rebreathers.

Categories: Events, Rebreathers

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5 replies »

  1. An interesting comment about the lack of knowledge about the relationship between depth and scrubber capacity. My system states 3 hours 40 meters and 2 hours 60 meters. However, the relationships between scrubber capacity and depth is not explained. I have been searching for literature. Even the EN 14143 does not detail anything useful. So where is the best information on this subject?

    • Hi Chris,
      Thanks for your interesting question. The short answer is that scrubbers last less time at depth due to the increased density of gas passing through it. More densely packed CO2 molecules = less scrubber time. PADI Rebreather Diver and Advanced Rebreather Diver and Tec 40 CCR Diver manuals explain this relationship. Tec 60 CCR and 100 CCR Diver manuals then go into increasing detail on this and other factors affected by depth.
      Cheers, Vikki

      • Are you saying that your body produces more co2 at greater depths? I’m not sure that’s true. Are you sure this isn’t much more about the denser gas needing a thicker reaction bed in the scrubber to be effective?

      • Hi Jef,
        No, the body does not produce more CO2 (all other factors being equal), but the gas is denser. The explanation for how this affects the reaction bed and why it shortens scrubber life is a little long for blog comments, but can be found in course materials and some manufacturer manuals. There was a great illustration of this on the Inspiration User list (and maybe other places) some time ago, which anyone subscribed to the list should be able to find in the archives.

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