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Helium in Commercial Diving

Discussion in 'Commercial Divers' started by CAPTAIN SINBAD, Mar 29, 2021.

  1. CAPTAIN SINBAD

    CAPTAIN SINBAD Divemaster Candidate

    # of Dives: 200 - 499
    Location: Woodbridge VA
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    1,076
    At what depth do commercial divers generally use helium? Can anyone explain how the recent studies in gas density and Dr. Simon's recommendation to be on helium at 100' (which are for technical divers) effect commercial diving? Thanks.
     
    OTF likes this.
  2. Akimbo

    Akimbo Just a diver Staff Member ScubaBoard Supporter

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    It varies by jurisdiction and by company policy where jurisdiction doesn't dictate. The company policy can be the diving company's, their insurance company, and/or the client's.

    The British and Norwegian sectors of the North Sea require Helium below 50 meters/165'. In addition, all Helium diving requires a closed bell and mating deck chamber (paraphrased). Effectively this requires saturation diving below 50M.

    I have heard of mixed gas (HeO2) saturation diving used as shallow as 30M/100'. Sometimes decompression considerations are more than offset the total DSV (Diving Support Vessel) ecosystem — DP (Dynamic Positioning), high seas operations inherent in moonpool handling systems, heavy lift support, ROV support, tool systems like burning & welding and hydraulic tools, and experienced crews (diving and boat crews).

    There is still some surface-supplied HeO2 diving in some areas of the world but it is increasingly only used for small jobs and when DSVs are not available. Some areas with no jurisdictional restrictions on diving and local companies can do whatever they want. Surface supplied air dives to the 180-200' range are not uncommon.

    However, Nitrogen Narcosis is far more manageable on surface supplied operations. Supervisors can talk to you, can usually see what you see with the hat-mounted CCTV camera or a supporting ROV, and you are on the end of an umbilical where they can yank your butt off the bottom if you loose control. Compare that to being on your own or maybe with an equally impaired dive buddy on Scuba. There is also a significant difference in training and experience. New dive school grads don't get in the water on deep air jobs unless the company is a fly-by-night with no expectation of getting more contracts.

    I hear of a few surface-supplied trimix jobs but they are pretty rare.
     

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