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    Control of bell blow-down – IMCA publishes information note

    Publications // May 12, 2010

    Diving contractors’ specific concerns about the bell diving supervisor not always being in control of the main blow-down, should any of the bell occupants lose consciousness, or become incapacitated, has resulted in the publication of an information note (IMCA D 02/10) by the International Marine Contractors Association (IMCA).
    “This information note results from the investigation of recent incidents, where there has been a reduction in the bell internal pressure, raising the issue of whether the bell diving supervisor has direct control of the blow-down in emergency scenarios depending on the configuration of the bell,” explained Jane Bugler, IMCA’s Technical Director.
    “The investigation also highlighted that some systems rely on the handover of the blow-down control from the bell diving supervisor to the bellman, whilst divers are in the bell. In such cases the bellman would then have overall control of the bell blow-down valve, until he hands control back to the supervisor."
    “The information note sets out current IMCA guidance, and explains just why diving supervisors should have control. It also notes that a risk assessment should identify the failure modes that could prevent the supervisor from having overall control of the bell pressurisation. It emphasises that the relevant offshore personnel should be included at all the stages of the risk assessment process.”
    The information note, available to all IMCA member companies, highlights risk assessment, preventative measures, divers’ training in emergency scenarios and emergency response measures as key areas for consideration.

    Further information on the contents of the information note, and on the benefits of IMCA membership are available from IMCA at and from the association at 52 Grosvenor Gardens, London SW1W 0AU, UK. Tel: +44 (0)20 7824 5520; Fax: +44 (0)7824 5521; email:


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