Skip to content

Guidance on Hyperbaric Evacuation Systems from IMCA

Published on 11 July 2013

When a vessel is severely damaged there may come a time when it has to be abandoned. For such a situation vessels are required to have adequate lifeboats (or life rafts) on board for all personnel. In such an emergency, the evacuation of divers in saturation represents a particular problem as they cannot be readily decompressed in order to be evacuated in the same way as other crew members. The divers need to be transferred to a pressurised compartment which can be detached from the diving system on the vessel and launched or floated into the sea.

“This means that for all saturation diving operations a hyperbaric rescue unit (HRU) needs to be provided that, in the event of a vessel evacuation, is capable of evacuating the maximum number of divers,” explains Jane Bugler, Technical Director of the International Marine Contractors Association (IMCA).

“Planning and facilities also need to be in place to ensure that the HRU and its occupants are taken to a designated location where they can be decompressed back to surface pressure in a safe and controlled manner.”

A newly published IMCA document ‘Guidance on Hyperbaric Evacuation Systems’ (IMCA D 052) aims to provide guidance on minimum requirements needed, and to identify the various factors that need to be considered during the planning phase before diving commences. It also aims to provide guidance on the risk assessment process required to ensure that the necessary standard of safety is achieved.

“IMCA D 052 also seeks to establish standard terminology for the various parts of a hyperbaric evacuation system.” adds Jane Bugler.”As it contains many items of technical advice in its 68 pages, it is assumed that the reader has knowledge of saturation diving technology, physiology and equipment.”

The new guidance document has sections on background and explanation; medical aspects of hyperbaric evacuation; elements to be considered in the development of a hyperbaric evacuation system; equipment and interfaces; development of documentation for hyperbaric evacuation system construction and operation; elements to be considered for the execution of a hyperbaric evacuation and subsequent decompression; operation emergency; risk assessment/hyperbaric evacuation plan guidance; personnel and competence (LSP/HRF); audit and assurance; and two appendices, one which contains acronyms and the other a glossary of terms.

Like all IMCA guidance document IMCA D 052 can be downloaded free of charge from the IMCA website at and printed copies can be purchased from the website or [email protected] at £5.00 for members and £10.00 for non-members.