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Enclosed Spaces on Sea-going Vessels

Entry into enclosed spaces onboard ships is sometimes a necessary but dangerous work activity. This guidance outlines regulations and provides information and advice on how to identify an enclosed space and how to reduce the risk to life.

An enclosed space is a space which is not designed for continuous worker occupancy and has either or both of the following characteristics:

  • limited openings for entry and exit

  • inadequate ventilation.

Spaces connected to an enclosed space should also be treated with caution, even when there is a closed door in-between. The connected space should be tested separately, as sometimes it can be dangerous even after the first space is emptied.

Even if a space appears to be safe, toxic gases or poorly oxygenated atmosphere can be trapped in pockets, even if the space has been ventilated and tested. Gas and liquid migration can occur through small gaps and cracks from connected unsafe spaces.

The guidance notes that when incidents do occur, they can be fatal and involve more than one person. Often a second person comes to rescue the first person and becomes unconscious themselves.

Advice is set out on how to reduce risk: identify your enclosed spaces; carry out risk assessments and familiarise yourself with guidance; precautions to take when entering an enclosed space.

Note: on 14 February 2022, new regulations (The merchant shipping and fishing vessels (entry into enclosed spaces) regulations 2022) on enclosed spaces were made. These come into force in May 2022 for vessels falling under the Safety of Life at Sea Convention, and May 2023 for other vessels.

Maritime and Coastguard Agency February 2022

Enclosed spaces on sea-going vessels
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