Guidance

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.

From:
Maritime and Coastguard Agency
Published
28 February 2022
Last updated
3 May 2022 — See all updates

On 14 February 2022, new regulations on enclosed spaces were made.

These come into force in May 2022 for vessels falling under the Safety of Life at Sea Convention (SOLAS), and May 2023 for other vessels.

Details of these regulations can be found in MGN 659 (M+F) amendment 1 entry into enclosed spaces.

Amendment 1 provides general exemptions to (“the 2022 Regulations”). See 10.1 of the notice and annex’s D, E and F, outlining the requirements of each exemption.

General Exemptions are available for vessels under 500 gross tonnes on domestic voyages from the UK, from regulation 8 (drills) and regulation 9 (testing equipment), subject to the conditions that are set out in regulation 10 and the applicable general exemption.

Guidance for merchant vessel operators

Enclosed spaces are dangerous. If you see someone in an enclosed space: do not attempt to enter. Sound the general alarm, and take action to prepare for an organised entry.

This guidance provides advice on how to identify an enclosed space, the risks of entry, and information on how to reduce the risk to life.

Enclosed spaces guidance leaflet

Enclosed spaces - Guidance for merchant vessel operators (PDF, 2.34 MB, 12 pages)

Order printed copies

This leaflet is also available to order free of charge as a printed item from the MCA Safety materials ordering service.

More detailed information can be found in the Code of Safe Working Practices for Merchant Seafarers (COSWP).

No one should enter an enclosed space without following proper precautions, even in an emergency.

What is an enclosed space?

Enclosed spaces are not always obvious but can be deadly.

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

These are just a few examples of enclosed spaces:

  • cargo holds
  • pipe tunnels
  • ballast tanks
  • pump rooms
  • peak tanks
  • void spaces
  • bunker tanks
  • cofferdams
  • fresh water tanks
  • chain lockers
  • battery lockers
  • bottom tanks
  • paint / chemical lockers
  • boiler furnaces
  • engine crankcases.

Some spaces such as paint and chemical lockers, CO2 rooms, and battery lockers can be entered through weathertight or shipboard doors – but these spaces should still be considered dangerous.

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.

Enclosed spaces can change

Special attention is needed when dealing with cargo, as some cargo can create hazardous vapours.

Changing conditions within an enclosed space such as water ingress, oxygen-depleting work such as burning or welding, ventilation failure and vapours from paint or cleaning materials must be monitored. Conditions can also change due to external factors including the inadvertent actions of other ship or shore staff, work in adjacent or connected spaces, cargo work, pumping ballast or fuel transfer and hot work.

Enclosed spaces can be deadly

Even small quantities of harmful gases can kill. An enclosed space may not contain enough oxygen to breathe properly or there could be a build-up of dangerous gases which can cause asphyxiation. This could result in serious injury, brain damage and death.

Oxygen deficiency can be caused by:

  • corrosion (rusting)
  • organic matter
  • paint drying

Hazardous gases can come from many sources, such as leaks and hazardous cargo.

The risk is serious

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.

Do not enter a space if you don’t know if it is dangerous or not – enclosed spaces and dangerous atmospheres are an invisible killer.

Real life examples:

  • Example 1: An engineer working on board a trawler was found collapsed inside a refrigerated saltwater tank. When he was found, three of his crewmates went into the tank to help him; they all suffered breathing difficulties and one also collapsed. Although the engineer was rescued from the tank, he could not be resuscitated. Two other crew members then donned breathing apparatus and rescued their struggling crewmates.
  • Example 2: Three seafarers on board a vessel lost their lives as a consequence of entering an enclosed space. One entered the chain locker to secure a rattling anchor chain and collapsed. Another seafarer entered the chain locker in an attempt to help, but he also collapsed. A third tried to help the first two, but all three died due to the oxygen deficient atmosphere within the confined space.

Case studies taken from reports from MAIB investigations.

How to reduce risk

1. Identify your enclosed spaces

  • identify the hazard of any contents of the space
  • ensure the spaces have hazardous warning signage and permit only access
  • all enclosed space access doors, hatches or manholes should be secured
  • avoid entering closed spaces if possible

2. Carry out risk assessments and familiarise yourself with guidance

Familiarise yourself with the advice provided in the Code of Safe Working Practices for Merchant Seafarers (COSWP).

This is the simplest way to establish company procedure for entry into enclosed spaces.

In addition, you must carry out a risk assessment and issue a permit to work.

3. Precautions to take when entering an enclosed space

No enclosed space should be entered without proper precautions.

 Before entry:

  • a competent person should undertake a risk assessment and identify any potential hazards
  • prepare the space
  • secure the space for entry
  • ensure persons undertaking the work are trained and have participated in appropriate drills
  • test the atmosphere of the space
  • complete a permit to work
  • make a contingency plan in case things go wrong
  • review risk assessment

On entry:

  • ensure you have a person assigned on standby for each entry
  • the standby person should be equipped with rescue equipment including self-contained breathing apparatus and radio
  • wear protective clothing and boots
  • the standby person should ensure they maintain radio contact with the bridge or engine control room, or in port with someone who can help in case of emergency
  • ensure the space is well ventilated - ventilation should continue during the period that the space is occupied and during temporary breaks

If things go wrong

  • if you see someone lying motionless do not rush to carry out a rescue by yourself - an unplanned rescue is likely to end in tragedy as personnel rush into lethal atmospheres under the misconception that they will be able to save colleagues
  • stop, think – why are they unconscious, could this be an enclosed space?
  • should an emergency occur, the general (or crew) alarm should be sounded so that back-up is immediately available to the rescue team
  • never enter the space before help has arrived and a plan for rescue confirmed

Rescue

  • do not enter the space without the authorisation of the master or a nominated responsible person
  • do not enter the space without testing the atmosphere
  • rescue equipment including breathing apparatus should be immediately available
  • if the atmosphere is unsafe, do not enter unless it is an emergency - if it is an emergency, you must wear breathing apparatus
  • emergency escape breathing devices (EEBDs) are NOT safe to use in enclosed space entries including for rescue
  • self-contained breathing apparatus should be used for rescue
  • rescue procedures should be established before entry - the rescue procedure should be specific for each type of enclosed space
  • drills on enclosed space entry must include rescue procedures - they should be practiced frequently enough to provide a level of proficiency that eliminates life-threatening rescue attempts and ensures an efficient and calm response to any emergency

Failure to follow this advice may result in multiple fatalities.

Regulations and guidance

Further reading

Industry engagement and public consultation

Industry engagement to improve the safety of enclosed spaces

In February 2016, the Maritime and Coastguard Agency (MCA) hosted a workshop with the shipping industry on the dangers of enclosed spaces, to explore why there are still many incidents and fatalities involving enclosed spaces.

Approximately 100 people including shipowners, unions, the fishing industry, seafarer training establishments and experts on enclosed space entry attended.

The outcome of the workshop was to look at ways to improve the safety of enclosed space entry and to review the Merchant Shipping (Entry into Dangerous Spaces) Regulations 1988.

Following an investigation into the death on a vessel, the Marine Accident Investigation Branch recommended that the MCA amend these Regulations to include fishing vessels.

Public Consultation

A public consultation on the proposal to revoke and replace the Merchant Shipping (Entry into Dangerous Spaces) Regulations 1988, was held 24th May – 19th July 2021.

In total 27 responses were received and represented both the shipping and fishing industries resulting in the review of enclosed spaces regulations on board ships.

The public consultation informed us of current marine industry concerns, acknowledging the need for appropriate action. The majority of responses were supportive of the proposed 2022 Regulations.

Further information

Seafarer Safety and Health Branch
Maritime and Coastguard Agency
Bay 2/17, Spring Place
105 Commercial Road
Southampton SO15 1EG

Telephone: +44 (0) 203 8172501

Email: seafarersafety@mcga.gov.uk

Updates to this page

Published 28 February 2022
Last updated 3 May 2022 + show all updates

  1. Updated to reflect the review of MGN 659 (M+F) amendment 1 merchant shipping and fishing vessels (entry into enclosed spaces) regulations 2022, with the provision of general exemptions provided as annex D, E and F of that notice.

  2. First published.

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