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Entry to confined spaces on marine craft

Untitled Document

Issued: 19 July 2005


To alert owners and operators of marine craft to the dangers of entering previously sealed confined space environments prior to verifying that the atmosphere is safe for human occupation.


An incident recently occurred where workers entered a previously sealed confined space within the hull of a barge to perform maintenance. Two of the workers were overcome by gas contained within the space and died. No prior testing of the atmosphere or ventilation of the space had been undertaken before entry.


Void confined space compartments within the hull of marine craft are generally sealed between maintenance periods and are rarely provided with ventilation in order to limit the effect of corrosion. When these spaces are opened for inspection or maintenance it is imperative that the atmosphere be verified as safe before entry of personnel is permitted. This can be carried out by the use of a probe connected to an intrinsically safe meter that measures the quality of the air in the structure.

During periods of closure, release of gas from applied surface coatings and decay of biological matter often takes place resulting in highly toxic atmospheric conditions. Oxidation of the hull structure (rusting) or bacterial activity may consume the oxygen leaving the atmosphere unable to support life.

Bacterial activity may also produce methane that can both displace oxygen and create an explosive atmosphere.


A person conducting a business  or undertaking must ensure a risk assessment is conducted by a competent person  in relation to the risks associated with working in, on or in the vicinity of  the confined space.  The risk assessment must  be recorded in writing.

A confined space entry permit  must be issued by the person conducting the business or undertaking before a  worker is directed or allowed to enter a confined space at a workplace.  The Work Health and Safety Regulation 2011  specifies, in section 67, what is to be included in a confined space entry  permit.

Continuous communication from  outside the space and monitoring of conditions within the space must be  included in the safe system of work.  The  Regulations for confined spaces include requirements for:

  • Connected plant and services
  • Atmosphere
  • Flammable gases and vapours
  • Fire and explosion
  • Emergency procedures
  • Information, training and instruction of workers

Legislative requirements

The Work Health and Safety Act 2011 places duties on  persons conducting businesses or undertakings to ensure the health and safety  of workers and others whilst within their workplace.  Part 4.3 of the Work Health and Safety Regulation 2011 prescribes the  duties that apply in relation to confined spaces.

Guidance on the requirements for confined spaces can be found in the Confined spaces code of practice 2021 (PDF, 1.43 MB).