Working in Confined Spaces

Last reviewed on 11/07/2013 11:01

This page gives information on risks presented by working in confined spaces, how to minimise those risks, and legal obligations and duties for employers.

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What is a 'confined space'?

A confined space is a place that is substantially (although not always entirely) enclosed where there is a risk of death or serious injury from hazardous substances or dangerous conditions (e.g. lack of oxygen).

Very often, injuries and deaths occur as a result of work being carried out such as welding, painting, flame cutting, use of chemicals.

Places can also become confined spaces during construction work, fabrication or modification.

Examples include:

  • chambers
  • tanks
  • silos
  • vats
  • pits
  • trenches
  • sewers
  • drains
  • flues
  • ductwork
  • unventilated or poorly ventilated rooms.

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What are the risks of working in confined spaces?

Every year, a number of people are killed and others seriously injured working in confined spaces across a wide range of industries in the UK, from those involving complex plant to simple storage vessels.

Those killed include not only people working in confined spaces but those who try to rescue them without proper training and equipment.

Dangers can arise in confined spaces because of:

  • lack of oxygen
  • poisonous gas, fume or vapour
  • liquids and solids suddenly filling the confined space, or releasing gases into it when disturbed
  • fire and explosions
  • residues left behind which can give off gas, fume or vapour
  • dust
  • hot working conditions.

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Legal duties and obligations relating to confined spaces

As well as the moral duty of employers to protect employees and members of the public, General Health and Safety Legislation covers all employers and workplaces.

The Management of Health and Safety at Work Regulations, 1999 require that a suitable and sufficient assessment of the risks for all work activities is carried out for the purpose of deciding what measures are necessary for safety.

For work in confined spaces this means identifying the hazards present, assessing the risks and determining what precautions to take.

In most cases the assessment will include consideration of:

  • the task
  • the working environment
  • working materials and tools
  • the suitability of those carrying out the task
  • arrangements for emergency rescue.

You may need to appoint competent people to help manage the risks and ensure that employees are adequately trained and instructed.

You may be the best person to do this, or you may need to train someone else to manage risks or engage the services of a competent person for additional help.

If your assessment identifies risks of serious injury from work in confined spaces, such as the dangers highlighted above, the Confined Spaces Regulations 1997 apply.

To view the full text of the above legislation online, please follow the links under Legislation.

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Reducing risks from working in confined spaces

The Confined Spaces Regulations 1997 contain the following key duties:

1. Avoid entry to confined spaces
Ask yourself if the work is really necessary, or if it can be done in some other way that avoids the need to enter the confined space?

2. If entry to a confined space is unavoidable, follow a safe system of work
The results of your risk assessment should help to identify the necessary precautions to reduce the risk of injury, depending on the type of confined space, the associated risk and the work involved.

The safe system of work should be implemented and everyone involved should be trained and instructed.

3. Put in place adequate emergency arrangements before the work starts
The preparation of suitable and sufficient measures to be taken to ensure the safe rescue of a person in an emergency are required before a person enters a confined space.

These arrangements should also consider the safety of rescuers, first aid procedures and liaison with emergency services.

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Further information on working in confined spaces

Free resources from Healthy Working Lives
Links below are to publications pages giving options to download these resources:

Guidance from the Health and Safety Executive
Note – all links are to external pages on the HSE website giving options to download or order these resources:

→ For more leaflets, visit the HSE webpage on Confined Spaces (external site).

Other sources

Confined Space Safe Practice
A comprehensive guide to safe working in confined spaces from the International Association of Classification Societies (external link):

→ Download IACS rec. no. 72: Confined Space Safe Practice (PDF 328 KB) (external site)


→ View The Confined Spaces Regulations 1997 (external site), or read more on The Management of Health and Safety at Work Regulations 1999 on this site.

This page has been partly adapted from "Safe Working in Confined Spaces" INDG258 (HSE).

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