Working in Confined Spaces

Frequently Asked Questions

Confined Space Sign

What is a confined space?

Confined Space refers to any place, including any vessel, tank, container, pit, bund, chamber, cellar or any other similar space which, by virtue of its enclosed nature, creates conditions that give rise to a likelihood of an accident, harm or injury of such a nature as to require emergency action due to

  • the presence or reasonable foreseeable presence of:
    -    flammable or explosive atmospheres
    -    harmful gas, fume or vapour
    -    free flowing solid or an increasing level of liquid
    -    excess of oxygen
    -    excessively high temperature
  • the lack or reasonably foreseeable lack of oxygen

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What are the key characteristics which define a confined space?

The key characteristics of a confined space are:

  • the space must be substantially enclosed
  • there must be a risk of at least one of the hazards listed above occurring within the space
  • the risk of serious injury from the hazard must be created by virtue of the enclosed nature of the space
  • the potential injury must be serious and be such as to require emergency action to rescue the person involved.

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What are the hazards associated with confined spaces?

The hazards associated confined spaces include:

  • Toxic Atmosphere
    A toxic atmosphere may cause various acute effects, including impairment of judgement, unconsciousness and death. A toxic atmosphere may occur due to the presence or ingress of hazardous substances. These substances may be present in the Confined Space for various reasons such as:
    -    remaining from previous processing or storage
    -    arising from the disturbance of sludge and other deposits
    -    the presence of a fire or flames within the space
    -    seepage from improperly isolated adjoining plant
    -    formation during the work processes carried out in the space
    -    being released from under scale and in brickwork as a result of the work process
  • Oxygen Deficiency
    Oxygen can be lacking a confined space for the following reasons:
    -    displacement of air by another gas
    -    various biological processes or chemical reactions (such as rotting of organic matter, rusting of metals, burning, etc)
    -    absorption of air onto steel surfaces, especially where these are damp
  • Oxygen Enrichment
    An excess of oxygen, in the presence of combustible materials, results in an increased risk of fire and explosion. Some materials, which do not burn in air, may burn vigorously or even spontaneously in an enriched oxygen atmosphere.
  • Flammable or Explosive Atmospheres
    A flammable atmosphere presents a risk of fire or explosion. Such an atmosphere can arise from the presence in the confined space of flammable liquids or gases or of a suspension of combustible dust in air. If a flammable atmosphere inside a confined space ignites, an explosion may occur, resulting in the expulsion of hot gases and the disintegration of the structure.
  • Flowing Liquid or Free Flowing Solids
    Liquids or solids can flow into the confined space causing drowning, suffocation, burns and other injuries.  Solids in powder form may also be disturbed in a confined space resulting in an asphyxiating atmosphere.
  • Excessive Heat
    The enclosed nature of a confined space can increase the risk of heat stroke or collapse from heat stress, if conditions are excessively hot. The risk may be exacerbated by the wearing of personal protective equipment or by lack of ventilation

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The Safety, Health and Welfare at Work (Confined Spaces) Regulations 2001 cover all work in relation to confined spaces.

Regulation 5 states that:

  • A person shall not carry out work in Confined Spaces if it is reasonably practical that it could be avoided
  • If the work must be carried out Hazard Identification and Risk Assessment must be carried out prior to the work commencing
  • A person shall not enter a confined space unless there is a system of work in place that has been planned, organised, performed and maintained so as to render that work safe and without risk to health
  • Anyone entering a confined space must be provided with appropriate information, training and instruction appropriate to the particular characteristics of the proposed work activities

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What are legal requirements in relation to Emergency Arrangements for confined spaces?

Regulation 6 of the Confined Space Regulations 2001 states that:

  • A person shall not enter a confined space unless there is a suitable emergency arrangements have been made which are appropriate to the confined space in question
  • The emergency arrangements shall include:
    -    all practical measures necessary to ensure the health and safety of  those taking part in the rescue
    -    the provision of a suitable and reliable means of raising the alarm in the event of an emergency
    -    having all necessary rescue equipment nearby and in a well maintained, good condition
    -    the provision of information, instruction and training to all involved in rescue procedures
    -    the provision of equipment and training for resuscitation procedures if there is a foreseeable risk that they will be needed.

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What must I look for in a confined space risk assessment?

When carrying out a risk assessment it is important to ensure that all risks associated with the hazards above are evaluated and controlled. When carrying out a risk assessment the following questions should be asked:

  • What could be inside the space that would pose a risk?
    -    Contents?
    -    Oxygen Deficiency?
    -    Previous Contents?             
    -    Oxygen Enrichment?
    -    Residues?                            
    -    Structure and Layout?
    -    Contamination?
  • What will be created due to the work carried out in the space?
    -    Sources of Ignition?            
    -   Flammable Substances?
  • What‘s outside the space that might pose a risk during the proposed work?
    -    Inadequate Isolation?
    -    Inadvertent Operation Of Plant?
    -    Nearby Work Activities?

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Are there any exemptions from the Safety, Health and Welfare (Confined Spaces) Regulations 2001?

Yes. The regulations do not apply to any place below ground in a mine (as defined by the Mines and Quarries Act 1965) or to any diving operations.

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What are the key elements of a safe system of work for a confined space?

The key elements to be considered when drawing up a safe system of work are:

  • Competence, training, supervision and suitability
  • Permit-to-work procedure
  • Gas purging and ventilation
  • Dangerous residues
  • Testing and monitoring of the atmosphere
  • Mechanical, electrical and process isolation
  • Respiratory protective equipment
  • Other personal protective equipment
  • Safe use of work equipment
  • Communications
  • Access and egress
  • Flammable or explosive atmospheres
  • Combustible materials

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What is a permit-to-work procedure?

A permit to work procedure is a means of achieving effective control of a system of work through formal written documentation known as a permit to work form.  The essential components of a permit-to-work system include:

  • A written procedure, which sets out how the system is to operate and clearly defines who may authorise particular jobs and who is responsible for specifying and implementing the necessary precautions
  • A form, known as the "permit-to-work form", which becomes a written and signed statement ensuring both the establishment of safe conditions for the work to commence and the maintenance of safe conditions for the duration of the work, including the provision of emergency arrangements
  • A method of informing the persons carrying out the work of the exact identity, location, nature and extent of the job, the hazards involved and the precautions to be taken, and
  • A system for ensuring the safe hand-back of the workplace after the job is completed and, in the case of confined space entry, after the space is vacated

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Where can I get a sample Permit-to-Work form and

A sample permit-to-work form is available in the Code of Practice Working in a Confined Space (PDF 1.6 MB opens in new window)

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Where can I get more information on Work in Confined Spaces?

Detailed information is available as a download - Code of Practice Working in a Confined Space (PDF 1.6 MB opens in new window)