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What is classified as a confined space?

Any enclosed space where there is a risk of death or serious injury from hazardous substances, lack of oxygen or other dangerous conditions is classed as a confined space. These spaces include any chamber, tank, vat, silo, pit, trench, pipe, sewer, flue and wells.

Specified Risks

  • Loss of consciousness of any person at work arising from an increase in body temperature (including industrial ovens, molten steel manufacturing, steel vessels in extreme temperatures, restrictive PPE)

  • Loss of consciousness or serious injury to any person arising from fire/explosion (flammable vapours, gases, introduced risk from oxygen lances)

  • Asphyxiation of any person at work (vapours chemical reactions (oxidisation) residues, inert gases (nitrogen))

  • Drowning due to an increase in level of fluids (sewers, ship holds, process tanks)

  • Free flowing solids - grain silos, ships holds, coal bunkers, lime pits

Risk Assessment

Identify the hazards and evaluate the risk to those entering or working in the confined spaces and others affected by the work. Individuals are encouraged to use the Hierarchy of Risk Control approach to help ensure that the risks have been reduced to a level of as low as reasonably practicable.

  1. PPE - Protect the worker with Personal Protective Equipment

  2. Administrative Controls - Change the way people working

  3. Engineering Controls - Isolate people from the hazard

  4. Substitution - Replace the hazard

  5. Elimination - Physically remove

Work in Confined Spaces

Factors to be assessed when planning work in confined spaces:

  • Supervision

  • Competency of personal

  • Communications

  • Atmospheric testing and monitoring

  • Gas purging

  • Ventilation - natural/forced

  • Working at height

  • Removal of residues

  • Isolations - gases, liquids, flowing materials

  • PPE and RPE

No person shall enter a confined space to carry out work for any purpose unless it is not reasonably practicable to achieve that purpose without such entry. There is a duty on designers to eliminate the need for entry. Use cameras and drones when and where possible.


An adequate communications system (ACS) must be in place and should enable communication:

  1. Between those inside the confined space

  2. Between those inside the confined space and outside the confined space

  3. To summon help in case of emergency


  • Low Risk - Shallow entry with adequate natural or mechanical ventilation, access is simple and unobstructed.

  • Medium Risk - Vertical direct unobstructed access with continuous attachment to a mechanical rescue device.

  • High Risk - When permanent attachment is not possible and the team moves away from the entry point.

This month, a wind turbine in Hull set alight, the cause is yet unknown. Fire and explosion causing injury to personnel is one of the specified risks for confined spaces. The majority of the industry don't classify the nacelle as a confined space. All areas within a turbine could be a confined space, a number of the specified risks within the regulations are "foreseeable"; such as fire, gases and internal body temperature. It would be a shame to wait until something went wrong before things changed. So what are your thoughts?

Should the Global Wind Organisation classify the nacelle as a confined space?

  • Yes

  • No


At HFR Solutions, we take the skills of the emergency services and deploy them in the business world. We offer a number of confined space courses and are able to upskill your staff to allow them to confidently work in confined spaces whilst confidently identifying hazards. Join the mailing list to receive insider knowledge and stay updated with the latest Solutions news and services.

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