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    Confined Spaces: The Rules That Keep You Alive

    6 min read·Reviewed April 2026
    By SiteKiln Editorial TeamFirst published 25 Mar 2026Updated 21 Apr 2026
    Site Safety & HSE
    UK-wide

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    ‍‌​​‌‌‌​​‌‌​‌‌​‌‌‌​​‌‌​​‌​‌​‌​​‍> Disclaimer: SiteKiln gives you plain-English information, not legal or health and safety advice. Always follow your site-specific risk assessments and talk to a qualified professional.

    The short version

    The Confined Spaces Regulations 1997 say your employer must avoid entry if at all possible, and if entry really is needed, the job must only be done under a safe system of work with proper controls and emergency arrangements.

    You should not be sent into a confined space without task-specific training, information about the hazards, and a plan for rescue -- you're not the canary in the coal mine.


    What counts as a "confined space" on your jobs

    HSE's definition is two-part: a confined space is substantially enclosed, and there is a reasonably foreseeable risk of serious injury from hazardous substances or conditions (like lack of oxygen).

    On construction, that can include:

    • Manholes, sewers, tanks, culverts, ducts, voids, service tunnels, some excavations.
    • Boiler rooms, plant rooms, loft/roof voids, lift shafts and service risers when sealed up.
    • Any space where fumes, gases, dusts, lack of oxygen, flooding, or entrapment could become a serious risk.

    It's not about size alone -- it's about enclosure plus a realistic risk of serious harm if something goes wrong.


    What the regulations actually require

    Key duties under the Confined Spaces Regulations 1997:

    Avoid entry wherever reasonably practicable

    No person at work should enter a confined space to carry out work if it's reasonably practicable to do it from outside -- e.g. using remote tools, rods, cameras, access panels.

    If entry is unavoidable, follow a safe system of work

    Safe systems must be based on a suitable and sufficient risk assessment, and normally cover:

    • Identification of all hazards (atmosphere, substances, oxygen lack, flooding, entrapment, mechanical hazards, etc.).
    • Control measures: isolation/lock-off, ventilation, cleaning, purging, continuous or pre-entry atmosphere testing, communication, PPE/RPE.
    • Competent supervision and training of everyone involved (entrants, attendants, supervisors).

    Put adequate emergency arrangements in place

    • You must have a specific rescue plan -- not "we'll call the fire brigade".
    • Rescue team, equipment (e.g. tripod and winch, harnesses, breathing apparatus, first aid) and communication must be sorted before entry.

    Employers also have to ensure these duties apply not just to their own staff but, so far as reasonably practicable, to others doing confined space work under their control (subbies, labour-only, etc.).


    Your right to training before entry

    The regs don't literally say the words "right to training", but they require that confined-space work is only done by competent people, with proper information and instruction, as part of a safe system of work.

    In practice, that means you should expect:

    • Training that covers what a confined space is, the hazards in the specific types you'll work in, and the controls used.
    • Instruction on using atmosphere monitors, ventilation, isolation/lock-off, harnesses, tripods, and any breathing apparatus you're expected to use.
    • Clear briefing on the entry permit or method statement for the job -- what must be done before, during and after entry.
    • Clear explanation of the emergency/rescue plan and your role in it -- including what you must not do (e.g. attendants must not enter to attempt a solo rescue).

    If you've never had proper confined-space training and someone is telling you to get down a manhole or into a void with a gas monitor you've never seen before, that's not compliant with the spirit or letter of the regs.


    When you should refuse entry

    You should not go into a confined space when, for example:

    • There's been no specific risk assessment or safe system of work -- it's just "get in and get it done".
    • There's no pre-entry and/or continuous atmosphere testing where hazardous atmospheres are possible.
    • Isolation/lock-off of services (electrical, mechanical, fluid, gas) hasn't been done where it should be.
    • There's no clear rescue plan and no rescue equipment on site.
    • You have had no training in confined spaces but are being asked to enter anyway.

    In those situations, the risk of serious and imminent danger is obvious -- you're well within your rights (and your duties) to refuse until it's sorted.

    You can do this work safely if it's set up properly, but you should never be the first person to test whether a space is deadly.


    What to do next

    • Never enter a confined space without a specific risk assessment, safe system of work and rescue plan -- if these don't exist, refuse to go in.
    • Make sure you've had proper confined-space training before entry, including how to use atmosphere monitors, harnesses and breathing apparatus.
    • Check that there's a trained attendant outside and rescue equipment on hand before anyone goes in.
    • If you can do the work from outside (cameras, rods, remote tools), do it from outside.
    • Ask to see the entry permit or method statement for any confined-space task -- if it doesn't exist, that's your answer.

    Sources


    Disclaimer

    This guide is general information for small UK construction businesses and trades, not formal legal advice.

    SiteKiln is not a law firm and this page is not a substitute for getting advice on your specific situation.

    Health and safety law and HSE guidance on confined spaces are updated from time to time, and how the Confined Spaces Regulations apply will always depend on the exact facts on your job and your role.

    If you're being sent into confined spaces without proper planning, training or equipment, or there's been a serious incident, get specific advice from a competent health and safety professional or solicitor before you make big decisions.

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