---
title: "Confined space — the definition catches more than you think"
description: "How Canadian regulations define a confined space, the entry permit and attendant requirements, and why the word 'confined' has nothing to do with how small the space is."
term: "Confined space"
definition: "A fully or partially enclosed space that is not designed for continuous human occupancy, has restricted means of entry or exit, and may become hazardous because of its atmosphere, its contents or its design."
alsoKnownAs:
  - "Restricted space"
  - "Confined space entry"
jurisdiction: "Canada"
locale: "en-CA"
publishedOn: 2026-09-06
reviewedOn: 2026-09-06
canonical: "https://safeally.net/en-ca/glossary/confined-space/"
sources:
  - label: "Confined space — introduction"
    url: "https://www.ccohs.ca/oshanswers/hsprograms/confinedspace_intro.html"
    publisher: "CCOHS"
  - label: "OHS Regulation, Part 9 — confined spaces"
    url: "https://www.worksafebc.com/en/law-policy/occupational-health-safety/searchable-ohs-regulation/ohs-regulation/part-09-confined-spaces"
    publisher: "WorkSafeBC"
  - label: "Confined Spaces, O. Reg. 632/05"
    url: "https://www.ontario.ca/laws/regulation/050632"
    publisher: "Government of Ontario"
---

# Confined space — the definition catches more than you think

A fully or partially enclosed space that is not designed for continuous human occupancy, has restricted means of entry or exit, and may become hazardous because of its atmosphere, its contents or its design.

Three tests, and all three have to be read together: enclosed or partially
enclosed, not designed for continuous occupancy, restricted entry or exit. A pit
two metres across passes all three. So do a tank, a silo, a sewer chamber, a
crawl space, the inside of a machine housing, and the trailer of a tanker.
**Nothing in the definition mentions size**, and the space does not have to be
hazardous today — it has to be capable of becoming so.

## What it means in practice

- **Entry is by written permit**, issued after a hazard assessment by a competent
  person, valid for that entry, and closed out when the work is done.
- **Atmospheric testing comes before entry and continues during it**: oxygen
  first, then flammables, then toxics. Ventilation is a control, never a
  substitute for testing.
- **An attendant stays outside**, in continuous communication, with the means to
  summon rescue and without entering. That last clause is the one written in
  blood: a large share of confined-space fatalities are would-be rescuers.
- **Rescue is arranged in advance**, and calling 911 is not an arrangement unless
  the responding service has confirmed the capability and the response time.
- **Entry counts as entry when any part of the body breaks the plane** of the
  opening — reaching in to grab something is an entry.

## What it is not

**It is not a permit-required space only when something has gone wrong.** The
classification is done on the space's potential, before anybody works there, and
it is recorded.

**It is not solved by a gas detector.** A detector without a procedure, a trained
entrant, an attendant and a rescue plan simply documents the atmosphere at the
moment somebody died.

**And it is not defined identically across Canada.** Ontario and British Columbia
word the tests differently, some jurisdictions add a "restricted space" category
below the confined-space threshold, and the federal Code has its own regime. A
corporate confined-space list built to one province's definition will be wrong in
another.