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Confined spaces are usually not designed for people to work in.

They often have poor ventilation, which allows hazardous atmospheres to quickly develop, especially if the space is small. In addition hazards are not always obvious and may change from one entry point to the next.

  • If possible you should eliminate the need for people to enter a confined space. Entry to a confined space is considered to happen when a person’s head or upper body enters the space.

Confined space: a definition

A confined space is determined by the hazards associated with the specific situation—not just because work is performed in a small space. 

A confined space means an enclosed or partially enclosed space that:

  • is not designed or intended to be occupied by a person
  • is at normal atmospheric pressure—or is designed or intended to be at normal atmospheric pressure—while a person is in the space
  • is a risk to health and safety from:
    • an atmosphere that doesn’t have a safe oxygen level
    • contaminants like airborne gases, vapours and dusts that may cause injury from fire or explosion
  • has harmful concentrations of any airborne contaminants
  • is at risk of engulfment.

Confined spaces are commonly found in vats, tanks, pits, pipes, ducts, flues, chimneys, silos, containers, pressure vessels, underground sewers, wet or dry wells, shafts, trenches, tunnels or other similar enclosed or partially enclosed structures, when these examples meet the definition of a confined space in the model WHS Regulations.

A space may become a confined one if work carried out in it could generate harmful concentrations of airborne contaminants.

Table 1: Applying the criteria to determine confined spaces

 

Confined space criteria

Confined space?

Description of the space and activity

A

B

C

D

If the answer to A, B, C and at least one of D is yes, then the space is a confined one.

Is the space enclosed or partially enclosed?

Is the space not designed or intended to be occupied by a person?

Is the space designed or intended to be at normal atmospheric pressure while any person is in the space?

Does the space present a risk from:

Harmful airborne contaminants or contaminants that may cause fire or explosion?

An unsafe oxygen level?

Engulfment?

Sewer with access via a vertical ladder

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Dislodging grain from a silo with sole access through a manhole at the top

Yes

Yes

Yes

Yes

No

Yes

Yes

Cleaning spilled cadmium pigment powder in a shipping container

Yes

Yes

Yes

Yes

No

No

Yes

Inspecting a fuel tank in the wing of an aircraft

Yes

Yes

Yes

Yes

No

No

Yes

Dislodging a sludge blockage in a drain pit

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Internal inspection of a new, clean tank prior to commissioning

Yes

Yes

Yes

No

No

No

No

Internal inspection of an empty cement silo through a door at ground level

Yes

 

No

 

Yes

 

No

 

No

 

No

 

No

Stocktake using an LPG forklift in a fruit cool store

Yes

No

Yes

Yes

No

No

No

Installing insulation in a roof cavity

Yes

Yes

Yes

No

No

No

No

What is not a confined space

For the purposes of the model WHS Regulations, a confined space does not include a mine shaft or the workings of a mine.

The following kinds of workplaces are also generally not confined spaces:

  • Places intended for human occupancy that have adequate ventilation, lighting and safe means of entry and exit such as offices and workshops.
  • Some enclosed or partially enclosed spaces that at particular times have harmful airborne contaminants but are designed for a person to occupy, for example abrasive blasting or spray painting booths.
  • Enclosed or partially enclosed spaces that are designed to be occasionally occupied by a person if the space has a readily and conveniently accessible means of entry and exit via a doorway at ground level, for example:
    • A cool store accessed by a LPG forklift to move stock. Although using an LPG forklift in a cool store can be hazardous, the door at ground level means that once the alarm is raised escape and rescue can happen quickly.
    • A fumigated shipping container with a large ground level opening will facilitate easy escape and rescue.

Trenches are not considered confined spaces based on the risk of structural collapse alone, but will be confined spaces if they potentially contain concentrations of airborne contaminants that may cause impairment, loss of consciousness or asphyxiation.

Hazards

Identifying hazards involves finding all the things and situations that could potentially cause harm to people. Hazards associated with confined spaces include:

  • Harmful airborne contaminants, for example build-up of hydrogen sulphide in sewers and pits and vapours from paints, adhesives, solvents or cleaning solutions.
    • A PCBU must ensure the concentration of airborne contaminants does not exceed workplace exposure standards.
    • Air monitoring is needed if there is uncertainty about whether the airborne concentration of a substance or mixture exceeds the relevant exposure standard, or if it is necessary to determine whether there is a risk to health.
  • Unsafe oxygen level, for example oxygen can be displaced by gases produced during biological processes such as methane in a sewer.
  • Fire and explosion. If an ignition source such as a sparking electrical tool or static on a person is introduced into a space containing a flammable atmosphere an explosion is likely to result.

Engulfment means to be swallowed up in or be immersed by material, which may result in asphyxiation. Examples of materials that may pose a risk of engulfment include plastics, sand, liquids, fertiliser, grain, coal, coal products, fly ash, animal feed and sewage. 

For more information on hazards in a confined space, see the model Code of Practice: Confined spaces.

Managing risks associated with confined spaces

A risk assessment involves considering what could happen if someone is exposed to a hazard and the likelihood of it happening. Under the model WHS Regulations, carrying out a risk assessment is mandatory for working in a confined space.

For more information on carrying out a risk assessment for working in a confined space, see Identify, assess and control hazards and the model Code of Practice: Confined spaces.

Information and training

Workers and supervisors must have the skills and knowledge to understand the:

  • hazards associated with working in a confined space
  • details on any confined space entry permit
  • control measures implemented for their protection. 

Training should be provided to workers who:

  • enter or work in confined spaces
  • undertake hazard identification or risk assessment in relation to a confined space
  • implement risk control measures
  • issue entry permits
  • act as a standby person or communicate with workers in a confined space
  • monitor conditions while work is being carried out
  • buy equipment for confined space work
  • design or lay out a work area that includes a confined space.

The training provided to relevant workers must cover:

  • the nature of all hazards related to a confined space
  • the need for, and appropriate use of, risk control measures
  • the selection, use, fit, testing and storage of any PPE
  • the contents of any relevant confined space entry permit
  • emergency procedures.

Records of all training provided to workers in relation to confined space work must be kept for two years.

Further advice

SWA is not a regulator and cannot advise you about compliance for confined spaces. If you need help, please contact your state or territory work health and safety authority.

Important

You must check with your WHS regulator if a model Code of Practice has been implemented in your jurisdiction. Check with your WHS Regulator.

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Last modified on Friday 17 March 2017 [1596|29446]