Suitability assessment – Task-related factors – Confined Space

Confined spaces pose dangers because they are usually not designed to be areas where people work. Confined spaces often have poor ventilation which allows hazardous atmospheres to quickly develop, especially if the space is small. The hazards are not always obvious and may change from one entry into the confined space to the next. The risks of working in confined spaces include loss of consciousness, impairment, injury or death from:

  • the immediate effects of airborne contaminants
  • fire or explosion from the ignition of flammable contaminants
  • difficulty rescuing and treating an injured or unconscious person
  • oxygen deficiency or immersion in a free-flowing material, such as grain, sand, fertiliser, water or other liquids
  • falls from a height
  • environmental factors, for example extremes in temperature
  • poor lighting, and
  • manual handling.

Work in confined spaces may pose psychosocial risks that can lead to both physical and psychological injuries. These risks may arise from psychosocial hazards such as poor environmental conditions, low job control, high job demands, and remote or isolated work.

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

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

A confined space is determined by the hazards associated with a set of specific circumstances and not just because work is performed in a small space. Entry into a confined space means a person’s head or upper body is in the confined space or within the boundary of the confined space.

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. Refer to your country/state/territory definition as it may vary slightly from the above.

In AS/NZS 1715:2009 Table 4.6 as below provides Selection consideration of use in oxygen deficiency or IDLH atmosphere or unknown concentrations of contaminants which are commonly present in confined spaces.

AS/NZS 1715:2009 Table 4.6

Selection Considerations of use in oxygen deficiency or IDLH atmosphere or unknown concentrations of contaminants
Expected Use Equipment Remarks
Escape SCBA, quick fill type Mines-continuous supply/rechargeable for

long escape route
Work, routine Full facepiece airline with EBD Limited mobility and distance to source of

respirable air
Work, including rescue use

 

 ·         Compressed air SCBA duration: > 15 minutes

·         Compressed oxygen SCBA

·         Air-line with SCBA

 ·         Limited Duration

·         Specialist training essential

·         Limited mobility and distance to source of respirable air
Special response HAZMAT incident. No O₂ deficiency Combined gas/vapour and particulate P3 full facepiece, PAPR or air-line with filter Assessed as suitable by emergency service personnel
Work, including rescue use

Special response HAZMAT incident. O₂ deficiency

 Compressed air SCBA duration: > 15 minutes

 
Work in Confined Space Refer to relevant Regulator Confined Space code of practice ·         If oxygen deficiency is suspected then supplied air equipment is suitable

·         Limited duration only

·         Specialist training essential

 

Refer to the following links for further Respirator Selection considerations for these commonly associated confined space hazardous atmospheres

Further Australia & New Zealand Confined Space Resources