Understanding risk assessment of confined space areas

05-11-2014

Confined spaces are a pain in the neck in more ways than one for Occupational Health and Safety people assessing them and those required to enter them alike. These are areas which carry a high consequence, high likelihood of incident rating should be treated as HIGH or VERY HIGH risk each and every time they are entered. As well as being atmospherically risky (ignition, asphyxiation, engulfment etc.) these areas are also often ergonomically challenging and exist in areas where rescue of persons can be difficult.

A confined space uses four tests for classification, the bearing of these tests comes together to form a recommendation of confined space, it is best to approach cautiously and select a ‘YES’ over a ‘NO’ to any question you are unsure of, as it is better to treat a borderline hazard as higher risk than lower.

The four questions which make the test of a confined space are:

  1. Is the space enclosed or partially enclosed?
  2. Is it likely to be entered and is it at normal atmospheric pressure?
  3. Does the space have a limited or restricted entry or exit?
  4. Is the space likely to contain:
    1. An atmosphere that has a harmful level of contaminant?
    2. An atmosphere that does not have a safe oxygen level?
    3. Any substance that could cause engulfment?

If the answer to A, B, C and any of D (i, ii, iii) is YES, then the test represents that the area is a confined space. If an area has been determined to be indeed a confined space, undertake a thorough risk assessment of the area:

Considerations for confined space areas

The hazards within the confined space

  • Low or enriched LEL, engulfment, volatile atmosphere etc.

The task required

  • Time, persons, extraneous factors etc.

The working environment

  • Tight squeezes or narrow planks increase risk.

Work materials and tools

  • Think carefully about equipment i.e. If the area is O2 enriched, you will need to ensure compliance to HB 13 – 2007 “Electrical Equipment for hazardous areas”, as some standard equipment may generate sparks.

All permits associated with the work

  • Valid for up to 24 hours, new permit per shift, completed, filed.

Physiological / psychological demands of the task

  • Have you discussed/reviewed physiological and psychological factors with the persons expected to enter?
    • Have they experienced claustrophobia in the past?
    • Do they have any injuries or illnesses that may affect their ability to undertake the task.

Arrangements for emergency rescue

  • What will occur in the event of an emergency?
    • Does everyone know the procedure and contact numbers?
    • If the site must be evacuations, who communicates this to you?

Training requirements

  • Is everyone competent to undertake the task?
    • Refresher training in confined spaces should be undertaken every 2-3 years.

Other things to remember:

  • Elimination is the best risk method of risk management, if placing persons within a confined space can be avoided this should be the first priority.
  • Isolate equipment to prevent inadvertent operation/release of asphyxiates when within a confined space.
  • Purge the area using natural or forced ventilation to ensure safe oxygen levels.
  • Check all your equipment before operation including PPE, gas testing equipment and operational equipment.
  • Plan and practice all foreseeable emergency scenarios.
  • Complete a compliant confined space entry permit (P.23 Compliance code – Worksafe Victoria)

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