What is a Confined Space?

In this video series, we aim to clarify some issues that arise around confusion and misinformation within workplaces about confined spaces and controlling risk within a confined space. In this particular video (part 1), Laurie answers the question “what is a confined space?”

Definition of a Confined Space

There is legislation relating to confined spaces, but we must all remember that the primary reason for confined space entry management is to ensure that we do not place our people at risk.

The definition of a confined space can vary depending on jurisdictions and the following one that I'm going to be talking about is actually based on the Safe Work Australia model, WHS regulations, and the confined space code of practice.

A confined space can be defined as an enclosed or partially enclosed place. For example, a tank and an open top tank will be regarded as a potentially partially enclosed or a vessel may be fully enclosed. It is not designed or intended primarily to be occupied by a person. It’s not something like a control room or something of that nature.

It's designed to be intended to be at normal atmospheric pressure. If we're entering confined spaces where it is not at atmospheric pressure, that will be a totally separate set of circumstances.

It is likely to contain an atmosphere with an unsafe oxygen level.

It could contain contaminants, such as airborne gases, vapour dust, which could cause injury from a fire or explosion occurring.

And it could contain harmful concentration of any airborne contaminants.

And last but not least, it could include engulfment.


Under legislation, for a confined space to be defined as confined space,

  • it must be enclosed or partially enclosed.
  • It must not be designed or intended primarily to be occupied by a person.
  • It must be designed to be at normal atmospheric pressure.

And it must include one of the following: -

  • an atmosphere with unsafe oxygen level,
  • a contaminant,
  • harmful concentrations of an airborne contaminant or
  • engulfment.

Any one of those will make it a confined space.

Once you define it as a confined space there be other hazards that we would need to look at for example,

  • is any electrical power entering that confined space?
  • Is there a mechanical energy in the confined space?
  • Are there manual handling injures?

These on their own would not make it a confined space, but we still need to manage the risks associated with it and often these are regarded and categorized as a restricted area.

In some organisations, they include restricted areas in their confined space entry procedures, and so it is necessary to check within your workplace to establish what the local requirements are.


Risk Management Process

The determination of a confined space should be through a formal application of the risk management process. You need to actually go through and systematically establish what the criteria is for that confined space.

Now, some examples of a confined space will be things like

  • A tank,
  • a pick,
  • a pipe,
  • a duct,
  • chimneys,
  • silos,
  • pressure vessels,
  • underground sewers,
  • storm water drains,
  • shafts,
  • trenches,
  • tunnels.

The legislation and goes on to specifically define what a confined space is not. For example, a mineshaft or a place which is designed for a person to occupy such as a cool room.

You need to refer to your regulator for specific information on confined spaces. And you will generally find that within the codes of practice in most jurisdictions, there is a flowchart for you to follow to assist in identification of the confined space.


Other videos in this series:


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