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What is a Confined Space? Everything You Need to Know

PostedNovember 11, 2023
UpdatedSeptember 7, 2024
ByTanya

What is a Confined Space?

Read our article to determine what is legally considered a confined space. Download our Confined Space Identification Checklist to assess spaces in your workplace.

*For internal use only. Not for resale or redistribution. By downloading any content from this article, you agree to our Free Resources Licensing Agreement.

Who Decides What is a Confined Space?

In Australia, each state has the authority to set work health and safety laws. To ensure you are using the correct legislation, you should access it from your jurisdictions local regulator.

The Harmonised WHS Legislation and Codes

Most of Australia uses the Harmonised WHS Legislation and that is the legislation we’ll be referencing today. This model legislation is published by Safe Work Australia and is comprised of the Work Health and Safety Act and Regulations.

Safe Work Australia also published model codes of practice. There is a model code of practice for confined space that has been adopted in most states. Once again, we’ll be referencing the harmonised confined spaces code of practice.

A Definition for Confined Spaces

The confined spaces code of practice contains a flowchart that is used to assess whether a space meets the criteria. Most of the questions are straight forward, however some can be tricky and even subjective. If you answer NO to any of the following questions, the space is NOT considered a confined space.

 

What is a confined space Identification checklist

Enclosed or Partially Enclosed?

Pretty straight forward. If the space isn’t enclosed (e.g. you are standing in the middle of a field) this obviously isn’t a confined space.

NOT Designed to Be Occupied by a Person?

Next question – is the space designed for human occupancy? Example – your car is an enclosed space, but it is designed for a person to be inside, therefore it is NOT considered a confined space. Your house is another example, it is designed with ventilation, lighting, safe access and egress etc. so it also NOT a confined space.

The tricky thing here is the question is a “double negative”. If the space IS designed for a person to be inside, the answer to the question is NO.

Designed to Be at Normal Atmospheric Pressure?

This is the question that confuses most people. Take the example of a high pressure vessel that isn’t at atmospheric pressure. The answer to this question is obviously NO. However that doesn’t mean that this space isn’t a confined space and that people can enter it without permit. Rather, it means that the space is highly dangerous and people must not enter it. Before it can be considered a confined space, it must be brought to atmospheric pressure.

LIKELY to Pose Health and Safety Risks?

This is the subjective question. After all, how do you quantify “likely”? The risks that may be present are:

  • Unsafe or low oxygen levels
  • Contaminants that may cause ignition or fire, including:
    • Gases
    • Vapors
    • Dusts
  • Harmful concentration of airborne contaminants (e.g. toxic gases or toxic fumes)
  • Engulfment

This question is best answered by a competent person conducting a written risk assessment in consultation with workers.

NOT a mine shaft or the workings of a mine?

Another double negative question. If the answer is NO, i.e. the space IS a mine shaft or mine, then the space is NOT a confined space. In this case, the space will be regulated by the mining regulator in your jurisdiction.

Examples of Confined Spaces

Lets run through those questions for two examples.

Underground Sewers / Manhole

Sewer Manhole - What is a Confined Space

  • Is the space enclosed or partially enclosed? Yes.
  • Is the space NOT designed for a person to be inside? Yes.
  • Is the space at atmospheric pressure? Yes.
  • Is the space likely to pose health and safety risks? Yes.
  • Is the space NOT a mine shaft or mine? Yes.

Therefore the space is a confined space.

New, Clean Storage Tanks (not connected)

  • New Tank - What is a Confined SpaceIs the space enclosed or partially enclosed? Yes.
  • Is the space NOT designed for a person to be inside? Yes.
  • Is the space at atmospheric pressure? Yes.
  • Is the space likely to pose health and safety risks? No (answer taken from the code of practice).
  • Is the space NOT a mine shaft or mine? Yes.

Therefore the space is NOT a confined space.

Some examples of what would likely be a confined space include silos, chimneys, dry wells, vats, ducts and flues.

Safety Controls for Confined Space Entry

Once it has been determined what is a confined space, various control measures may be required including:

  • Confined space entry permit
  • Personal protective equipment (PPE) (e.g. respiratory protective equipment and harnesses)
  • Purging or forced ventilation
  • Atmospheric monitoring
  • Isolation of machinery or pipes / valves
  • Rescue procedures, first aid and emergency procedures (including means of communication)
  • Trained and competent workers
  • Safe system of work (SWMS) or safe work practices

Check with your local regulator to determine specific duties in your state:

FAQs

What is a confined space?

A confined space is an enclosed or partially enclosed area that is not intended for continuous occupancy and poses health and safety risks due to factors like lack of oxygen, presence of harmful gases, vapors, dust, or the risk of being buried or crushed.

What are common examples of confined spaces?

Common examples include vats, tanks, pits, pipes, ducts, flues, chimneys, silos, containers, pressure vessels, underground sewers and wells.

What are the main hazards associated with confined spaces?

The primary hazards include oxygen deficiency, toxic atmospheres, flammable atmospheres, and physical hazards such as engulfment or entrapment.

Who is responsible for managing the risks associated with confined spaces?

The person conducting a business or undertaking (PCBU) is responsible for managing risks. This includes ensuring proper risk assessments, providing necessary training, and implementing safety measures.

What safety measures should be taken before entering a confined space?

Safety measures include conducting a risk assessment, ensuring proper ventilation, using personal protective equipment (PPE), having an entry permit system, and establishing emergency and rescue procedures.

What is a confined space entry permit system?

An entry permit system is a formal process that ensures all necessary safety measures are in place before a worker enters a confined space. It includes details about the work to be done, hazards identified, and control measures implemented.

Did You Know

In 2008, a tragic confined space incident occurred at a water treatment plant in Victoria, Australia. Three workers lost their lives while attempting to rescue a colleague who had collapsed inside a confined space. The initial worker was overcome by toxic gases, and the subsequent rescuers, lacking proper safety equipment and training, also succumbed to the hazardous atmosphere1.

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