What counts as a confined space, and what must you do?

What is a confined space under the WHS Regulations?

Regulation 5 of the model WHS Regulations defines a confined space as an enclosed or partially enclosed space that meets all three of these tests:

1. it is not designed or intended primarily to be occupied by a person;
2. it is, or is designed or intended to be, at normal atmospheric pressure while any person is in it; and
3. it is or is likely to be a risk to health and safety from an atmosphere without a safe oxygen level, contaminants (including airborne gases, vapours and dusts) that may cause injury from fire or explosion, harmful concentrations of any airborne contaminant, or engulfment.

The definition does not include a mine shaft or the workings of a mine. Pressurised spaces also fall outside it, because the space must be at normal atmospheric pressure.

The Part 4.3 rules apply to any confined space that is entered, is intended or likely to be entered, or could be entered inadvertently. A confined space is defined by its hazards, not its size.

Which spaces on a construction site are confined spaces?

The model Code of Practice lists vats, tanks, pits, pipes, ducts, flues, chimneys, silos, containers, pressure vessels, underground sewers, wet or dry wells, shafts, trenches and tunnels as common examples — but only when they meet the definition. On construction and civil sites, the usual candidates are:

• Pits and access chambers for stormwater, sewer, electrical and telecommunications services.
• Sewers and stormwater pipes, where hydrogen sulphide and other gases can build up.
• Tanks — rainwater, septic, fuel and chemical tanks, and the inside of large pipes or ducts.
• Deep excavations, shafts and trenches, where gases heavier than air (or exhaust fumes from nearby plant) can collect, or where loose material could engulf a worker.
• Lift pits, sealed voids and similar spaces can also qualify if they are poorly ventilated, not designed to be worked in, and likely to hold a hazardous atmosphere.

Work that changes the atmosphere — welding, solvents, or a petrol pump running in a pit — can turn an ordinary space into a confined space. Our guide to excavation and trenching explains when a trench can also be a confined space.

What must happen before anyone goes in?

Regulation 65 says a business must ensure, so far as is reasonably practicable, that no worker enters a confined space until the confined space rules have been complied with. Before entry:

• Ask whether entry is needed at all, for example by using cameras or remote tools.
• Have a competent person assess the risks, in writing. Regulation 66 requires the assessment to consider the space, how oxygen or contaminant levels may change, the work methods, and the emergency and rescue procedures needed.
• Isolate connected plant and services. Under regulation 70, the risk of substances entering through connected pipes or plant, or of connected plant being energised, must be eliminated so far as is reasonably practicable — for example by isolation and lockout.
• Prevent inadvertent entry. Cover or barricade openings when no work is happening.

What must an entry permit and signs include?

Under regulation 67, a business must not direct a worker to enter a confined space to carry out work unless it has issued a confined space entry permit for that work. The permit must be completed by a competent person, be in writing, and specify:

• the confined space it relates to;
• the names of the people permitted to enter;
• the period during which the work will be carried out; and
• the control measures for the work, based on the risk assessment, including the measures for safe entry and the communication and monitoring system.

It must also have space to record that the work is finished and everyone has left the space, and the competent person must complete that acknowledgement when the work ends.

Regulation 68 requires signs next to each entry, put up immediately before work starts and kept up during the work and while preparing for and finishing it. The signs must identify the confined space, tell workers not to enter without a permit, and be clear and prominently located.

How must the atmosphere be tested and controlled?

Regulations 71 to 73 set firm limits while work is under way:

• Oxygen: the space must have a safe oxygen level, which the Regulations define as 19.5% to 23.5% by volume. If that is not reasonably practicable and oxygen is below 19.5%, workers must be given air-supplied respiratory equipment.
• Purging and ventilation: contaminants must be purged or ventilated out so far as is reasonably practicable, and pure oxygen, or gas mixtures above 21% oxygen, must never be used to do it.
• Flammable gases and vapours: the concentration must be kept below 5% of the lower explosive limit (LEL) so far as is reasonably practicable. From 5% to under 10% of the LEL, workers must leave immediately unless a suitably calibrated, continuous-monitoring flammable gas detector is used in the space. At 10% of the LEL or more, workers must leave immediately.
• Ignition sources must not be introduced if they could cause a fire or explosion.

The Code of Practice says testing should be done by a competent person with a correctly calibrated gas detector, from outside the space and top to bottom, because gases settle at different levels. Test for oxygen, flammable gases and toxic gases such as hydrogen sulphide and carbon monoxide, re-test after ventilating, and never rely on your senses.

Who must watch the worker, and how does rescue work?

Regulation 69 says a worker must not enter a confined space unless there is a system of work that includes continuous communication with the worker from outside the space, and monitoring of conditions by a standby person who is near the space and, if practicable, watching the work.

For emergencies, regulations 74 and 75 require the business to:

• establish first aid and rescue procedures for the space and practise them as often as needed to keep them effective;
• ensure first aid and rescue are started from outside the space as soon as practicable;
• keep entry and exit openings large enough for emergency access and unobstructed, and rescue equipment in good order; and
• provide air-supplied respiratory equipment to rescuers where the atmosphere is or may become unsafe, and suitable protective equipment where there is an engulfment risk.

What training and records are required?

Regulation 76 requires information, training and instruction for every worker who could enter a confined space, anyone with a role in the work or emergency procedures (such as the standby person), and their supervisors. It must cover the hazards, control measures, personal protective equipment, the entry permit and the emergency procedures. A record of the training must be kept for 2 years.

Under regulation 77:

• the risk assessment must be kept until at least 28 days after the work is completed;
• the entry permit must be kept at least until the work is completed; and
• if a notifiable incident occurs, both must be kept for at least 2 years after the incident.

Copies must be available for inspection and to relevant workers on request.

Is confined space work high risk construction work?

Yes. Under regulation 291 of the model WHS Regulations, construction work in or near a confined space is high risk construction work, so a safe work method statement (SWMS) must be prepared before it starts. The SWMS sits alongside the entry permit — it does not replace it. See our guide to safe work method statements.

Access into pits and shafts often involves a fall risk too. Our guide to working at heights covers those controls.

How is Victoria different?

Victoria has not adopted the model WHS laws. Confined spaces are regulated by Part 3.4 of the Occupational Health and Safety Regulations 2017, supported by WorkSafe Victoria’s compliance code. The core duties are similar, but the details differ:

• The definition is different. Victoria’s definition lists types of structure (such as vats, tanks, pits, pipes, ducts, silos, underground sewers, wells, shafts, trenches and tunnels) and requires that the space has a limited or restricted means of entry or exit that makes it physically difficult to get in or out. Its engulfment limb covers stored substances other than liquids.
• Permits: each permit applies to one confined space only, may cover one or more employees, and must name any person assigned to the communication role.
• Records: the employer must keep each permit until the work is completed, or for at least 2 years after a notifiable incident, and must keep a written record that all employees have left the space.

Victoria’s list of high risk construction work also includes work involving a confined space, so a SWMS is required there too.

Confined space checklist

1. Identify pits, tanks, sewers, shafts and deep excavations that meet the definition.
2. Avoid entry if the work can be done from outside.
3. Get a written risk assessment from a competent person.
4. Isolate and lock out connected pipes, plant and services.
5. Prepare a SWMS and issue a written entry permit.
6. Erect signs at every entry and barricade openings.
7. Test, ventilate and re-test the atmosphere, and monitor during the work.
8. Station a standby person with continuous communication.
9. Rehearse rescue from outside, with equipment ready.
10. Close out the permit once everyone is out, and keep the records.

Frequently asked questions