Workplace safety - confined spaces

What is a confined space?

A confined space is any enclosed or partially enclosed structure that is intended or likely to be entered by any person, has limited or restricted entry or exit access and contains a potentially harmful atmosphere. Examples include tanks, pits, chimneys, silos, underground sewers, tunnels and wells.

A confined space may contain a harmful atmosphere, dangerous vapours, flammable gases, reduced or unsafe oxygen levels or stored substances that might collapse and engulf a person.

In many instances, people killed in confined spaces die trying to rescue someone already overcome by a harmful atmosphere. Rescues should never be attempted without proper emergency management procedures and appropriate safety equipment such as air-supplied respiratory protective equipment.

Examples of confined space hazards

Confined spaces are particularly dangerous because the hazards may not be immediately apparent. The dangers of confined spaces can include:

• biological hazards, such as bacteria
• exhaust gases
• flammable gases
• low oxygen levels
• risk of engulfment by stored substances such as wheat or sand
• toxic gases.

Confined spaces – assessing the risk

Preventing injury and death in the workplace requires identifying confined spaces and assessing the risk of performing work inside them. WorkSafe Victoria Advisory service can offer information and advice.

To reduce the risks of working in confined spaces:

• Whenever possible, eliminate the need for anyone to go inside the confined space – for example, use mechanical aids instead.
• Find out what is in the confined space before planning entry.
• Test the air in the confined space. This should be done if you don’t know for certain what’s been in there in the past. Do not assume it is safe.
• Devise safety procedures for working inside the confined space and provide induction and training.
• Make sure that any cleaning compounds or equipment used in the confined space are properly assessed.
• Make sure anyone going into a confined space has appropriate protection and an entry permit.
• Devise emergency and rescue procedures.
• Rehearse emergency and rescue procedures regularly.
• Thoroughly train the people who work inside the confined space.

Signposts and permits for confined spaces

All confined spaces should be clearly signposted. Victorian safety regulations state that only employees with valid entry permits may go inside a confined space. Those employees should be thoroughly trained and be familiar with emergency procedures.

Improving the safety of a confined space

Suggestions on improving the safety of a confined space include:

• Eliminate the need to enter the confined space, for example, by using mechanical aids to carry out maintenance tasks.
• Ensure entrances and exits are big enough to allow free access of people wearing protective clothing and rescue equipment that may be bulky.
• Make sure that any structures leading to the confined space, such as ladders and walkways, are safe.
• Include sufficient entry and exit openings in long confined spaces, such as tunnels or pipelines.
• Make sure the confined space is well lit and properly ventilated.

Ventilation and confined spaces

Two of the possible risks of confined spaces are low oxygen levels and harmful atmospheres (including vapours and flammable gases).

It is impossible to smell oxygen or some lethal gases so the human nose is an unreliable indicator of safe or harmful atmospheres. Instead, the air in confined spaces needs to be regularly tested for oxygen and contaminants using proper equipment.

Purging or mechanical ventilation, such as fresh air blowers or extractors, should always be used, so far as is reasonably practicable.

Safety suggestions include:

• Make sure any equipment is suitable for use in a confined space, especially equipment being used in flammable areas, which should be non-sparking and flameproof.
• Make sure the purging or ventilation system is powerful enough to be effective.
• Operate the purging or ventilation system before anyone enters the confined space to make sure the atmosphere is safe.
• Operate the purging or ventilation system continuously while anyone is inside the confined space.
• Make sure the purging or ventilation line is close to the working face.
• Vent exhaust from machinery straight out of the confined space.
• When using vaporous chemicals such as solvents, refer to Material Safety Data Sheets (MSDS) for their safe use.

Safety equipment and confined spaces

If a safe atmosphere can’t be guaranteed, appropriate safety equipment such as air-supplied respiratory protective equipment must be used.
If the confined space contains chemicals or dangerous substances, other protective equipment required may include gloves, goggles and overalls.
Harnesses and winches, when attached to the person entering the confined space, are an excellent backup, but they must be properly tested and appropriate training in their use must be provided to those using them.

Observation and communication when working in confined spaces

Make sure the people inside the confined space are monitored from the outside. There should be a person trained in initiating emergency procedures observing those inside the confined space from a safe vantage point outside the space. Practical communication methods include:

• mobile telephones
• two-way radios
• closed circuit television
• hand signals
• rope signals.

Emergency procedures for confined spaces

It is vital to devise proper emergency procedures and to rehearse them often. Suggestions include:

• Contact WorkSafe Victoria for advice and information.
• Train employees in first aid.
• Keep a suitable first aid kit in an accessible place.
• Provide rescue equipment – such as lifelines, lifting equipment, stretchers, and air-supplied, escape-type or self-rescue respiratory protective equipment and train employees in how to use them.
• Install emergency equipment, such as fire extinguishers.
• Ensure easy access to medical treatment and emergency services.

Where to get help

• In an emergency, always call 000 for an ambulance
• Your GP (doctor)
• WorkSafe Victoria Advisory Service Tel. (03) 9641 1444 or 1800 136 089 (toll free) – for general enquiries
• WorkSafe Victoria Emergency Response Line Tel. 13 23 60 (24 hours, 7 days) – for employers to report serious workplace emergencies such as fatalities, serious injuries or serious incidents