Regulation 3.82 of the Occupational Safety and Health Regulations 1996, defines a confined space as an enclosed or partially enclosed space which:

• is not intended or designed primarily as a workplace; 
• is at atmospheric pressure during occupancy; and  
• has restricted means for entry and exit;

and which either:

• has an atmosphere containing or likely to contain potentially harmful levels of contaminant; 
• has or is likely to have an unsafe oxygen level; or 
• is of a nature or is likely to be of a nature that could contribute to a person in the space being overwhelmed by an unsafe atmosphere or contaminant.

In accordance with regulation 3.85 of the Occupational Safety and Health Regulations 1996, any work carried out in confined spaces must comply with Australian Standard AS2865.

A person working in a designated confined space may be at risk of exposure to: 

• electrical shock or electrocution; 
• oxygen deficiency; 
• toxic gases or fumes; 
• engulfment/suffocation by solids; 
• fire and/or explosion; 
• drowning in liquids; 
• falls from height; and 
• environmental factors such as noise, extremes of temperature, poor lighting, manual handling and radiation.

Yes. A person must be on standby in the immediate vicinity outside the designated confined space. 

As the person on standby has to remain outside the confined space it is not always possible for them to keep the person/s working inside the confined space in sight at all times. 

Continuous communication with the worker/s inside the confined space must be maintained. Dependent upon the location, communications may be achieved using: 

• voice; 
• radio (intrinsically safe one if used in flammable conditions); 
• mobile phone (not to be used if flammable gas or vapour is present in sufficient concentration to cause explosion or fire); or 
• hard wired communications.

Before work in a confined space begins, a competent person must carry out a risk assessment. The risk assessment must be in writing and take account of the hazards involved; work methods to be adopted; risk factors to be considered and the control measures to be adopted. One of the risk factors to be considered is the arrangement for emergency response procedures including rescue, first aid and resuscitation. 

A rescue plan needs to be put in place that can be implemented in an emergency. All necessary equipment that may be required in an emergency (such as harnesses, respirators and stretchers) must be available and serviceable. The relevant members of the emergency response team required to use the equipment must be trained in its use.  The rescue members shall be trained in rescue work including first aid administration. The standby person may form part of an emergency response team by acting as the coordinator but must remain outside the confined space.

Safety harnesses and safety lines complying with AS/NZS 1891.1 should be worn where there is a risk of falling whilst descending into or ascending out of the designated confined space; or where rescue by a direct horizontal or vertical route is possible.

The use of hand operated lifting equipment should be considered, where appropriate, to facilitate the removal of an unconscious person from a confined space.

A confined space should never be purged with pure oxygen. Where necessary the confined space should be cleared of contaminants using a suitable purging agent. Gas mixtures used for this purpose should not contain an oxygen content of greater than 21%. Compressed clean air is economical and suitable for use.

Supplied-air respiratory protection devices complying with AS/NZS 1716 should be worn when:

• control measures cannot establish or maintain a safe atmosphere; or 
• the work to be carried out within the confined space is likely to degrade/contaminate the atmosphere, e.g. hot work or painting. 

For further information please refer to: 

• Australian Standard AS 2865 
• Regulations 3.82 - 3.87 of the Occupational Safety and Health Regulations 1996; and 
• Occupational Safety and Health Act 1984.