GETEX has written about the safety issues revolving around confined spaces, and their associated regulations and guidelines.
Confined spaces are fully or partially enclosed spaces not designed or intended as a place of work. They can have abnormal atmospheric pressures and restricted access.
Atmospheres in confined spaces can contain harmful levels of contaminant, be deficient or excessive in oxygen, or cause engulfment. The nature of partially enclosed spaces allow contaminants to accumulate, particularly heavier-than-air gases.
The oxygen content is used to identify a confined space. If the oxygen falls below 20.9% by volume at any time, the space is considered a confined space.
In NSW, the standard AS/NZS 2865:2001 and the NSW Occupational Health and Safety Regulation 2001 provide a regulatory framework for working in confined spaces, while HB 213:2003 provides guidelines for safe working in such spaces.
A worker enters a confined space when the person’s breathing zone of head or upper body is within the boundary of the space. Before entry, the hazards and risks of working in the space must be formally identified and assessed.
Frequently, these risks include explosion, lack of oxygen or the presence of toxic gases.
The risk assessment for explosions involves measuring the concentration of flammable contamination in the space. If the level is less than 5% of the lower explosive limit, work and entry is allowed. Monitored work is allowed at levels up to 10% before immediate evacuation is required.
The oxygen content of the atmosphere must not exceed 23.5%, and it must not fall below 19.5%. If the oxygen levels are liable to fluctuation, workers should wear personal protective equipment such as air-supplied respirators.
Too much carbon dioxide can cause engulfment. The gas is heavier than air, so it can be concentrated at the bottoms of trenches. Trenches deeper than 1.5m must be shored. Beyond 1.5m, work in a trench must be monitored, although the threat is not mitigated in shallower trenches.
When workers are in the space, separate standby and rescue staff equipped with rescue equipment must be ready to move in for retrieval. Workers in the space must be trained and competent, as must rescuers. According to some studies, 39% of deaths from entries into confined spaces are caused by attempts to rescue another person.
There must also be written confirmation after the job is over, making sure all persons have left the confined space before returning the space to its normal service tasks.
Confined spaces may also involve less common situations. For example, a coal transport ship’s hold might have an amount of coal dust which can only be mitigated by keeping the area very wet with water.
According to GETEX, it provides a range of monitoring, inspection and consultancy services for safe working in confined spaces. It can provide hazard and risk assessment, advice on standards and codes, supervise entry to confined spaces, and undertake levels measurement.

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