Why confined space work is high risk
Work in or near a confined space is high risk construction work under the model WHS Regulations and requires a SWMS. A confined space is an enclosed or partially enclosed space that is not designed for continuous occupancy, has restricted entry and exit, and may have an unsafe atmosphere or other hazard. Examples include tanks, pits, pipes, ducts, and silos.
The hazards in confined spaces can be invisible and can change quickly. A confined spaces SWMS should identify the specific space, the reason for entry, and the controls for atmosphere, engulfment, and rescue.
Atmospheric hazards and testing
Unsafe atmosphere is a leading cause of confined space fatalities. Hazards include oxygen deficiency, flammable gases, and toxic gases such as hydrogen sulfide or carbon monoxide. The atmosphere must be tested before entry and monitored while work is underway.
The SWMS should describe how the atmosphere is tested, what levels are acceptable, what equipment is used, and what happens if readings are outside safe limits. Ventilation and purging should be addressed where relevant, and the space re-tested after any interruption.
Entry permits and stand-by persons
Confined space entry requires an entry permit that authorises the work and records the controls in place. A stand-by person should be stationed outside the space to monitor the entrants and initiate rescue if needed.
The SWMS should set out the permit process, the role of the stand-by person, communication methods, and the training and competencies required for everyone involved in the entry. Isolation of incoming services is also a key control before entry.
Rescue planning
Emergency rescue from a confined space is difficult and dangerous. A rescue plan should be prepared before entry, with the right equipment available and rescuers trained in its use. Improvised rescue attempts are a frequent cause of multiple fatalities.
The SWMS should describe the rescue procedure, the equipment on hand, and how emergency services will be contacted. The plan should be specific to the space and the work being done, and rehearsed where possible.