A location deemed to be a ‘confined space’ is one that is large enough for an employee to enter and perform their work, one that is not designed for continuous occupancy, and one that has limited or restricted means of entry or exit. If there is any chance that this location could become a hazardous atmosphere, you will need to ensure that there is appropriate confined space monitoring systems in place.

There are a number of hazards that these sorts of systems are designed to protect employees against, including:

  • Combustible gases – the system will alarm when the substance present begins to reach levels that could cause it to ignite. This could also alert workers to a leak that has developed.
  • Toxic gases and vapours – such as hydrogen sulphide and carbon monoxide. These vapours can be present in exhaust fumes when working with machinery in confined areas.
  • Oxygen – if the concentration of oxygen in the atmosphere falls below 19.5% or rises above 23.5%, workers are at serious risk. Agility impairment is first experienced, followed by death.


As working in such an enclosed space could make getting out of the area quickly extremely difficult, it is important that the confined space monitoring system that you use is able to alert workers to potential dangers well in advance, giving them plenty of time to vacate the area. You should also ensure that the system you are using is suitable for detecting the kinds of hazards that your enclosed spaces are likely to be subjected to.