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Control measure
Carry out atmospheric testing and monitoring

Control measure knowledge

Atmospheric monitoring should be carried out whenever operations take place in a confined space.

Before entry, the atmosphere within a confined space should be tested to check oxygen concentration and to check for the presence of hazardous gases or vapours. Atmospheric testing should be carried out by competent personnel aware of the limitations of the equipment in use.

Testing should be carried out if the atmosphere might be toxic, asphyxiating or hypoxic. Testing should also be carried out if it is known that the atmosphere was previously contaminated and subsequently ventilated.

Regular monitoring is necessary to identify any changes in the atmosphere while work is being carried out. The results of testing and monitoring should be recorded. Testing and monitoring requirements should be defined by a competent confined space supervisor, within the safe system of work.

The atmosphere in a confined space may be regularly monitored to protect personnel by using on-site or fire and rescue service monitors in a fixed location. Personal or portable monitors carried by individuals can also be used.

Strategic actions

Fire and rescue services should:
  • Enable access to suitable atmospheric monitoring equipment that is can be  used in a confined space

Tactical actions

Incident commanders should:
  • Carry out testing and monitoring of the atmosphere and use the results to inform the incident plan

  • Consider requesting specialist advice or assistance for atmospheric monitoring