Safety begins before entering

Work in containers and confined spaces must only be carried out by well trained personnel. These workers must not only be well familiar with the correct behavior in a confined workspace. They must also be able to assess the risks of hazardous gases correctly and be able to handle them professionally. As a general rule, the following applies: In confined spaces toxic and/or flammable gases can be generated or accumulate at any time. Both too much and not enough oxygen also poses a risk.

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Measuring safe levels in plants

Even before entering a confined space and/or container it needs to be checked how safe a workplace is and whether any arrangements with regard to, for instance, a breathing apparatus have to be made.

Are there any toxic or explosive substances in the space and if so, what are they? How much oxygen is there? Both questions will be answered, if measuring for safe levels is carried out correctly. When carrying out a risk assessment it also plays an important part if the containers have been emptied completely, whether there is any contamination which could release gases or whether it is possible that hazardous substances could enter.

Measuring safe levels on plants requires specialist knowledge in how to select and apply suitable measuring methods. Also, the evaluation of the results can only be carried out safely with the right specialist knowledge; thorough training and preparation is therefore essential.

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Major hazards in confined spaces are caused by:

  • Formation and accumulation of explosive substances ("Ex" measurement)
  • Lack of oxygen or excess oxygen ("Ox" measurement)
  • Formation and accumulation of toxic substances ("Tox" measurements)
  • An Ex measurement and an Ox measurement will have to be carried out in any case.
  • Lack of oxygen (O2 concentration less than 19.0 vol%) in confined spaces means a risk of suffocation.


Excess oxygen (O2 concentration higher than 23.0 vol %) means that all substances burn more easily, more quickly and at higher temperatures, including protective clothing which would be fire-retardant in a normal atmosphere.

Dräger X-am 5000