Have you got gas?

By - , Build 132

Hazardous gases can lurk in the workspace and combust or give off toxic fumes. Bring in an expert to track them down.

Use a correctly calibrated detector.
Use a correctly calibrated detector.

ASKING IF YOU HAVE GAS is not a medical question. I’m talking about a hazardous atmosphere. Traditionally, people associate hazardous atmospheres with confined spaces, but there are other workspaces where a hazardous atmosphere may be present.

Spaces to watch

Confined spaces in the workplace must be clearly identified. It’s usually simple to identify potentially hazardous atmospheres such as:

  • storage tanks
  • reaction vessels
  • enclosed drains
  • sewers.

Other areas not typically considered confined spaces can be equally dangerous, including:

  • open-topped chambers
  • vats
  • ductwork
  • unventilated or poorly ventilated rooms
  • excavations and pits
  • ceiling or basement voids
  • freight containers.

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Three categories of hazards

Hazardous atmospheres are typically categorised into three main classifications:

  • Flammable or explosive gases – the concentration of gas to normal air reaches a ratio where combustion can occur when an ignition source is introduced.
  • Oxygen levels that are too low or too high – oxygen levels even a few percent below normal can be too low to support life and levels above normal can result in a fire or explosion of materials that would not normally ignite.
  • Toxic gases.

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Handling the hazards

The first step in controlling atmospheric hazards is detection. Check that the atmosphere in the work environment is free from toxic and flammable gases and that oxygen levels are sufficient to sustain life.

Testing should be carried out by a competent person using correctly calibrated gas detector equipment designed and programmed to detect the chemicals that may be present at levels well below the defined exposure limits. Gas detectors can be programmed to detect a number of gases simultaneously.

Where a hazard assessment indicates that conditions may change or as a further precaution, continuous monitoring of the air is necessary.

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Testing in deep workspaces

For workspaces that are deep or have areas leading away from the entry point, the atmosphere may be layered or may be different in remote areas. Testing will need to be carried out at a number of locations within the workspace.

This may involve attaching tubes to the sensor to draw in the air without exposing the workers carrying out the test. Sufficient time must be allowed for the air sample to be drawn in.

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Use a correctly calibrated detector.
Use a correctly calibrated detector.