Under the Health and Safety at Work Act and The Management of Health and Safety at Work Regulations, testing for radon gas is a requirement in the workplace in the following circumstances:

Above ground workplaces

For above ground workplaces, radon measurements should be taken in appropriate ground floor rooms when the building is located in a radon Affected Area.

Below ground workplaces

For occupied below-ground workplaces (those occupied for over an hour per week or approximately 50 hours per year), or those containing an open water source, radon measurements should be taken. This applies to basements, cellars, mines, caves, tunnels, etc, irrespective of the above ground Affected Areas status.