How is radon in the workplace measured?

• By law, radon measurement in the workplace must be undertaken by an approved measurement service
• Radon concentrations are measured at basement and ground floor levels of workplaces, in locations that are occupied by workers for more than 100 hours a year (i.e. workshops and offices, as opposed to corridors and washrooms)
• The booklet Planning radon surveys in workplaces – Guidance notes gives detailed guidance to help you carry out a workplace survey. sarah

What is the safe level of radon in the workplace?

Irish legislation sets a national Reference Level of 400 becquerels per cubic metre (Bq/m³) in workplaces, measured over a consecutive three-month period.

What next after measuring?

• If the workplace has radon levels below the national Reference Level (400 Bq/m³), no further action is required
• If the workplace has radon concentrations above the national Reference Level (400 Bq/m³):
  • The RPII must be notified immediately
  • The preferred and simplest course of action is to carry out remedial work to reduce the radon level to below the national Reference Level (see below)
  • Alternatively, where radon concentrations are between 400-800 Bq/m³, the employer may carry out an evaluation to decide whether remediation is justified
  • Where radon concentrations exceed 800 Bq/m3, remedial work must be carried out as soon as is practicable.

Carrying out remediation

• For workplaces with radon levels above 400 Bq/m3, the RPII recommends remediation
• The purpose of remediation is to reduce the radon concentrations to below the national Reference Level for workplaces
• It is the preferred and simplest course of action
• Radon remediation works either by preventing radon from entering the building or by removing it after it has entered. This is achieved with one or more of the following techniques:
  • Sub-floor depressurisation
  • Increased under-floor ventilation
  • Positive pressurisation
  • Increased indoor ventilation
  • Sealing cracks and gaps in the floor and around service entry points
• In some cases, more than one solution will need to be used. We recommend you consult a specialist for advice specific to your workplace as the RPII does not have remediation expertise
• Remediation should be completed as soon as practicable but no later than six months from the date of the measurement.

What next after remediation?

• All remediated areas must be retested to ensure the work has been successful
• The RPII must be informed that the remedial work has been finished, within six months of completion
• The remediation systems must be properly maintained to ensure they remain effective at minimising the radon build-up within the workplace.