Radon at the workplace

The Radiation Decree specifies the limits for radon concentration at the workplace. During working hours at a workplace where work is performed on a regular basis, the radon concentration must not exceed 400 Bq/m3. This action level applies also to schools, day care centres and other public facilities. 

It is the employer’s duty to have the radon concentration of the workplace analyzed if there is reason to suspect that the maximum value is exceeded. Instruction ST 12.1 provides more detailed instructions on the employer’s obligation to measure radon concentration at the workplace. In some municipalities, radon measurements are obligatory.

Radon concentration at the workplace is determined using a radon measurement box. The box is kept at the workplace for two months during the heating season. After this, if necessary, daily variations in the radon concentration can be analyzed using measuring equipment approved by STUK.

Any instances of exceeded action levels must be reported to STUK to the authority in charge of radon surveillance at workplaces. 

The responsible party shall investigate the radiation exposure caused by natural radiation if there is reason to suspect that the operations constitute radiation practices (Radiation Act section 45). In this case, radiation practice means that radiation exposure of people caused by natural radiation is or may be hazardous to health.

At the workplace, the radon concentration is measured on the lowest floor of the building in areas where people work. In offices, one measurement per approximately each 200 m2 is enough; in industrial halls one or two measurements per hall. At least one measurement must be made in each separate building.

The radon concentration measurement should be repeated if major renovations have been carried out at the workplace that involve substantial changes to ventilation on premises or opening of floor structures for reasons such as water damage. The measurement should also be repeated if a long time (more than 10 years) has passed since the last measurement and the last result was close to the action level of 400 Bq/m3.

Radon concentration measurement can be ordered from STUK.

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  • Katja Kojo / Inspector
    Tel. +358975988472