If the radon measurement at workplace has been conducted using detectors from STUK’s radon measurement service, the radon measurement service sends a test report to the customer. The STUK's radon measurement service delivers the measurement results directly to STUK’s Natural Radiation Regulation.
If the radon measurement has been ordered from a private radon measurement company, the employer must notify STUK immediately of the radon measurement results (Radiation Act 859/2018, §146 and §155). The notifications are made via the electronic service: https://stukasiointi.stuk.fi/asiointi/en/. The measurements ordered from STUK don't have to be notified.
- Log in the electronic service: stukasiointi.stuk.fi/asiointi/en
- STUK's web-based service requires strong user authentication via the Suomi.fi service.
- To log in, use a bank account, a mobile certificate or a certificate card.
- STUK only receives information related to the measurement site and the employer.
- Note! The service does not work with Internet Explorer.
The notification is submitted via the electronic service and the measurement results must be attached to the notification. Please make sure that you have the radon test report file (in electronic form) from the laboratory available before logging in. Results will not be saved if the test report is missing.
All results are saved in the national radon database. Be prepared to answer a supplementary information questionnaire if your measurements show radon concentrations above 333 Bq/m³ (annual average above 300 Bq/m³). Additional information is requested on the surface area and number of employees in the workplace, the floor area of the measurement point, the ventilation, the number of employees and the annual working time at the measurement point.
If the e-service is not available, the results of radon measurements can be reported by e-mail to radonvalvonta(at)stuk.fi. Please also remember to attach the test report of the radon measurements to the notification.
Reference values for radon
The radon concentration during working hours for regular work (over 600 hours per year) must not exceed 300 becquerels per cubic meter (Bq/m³). The radon concentration is calculated as the annual average of the radon concentration during working hours (measurement result x 0.9). The reference value of occupational exposure for radon is 500,000 becquerel hours per cubic meter per year. Exposure is calculated as the sum of the exposures accumulated during the year in all workspaces.
Radon exposure calculator (Form M2 in Finnish, .xlsx)
With the Radon exposure calculator the employer can calculate and report the exposure of the employees to STUK.
What to do if the measured radon concentration is higher than the reference value?
If the radon concentration measured for at least two months exceeds the reference value, the employer must conduct additional analyses or perform measures that reduce the radon concentration. STUK's inspector will contact the employer and ask for additional information. After this, STUK will give demands to the employer for further measures to be taken and deadlines to carry them out. A few examples:
- The employer fills in a radon exposure calculator and if the radon exposure of workers is below the reference value of 500 000 Bq h/m3 on an annual basis (exposure is calculated as the sum of exposures accumulated in all workplaces during the year).
The radon exposure calculator M2 (in Finnish)
- If the ventilation of the property is not set with timing, the only option is to carry out remedial work on the property, i.e. radon mitigation. The planning of workplace radon mitigation is subject to the same rules as radon mitigation for dwellings. The success of the mitigation must be verified by a radon detector measurement lasting at least two months.
Radon mitigation on STUK web pages
- In properties where ventilation is set with timing, the radon concentration may be considerably lower during working hours than at other times. If the radon concentration measured with a detectorin such property exceeds the action level, so-called continuous radon measurement may be conducted, for a minimum of one week.
Radon concentration during working hours on STUK web pages
- To calculate the radon concentration during working hours, both a radon measurement with a detector (box) and a continuous measurement are required, taken under the same conditions (no remedial actions between these measurements).
- If the radon concentration during working hours is above the reference value, radon mitigation must be carried out. The success of the mitigation must be verified by a radon detector measurement lasting at least two months.
- Repair companies may carry out a continuous radon measurement after the repairs, which gives a quick result of the impact of the repair measures. This measurement alone is not sufficient to determine the success of the remedial measures, but a further radon detector measurement of at least two months is required.
If measures to reduce the radon exposure are to be taken at the workplace, these measures must be taken without delay. The adequacy of the measures must be demonstrated by similar measurements or calculations which have earlier shown the radon concentrations or exposure above the reference value.The results of the measurements must be reported to STUK.