Indoor air alpha track radon detector measurements

1. Order a radon measurement from STUK. The ordered alpha track radon detectors arrive by mail.
2. The detectors ordered from STUK should be set up for measurement within two weeks (14 days) of their delivery to ensure the most reliable measurement result.
3. Place the detectors in the space to be measured at a height of about one metre.
4. Keep the detectors continuously in the space to be measured for at least 2 months. Fill in the measurement information either on the forms supplied with the detectors or online.
5. Return the detectors in the return envelope to STUK for analysis. Please remember to pay the postage on the return envelope to ensure that the detectors reach STUK.
6. The measurement results will be sent to the you in about a month after the detectors have been received.

STUK offers measurements of radon in indoor air that use an alpha track radon detector (integrative measurement). Alpha track radon detector shows the average radon concentration over the measurement period. The measurement period for measurements with a detector is at least two months, and the measurement must be carried out between the beginning of September (1 September) and the end of May (31 May). If the duration of the measurement is less than two months, the result cannot be used to estimate a long-term average with sufficient confidence.

Radon measurement is carried out in terraced houses and in every apartment on the 1st floor of multi-storey buildings. If the housing company has living areas on the ground floor or in the basement and some residents spend a lot of time there, these should also be measured. The residential areas on the second floor and above do not need to be measured because they have small radon concentrations. Similarly, sauna, storage and technical rooms do not need to be measured if the time spent in these rooms is brief.

Sometimes the ground floor of a housing company is used as a working or business premises. These should also be measured at the same time as the dwellings and residential areas. The employer is legally responsible for ensuring that the radon exposure of workers is low enough and that the measurement results are submitted to STUK.

Radon measurements shall be carried out with a radon detector between the beginning of September and the end of May for a period of at least two months. Radon measurements can be ordered from an operator using a measurement method approved by STUK.

If the dwelling (e.g. a summer cottage) is usually occupied outside the measurement period, as in summer, the radon measurement can be carried out during this period. The detectors do not cause any health hazard.

Which spaces should be measured?

• Place the detector in the rooms on the lowest floors where people stay the most.
• When measuring with one detector, place the detector on the lowest residential floor.
• When measuring with more than one detector, place the detectors in different rooms and/or floors (not in storage spaces). 

How many radon detectors are needed?

• In apartments of less than 100 m², you only need one detector.
• In apartments of more than 100 m², you need at least two detectors. 

Note. STUK only gives the measurement results to the client of the measurement and it is the responsibility of that client to distribute the measurement results to all those to whom they belong.

Links:

• Measurement instructions: Measurement of radon in a dwelling (pdf)
• Measurement of radon in a dwelling - measurement detector form (pdf) 
• Brochure: Protecting yourself against radon in indoor air is easy (pdf) (julkari.fi)
• Reference levels and regulations concerning radon in dwellings (Stuk.fi)
• Radon concentrations in low-rise residential buildings in Finnish municipalities (Stuk.fi)

STUK offers measurements of radon in indoor air that use an alpha track radon detector (integrative measurement). The alpha track radon detector shows the average radon concentration over the measurement period. The measurement period for measurements with a detector is at least two months, and the measurement must be carried out between the beginning of September (1 September) and the end of May (31 May). If the duration of the measurement is less than two months, the result cannot be used to estimate a long-term average with sufficient confidence. If the workplace is usually occupied outside the measurement period, such as in the summer, the radon measurement can be carried out during that time. The detectors do not cause any health hazards.

Which spaces should be measured?

• At least one measurement must be made in each separate building of the workplace. The detectors must be placed on lowest floors of the building in spaces in which the employees spent most of their time.
• If a building has several ventilation systems, measurements must be conducted separately for each area covered by a ventilation unit.
• Any partially or completely underground premises at the workplace must also be measured.

How many radon detectors are needed?

The workspace under each ventilation machine and the separate building are measured as follows:

Each hall like space under each ventilation machine or another similar open space are measured as follows:

Note. STUK only gives the measurement results to the client of the measurement and it is the responsibility of that client to distribute the measurement results to all those to whom they belong.

Links:

• Measurement instructions: Radon measurement at workplaces (pdf)
• Radon measurement at a workplace - form for the air alpha track radon detector (pdf)
• Brochure: Radon at the workplace (pdf) (Julkari.fi)
• Radon at the workplace (Stuk.fi)
• Find the workplace radon measurement data for your municipality or postal code area (Stuk.fi)

• Order Radon measurement for a workplace (STUK Store)
• ​​​​Order radon measurement for a housing company (STUK Store)
• Order radon measurement for a  private residence (STUK Store)​​​​
• Radon measurement operators approved by STUK (Stuk.fi)

The measurement of radon in indoor air ordered from STUK includes the ordered alpha track radon detectors and the necessary supplies, laboratory analysis and delivery of the results to the customer. When mailing the detectors to STUK in the return envelope, the customer has to pay for postage to ensure that the detectors reach STUK. For an extra fee, you can specify the order as urgent, in which case the detectors and the measurement results will be delivered faster. You cannot cancel your order after paying it or after the detectors have been sent to you.
 
The other operators approved by STUK are private companies whose measurement methods have been approved by STUK.

STUK's price list for alpha track radon detectors as of 1 Sept 2024: