Radon measurements in residential dwellings

The Radiation Protection Regulations stipulates limits for the levels of radiation permitted in residential properties that are rented out. It is both inexpensive and easy to measure radon. Furthermore, it is impossible to predict whether or not radon is a problem in your dwelling. Radon measurements are the only means of determining this. With respect to apartment blocks, radon measurements in a selected number of apartments may suffice. 

How to measure radon

• Measure radon during the winter months, between the middle of October and the middle of April.

• Measurements should be carried out for a period of at least two months.

• Measurements should be carried out in at least two frequently occupied rooms, for example the living room and in a bedroom. If the dwelling has several floors, it is recommended that radon measurements be performed in at least one frequently occupied room on each floor. Radon does not usually need to be measured in apartments that are found on and above the second floor of the apartment block. 

• Use the internet or other information services to contact a company who sells radon measurement equipment. In order to compare price and quality, we recommend that you get in touch with several different companies. The trade association Norwegian Radon Association (Norsk Radonforening) has a list of their members on their web site. There are also other companies. There is no public approval system of firms carrying out measurements, and DSA does not recommend any one particular firm. Radon measurements are not sold by the DSA.

• You do not need a company to place the equipment in your home – you can do it yourself. Simply follow the instructions which accompany the equipment.

• Measurements may be carried out using etched track detectors or electronic measurement devices.  The same procedure applies for both devices.

• Determine whether or not the measurements are in accordance with DSA’s protocol for radon measurements in residential dwellings. This may be achieved by receiving a positive reply to the following questions:

  • Do you perform radon measurements which adhere to DSA’s protocol for radon measurements in residential dwellings?

  • Do you perform long-term measurements which are carried out for a period of at least two months?

  • Are there accompanying instructions concerning where in the house the measurement equipment should be placed?

  • Do you sell radon measurement devices or services which have been calibrated?

  • Do you use an accredited laboratory or are you able to document that the equipment has participated in international comparison of measurements with approved results?

  • Will I receive a measurement report after the final measurement

• Certain municipalities offer radon measurements at an attractive price. For more information, contact your local municipality.

DSA’s protocol for radon measurements in residential dwellings

DSA has established a protocol for radon measurements in residential dwellings. When ordering a measurement from a particular company, we recommend that you ensure that the company adheres to this protocol. With respect to rental accommodation, which is governed by The Radiation Protection Regulations, a measurement carried out according to this protocol may be used as documentation of the radon level.  For other residential dwellings, this protocol may be employed as a guide.

Protocol for radon measurements in residential dwellings (in Norwegian only) 

Measuring radon with etched track detectors

An etched track detector should be left in the same room and the same place throughout the entire measurement period. Usually two detectors cost between 400 and 600 Norwegian kroner, but prices may vary. Detectors may be sent in the post and you may place them in the residence yourself. One detector is required for each room that you intend performing a radon measurement in. Given that it is recommended to carry out radon measurements in at least two frequently occupied rooms in the residence, at least two detectors are required.

Upon completion of the measurement, the detectors may be returned to the company where they were purchased. Upon completion of analysis of the detectors, a report, containing the results of the measurement in addition to the calculated annual mean, is sent out. This report represents documentation of the measurement which has been carried out. It is the responsibility of the laboratory, which carries out analysis of the detectors, to quality control the measurement.

There is no public approval system of companies carrying out measurements: Furthermore DSA does not recommend any one particular company. In order to compare both price and quality, we recommend that you get in touch with several different companies. It is however important to bear in mind that detectors may be sent in the post and it is therefore unimportant where the company is located.

Measuring radon using an electronic device 

Several different electronic devices exist which may be used to measure radon. The way in which these measurements are carried out is identical to that previously described for the etched track detectors. Measurements are carried out in at least two frequently occupied rooms in the dwelling with at least one room being located on each floor. The electronic device should be placed for a minimum of two months in each of the rooms in which a radon measurement is carried out. At the end of the measurement period, the annual mean may be calculated, based on the measurement results. 

Use of electronic device requires that the consumer is personally responsible for: 

• learning how the device works in order to ensure that the measurements are correct 

• ensuring that the device is calibrated – in other words that the display values are correct 

• calculating the annual mean 

• finding a satisfactory manner to document the result when/if necessary (for example in the case of rental accommodation). 

Advantages with electronic devices include the fact that they may be used several times, and that changes in radon concentration during the measurement period may be observed. In the case of a number of these devices, this information may be accessed at the end of the measurement period. 

DSA has no approval system for these electronic devices and does therefore not recommend any one particular device. 

Radon measurements in apartment blocks 

If you live in an apartment block, DSA recommends the following: Everyone who lives in a ground floor or first floor apartment should perform a radon measurement. Measurements should be carried out in at least two frequently occupied rooms. In this context ground floor apartments may be defined as apartments where the floor and/or one or more of the walls are in direct contact with the ground. If an apartment block, for example is built on a slope, several of the floors in the building may be in contact with ground level. 

An increase in height usually results in a decrease in radon levels and the likelihood of high levels is therefore reduced the higher up one lives. It is therefore unnecessary to measure radon in apartments which are located on floors above the first floor (see illustration). Naturally there may be some exceptions to this rule. These exceptions may include high levels of radon being measured in a neighbour apartment or that the apartment block is located in a known radon-exposed area. If in doubt, the easiest solution is to carry out a radon measurement.

Alternatively the housing cooperative or owner of an apartment block can perform a radon measurement on the block as a whole. In this case, the following, is recommended: that measurements are carried out in all apartments which are in contact with ground level. With respect to the other apartments located on higher floors, measurements should be carried out in a representative selection of these apartments. Measurements should be carried out in at least two frequently occupied rooms in each apartment. If radon measurements are carried out as described above and show that radon levels are low, it may thus be assumed that the radon levels in the unmeasured apartments are also low. 

Further readings

• Recommendations for radon in dwellings in the Nordic countries