Interlaboratory comparison and proficiency testing of passive radon measuring instruments

Since 2003 the German Federal Office for Radiation Protection (BfS) regularly conducts interlaboratory comparisons of passive radon measurement instruments such as

• solid state nuclear track-etch detectors (SSNTD) or
• electret ionisation chambers.

Within the framework of the Federal Coordinating Office for questions of monitoring of the radioactivity at enhanced natural radioactivity (ENORM) this activity addresses the reliability of the determination of exposure to radon and serves for the quality assurance of passive radon measurement instruments.

Vorbereitung der Radon-Detektoren für die Prüfung

The measurements instruments will be exposed in the calibration chambers of the German Federal Office for Radiation Protection. The BfS Radon Calibration Laboratory is accredited by the German accreditation body Deutsche Akkreditierungsstelle GmbH (DAkkS) for measuring the activity concentration of radon-222 in air and the potential alpha energy concentration of short-lived radon-222 decay products in air.

Since 2019, a proficiency testing is performed.

Participants

• Measuring bodies according to §169 of the Radiation Protection Act, which hand out measurement instruments for monitoring occupational radiation exposures to radon or radon decay products in Germany are obliged to take part regularly in BfS measures of quality assurance (here: the interlaboratory comparison).
• Bodies recognised for the measurement of radon-222 activity concentration according to §155 of the Radiation Protection Ordinance are obliged to take part regularly in BfS measures for quality assurance (here: the interlaboratory comparison).
• Laboratories which possess or wish to acquire an accreditation for measuring the activity concentration of radon-222 can fulfil the obligation to validate their measuring method in accordance with DIN EN ISO/IEC 17025 by participating in the interlaboratory comparison.
• We recommend participation also for radon measuring services which quantify radon activity concentration indoors and outdoors and are not associated with occupational radiation exposures. Participation should enhance confidence in performed measurements and results.

National as well as international institutions can apply for participation. The participation will incur a fee.

Due to limited capacities in the BfS Radon Calibration Laboratory the number of participants is limited. Radon measuring bodies according to §169 of the Radiation Protection Act as well as measuring bodies that are recognised or have applied for recognition according to §155 of the Radiation Protection Ordinance will have preferred access to the interlaboratory comparison.

Participation fee

The BfS charges an amount of 779 EUR plus tax (if due) for participation at the BfS interlaboratory comparison and proficiency testing.
This comprises:

• Organisation of the interlaboratory comparison and proficiency testing,
• Handling of the test items,
• Realisation of four reference atmospheres including characterisation and documentation with BfS working standards,
• Monitoring and documentation of the stability of the reference atmospheres,
• Provision of appropriate atmospheres for the determination of effects due to transport and storage,
• Packaging and reconsignment
• Processing of the measurement results submitted by the participant,
• Proficiency testing based on DIN EN ISO/IEC 17043:2010-05,
• Individual report,
• Comprehensive report.

The participant pays the shipping charges for the transport of the devices to the Radon Calibration Laboratory at BfS site Berlin as well as customs charges (if any).

Implementation

Applicants should complete the application form and submit it via e-mail to comparison-radon@bfs.de. After confirmation of participation the participants will receive a contract via e-mail (except for measuring bodies or recognised bodies) that should be signed and returned promptly. In general, the billing will be performed after service provision.

The participants will receive individual labels to attach to their measurement instruments before shipping them to the BfS.

Submitted sets will be divided at random into a number of exposure groups and will be exposed at different radon-222 activity concentrations of up to 10 kilobecquerel per cubic metre at normal room conditions (temperature: 20 to 25 degrees Celsius, relative humidity: 20 to 60 per cent). The exposures to radon reach values of up to 3,000 kilobecquerel-hours per cubic metre.

A supplementary group is used to determine the effects of transportation and storage during the interlaboratory comparison (transit group).

After all exposures have been accomplished the devices are re-packed and sent.

Evaluation

The participants will evaluate their measurement instruments and report the measurement results to the BfS. After having received all measurement results BfS performs the assessment. To this end, the measurement results are compared with the reference exposures and the performance is evaluated on the basis of the respective deviation.

Participants in the interlaboratory comparison and proficiency testing will receive

• an individual report containing the measurement results as well as the corresponding reference exposures and the evaluation of performance,
• a comprehensive report which includes the results of all participants in anonymous form with detailed information on the conditions of exposure and statistical information on the proficiency testing.

BfS is committed to treating the data received and established confidentially. Results will be disclosed exclusively in anonymous form.

Details on measurement instruments and exposure data

In the first half of 2025, the Federal Office for Radiation Protection (BfS) carries out an interlaboratory comparison for passive radon measurement instruments using track-etch detectors (SSNTD, in diffusion chambers) or electret ionisation chambers. Deadline for application is by January 24, 2025. Participation will incur a fee.

Further information and application form

Further information as well as the application form can be requested by e-mail at comparison-radon@bfs.de.