TY - CONF A1 - Hofmann, Michael A1 - Richter, Matthias A1 - Jann, Oliver T1 - Proficiency test of commercial radon monitors for low level radon exhalation measurements in chambers with air exchange N2 - Compared to the designated European upper reference level of 300 Bq m-3 for indoor radon concentrations, the contribution of building materials appears to be low. Taking into account the recommended limit of 100 Bq m-3 by WHO as well as the increased dose conversion factor, the contribution of building products is quite relevant, especially at low air change rates. Therefore in Germany a maximum contribution of building materials to the indoor radon concentration of 20 Bq m-3 is discussed. Because measurements of low concentrations are associated with high uncertainties, radon exhalation rates are often determined in chambers without air exchange and indoor conditions are extrapolated. This study investigated the suitability of direct low level radon measurement under simulated indoor conditions with commercially available instruments, based on the preliminary EU standard for the determination of the emission of volatile organic compounds (VOC) from building materials in test chambers. Measurements are possible with a relative uncertainty ranging from 7 to 18 %. Four major problems were identified: 1. Detector sensitivity: Two of four instruments were identified to determine low radon concentrations in a sufficiently short measuring time. 2. Thoron discrimination: Thoron was discriminated by aging the sampled air in a hose before the detector. 3. Sampling setup: An external chamber measurement was feasible as long as all main system parts were under slight overpressure. 4. Blank value: For VOC-emission testing ambient air, conditioned by filtration and sorption, is used to generate an air exchange. Regarding radon, this treatment is non-effective. If all instrument background levels have been characterized, the blank value must be measured with a second detector in parallel. T2 - 8th International Conference on Protection against Radon at Home and at Work CY - Prague; Czechia DA - 12.09.2016 KW - Radon exhalation KW - Building materials KW - Radon measurement KW - VOC emission test chamber PY - 2016 AN - OPUS4-37437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann, Michael A1 - Richter, Matthias A1 - Jann, Oliver T1 - Prüfverfahren zur Bestimmung der Radon-Exhalationsrate aus Bauprodukten in VOC-Emissionskammern N2 - Es wurden die wesentlichen Ergebnisse des abgeschlossenen UFOPLAN-Vorschungsvorhabens "Methodische Untersuchungen zur Qualifizierung der VOC-Kammern zur Bestimmung der Radonexhalationsrate von Bauprodukten, Los 1" vorgestellt. Das entwickelte Prüfverfahren eignet sich zur Bestimmung der Radonexhalationsrate von Bauprodukten mittels kommerziell erhältlicher Radon-Messtechnik in dynamisch betriebenen VOC-Emissionsprüfkammern. Es ist robust gegenüber einem weiten Bereich von Parametereinstellungen hinsichtlich der Prüfparameter Prüfkammervolumen, Produktbeladung, Luftwechselrate und flächenspezifische Luftdurchflussrate. Entscheidend für die Messung im Bereich geringer Radonaktivitätskonzentration ist es, die Zuluftkonzentration (Blindwert) der Emissionsprüfkammern auf einem konstant geringen Niveau zu halten oder durch eine – zur eigentlichen Baustoffmessung – parallele Messung der Zuluft zu kompensieren. Die gängige Aufbereitung der Zuluft der VOC-Prüfkammern mittels mehrfacher Filtration und Sorption über Silica-Gel- sowie verhältnismäßig kleinvolumigen Aktivkohle-Filtern ist bezüglich Radon unwirksam. T2 - 11. Radon-Fachgespräch CY - Berlin, Germany DA - 02.03.2017 KW - Radon KW - Exhalationsrate KW - Bauprodukt KW - VOC-Emissionsprüfkammer KW - Prüfverfahren PY - 2017 AN - OPUS4-39334 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -