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A European round robin test according to ISO 5725-2 was conceptually prepared, realised, and evaluated. The aim was to determine the inter-laboratory variability of the overall process for the ecotoxicological characterization of construction products in eluates and bioassays. To this end, two construction products BAM-G1 (granulate) and HSR-2 (roof sealing sheet), both made of EPDM polymers (rubber), were selected. The granular construction product was eluted in a one stage batch test, the planar product in the Dynamic Surface Leaching test (DSLT). A total of 17 laboratories from 5 countries participated in the round robin test: Germany (12), Austria (2), Belgium (1), Czech Republic (1) and France (1). A test battery of four standardised ecotoxicity tests with algae, daphnia, luminescent bacteria and zebrafish eggs was used. As toxicity measures, EC50 and LID values were calculated. All tests, except the fish egg test, were basically able to demonstrate toxic effects and the level of toxicity. The reproducibility of test results depended on the test specimens and the test organisms. Generally, the variability of the EC50 or LID values increased with the overall level of toxicity. For the very toxic BAM-G1 eluate a relative high variability of CV ¼ 73%e110% was observed for EC50 in all biotests, while for the less toxic HSR-2 eluate the reproducibility of EC50 varied with sensitivity: it was very good (CV ¼ 9.3%) for the daphnia test with the lowest sensitivity, followed by the algae test (CV ¼ 36.4%). The luminescent bacteria test, being the most sensitive bioassay for HSR-2 Eluate, showed the highest variability (CV ¼ 74.8%). When considering the complex overall process the reproducibility of bioassays with eluates from construction products was acceptable.
In den letzten Jahren ist der Markt für Grobspanplatten (engl.: Oriented Strand Boards, OSB) zum Einsatz beim Hausbau gewachsen. Die Platten werden in Deutschland und Europa hauptsächlich aus Kiefernholz hergestellt und finden Verwendung in Bodenbelägen, Decken und Wänden. Durch ihren Einsatz kann es zu gesundheitlichen Beschwerden, wie Geruchsbelästigungen oder Schleimhautreizungen, kommen. Die Bundesanstalt für Materialforschung und -prüfung (BAM) hat im Auftrag des Umweltbundesamtes (UBA) ein Forschungsvorhaben zu Emissionen aus Holz und Holzwerkstoffen durchgeführt. In Emissionsprüfkammern wurden unter anderem Proben von sechs OSB-Platten aus Baumärkten untersucht und ihre VOC-Emissionen (engl.: Volatile Organic Compounds, VOC) gemessen. Vier dieser Platten von drei verschiedenen Herstellern würden die Anforderungen des Ausschusses zur gesundheitlichen Bewertung von Bauprodukten (AgBB) nicht einhalten. Größtes Problem hierbei sind die ungesättigten Aldehyde. Der Einsatz von Antioxidantien während der Produktion kann helfen, ungewollte Emissionen deutlich zu reduzieren.
MSL compatible isothermal furnace insert for high temperature shear-cell diffusion experiments
(2011)
For long-time diffusion experiments shear-cell techniques offer more favourable terms than the traditional long capillary techniques. Here, we present a further developed shear-cell that enables the measurement of diffusion coefficients up to temperatures of 1600 °C. Hence, diffusion experiments can be carried out at temperatures not accessible until now by conventional capillary or shear-cell techniques. The modified shear-cell, which can contain up to six samples of a total length of 90mm and a diameter of 1.5 mm, is built of 30 shear discs of 3mm thickness each. It is operated in an isothermal furnace insert which can be accommodated in the Materials Science Laboratory of the International Space Station. This provides the opportunity that the shear-cell can be applied to microgravity and to ground-based experiments, respectively. The heater insert with an overall length of 518mm and a diameter of 210mm consists of four heating zones with a total power of 3.5 kW. Temperature homogeneity along the graphite sample compartment is better than 2K at 1600°C. Details of the new design are discussed and results of first successfully performed heating and shearing cycles are presented.