Volatile Organic Compounds (VOC) are ubiquitous in the indoor air, since they emit from materials used indoors. Investigations of these materials are mostly carried out in test chambers under controlled climatic conditions. Quality control of these test chamber measurements is important but there is a lack of commercially available homogenous reference materials as required for round robin tests or quality assurance of laboratories. The approach of the present study is the impregnation of a supporting material with VOC, which are reproducibly released in measurable chamber air concentrations under standardised test conditions. A polymer made of Thermoplastic Polyurethane (TPU) was chosen as carrier material. It was impregnated with the VOC trimethyl pentanediol isobutyrat (texanol).
Volatile Organic Compounds (VOC) are ubiquitous in the indoor air since they are emitted from materials used indoors. Investigations of these materials are mostly carried out in emission test chambers under controlled climatic conditions. Reference materials are an important tool for quality assurance/Quality control of emission test chamber measurements but so far they are not commercially available. In this study, a new approach was tested to develop an appropriate reference material with homogenous and reproducible emission of the VOC with well measurable air concentrations in emission test Chambers larger than 20 L at air change rates of 0.5 - 1 /h.
Thermoplastic Polyurethane (TPU) was selected as Matrix material which was impregnated with 2,2,4- trimethyl-1,3-pentanediol monoisobutyrate (texanol) as test VOC using compressed carbon dioxide. An optimization of the impregnation parameters such as temperature, pressure, time, VOC injection volume and TPU sample size was performed until the targeted area specific Emission rate (SERa) value was reached. Further aspects like process control, storage effects and correlation of the sample size to the emission rate were investigated. It was found that the SERa immediately after sample preparation were not reproducible between the batches but became unified 10 days after loading into the test chamber indicating the necessity of aging before use. SERa between 13,000 and 18,000 mg m-2 h-1 were obtained, and the impregnated materials could be well stored in aluminum-coated polyethylene foil for at least seven weeks without significant losses. Furthermore, the impregnation of styrene and the SVOC 2,6-diisopropylnaphthalene was tested.
There has been an increasing use of oriented strand boards (OSBs) for the construction of floors, ceilings and walls of buildings. In Germany and other European countries, OSBs are mainly produced from pine wood (Pinus sylvestris). In response to complaints about the odour and irritation of mucous membranes in connection with the use of OSBs, samples of OSBs were bought from do-it-yourself stores to test their volatile organic compound (VOC) emissions by using emission test chambers. The boards emitted predominantly monoterpenes, aldehydes, acids and acetone. Aldehydes are generated during the production process by the oxidation of unsaturated fatty acids such as linoleic acid. Pine wood, compared with other wood species, contains more unsaturated fatty acids. Of the six acquired OSBs, four boards from three manufacturers would not meet the requirements of the German AgBB (Ausschuss zur gesundheitlichen Bewertung von Bauprodukten, Committee for Health Evaluation of Building Products), mainly because of the emissions of unsaturated aldehydes. These compounds have low LCI values (lowest concentration of interest) and are therefore problematic substances based on a health-related evaluation of building products according to the AgBB scheme.
Beschichtete Holzwerkstoffe und daraus hergestellte Produkte, wie z.B. Möbel, sind in nahezu jedem Innenraum mit vergleichsweise großen Oberflächen anzutreffen. Vor dem Hintergrund einer Vielzahl von in Innenräumen verwendeten unterschiedlichen Materialien und Produkten und dem Ziel, die Belastung der Innenraumluft mit flüchtigen organischen
Verbindungen möglichst gering zu halten, ist eine weitgehende Minimierung von Emissionen dieser Verbindungen aus den genannten möglichen Quellen notwendig. Zu diesem Zweck, auch im Hinblick auf die Umsetzung der Konzeption der Bundesregierung zur Verbesserung der Luftqualität in Innenräumen wurde das bestehende deutsche Umweltzeichen RAL-UZ 38 (Blauer Engel) Formaldehydarme Produkte aus Holz und Holzwerkstoffen überarbeitet. Für das Ziel einer Erweiterung von der Einzelverbindung Formaldehyd auf ein breites Spektrum an flüchtigen organischen Verbindungen war ein geeignetes Prüfverfahren als Basis der neuen Umweltzeichen-Vergabegrundlage zu entwickeln. Die Ergebnisse der hierfür durchgeführten Untersuchungen können dem Abschlußbericht entnommen werden.