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- Englisch (19)
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- Emission test chamber (5)
- VOC (5)
- Reference material (4)
- Volatile organic compounds (4)
- CO2 assisted impregnation (3)
- Indoor air (3)
- Emission testing (2)
- Emissions testing (2)
- FEM model (2)
- Gas mixing device (2)
Organisationseinheit der BAM
Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt für Materialforschung und -prüfung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m3. This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m3. In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28 % in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51 %.
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.
The development of a gas mixing system (GMS) that enables dynamic and retraceable production of stable long-term VOC gas mixtures within the ppb range is discussed. In this system pure liquid substances are kept separately at a constant temperature, evaporated according to their vapour pressure and removed by a small inert gas flow. A modular set-up allows flexible handling. All vapours generated are finally united in a mixing chamber. Any concentration level of the gas mixture can be produced by a suitable combination of evaporation temperature, carrier and dilution gas flows. Test results from continuous operation over six weeks are presented. The equipment was tested on seven volatile organic compounds (VOC) of different vapour pressure ranges. It was possible to establish stable operation for the equipment during the entire period and reproducible gas concentrations which were traceable to the mass as an SI unit, thus the system is suitable for long-term tests.---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Im Beitrag wird die Entwicklung eines Gasmischsystems (GMS) beschrieben, das die dynamische und rückführbare Generierung von langzeitstabilen VOC-Gasgemischen im ppb-Bereich erlaubt. Dabei werden Reinsubstanzen separat temperiert, ihrem Dampfdruck entsprechend verdampft und durch einen kleinen Inertgasstrom abgeführt. In einer Mischkammer werden sie schließlich zusammengeführt. Durch die Kombination von Verdampfungstemperatur, Träger- und Verdünnungsgasflüssen ist die Einstellung eines beliebigen Konzentrationsniveaus des Gasgemischs möglich. Aus einem Dauerbetrieb von sechs Wochen werden Untersuchungsergebnisse gezeigt. Dabei wurde die Apparatur mit insgesamt sieben flüchtigen organischen Verbindungen (VOC) unterschiedlicher Dampfdruckbereiche betrieben. Die Anlage lief über den gesamten Zeitraum stabil und lieferte reproduzierbare und auf die Masse als SI-Einheit rückführbare Gaskonzentrationen. Somit ist das Verfahren für Langzeitanwendungen geeignet.
Two new approaches towards an emission reference material for use in quality assurance measures for materials emissions testing were developed and intensively tested. The overall goal was to obtain solid materials with homogenous and reproducible (S)VOC release. Since the application in inter-laboratory comparisons is aimed at, it should furthermore be long-term stable to ensure safe shipment to the customer without sustaining compound losses. In the first approach, thermoplastic polyurethane (TPU) was impregnated with the VOC texanol under high-pressure with liquid CO2 as solvent. In the second, styrene (VOC) and the SVOC 2,6-diisopropylnaphthalene (DIPN) were spiked into vacuum grease (VG) and a mixture of paraf-fin/squalane (P/S). For the prediction of the emission rates a finite element model (FEM) was developed for the VG and P/S type materials. All requirements for reference materials were fulfilled, whereas the TPU samples need to be aged for about 10 days until repeatable and re-producible emission rates were obtained.
Natural building materials for interior fitting and refurbishment - What about indoor emissions?
(2021)
Indoor air quality can be adversely affected by emissions from building materials, consequently having a negative impact on human health and well-being. In this study, more than 30 natural building materials (earth dry boards and plasters, bio-based insulation materials, and boards made of wood, flax, reed, straw, etc.) used for interior works were investigated as to their emissions of (semi-) volatile organic compounds ((S)VOC), formaldehyde, and radon. The study focused on the emissions from complete wall build-ups as they can be used for internal Partition walls and the internal insulation of external walls. Test chambers were designed, allowing the compounds to release only from the surface of the material facing indoors under testing Parameters that were chosen to simulate model room conditions. The emission test results were evaluated using the AgBB evaluation scheme, a procedure for the health-related evaluation of construction products and currently applied for the approval of specific groups of building materials in Germany.
Seventeen out of 19 sample build-ups tested in this study would have passed this scheme since they generally proved to be low-emitting and although the combined emissions of multiple materials were tested, 50% of the measurements could be terminated before half of the total testing time.
Emissions of building materials might have negative impact on human health and well-being. In the EU-funded research project H-House more than 30 natural materials (earthen dry boards and plasters, bio-based insulation materials made of wood, flax, reed, straw, etc.) used for renovation and refurbishment were tested regarding emissions of VOC, formaldehyde and radon. Different to ordinary emission tests on single materials this study focuses on the emissions from complete wall assemblies. Therefore, specially designed test chambers were used allowing the compounds to release only from the surface of the material facing indoors. The testing parameters were chosen in order to simulate model room conditions. The emission results were finally evaluated using the AgBB evaluation scheme, a procedure currently applied for the approval of flooring materials in Germany.
With a gas mixing system (GMS) developed in our laboratory we created a gas mixture of
four substances. Adsorptive wall materials of four different compositions were exposed to this
gas mixture, consisting of 1-pentanol, hexanal, butyl acetate and n-decane. Aim of this study
was to scrutinize the ability of these samples to reduce the concentration of the supplied gas.
This capacity is expressed in the sorption flux F or area specific adsorption rate respectively.
The test was performed referring to a draft of ISO 16000-24.
Volatile organic compounds (VOCs) found indoors have the potential to affect human health. Typical sources include building materials, furnishings, cleaning agents, etc. To address this risk, chemical emission testing is used to assess the potential of different materials to pollute indoor air. One objective of the European Joint Research Project 'MACPoll' (Metrology for Chemical Pollutants in Air) aims at developing and testing a reference material for the quality control of the emission testing procedure. Furthermore, it would enable comparison of measurement results between test laboratories. The heterogeneity of the majority of materials makes it difficult to find a suitable reference sample.
In the present study, styrene, 2-ethyl-1-hexanol, N-methyl-α-pyrrolidone, lindane, n-hexadecane, 1,2-dimethyl- and 1,2-di-n-butyl-phthalate were added to 12 commercially available lacquers (6 alkyd and 6 acrylic polymer based lacquers) serving as carrier substrate. After homogenization, the mixtures were loaded into a Markes Micro-Chamber/Thermal Extractor (µ-CTE) for curing and investigation of the emission behavior for each compound. For almost all of the investigated chemicals, the preferred glossy acrylic lacquer showed emissions that were reproducible with a variation of less than 20% RSD. Such lacquer systems have therefore been shown to be good candidates for use as reference materials in inter-laboratory studies.