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Volatile organic compounds (VOCs) emitted by furniture and building materials can cause health issues. For an improvement of indoor air quality low emitting materials should be used. Quality assurance and –control (QA/QC) measures require an emission reference material (ERM) with a predictable emission rate of VOCs. The idea is to use porous materials as ERM, which store the VOCs inside their pores and emit them constantly.
In industrialised countries more than 80% of the time is spent indoors. Products, such as building materials and furniture, emit volatile organic compounds (VOCs), which are therefore ubiquitous in indoor air. VOC in combination may, under certain environmental and occupational conditions, result in reported sensory irritation and health complaints. Emission concentrations can become further elevated in new or refurbished buildings where the rate of air exchange with fresh ambient air may be limited due to improved energy saving aspects. A healthy indoor environment can be achieved by controlling the sources and by eliminating or limiting the release of harmful substances into the air. One way is to use (building) materials proved to be low emitting. Meanwhile, a worldwide network of professional commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability of test results must be ensured. A laboratory’s proficiency can be proven by internal and external validation measures that both include the application of suitable emission reference materials (ERM). For the emission test chamber procedure according to EN 16516, no artificial ERM is commercially available. The EU-funded EMPIR project MetrIAQ aims to fill this gap by developing new and improved ERMs. The goal is to obtain a material with a reproducible and temporally constant compound release (less than 10 % variability over 14 days). Two approaches were tested: the impregnation of porous materials with VOC, and the encapsulation of VOC in polymer microcapsules. Impregnation is performed with help of an autoclave and supercritical CO2. The encapsulation is done by interfacial polymerisation on VOC droplets. For both approaches, synthesis and/or material parameters were varied to obtain an optimal ERM. Findings about the optimisation of ERM generation, as well as performance of the best emission reference materials, will be presented.
Volatile organic compounds (VOCs) emitted by furniture and
building materials can cause health issues. For an
improvement of indoor air quality low emitting materials
should be used. Quality assurance and –control (QA/QC)
measures require an emission reference material (ERM) with a
predictable emission rate of VOCs. The idea is to use porous
materials as ERM, which store the VOCs inside their pores and
emit them constantly.
In industrialised countries more than 80% of the time is spent indoors. Products, such as building materials and furniture, emit volatile organic compounds (VOCs), which are therefore ubiquitous in indoor air. Different VOC combinations may, under certain environmental and occupational conditions, result in reported sensory irritation and health complaints. A healthy indoor environment can be achieved by controlling the sources and by eliminating or limiting the release of harmful substances into the air. One way is to use materials proven to be low emitting. Meanwhile, a worldwide network of professional commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability and metrological traceability of test results must be ensured. A laboratory’s proficiency can be proven by internal and external validation measures that both include the application of suitable reference materials. The emission test chamber procedure according to EN 16516 comprises several steps from sample preparation to sampling of test chamber air and chromatographic analysis. Quality assurance and quality control (QA/QC) must therefore be ensured. Currently, there is a lack of suitable reference products containing components relevant for the health-related evaluation of building products.
The EU-funded EMPIR project 20NRM04 MetrIAQ (Metrology for the determination of emissions of dangerous substances from building materials into indoor air) aims to develop 1) gaseous primary reference materials (gPRM), which are used for the certification of gaseous (certified) reference materials (gCRM) and 2) emission reference materials (ERM).
Most commercial gas standards of indoor-relevant compounds are not certified due to the lack of primary reference materials to which the project aims to contribute. The gPRM under development is a gas-phase standard containing trace levels of VOCs in nitrogen or air from the check standard according to EN 16516 (n-hexane, methyl isobutyl ketone, toluene, butyl acetate, cyclohexanone, o-xylene, phenol, 1,3,5-trimethylbenzene) with a target uncertainty of 5 %. The gPRM can be sampled into sorbent tubes to obtain transfer standards in the form of gCRM.
The well characterised ERM represents a sample of a test specimen, e.g. building material, that is loaded into the emission test chamber for a period of several days and is used to evaluate the whole emission test chamber procedure. It shall have a reproducible and temporally constant compound release of less than 10 % variability over 14 days. Different approaches for retarded VOC release, such as the encapsulation of pure compounds and the impregnation of porous materials, are being tested to reach this aim. Furthermore, the design of the ERM is accompanied by the development of a numerical model for the prediction of the emissions for each of the target VOCs. The current progress of the work on both materials will be presented.
Die passive Probenahme von VOC (Volatile Organic Compounds) mit Tenax® TA und Thermodesorption GC/MS Analytik ist eine einfache, kosteneffiziente und repräsentative Methode zur Bestimmung der VOC-Konzentrationen in der Innenraumluft. In der Theorie ist die Stoffaufnahme in den Passivsammler nur abhängig vom Diffusionskoeffizienten der Substanz in Luft und der Geometrie des Sammlers (ideale Adsorption). Um sie zu charakterisieren, wird die Aufnahmerate (UR), definiert als Quotient der Massenaufnahme und dem Produkt aus Konzentration und Expositionszeit, verwendet. Viele effektive Aufnahmeraten (UR,eff) unterscheiden sich beträchtlich von idealen (theoretischen) Werten (UR,id). Literaturwerte sind in nationalen und internationalen Normen lediglich für bestimmte Expositionszeiten vorgegeben, während detaillierte Informationen über den zugehörigen Konzentrationsbereich fehlen. Außerdem ist die Anzahl der insgesamt in der Literatur beschriebenen Substanzen begrenzt. Das Ziel der vorgestellten Studie ist es diesen Fundus an Aufnahmeraten zu begutachten und zu prüfen und ihn durch die Bestimmung eigener qualitätsgesicherter Laborwerte zu ergänzen. Die bestimmten Aufnahmeraten werden als akkurat bezüglich ihrer relativen Standardabweichung und Vergleichbarkeit zu Literaturwerten betrachtet und können für Expositionszeiten von 7 Tagen bei Konzentrationen von 50 100 µg/m³ (ca. 100 300 ppm min) empfohlen werden. Die Sieben Tage Aufnahmeraten aus ISO16017 2 und ASTM D6196 sind nicht generell für diesen Zweck geeignet, wie exemplarisch für Benzol gezeigt wurde.
Museums worldwide are equipped with different display cases. Exhibit display cases should protect cultural objects from dust as well as from mechanical and physical damage. To ensure a stable climate inside the display cases, a low air exchange rate is maintained. Typically air exchange rates are often smaller than 0.1 d 1, which can result in rising concentrations of potential harmful immissions inside of the display cases due to emissions from materials. Especially high concentrations of organic acids, which can emit from e.g. sealing materials, can produce damage of cultural objects. In 2012 BAM introduced a procedure witch is called: BEMMA-Scheme (Bewertung von Emissionen aus Materialien für Museumsausstattungen) which stands for: “Assessment of Emissions from Materials for Museum Equipment”. Micro chambers are used for VOC emission tests of display case construction materials, e.g. textiles, plastics, sealing material, coatings and others. Each sampling procedure is carried out in duplicate. Emissions like formic acid, acetic acid, formaldehyde and oximes are excluded and the sum of emissions of VVOCs, VOCs and SVOCs is limited. For a positive assessment all listed criteria must be fulfilled; otherwise the display construction material fails the BEMMA scheme. The BEMMA scheme is not a guarantee for an emission free display case, but a necessary requirement for the choice of suitable materials for emission and immission reduced display cases.
Mit dem Fokus auf eine saubere Innenraumluft wird darauf eingegangen, welche Emissionen aus Materialien und Produkten es gibt und wie sie nach Art und Flüchtigkeit definiert sind und wie sie gemessen werden. Im weiteren wird dargestellt, was und wie viel aus Materialien und Produkten emittieren kann und wie die Emissionen zu bewerten sind. Hierbei wird auch auf besonders emissionsarme Materialien und Produkte eingegangen.
Summary: A screening test for potential emissions of volatile organic compounds (VOC) was run on different thermoplastic filaments used for 3D printing. The method of direct thermal desorption was used to simulate the high temperatures during the 3D printing process and to identify the main compounds emitted from the filaments. A large number of unexpected compounds were detected that might affect the user’s health and have an impact on indoor air chemistry.
Introduction: The use of desktop 3D printers is increasing. Compared to other devices with known emissions, e.g. laser printers, there is still a lack of information on possible emissions of VOC and ultrafine particles during operation and the effect on indoor air quality. Most of the commercially available desktop 3D printers operate with a molten polymer deposition. For this process a solid thermoplastic filament is heated in an extrusion nozzle. Most filaments for desktop 3D printers use either acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA) as filament. Alternatives are polyvinyl alcohol (PVA) or polycarbonate (PC).
Method: Eight different thermoplastic filaments for 3D printers were analysed by direct thermal desorption followed by GC-MS identification of the emitted substances. Direct thermal desorption was done by desorbing 5 mg of the feedstock for 1 minute at a temperature of 210°C. This is an average temperature for 3D printing with thermoplastic filaments.
Results and conclusions: The comparison of the 4 different filament groups showed the highest overall emissions from ABS, followed by PLA, PC and PVA. Filament ABS 2 emitted mainly SVOCs and triphenyl phosphate, the latter has the highest emission for a single compound from all evaluated filaments.
Thermoplastic filaments are a new source of VOC emissions due to the high temperatures associated with 3D printing, which can reach up to 270°C. Some of the detected compounds like lactic acid, lactide and bisphenol A have never been described before in the indoor environment. Additionally some of the main substances could not be identified and some others might have the potential to affect the indoor air chemistry.
The appearance of some newly detected compounds raises concerns about potential health effects for the users of 3D printers at home.