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UBA und BAM schlagen die Durchführung der Prüfkammermessungen bei 23 °C und 50% relativer Luftfeuchte, einer Beladung von 1,8 m²/m³ und einem Luftwechsel von 0,5 pro Stunde vor. Diese Parameter orientieren sich an der EN 16516, die als zukünftige „Referenznorm“ zu betrachten ist. Die Schmalflächenversiegelung ist auch zukünftig wie in der EN 717-1 beschrieben vorzunehmen. Nach 28 Tagen wird der Mittelwert einer Doppelbestimmung als Endkonzentration („entsprechend der Ausgleichskonzentration“) berechnet. Alternativ dazu kann die Prüfung vorzeitig abgebrochen werden, wenn an 5 Messtagen der Prüfung eine Formaldehydkonzentration von 0,1 ppm nicht überschritten wird.
Prüfungen nach der EN 717-1 sollen weiterhin gleichberechtigt möglich sein. Ergebnisse von Messungen, die nach der EN 717-1 ermittelt wurden, sind mit dem Faktor 2,0 zu multiplizieren.
Abgeleitete Verfahren wie z.B. das Gasanalyseverfahren sollen weiterhin möglich sein. Das Perforatorverfahren entfällt hier, da eine allgemeine für alle Holzwerkstoffe gültige Korrelationen nicht existiert.
Die entsprechenden Änderungen sind in der vom BMUB veröffentlichten „Bekanntmachung analytischer Verfahren für Probenahmen und Untersuchungen für die im Anhang der Chemikalien-Verbotsverordnung genannten Stoffe und Stoffgruppen“ entsprechend zu ändern.
There is a need for an assessment of the emission properties of volatile organic compounds (VOCs) from consumer products. A method comparison was carried out to evaluate adapted and cost-effective procedures for such items. Smaller and automated emission chambers de-picted similar kinetics compared to a 203 L standard chamber. Toy samples made of PVC (Polyvinyl chloride) emitted more VOCs compared to other tested polymeric products. The emissions from 2 selected samples were studied to allow an evaluation of the resulting room concentration and external exposure of a child. Obtained concentrations were not of concern.
Comparison of Formaldehyde Concentrations in Emission Test Chambers Using EN 717-1 and EN 16516
(2018)
For more than 25 years EN 717-1 (Wood-based panels - Determination of formaldehyde re-lease - Part 1: Formaldehyde emission by the chamber method) is the standard for formalde-hyde emission testing of wooden boards. In 2017 EN 16516 (Construction products - Assess-ment of release of dangerous substances - Determination of emissions into indoor air) was published as a new harmonised standard for the emission testing of construction products. Because test chamber conditions are different, both standards give different concentrations for formaldehyde. To determine a conversion factor four test series were set up with different wooden boards. For a loading of 1 m²/m³ the conversion factor is 1.6. This means that the formaldehyde concentration measured under the conditions of EN 16516 is a factor of 1.6 higher compared to EN 717-1.
Initial situation:
Aluminum is an often-used building material in modern architecture, not only for construction but as well for facades and decorative elements. In the 1950th and 1960th, after World War II, many buildings in Germany were constructed with aluminum or contain elements of colored anodized aluminum. In the last years a larger number of these buildings are increasingly in the sight of conservation works including the aluminum parts such as window frames or facade coverings.
Damaged Aluminum Surfaces:
Common damages are a change of color or gloss changes through weathering processes, drill holes or marks due to later modifications, scratches in the anodized layer due to extensive wear e.g. at handrails or door handles.
To repair damaged aluminum surfaces, there are usually two options: smaller damaged areas are repaired by using a touch-up pen. In case of larger damages, the complete re-anodization is necessary. This includes to de-anodize the surface with cleaning and grinding the whole aluminum object. Both possibilities are disadvantageous for the objects. The touch-up pen often does not match the color of the original surface together with an insufficient corrosion protection for outdoors. While the newly anodized surface differs in color and gloss from the originally applied color.
Research Approach:
The whole procedure contrasts with the principal approach in conservation which aims to intervene as less as possible, in case of the conservation of an object. To fulfill this approach in a more appropriate way the research project focuses on a mobile and partial application for colored, anodized aluminum parts.
To anodize aluminum the application of an electrolyte onto the surface together with sufficient voltage and current is necessary. Generally diluted sulfuric acid is used as electrolyte. Different possibilities are examined to enable the mobile application of the electrolyte, e. g. the application by producing a gel matrix or like in electroplating by pen or brush wrapped with a fleece fabric.
Experimental part:
First experiments are conducted to examine the structure of the anodized layer in relation with proper cleaning, anodization time with applied voltage and current and the coloring process. The aim was to reduce the preparation procedure and the anodization time as much as possible to facilitate the mobile application.
Examinations with Keyence microscope, Eddy current testing and REM are performed to characterize the layers. The results are shown in table 1. A clear connection between proper cleaning, anodization time, voltage and amperage and the achieved thickness of the anodized layer is significant. Cracks in the layer show that raising the voltage and amperage results in thicker layers but as well in a crumbled and less stable anodized surface.
Gel preparation:
In addition to the anodization process with a liquid e.g. sulfuric acid a gel application is tested to prevent the electrolyte from rinsing down during the mobile application. For this purpose, several gel-forming agents are tested together with their stability in acid systems. It was observed, that the consistency of the gels varies dependent of the time.
Conductivity:
The conductivity of sulfuric acid combined with different gel-systems was measured and compared in order to predict the possible growth of layers during anodic oxidation process.
Further steps:
Determination and optimization of application parameters like voltage, amperage and anodization-time to build up a preferably stable and sufficient thick anodized layer. Examination of gel preparation to guarantee a stable product, enforcing with textile tape for easy application.
Sintered bioactive glass scaffolds of defined shape and porosity, e.g. made via additive manufacturing, must provide sufficient bioactivity and sinterability. As higher bioactivity is often linked to high corrosion and crystallization tendency, a certain compromise between sintering ability and bioactivity is therefore required. Groh et al. developed a fluoride-containing bioactive glass (F3), which allows fiber drawing and shows a bioactivity well comparable to that of Bioglass®45S5.
To study whether and to what extent the sinterability of F3 glass powder is controlled by particle size, coarse and fine F3 glass powders (300-310µm and 0-32µm) were prepared by crushing, sieving and milling. Sintering, degassing and phase transformation during heating were studied with heating microscopy, vacuum hot extraction (VHE), DTA, XRD, and SEM.
For the coarse glass powder, sintering proceeds slowly and is limited by surface crystallization of primary Na2CaSi2O6 crystals. Although the crystallization onset of Na2CaSi2O6 is shifted to lower temperature, full densification is attained for the fine powder. This finding indicate that certain porosity might be tuned via particle size variation. Above 900°C, intensive foaming is evident for the fine powder. VHE studies revealed that carbon species are the main foaming source.
There is a need for an assessment of the emission properties of volatile organic compounds (VOCs) from consumer products. A method comparison was carried out to evaluate adapted and cost-effective procedures for such items. Smaller and automated emission chambers depicted similar kinetics compared to a 203 L standard chamber. Toy samples made of PVC (Polyvinyl chloride) emitted more VOCs compared to other tested polymeric products. The emissions from 2 selected samples were studied to allow an evaluation of the resulting room concentration and external exposure of a child. Obtained concentrations were not of concern.
Comparison of Formaldehyde Concentrations in Emission Test Chambers Using EN 717-1 and EN 16516
(2018)
For many years EN 717-1 (Wood-based panels - Determination of formaldehyde release - Part 1: Formaldehyde emission by the chamber method) is the standard for formaldehyde emission testing of wooden boards. In 2017 EN 16516 (Construction products - Assessment of release of dangerous substances - Determination of emissions into indoor air) was published as a new harmonised standard for the emission testing of construction products. Because test chamber conditions are different, both standards give different concentrations for formaldehyde. For the determination of a conversion factor four test series were set up with different wooden boards.
In Vorbereitung einer Restaurierung erfolgten naturwissenschaftliche Untersuchungen zu Schadensphänomenen und Glaszusammensetzungen an mittelalterlichen Gläsern aus der Dorfkirche in Koszewko (Polen)im Environmental Scanning Electron Microscope (ESEM) mit EDX. Die Ergebnisse zeigen, dass die Glasverwitterung schon sehr stark vorangeschritten ist und ein zukünftiger Schutz der mittelalterlichen Glasmalereifelder vor Umwelteinflüssen unbedingt notwendig ist. Es wurde ein Schutzverglasungsystem entwickelt, das speziell auf den langfristigen Erhalt der einzelnen mittelalterlichen Glasmalereifelder ausgelegt ist.
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.
3D-printing or additive manufacturing has many promising and unique advantages. Especially low cost molten polymer Deposition Printers are increasingly populär in the private and educational sector.
Their environmental friendliness can be questioned due to recently reported ultrafine particle and suspected VOC emissions, To further investigate 3D-printing as a potential indoor air pollution source we characterized fine and ultrafine particle emissions from a molten polymer deposition printer producing a 3D object with ten marketable polymer filament materials under controlled conditions in a test chamber. VOC emissions from the filaments have also been compared. Using a straightforward emission model time dependent and averaged particle emission rates were determined. The results indicate that under comparable conditions some filament materials produce mainly ultrafine particles up to an average rate of 1013 per minute. This value is in the upper ränge of typical indoor ultrafine particle sources (e.g. Smoking, frying, candle light, laser printer). The observed material-specific rates differ by five Orders of magnitude. Filament-specific gaseous emissions of organic compounds such as bisphenol A, styrene and others were also detected.
Our results suggest a detailed evaluation of related risks and considering protective measures such as housing and filtering.
Equipping ZIF particles with a polyelectrolyte membrane provides functional groups at their interface, enabling further conjugations necessary for applications such as targeted drug delivery. Previous approaches to coat ZIF particles with polyelectrolytes led to surface corrosion of the template material. This work overcomes previous limitations by performing a Layer-by-Layer (LbL) polyelectrolyte coating onto ZIF-8 and ZIF-67 particles in nonaqueous environment. Using the 2-methylimidazolium salt of polystyrensulfonic acid instead of the acid itself and polyethyleneimine in methanol led to intact ZIF particles after polyelectrolyte coating. This was verified by electron microscopy. Further, zetapotential and atomic force microscopy measurements confirmed a continuous polyelectrolyte multilayer built up. The here reported adaption to the well-studied (LbL) polyelectrolyte selfassembly process provides a facile method to equip ZIF particles with a nanometer thin polyelectrolyte multilayer membrane.
Ziel des Projektes war es, schwermetallfreie Schmelzfarben für den Einsatz auf einem Digitaldrucker zu entwickeln. Dafür sollten die Glasfarben, bei Temperaturen unter 630°C verarbeitbar und deren Eigenschaften kompatibel mit denen von Floatgläsern sein. Zudem sollte die aufgeschmolzene Farbe transparent und im Außenbereich eingesetzt beständig sein. Weiterhin mussten die Farben eine Partikelkorngröße kleiner als 20µm besitzen, um die Druckköpfe des Digitaldruckers nicht zu verstopfen. Gute Dispergierbarkeit, thixotropes Verhalten und eine schnelle Trocknung waren weitere Voraussetzungen. Die Ersetzung von PbO durch ZnO und Bi2O3 wurde getestet und zeigte positive Ergebnisse. Ein geeigneter Mahl-und Dispergierprozess wurde entwickelt. Bei der Firma „glas&räume“ wurden die Musterfarben getestet und zeigten ein gutes Druckverhalten. Bedingt durch das Tintenstrahlverfahren erreicht der Farbauftrag keine 100%ige Transparenz. Trotzdem erscheint die transparente keramische Schmelzfarbe im Vergleich zur Verwendung von opaker Schmelzfarbe tatsächlich völlig transparent. Der Unterschied ist signifikant und öffnet so ein neues Kapitel im keramischen Digitaldruck.
Im Januar 2018 wurde die DIN EN 16516 „Bauprodukte: Bewertung der Freisetzung gefährlicher Stoffe – Bestimmung von Emissionen in die Innenraumluft“ als harmonisierte europäische Prüfnorm veröffentlicht. Für die Etablierung der DIN EN 16516 als neue Referenznorm wurden verschiedene Emissionsprüfungen mit dem Ziel durchgeführt, ein neues Prüfverfahren für Formaldehydemissionen aus Holzwerkstoffen zu erarbeiten. Das übergeordnete Ziel ist die Minimierung des Risikos von Überschreitungen des Innenraumrichtwertes für Formaldehyd. Die Untersuchungen ergaben teilweise hohe Formaldehydemissionen, insbesondere bei höheren Beladungsfaktoren und Temperaturen, sowie bei niedrigen Luftwechselraten. Eine getestete Spanplatte hätte aufgrund ihrer hohen Formaldehydemission nicht auf den deutschen Markt gebracht werden dürfen. Durch vergleichende Untersuchungen konnte ein Umrechnungsfaktor in Höhe von 2,0 für die Umrechnung von Prüfwerten nach DIN EN 717-1 zu DIN EN 16516 abgeleitet werden.
Neuartige Materialien, die bekannte (Werk-)Stoffe mit neuen Funktionalitäten ausstatten, spielen eine zunehmend wichtige Rolle im Bereich der Materialforschung und -prüfung. Das Spektrum neuartiger Materialien reicht von der gezielten Oberflächenfunktionalisierung und -strukturierung makroskopischer Materialien, dünnen Beschichtungen bis hin zu mikro- und nanoskaligen Kompositmaterialien und funktionalen Materialien an der Schnittstelle zur Biologie, Biotechnologie, nachhaltige Energiespeicherung und Sensorik. Dabei bieten neuartige Materialien die Chance, Werkstoffe und Produkte mit erweiterter oder verbesserter Funktionalität zu erhalten und Sicherheit bereits im Designprozess zu berücksichtigen. Durch dieses breite Anwendungsspektrum und die Herausforderungen, die solche Materialien für die Sicherheit in Chemie und Technik mit sich bringen, sind diese in allen Themenfeldern der BAM repräsentiert (Material, Analytical Sciences, Energie, Infrastruktur und Umwelt).
Die Aufgaben der BAM erstrecken sich dabei von der Herstellung von Referenzmaterialien für Industrie, Forschung und Regulation, über die Erstellung von standardisierten Referenzverfahren für nachhaltige Messungen im Umwelt- und Lebenswissenschaftsbereich bis hin zur Bereitstellung von belastbaren und zitierbaren Referenzdaten. Durch die genaue Charakterisierung neuartiger Materialien können potentiell problematische Substanzen identifiziert und deren Risiken besser abgeschätzt werden. In diesem Beitrag werden einige aktuelle Beispiele aus diesen Bereichen vorgestellt.
The European building sector is moving towards more complex and high-tech building approaches. While focusing on energy efficiency, aspects e.g. occupant health, sustainability and life cycle costing are often neglected. This study highlights the potential of earthen plasters in combination with natural ventilation for low-tech solutions.
The EU funded project [H]house established the outstanding performance of earthen materials in light of hygrothermal and air purifying properties, which were further supported by experimental data from monitoring of naturally ventilated pilot buildings in Berlin. Additionally, [H]house demonstrated through LCC an increased cost efficiency of earth based low-tech solutions in comparison to conventional constructions relying on mechanical ventilation.
Das Prozessmonitoring stellt einen wichtigen Baustein für eine Qualitätssicherung additiv gefertigter Bauteile dar, insbesondere bei kleinen Losgrößen. Der Vortrag zeigt einen Überblick aktueller Entwicklungen der BAM im Bereich des Prozessmonitorings für das Laserstrahlschmelzen (laser powder bed fusion) metallischer Werkstoffe. Durch Vergleich mit der Referenzmethode Computertomografie wird am Beispiel der thermografischen Verfahren gezeigt, wie relevante Defekte in Bauteilen detektiert werden können und Einsatzpotenziale sowie Limitierungen aufgezeigt.
Die von der BAM eingekauften Holzwerkstoffplatten (Verlegespanplatten, OSB, Multiplexplatten) verschiedener Hersteller zeigten teilweise hohe Formaldehyd-emissionen unter den Prüfbedingungen nach EN 16516, eine Spanplatte hielt den Grenzwert von 0,1 ppm selbst bei Prüfung nach DIN EN 717-1 nicht ein, dürfte also in Deutschland gar nicht in den Verkauf gelangen.
Holzwerkstoffe, die unter den Prüfbedingungen der DIN EN 717-1 die Formaldehydklasse E1 einhalten, können insbesondere bei großflächigem Einsatz im Innenraum zu Überschreitungen des Richtwertes für die Innenraumluft führen. Zusätzlich zur Anpassung des Luftwechsels ist auch der Parameter Beladung bei einer Überarbeitung der Norm anzupassen. In der DIN EN 16516 werden produktspezifische (am Einsatz der Produkte orientierte) Beladungsfaktoren vorgegeben. Für den Einsatz von Holzwerkstoffplatten ergäben sich Beladungen von 0,4 (Boden oder Decke), 1,0 (Wände), 1,4 (Wände plus Boden oder Decke) und 1,8 m²/m³ (Wände, Boden und Decke). Um die realen Bedingungen in modernen Gebäuden abzubilden, ist deshalb eine Beladung von 1,8 m²/m³ für die Prüfkammermessung erforderlich. Hierbei ist darauf hinzuweisen, dass für die Beladung im Referenzraum Möbel nicht berücksichtigt wurden.
Damit soll sichergestellt werden, dass die Einhaltung des Schutzniveaus bei realen Innenraumbedingungen auch unter den Randbedingungen eines niedrigen Luftwechsels sowie bei sommerlichen Bedingungen und heutigem Lüftungsverhalten der Menschen soweit wie möglich gewährleistet ist.
The church of Koszewko (Poland) is a brick building edified in the 15th century built on cobblestone foundations. There are five windows in the sanctuary. Three of them enclose heraldic panels from the Küssow’s family from the 15th century which are surrounded with Goethe glass from the 18th century to complete the windows. The colored heraldic panels are strongly damaged and corroded with massive paint layer losses, glass- and leadbreakages. Those medieval glass fragments have been shortly discovered and are of particular interest for Poland since only few medieval glazing have been conserved.
The damages as well as the glass compositions have been investigated with ESEM/EDX. Two categories of medieval glass compositions have been identified. The blue glass is particularly sensible to corrosion because of his high content in K2O. The colorless and the red glass samples belong to a stable glass type. Due to the thickness of the gel layer, it is easy to see that the degradation is strongly proceeded. The protection of those medieval stained-glass panels is absolute necessary.
The medieval panels have been restored and surrounded from a copper frame. Then they have been fixed on the wood frame in the church. The exterior glazing has been closed with a panel of Goethe glass. The gap between the Goethe- and the medieval glass is about 3 cm. The Goethe glass panel has been stabilized with a film based on polyester to protect the medieval glasses against any damages. In this way, a low cost protective glazing has been installed for a long-term conservation of each medieval stained-glass panels. The climate measurements over the period of one year on the restored windows are in process. The temperature and the relative humidity are recorded in the church interior, in the gap between the original and the Goethe glass and outdoors.
Today glass is broadly used in modern architecture. For indoor applications it is possible to produce decorated glass by using enamel colours and glass painting techniques without any problems. However, this is more limited for applications out of doors. Humidity and environmental pollution attack the surface of the coating and can damage it. There are only a few colours on the market which are resistant towards acids and bases until now. Additionally, most of those colours are opaque. To extend the colour palette, chemically resistant low melting coloured glasses are being developed which are transparent and intensively toned even in thin coating thicknesses. To achieve such an ambitious aim, many parameters have to combine and act in a complex manner. New compositions of lead borosilicate, zinc borosilicate and lead-zinc borosilicate glasses were produced and milled as powder. The thermal properties as well as the environmental stability were analysed. The influence of PbO and ZnO on the thermal properties and the environmental stability were investigated. Evaluation of the fusing results shows that the production and mixture of transparent vitreous enamels for the exterior side of glasses is possible. The tests made it clear that the original materials for making the vitreous enamels must be excellently ground and prepared to achieve a satisfactory result. The method to produce durable vitreous enamels for exterior application also seems to allow the production of glass colours.