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- Air sampling (2)
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Light damage to selected organic materials in display cases: A study of different light sources
(2016)
The protection of works of art and cultural assets against light-induced aging is vital when planning exhibitions. Newly developed lighting systems render the selection of suitable light sources more difficult, not least in the context of energy–economical systems. This study accordingly examines different lighting systems (fluorescent tubes, halogen lamps, low-voltage metal halide lamps, and LED lamps) in terms of the damage potential they hold for the materials concerned. The changes in color were evaluated using the CIEDE2000 color-difference formula. This study focuses on selected organic materials and shows that changes in color already occur after only a brief exposure time. The color changes induced by the fluorescent tubes were consistently more intense than those induced by the other light sources. The results obtained with the remaining lamps show that the color changes depend more on the material under investigation than on the source used. The changes determined after a relatively short exposure period (five months) vividly demonstrate that exposing sensitive materials to light for longer terms (as is the case during a permanent exhibition) is most definitely a non-viable option.
Formic and acetic acids are often responsible for damage of cultural objects, e. g. glass and metal corrosion or changing and fading of colours. Museums all around the world are equipped with different show cases. Display cases should protect cultural objects from dust as well as from mechanical damage. Several construction materials which are used for display cases, including wood, glue and coatings, are possible sources of very volatile organic compounds (VVOCs), volatile organic compounds (VOCs) and semi volatile organic compounds (SVOCs). These construction products can emit formic and acetic acids into the indoor or display case air. Modern display cases with small air change rates can cause higher concentrations of formic and acetic acids if any source is installed in the display case (Salthammer and Uhde, 2009). To minimize the risk of damage emissions from building products must be quantified. There is a need for a method for identification and quantification of acetic and formic acid. Some possibilities for the identification of acetic acid exist. The quantification of acetic acid for example after sampling on TENAX® or CARBOTRAP and thermal desorption-GC in accordance with ISO 16000-6 and ISO 16017-1 results in very low recovery rates. A new method should be stabile, robust, reproducible and comparable, with an easy local sampling and determination in laboratories. Miniaturised emission test chambers and model display cases were used to study the recovery rates.
Nicht nur Schadstoffe aus der Umwelt können Museumsexponate schädigen. Auch interne Schadstoffquellen wie objektimmanente Exhalate und Emissionen von Lösemitteln oder organischen Säuren können den wertvollen Gu¨tern Schaden zufu¨gen. Auf Schadstoffe zu pru¨fen sowie geeignete Messmethoden zu entwickeln und zu optimieren, ist daher von großer Bedeutung. Neuste Forschungen stellen die Autoren vor.
Several construction and building materials, including wood, glue and coatings, are possible sources of very volatile organic compounds (VVOCs) and volatile organic compounds (VOCs) like formic and acetic acid. Due to very high air tightness and very low air exchange rates in new buildings concentrations of these harmful substances can increase considerably. To minimize the risk, emissions from building products should be identified and quantified. With the common standard method, this means Tenax® sampling followed by thermal desorption and GC-MS analysis, these acids could not be detected sufficiently. The aim oft this study is the comparison of two different methods for the determination of acetic and formic acid. The sampling of method one, which is usually used for identification and quantification of VOCs, is done in accordance with ISO 16000-6 and ISO 16017-1 on Carbotrap® 202 multi-bed thermal desorption tube by subsequent identification and quantification with GC-MS. Method two is based on sampling on 2,4-dinitrophenylhydrazine (DNPH) cartridges, derivatisation, elution, identification and quantification of the derivatives with LC-MS/MS (liquid chromatography mass spectrometry/mass spectrometry).
Ausstellungskuratoren, Restauratoren oder Fachplaner stehen immer wieder vor der Entscheidung, geeignete Materialien für Museumsausstattungen auswählen zu müssen. Vitrinen, Depoteinrichtungen, aber auch Transportverpackungen für Kunst- und Kulturgut sollten unbedingt frei von Schadstoffen sein. Ein neues Verfahren ermöglicht nun eine problemorientierte Untersuchung und Bewertung von Materialien mit belastbaren und reproduzierbaren Ergebnissen.
Unterschiedliche Befeuchtungssysteme für Vitrinen, die die Ausstellungsobjekte bei definierter Luftfeuchtigkeit vor externen Einflüssen wie Staub bewahren sollen, wurden im Hinblick auf die Möglichkeit der potenziellen mikrobiologischen Kontamination untersucht. Ergänzend hierzu wurden Parameter wie pH-Wert und Leitfähigkeit des Wassers im Befeuchter untersucht und die mikrobiellen flüchtigen organischen Verbindungen (MVOC, microbial volatile organic compounds) in der Modellvitrine bestimmt. Die Leitfähigkeitsmessung kann als Indikator für den Verunreinigungsgrad des Wassers dienen, weil sie mit der mikrobiologischen Belastung korreliert. Weiterhin war eine mikrobiologische Belastung der Luft in der Modellvitrine auch bei relativ hoher Verunreinigung des Befeuchtungswassers nicht nachzuweisen.
Schadstoffe beschäftigen derzeit Museen weltweit Heute weiß man, dass diese auch aus Materialien, die für den Ausstellungsbau verwendet werden, austreten können, was eine Gefahr für Exponate darstellt. Ein neues Verfahren namens BEMMA bietet nun erstmalig die Möglichkeit, relativ schnell und effektiv eine problemorientierte Untersuchung und Bewertung mit belastbaren und reproduzierbaren Ergebnissen vorzunehmen.