Emissions from Construction and Decoration Materials for Museum Showcases

Emissions from construction and decoration materials for museum showcases are of high relevance within preventive conservation. Therefore, emission analyses of a broad variety of single materials have been performed. Specimens were screened for organic volatiles and were subsequently investigated in test chambers to study time-dependent emission profiles. Concentrations of formaldehyde, formic acid, acetic acid and volatile organic compounds (VOCs) were determined by active sampling and chemical analysis. It was found that solvent-borne lacquers, gasket materials and ultraviolet (UV)-curing systems are currently the main emission sources in showcases due to high solvent contents and the release of fragmentation products. Beneath such primary emissions, secondary products occurred. The most important reaction is hydrolytic cleavage of acetyl esters contained in coating formulations yielding high concentrations of acetic acid even in modern showcases. Compounds known for adverse effects on human health have also been detected. Furthermore, labelled products do not ensure any reliability for museum applications as testing conditions are targeted to normal indoor conditions and differ markedly from those in museum interiors, especially from those within showcases. As, in general, emission-free materials do not exist, alternative concepts, e.g. for ventilating showcases and the implementation of sorbent materials, are necessitated.