Those who are dedicated to the preservation of cultural heritage, are constantly searching for ways and means to minimise and preferably prevent the contamination of cultural goods and artefacts.
Today's advanced museum display cases provide extensive protection against external pollutants such as spores, pollen, dust particles, sulphur dioxide, ozone, nitrogen oxides or hydro carbonates, etc..
However, display cases offer little protection against internal sources of pollutants, on the one hand against vapours emanated by the object, and on the other hand emissions such as organic solvents and acids, formaldehyde and other substances inherent to the materials used to build the display case itself.
While emissions originating from the object displayed can hardly be prevented, the control of the construction materials used is possible.
To ensure a stable micro-climate inside the case, a low air exchange rate is maintained, which leads to a rising concentration of potential pollutants derived from both historical object materials and display case construction materials.
The standard assessment of construction materials according to toxicological criteria, such as e.g. "E1-Formaldehyde free", "Blue Angel", "Ecotex-Standard", "ZE–Zero Emission" etc., are no benchmark for defining the specific material requirements in museum display case construction. These criteria refer to a variety of different specifications.
Established methods for analysis and indicator tests such as the photo ionisation detector, Dräger-Biocheck, Oddy-Test, glass sensors or Acid Detecting Strips are reliable tools, but they are far from serving the requirements for display cases, as the results yield no exact figures. Obligatory "museum standards" do not exist.
¹ Compare document of Vantaa. Proposals for a European strategy
for preventive conservation in the context of the Raphael Program by the European Commission, passed in Vantaa, Finland in September 2000
² Vapours emanating from the object means pollutants originating from
the object material itself, or from materials added to the object during restoration or conservation measures.