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When specifying new case or display structures care must be taken with choice of materials and surface finishes. In addition to fulfilling fire regulations materials used in the construction of showcases and display mounts, frames, supports and plinths should be chosen with care as many materials will emit gasses or vapours that can damage objects placed in a sealed environment of a display case. Surface coating finishes, paints, varnish, polish etc. subsequently used to seal construction materials will emit their own gasses, or spirit based chemical vapours. If finished boards are used e.g. formica clad blackboard or MDF, these will have been bonded with strong chemical adhesives which in turn will emit gasses.
These problems are lessened in an older showcase where the gas emissions have reduced over it's life, but should still be taken into consideration where new objects are being installed into old cases however.
Composite wood products such as MDF contains formaldehyde in the adhesives used in its composition, this will be emitted into any enclosed structure and then into object if not addressed. Conservation grade MDF should be specified in showcase construction, if additional fireproofing is required this should be applied externally with other decorative surface treatments. Ideally this should be carried out and allowed to 'off-gas' well before the of installation of objects. Plywood is actually a better construction material than MDF is it contains less adhesives.
Safer materials that do not emit harmful gases include glass, metal and some plastics e.g. perspex. |
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