Access and Security
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Lift-off Case Access
Both curatorial and conservation input should be considered in the design of case access. Lift-off vitrine size and weight should allow access by a single individual whenever possible. Consider the following when establishing case access design:
- frequency of use
- time required to access
- number of staff required
- difficulty of re-securing component
- difficulty of creating seal
Lift-off vitrines should never be so large that they cannot be lifted safely over the objects inside the case. 30"x 30"x 30" is generally considered the largest vitrine safe for lift off access. Large units weighing over 75 lbs. are to heavy even for two people to move safely.
Glass components are just over twice as heavy as equally designed items in acrylic or poly carbonate. Large glass vitrines or glazed panels should be of laminated safety glass to prevent acci- dental damage to display objects.
Hinged Door Access to Cases
Both curatorial and conservation input should be considered for the design of case access. Door size and weight should allow access by a single individual whenever possible. Glass doors are just over twice as heavy as equally designed doors in acrylic or poly carbonate. When establishing case access design consider the following:
- frequency of use
- time required to access
- effect on case stability
- hardware selection and lock location
- difficulty of re-securing door
- difficulty of creating case seal
Hinged doors that are oversized may need additional support such as pneumatic cylinders or supporting legs to prevent destabilizing the case.
Special attention is required to properly seal the hinge area in well-sealed cases. Hinged doors tend to pinch the gasketry nearest the hinge.
Specialized Case Access
Large glass panel doors have traditionally presented a challenge to exhibit designers. Generally the glazing is set in a track and slid to one side to enter the case. Where the glazing is overlapped a gap remains.
From a preservation perspective this design is unsatisfactory because of the large gap size (even when plastic extrusions are utilized) and the difficulty of sealing the case. Without careful attention to detail, this case design can result in dusty and insect-filled enclosures.
New, specialized hardware is available that allows even heavy, over- sized glass panels to pull forward and roll to the side on hanging track.
These sophisticated hinges allow for a relatively tight seal and single person access. In some cases a removable mullion is used to ensure the glass seats correctly against a gasket.
Different levels of physical security (protection against theft and vandalism) can be achieved through case design. The physical structure and shell of a case serves to isolate from the visitor the display contents; locking hardware discourages unofficial access yet facilitates authorized access. Early in the design phase the level of security design and hardware should be selected; this includes appropriately resistant construction materials and glazing, and locking systems.
The designer should always consider the concealment of all case screws and the use of tamper-resistant screws where visible. Where warranted, electronic detection sensors should be installed.
The degree of physical security offered by an exhibit case depends primarily on the materials used in the construction of its structure and shell. The specific level of resistance required of case materials is determined by an assessment of the security risks associated with an exhibit's particular circumstances. In most instances standard case construction is adequate, however, there are circumstances when a higher degree of resistance is paramount. In the illustrations below a range of different materials are shown. When used in combination these materials can meet the security needs of most exhibits.
The most widely used methods for electronic security are remote sensing and direct wired sensing. Sensors are available for exhibit cases to cover a wide variety of security needs, for example:
- magnetic door and window sensors;
- motion detectors (infrared and passive infrared);
- glass break sensors (acoustic & shock);
- metal attack sensors;
- light level threshold sensors;
- heat and relative humidity threshold sensors;
- water and moisture sensors;
- laser beamIfield sensors.