There are also hazards when analogue or digitized data on magnetic tape or cassettes is stored or transported. The fidelity of vital recorded information may be distorted or even partially erased by unforeseen external magnetic fields, or by carelessness of unheeding or uninformed personnel, or by deliberate vandalism with powerful permanent magnets. Tape data protectors provide needed shielding against such hazards. The proctectors are used by all branches of the armed forces, NASA, other governmental organizations and many private firms. It is available for immediate delivery in various convenient widths, lengths and shielding strengths for high or low permeability requirements with a range of electrical conductivities.
Foil is easily, quickly cut with ordinary scissors and hand shaped to the desired outline.
Many shielding problems thus can be solved quickly. After hand shaping around the component to be shielded, the foil can be held in place with simple adhesive tape. Thickness and number of layers can be determined by ordinary trial and error procedure, or a formula to follow may be requested from the manufacturer. Begin by using a single layer and then adding layers until the desired shielding effect is achieved. When using multiple layers in steady fields and at low frequencies, the low permeability layer should be closest to the field source.