Temperature

In general, the higher the temperature the more rapidly materials will deteriorate, and the lower the temperature the longer materials will last. However, because people must have access to library and archival materials, there is a practical limit to how low the temperature can be maintained. Ideally, the temperature should be closely controlled at 20° to 21° Centigrade (68° to -70° Fahrenheit) and consistently maintained in all areas of a storage facility. This temperature range is regarded as tolerable to staff and users and appropriate for most materials. Keep in mind, however, that standards for temperature as well as for relative humidity are based on conditions in temperate climates and may be unattainable in humid tropical areas. If temperature cannot be controlled because of inadequate mechanical systems, other preservation measures can be taken (see Passive Climate Control).

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