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Document, Paper and Historical Artifact Climate Control

Libraries, archives, galleries and many other environments contain materials such as paper, leather, textiles and glue which tend to deteriorate over time. To ensure the longest possible life for the objects, a balance must be found between careful climate control, cost limitation, human comfort and access to the materials. The best solutions for an institution will vary according to the collections in their care. It is rarely practical, or indeed possible, to reduce risks to zero.

In the past, the negative effects of fluctuation in temperature and relative humidity levels were probably exaggerated. Nonetheless, large and rapid changes, particularly in relative humidity, are detrimental and should be avoided.

Various kinds of damage may occur because of poor climate control. The right set points depend on the materials. Not all materials are especially vulnerable in low temperatures, for example. However, brittleness can occur with paints, which may make materials more difficult to handle. Structural vulnerability can also occur in paper with low humidity. In addition, high static loads (with consequent paper sticking) or print distortion from contracted paper can be a problem. Damp edges, wavy paper, mould and discolouration can result from high RH levels. Metals can corrode, and magnetic media and many photographic materials can quickly become unusable if not kept at low temperatures.

At relatively high temperatures (room temperature or higher), chemical, physical or biological damage may occur. Chemical degradation at under these conditions is a special problem for sensitive collections. The rule of thumb most often applied is that a 5 °C reduction in temperature doubles the lifetime of an object. While temperature fluctuation can cause damage because of expansion and contraction, research in recent decades has indicated that this danger is smaller than commonly believed.

The type of ambient control systems that are needed likewise vary. Extremely sensitive materials may need to be placed in cold storage, at a stable relative humidity. For example, estimates of the ideal ranges of relative humidity at which to store paper vary, but 45-55% at 18-22 °C is widely considered acceptable for paper that is not of historical importance.

CFW supplies temperature and humidity control solutions to ensure that the correct ambient conditions are maintained. Take a look at the links above for some applications for which we provide equipment, or browse www.dampcontrol.co.za to see our dehumidifiers.

 

We offer solutions for:

 

Contact Us

Address

Cape Town, South Africa (HQ)

3 Parin Road, Parow Industria, 7500, Western Cape

Johannesburg, South Africa

4 Chilworth Road, Founders View North, Modderfontein, Edenvale, 1645, Gauteng

Phone

Cape Town, South Africa (HQ)

T +27 (0)21 931 8331
F +27 (0)21 931 3165

Johannesburg, South Africa

T +27 (0)11 452 5830 / 5146
F +27 (0)11 452 5132

Email

Cape Town, South Africa (HQ)

environmental@cfw.co.za

 Johannesburg, South Africa

environmentaljhb@cfw.co.za

Mailing address:

P.O. Box 1542, Parow, 7499, South Africa