Books and documents require careful storage. Paper cellulose tends to break down over time as a result of chemical reactions, which are accelerated by warm and damp conditions. Depending on the material, the rate of chemical reactions that cause decay may double with an increase in temperature of as little as 5 °C.

The materials are also subject to expansion and contraction from changes in relative humidity, as they are hygroscopic and easily absorb and release moisture. Non-uniform shrinkage leads to wrinkling (or “cockling”), ink flaking, warped covers and cracking photograph emulsion. The effects of poor handling and packing may be exacerbated when the ambient conditions are hot and dry, while hot and moist conditions encourage decay from mould and insect activity. Unfortunately, controlling humidity is much more difficult than controlling temperature.

Gaseous pollutants may also contribute to degradation. The effect of one such gas, sulphur dioxide, is increased with higher humidity.

Library and archive environments are not uniform in climate; rather, the macroenvironment or general space in the building contains a number of microenvironments. These may have pockets that are not as closely controlled as the main areas. The extent to which close control is possible will depend on the performance of the HVAC system. The effect that uneven control of the environment has on materials can be mitigated by proper enclosure or packaging. However, packaging alone will not be sufficient, as some records and documents are accessed relatively frequently.

While perfect control of the environment is impossible, a climate control system designed and installed by professionals can significantly reduce the damage.

CFW is a leader in climate control technology that has been active in fan design and manufacture since 1966. We provide many kinds of climate control solutions, from turnkey projects to supplying spare parts. Our list of products includes refrigerative and desiccant dehumidifiers, humidifiers, fans, and fan accessories.