page_title: Mold control and prevention in libraries
section_title: Prevention
hierarchical_section_title: Mold control and prevention in libraries / Prevention
caption_attribution_description: English: CCAHA’s conservation staff laying out fire, water, and mold-damaged items to dry.
context_page_description: Mold prevention is a conservation activity that is performed in libraries to protect books and
  other materials from deterioration caused by mold growth. Mold prevention consists of
  different methods, such as chemical treatments, careful environmental control, and manual
  cleaning. Preservationists use one or a combination of these methods to combat mold spores in library collections.
  Due to the resilient nature of mold and its potential for damage to library collections, mold prevention has become an important activity among preservation librarians. Although mold is naturally present in both indoor and outdoor environments, under the right circumstances it can become active after being in a dormant state. Mold growth responds to increased moisture, high humidity, and warm temperatures. Library collections are particularily vulnerable to mold since mold thrives off of organic, cellulose-based materials such as paper, wood, and textiles made of natural fibers. Changes in the moisture in the atmosphere can lead to mold growth and irreparable damage to library collections.
context_section_description: The only way to control mold is by altering conditions conducive to its growth. The generally accepted threshold for mold growth is about 15% moisture content because the predominant cause of mold is excess water. Excess water can come from liquid water, as a result of leaks, or water vapor, as a result of high relative humidity due to improper storage, faulty humidifiers, or HVAC malfunctions. While most research shows that fungal growth is most prevalent in conditions in which relative humidity is above 60%, humidity levels below this threshold alone will not prevent mold growth, given the fact that favorable germination environments vary from species to species.
caption: Conservation staff drying mold-damaged materials
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