Strict Climate Control in the Niels Bohr Library and Archives
Creating state-of-the-art environmental conditions for all of our collections -- archives, books, and photographs -- was a major goal when the American Institute of Physics moved to its new building in College Park back in 1993. People touring our facilities were surprised to find, for example, that visiting the photo collection meant passing through a rubber-sealed door into a noticeably colder room. But despite careful advanced planning, errors in construction brought a variety of problems. Keeping the archives safe through the remarkably muggy Maryland summers required almost daily adjustments of the controls that govern air flow. We overcame these problems only after sustained effort, including construction work and the replacement of defective machinery. By early 1998 the system could automatically and reliably keep the temperature and relative humidity in the archives stacks, the book stacks, and the visual archives within the strictly prescribed set points twenty-four hours a day, seven days week. Our collections are now stored under optimum climate conditions, which are different for each collection. For example, materials stored in the archives are kept at consistently cool temperatures (60-65 degrees Fahrenheit) and moderately low humidity (30-35% relative humidity); the book collection can be slightly warmer, etc.
The final step in controlling the physical environment was completed in December when the raw concrete floor in the archives stacks, which the original contractor had failed to finish, was sealed. Unsealed concrete releases airborne particles that over the long run may damage sensitive materials such as film emulsions and fragile paper. The challenge was to seal the floor without moving the collection and without introducing more dust or "off-gassing" of volatile organic compounds that are used in virtually all sealants. We met the challenge with the help of a conservation archivist at the Natonal Archives and Records Administration, who recommended a non-solvent epoxy that was specially formulated for the Archives II building in College Park. We wrapped the shelves and furniture in polyethylene to protect the collection and closed access to the archival collection for one week. At the end we had a newly sealed floor, which not only removes any danger from contaminants but also gives the archives a bright new look.