Library Preservation

Preservation Policy

The Harvey Library Preservation department oversees the establishment and maintenance of sound environmental standards for preventive maintenance.  To best protect their collections, it is suggested that satellite libraries conform to minimum standards for preventive conservation set within the Harvey Library.  Preventive measures affect the entire collection and are significantly more cost-effective than remedial treatment or replacement of individual items.

1. The Harvey Library protects its print, analog, and digital media from exposure to excessive light levels in storage and exhibit areas.  All wavelengths of light cause irreversible, cumulative damage to paper, leather, cloth, other organic materials, and plastics. 

1. Illumination Target Range: The Harvey Library follows the standard recommendation of 5 foot-candles (50 lux) as the maximum illumination levels for storage and exhibition areas for organic materials.  This light level has been demonstrated scientifically as the minimum level for human comfort, because no light level can actually be declared “safe” for textiles, leather, or paper. 

For human comfort and convenience, deviation from that standard is permitted in reading and task areas, where light levels up to 660 lux may be needed.  To best preserve the collection, lower overall light levels should be augmented by brighter targeted task lighting, rather than exposing stored collections to high light levels.

2. Light Monitoring Program: The Harvey Library measures and records light levels throughout the building on an annual basis.  Light levels are also measured and recorded before each exhibit.

3. Ultraviolet Monitoring Program: The Harvey Library measures and records levels of ultraviolet radiation throughout the building.  Although all wavelengths of light cause some damage, ultraviolet radiation causes more damage than visible light, while providing no benefits.  The Harvey Library reduces exposure of its collections to ultraviolet radiation through the use of filters on light fixtures and blinds on windows.  In the absence of ultraviolet filtering window films or glazing, the blinds are closed in areas where collections are handled.

4. Conditions Triggering Corrective Action:  Any uncovered window or light fixture presents an immediate hazard, so all efforts are made to reduce the amount and rate of damage.

Until windows are replaced or new ultraviolet filtration is installed, all windows in the Harvey Library storage areas and offices transmit unsafe levels of ultraviolet radiation (there is no safe level).  Open blinds are closed and broken blinds are replaced to reduce both ultraviolet and visible light.  It is preferable to use artificial light sources where ultraviolet radiation can be eliminated and target light levels can be met, rather than windows, which permit varying light levels requiring constant monitoring throughout each day.  Because staff and patrons frequently open the blinds, it is recommended that permanently closed sheer shades be used in their place. 

Fluorescent light fixtures are filtered or replaced with low-UV alternatives, reducing ultraviolet radiation in exhibit, storage, and task areas.  Currently, the Harvey Library uses several types of light fixtures; those lacking a solid sheet diffusion screen should be covered in sleeves, as are found in the Peabody stacks.  The diffusion screens in the Technical Services, Preservation, and other office and task areas absorb most ultraviolet radiation.  Recent compact fluorescent lights installed in recessed can fixtures have been tested to emit minimal UV.  The regular fluorescent tubes in the stacks also emit fairly low levels of radiation (not more than 1 microwatt per cm²).

The maximum level of 75 microwatts per lumen was a practical limit, based on older incandescent light fixtures, not a preservation target.  Any level above zero should be reduced with filtering materials or replaced with low-UV lamps (including LED or ESL types). 

2. The Harvey Library works with the Physical Plant staff and/or outside contractors to monitor plumbing and HVAC systems to prevent liquid leaks and excessive humidity levels. 

1. Temperature and Humidity Target Range:  The standard temperature range for the library is 65º F to 70º F at a relative humidity range of 45% to 55%.  Lower temperatures prevent or retard the deterioration of paper, textiles, plastic and, leather.  Temperatures above 60º F exist solely for the comfort of library staff and patrons.

2. Climate Monitoring Program:  Data loggers or recording hygrothermographs are used to collect temperature and humidity readings throughout the building.  This method permits monitoring of the building on evenings and weekends.  This data allows the Preservation Department to chart trends and to detect problems more rapidly than would be possible with human observation alone.

3. Conditions Triggering Corrective Action:  Conditions in excess of 73º F and/or 60% RH require correction within 24 hours to avoid permanent damage to the collection.  High humidity promotes mold growth and encourages degradation.  Elevated temperatures also increase the rate of oxidation and chain scission reactions that weaken organic materials.  Fluctuations in temperature and humidity encourage warping and delamination of layered objects, such as photographs, book covers, and veneered furniture. 

3. The Harvey Library utilizes closed stacks to provide optimum climate control for rare and unique research collections.

1. Preservation Vault:  The Peabody Preservation Vault maintains a cooler, drier climate than that possible in public areas of the stacks (55° F to 60° F at 40% to 50% RH). 

2. Peabody Stacks:  The closed Peabody stacks are maintained at an intermediate level between the vault and the open Harvey Library stacks (60° F to 65° F at 45% to 55% RH). 

4. Housekeeping staff follow a regular cleaning schedule throughout the building.

1. Routine Vacuum Cleaning:  Vacuum cleaning will be carried out using HEPA or ULPA rated vacuum cleaners.  This high efficiency particulate filtration will reduce the spread of mold spores and other airborne particulate matter.

2. Wet Cleaning (of floors):  Any wet carpet cleaning will be conducted so as to minimize the volume of liquid and corresponding increase in humidity.  Non-porous flooring in such areas as the break room and conservation lab would facilitate cleaning those rooms.

3. Cleaning Solutions:  Chemical cleaners will be selected to release minimal fumes, particularly airborne oxidizing agents.

5. Stack cleaning is conducted on an annual basis.

1. Cleaning Schedule:  To reduce disruptions of library service, stack cleaning is conducted at the end of each semester, during Spring Break, or the Summer Session.  Stack cleaning may also be coordinated with stack shifting.

2. Cleaning Method:  Books are systematically removed from a single shelf, placed on a book truck, and dusted with a soft brush (hake) toward a HEPA or ULPA canister vacuum cleaner with variable suction.  Shelves are vacuumed or wiped with a clean microfiber cloth and books are returned to the shelves.  (cloth should only be used on materials that appear to be clean and are only slightly dusty, not on materials with visible dust).

6. The Library follows an integrated pest management (IPM) program, mitigating pest infestation by cutting off points of entry, reducing food supplies, and maintaining a cool, dry environment.  The IPM technique limits the use of pesticide to targeting specific organisms following careful monitoring. 

1. Gift Quarantine:  New gift acquisitions are quarantined in the receiving area and examined for infestation prior to acceptance into the Acquisition Department work area.  Such materials are decontaminated by freezing or anoxia (nitrogen), which do not deposit chemical residues onto library materials.

Moldy collections are quarantined in the receiving room.  Moldy materials are enclosed in semi-porous housings that will prevent cross-contamination, while reducing risks of further mold growth.  For example, a paper wrapper inside a cardboard box or Tyvek envelope will permit some air circulation, while reducing cross contamination.  A sealed plastic bag may worsen a mold infestation, if the relative humidity inside the bag is too high.  To prevent mold, wet items are frozen or dried as directed by the Preservation and Access Manager in disaster preparedness training for staff.

2. Staff Dining:  Library staff and patrons consume food and beverages in designated break rooms or other designated appropriate places.  Traces of oily, sticky, or crumbly foods may adhere to books, optical disks, microforms, etc.  These residues are attractive to fungi, insects, and microorganisms.  Library staff members wash their hands after eating to avoid the deposition of food residues onto library materials.

3. Use of Spill-resistant Containers:  Beverage consumption is limited to specific areas where library collections are not handled.  A warm beverage in an insulated travel mug with a secure lid may be consumed in non-public work areas.  A cold beverage in a travel mug or plastic sports water bottle (“bicycle”-type) may also be consumed in non-public work areas.  To avoid the risks presented by condensation on the outside of beverage containers, the travel mug or water bottle will not be placed within one meter (about 39 inches) of library materials.  Paper and polystyrene disposable cups are prone to leaks, and their lids are not securely attached.  Such disposable cups should not be used outside of the break room, meeting room, 24-hour study, or other designated food consumption area. 

4. Plants:  Library collections are free from hazards presented by potted plants and cut flowers.  Cut flowers from greenhouses (insect-free) are removed and discarded within 24 hours of use.  A limited quantity of non-flowering plants may be located in the atrium, bridge, meeting room or other area where library collections are not handled.  Damp mulch and soil provide fertile breeding grounds for fungi and insect pests; their presence should be minimized in a building which houses collections of enduring value.

7. Volatile organic compounds (VOC) are monitored and kept to a minimum.  Low VOC paints will be selected if used in collection storage or work areas.  Portable or permanent fume extractors are used to evacuate solvents harmful to artifacts and/or humans.  All potentially off-gassing materials (e.g. new carpets, new painted furniture, etc.) are placed in a quarantined area and aired out prior to placement in collection storage areas.  Oddy tests, MEK tests or other in-house tests will be used to evaluate unknown storage and exhibit materials.  The Harvey Library purchases new storage and exhibit furniture that meets preservation standards for chemical stability and passes all relevant tests.