Mansfield Library Collections Environment

Mansfield Library Collection Environment Statement

The Mansfield Library's collections represent an invaluable resource to
the campus community and the broader scholarly public. In addition to a
circulating collection of nearly 1.5 million books and serials, the
collections include rare, and in many cases irreplaceable, manuscripts
and books as well as media in a variety of formats.

The effect of environmental conditions on the health of library
materials is clearly recognized in the literature of library
preservation. While ideal conditions may be difficult or impossible to
maintain, the Mansfield Library makes every effort to create an
environment that does as little harm as possible to our materials.
Preservation staff monitor the maximum and minimum temperatures at two
locations on each floor, and climate data is also recorded at three
additional locations using the Image Permanence Institute’s
Preservation Environment Monitor (PEM) recorders.

Ideal storage conditions vary by form of media, but all preservation
guidelines recommend maintaining stability of temperature and relative
humidity as a primary criterion for ensuring collection health. The
Northeast Document Conservation Center notes that a "frequent
recommendation is a stable temperature no higher than 70°F and a stable
relative humidity between a minimum of 30% and a maximum of 50%," and
fluctuations of temperature and humidity are particularly singled out
for criticism:

Maintaining stable
conditions is crucial. An institution should choose a temperature and
relative humidity within the recommended ranges that can be maintained
twenty-four hours a day, 365 days a year. The climate-control system
should never be turned off, and settings should not be lowered at
night, on weekends, or at other times when the library or archives is

Likewise, the National Information Standards Organization has published
guidelines for the preservation of paper-based collections, which offer
similar recommendations and also single out rapid temperature and
humidity fluctuations over short spaces as particularly dangerous to
collections: "A facility that is hot during the day and cool at night
is especially harmful, as cycling of temperature and relative humidity
accelerates degradation".2

1. Sherelyn Ogden. "Temperature, Relative Humidity, Light, and Air Quality: Basic Guidelines for Preservation." Northeast Document Conservation Center Preservation Leaflets 2.1. Available online at

2. William K. Wilson and National Information Standards Organization (U. S.). Environmental Guidelines for the Storage of Paper Records. NISO technical report TR01-1995. Bethesda, Md.: NISO Press, 1995. Available online at