Craig Preservation Lab

Why Environmental Conditions Matter for Library Collections

Indiana University’s library and archival collections are absolutely vital for the research, learning, and creative activity at the heart of IU’s mission. Caring for and preserving our collections enables the scholarly exchange and dialogue across time that help us make sense of our world, learn from one another, and learn from the past.

Indiana University’s collections number in the many millions and students, faculty, and scholars here and around the world use them every day.

Two IU women students reading books in their dorm.

Our libraries and archives contain amazing treasures, many of which are unique and irreplaceable.

Silk banner commemorating a IU baseball and a trip to play Waseda University in 1922.

The collections are also valuable in the aggregate due to their depth and comprehensive coverage of subjects, having been curated over the past 200+ years to support the University’s degree programs and research agendas.

Beyond their value for learning and research, the books, journals, archival records, literary manuscripts, motion picture films, sound recordings, maps, posters, works of art, and artifacts are the University’s capital assets — acquired, cataloged, cared for, and made available at considerable effort and expense.

While the preservation mission of research libraries is widely understood, what may be less obvious is that to accomplish it means preserving the collections in perpetuity.

But decay is the natural order of things — in the fullness of time, everything deteriorates.

So how do we deal with this reality?

Among the many things we do to protect the collections, the single most critical factor affecting their long-term survival is maintaining environmental conditions that slow the rate of deterioration as much as possible.

Why do environmental conditions matter?

They matter because heat, moisture, light, and pollutants accelerate the chemical reactions that cause decay. Although their detrimental effects on collections are gradual, unfortunately they are also cumulative and irreversible. The rate of decay approximately doubles with every ten-degree Celsius rise in temperature. Although optimal conditions vary somewhat for different kinds of objects, all materials benefit from consistently maintained cool, dry storage.

Graph showing how temperature and relative humidity affects longevity of collections.

High temperature and humidity can also result in conditions that allow mold and insects to feed on collections and cause considerable damage. Heating and cooling system failures, if not recognized and repaired quickly, can result in an outbreak of mold in a very short time and can also cause other kinds of mechanical damage.

Book severely damaged by mold

An Indian cinema booklet damaged by insects.

Outbreak of mold on a shelf of books

The conditions in the storage environment affect the collections around the clock and every day of the year. Maintaining optimal conditions is not only critical to the University’s mission — it is also a wise investment. Environmental conditions and systems in the buildings that house the collections need to be maintained 24/7 and actively monitored so that when problems occur, they are identified and correctly promptly.

Our role as caretakers

Sound buildings with proper heating and cooling systems, fire protection and suppression, and security form the first line of protection.

Since 2001 the University has invested in constructing and then expanding a top-notch facility that provides the best conditions for IU Libraries’ collections. The building also houses some of IU’s museum collections. The state-of-the-art building known as the Auxiliary Library Facility, or ALF, has the capacity to house over 6 million volumes at a constant 50 degrees F and 30% relative humidity. It also has spaces specially designed for motion picture films, works of art, other museum objects, costume, and textiles, each with their specific temperature and RH set points. The Lilly Library, in the center of the Bloomington campus, is the University’s world-renowned rare book and manuscript library. The building was completely renovated in 2020-2021, including the installation of a new heating and cooling system to safeguard the collections housed there.

In 2023 the IU Libraries installed environmental monitoring equipment to keep close tabs on the conditions where our collections are stored. These new tools help us track conditions over time, and know if system problems are occurring. Dataloggers are deployed in the ALF, Lilly Library, Wylie House, Wells Library and the Cook Music Library. Staff in each location check the loggers, which record the temperature and relative humidity every 30 minutes. The readings can be viewed on the logger’s LED display, or accessed by cell phone or tablet using Bluetooth. The readings are collected weekly and uploaded to a web-based system for viewing, maintaining, and analyzing the collected data.

What’s next

The dataloggers provide real-time information during work hours when staff are in proximity of the loggers. And they have already proven their worth numerous times by identifying spikes in humidity or temperature when systems have faltered or failed. When these events occur we can alert IU Facilities promptly so they can investigate and correct the problem.

Our next step is to add additional equipment that collects the readings automatically and sends the data to the cloud so that we can check on conditions anytime (e.g., nights and weekends) from anywhere (e.g., from home or on vacation at the lake) and get alerts on our phones or computers when conditions go out of a specified range.

The first gateway will be tested and installed in the ALF, which will add another layer of protection for our extraordinary collections.

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