Temperature control for Yale Beineke Library

During a major renovation, the Beinecke Rare Book & Manuscript Library at Yale University was left without its permanent HVAC system, putting one of the world’s most significant collections of rare books and manuscripts at risk. The library houses priceless materials, including Gutenberg Bibles, early maps, and centuries old texts stored in a central glass tower and extensive underground stacks.

CHALLENGE

With the project overlapping seasonal transition, spring thaw conditions introduced an added layer of risk. As temperatures rise and snow melts, buildings face increased humidity, condensation, and water intrusion. For libraries and archives, this creates ideal conditions for mold and material damage, especially during construction.

Moisture-driven damage often happens quietly and quickly. In environments filled with paper-based materials, even small increases in humidity can have lasting effects.

During spring conditions, risks typically come from:

• Moisture infiltration from melting snow and rain
• Condensation forming on cooler interior surfaces
• Elevated ambient humidity overwhelming existing controls
• Construction activity introduces additional pathways for air and moisture

These factors can combine to create ideal conditions for mold growth, warping, and material degradation, especially when systems designed to regulate the environment are offline.

Illuminated display cases on the mezzanine level hold temporary exhibits.

SOLUTION

Polygon was brought on by Shawmut to ensure the integrity of the collection. Polygon implemented a temporary climate control solution designed to maintain stable conditions of approximately 72°F and 50 percent relative humidity, even as outdoor conditions fluctuated.

The building was divided into multiple zones, allowing each archive area to be individually controlled and kept within specification. This level of precision ensured that even the most sensitive materials remained protected, regardless of their location within the facility.

In addition to temperature and humidity control, Polygon deployed advanced digital monitoring solutions to continuously track environmental conditions. This included real-time monitoring of relative humidity, temperature, volatile organic compounds (VOCs), and airborne particulates, providing a more complete picture of air quality and potential risks to the collection.

Because the historic structure could not be altered, all equipment was installed outside the building and ducted in, preserving the integrity of the architecture while still delivering precise environmental control inside.

The two volumes of an original Gutenberg Bible

RESULTS

Polygon’s solution maintained stable environmental conditions throughout the renovation, despite ongoing construction and seasonal humidity fluctuations during the spring thaw. Tight control of temperature, humidity, and air quality helped ensure all areas of the library remained within specification.

By combining zoned climate control with continuous digital monitoring, the system minimized environmental variability and reduced the risk of moisture-related damage across the entire facility.

This approach helped:

• Prevent mold growth and condensation on sensitive materials
• Maintain consistent preservation conditions across multiple archive zones
• Protect paper, bindings, and adhesives from humidity-driven deterioration

The result was a controlled environment that allowed construction to proceed without disruption, while safeguarding one of the world’s most valuable rare book collections in place.

Talk to Polygon about temporary climate control solutions that protect your collections, prevent mold, and keep your project on track.

- “Beinecke-gutenburg-bible.jpg” by Henry Trotter, via Wikimedia Commons, Public domain.
- “Beinecke Rare Book & Manuscript Library Interior (34254026911).jpg” by Gunnar Klack, via Wikimedia Commons, licensed under CC BY-SA 2.0.