Project Objectives
Building upon results from a previous GCI project on ventilation and heating strategies for the protection of collections in historic structures (Collections in Hot and Humid Environments), this project focuses on the economical and sustainable application of these techniques to improve the physical environment of collections in historic buildings in hot and humid regions in order to prevent microbial-induced biodeterioration (i.e., damage due to fungi and bacteria). Specifically, it applies alternative strategies to conventional air-conditioning systems by controlling relative humidity through ventilation and heating or dehumidification while allowing for larger variations in temperature. The primary objectives of the project are:

• to document case studies for the application of ventilator-and heater/dehumidifier-based climate improvement strategies for historic buildings using locally sustainable technologies;
• to analyze the performance of climate control systems for improved operation;
• to disseminate information generated by the project through publications and presentations.

	Fungal growth on this book (part of the Historic Archive of La Laguna, Tenerife Island, Spain) is due to extended exposure to high levels of relative humidity. Photo: Shin Maekawa.

Project Overview
Biodeterioration has been a major threat to museum collections in hot and humid regions; this is a result of exposure to prolonged periods of elevated relative humidity. Although air-conditioning may be used to lower relative humidity in the collection space, excessive cost and intrusion to the fabric of historic structures are prohibitive factors in its installation. Field studies at Tenerife Island, Spain, and Jekyll Island, Georgia—initiated by the GCI in 1997 and completed in 2002—examined the use of humidistat-controlled ventilation and heating as a viable alternative to air-conditioning in reducing relative humidity in the collection space.

	Severe wood decay of interior sheathings and floors on the ground floor of Hollybourne Cottage in Jekyll Island, Georgia, the result of elevated relative humidity in the walls and basement. Photo: Shin Maekawa.

Results from these multi-year experiments quantified the efficacy of economically sustainable strategies and produced ventilating and heating requirements for the care of collections in historic buildings located in tropical and subtropical regions. These studies demonstrated an impressive capability to improve climates with systems that, relative to air-conditioning, are inexpensive and simple to install, operate, and maintain. Results of this research have been presented at the Indoor Air Quality meeting of the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) in San Francisco, California; the annual meeting of Passive, Low Energy Architecture (PLEA) in Florianópolis, Brazil; the 2003 meeting of the Western Association for Art Conservation (WAAC) in Honolulu, Hawaii; and ICOM-CC in Rio de Janeiro, Brazil.

As a result of the successes of these experimental trials, a number of past and present partners are installing climate control systems in their facilities. These projects are supported through the use of local resources, which include funding for labor and equipment and the hiring of local engineers, architects, and contractors. The GCI is also providing technical support during the design and installation of these systems, as well as performance monitoring and suggestions for improvement to these projects.

Last updated: October, 2005