Critical Review of the Application of the Principal International Standards and Guidelines on Indoor Microclimates for the Preventive Conservation of Cultural Heritage

Assessments of indoor microclimates are the first act of preventive conservation of cultural heritage. Interest in this subject has led to the development of an increasing number of standards and guidelines. This critical review examines the application of the main standards and guidelines for indoor microclimates for the preventive conservation of cultural heritage and proposes their synthesis in a common framework. In this manner, this study tries to shed light on their coordination and to propose guidance for better understanding and application. Generally speaking, there are two kinds of guidelines: the first is based on the fixed values of specific parameters, used as limits for the best preservation of the various materials, whereas the second identifies the historical microclimate specific to the environment as the reference for appropriate preservation, especially in the case of organic and hygroscopic materials. After analysing different standards and guidelines, the various parameters and calculation methods are discussed and summarised in a table for a synoptic comparison.