Standardization activity in the evaluation of moisture content

This review paper comments the international standards to measure the moisture content in building materials, i.e. EN 772-10:1999; EN 13183-1:2002; EN 13183-2:2002; EN 13183-3:2005; EN 1428:2012; EN-ISO 11461: 2014; EN-ISO 15512:2014; ISO 11465:1993; ISO 12570: 2013; ISO 16979:2003 and ISO 760:1978. The above standards do apply to new building materials, with standardized composition and shape, in satisfactory state of conservation, without sampling restrictions. If they are applied to aged and deteriorated materials, as in the field of cultural heritage, the results may be misleading. The paper discusses the difference between 'moisture content' and 'water content' and the various problems met with cultural heritage materials, e.g. ethical problem when test specimens are needed; the biased response when wood was attacked by moulds or insect tunnelling, or was impregnated with oil, wax or preservatives; or when masonry contains soluble salts or subsurface discontinuities. The most recent, comprehensive standard is presented, i.e. EN16682 (2017) 'Conservation of cultural heritage - Methods of measurement of moisture content, or water content, in materials constituting immovable cultural heritage' that considers all existing methods and discusses pros and cons of each of them in relation with the real world of aged and deteriorated materials.