Technical regulations: limitations or resource? The case of building limes

EN 459 is the only standard currently available on building lime at European level and, even if it is a not compulsory norm, it has been acquired as national laws by all countries of European Union. Consequently, EN 459 is the only reference point for the lime used in the construction industry. As any specific standard for binders used in restoration works has been written until now, this means that EN 459 is also the only reference point in the field of conservation of cultural heritage. Consequently EN 459 can be seen both, as resource (because any other tool is given as guarantee of product quality) and as limitation (because this standard has not been designed for the conservation field but for all the limes used in the construction industry). Comparison between new (2010) and old (2001) version of the norm highlights an improvement process that drives some parts of this regulation toward the needs of conservation. But, as the norm is made to regulate all lime based products, it is clear that it will never meet the specific needs of conservation. For this reason, a technical analysis of different versions of this norm can help to understand some of the processes that drive innovation in one of the most important aspects of the restoration of cultural heritage.