Comparative methods to assess renovation impact on indoor hygrothermal quality in a historical art gallery

This paper presents a set of methods for renovation impact assessment of indoor hygrothermal conditions in a culturally significant historical building, functioning as an art gallery. A new parameter, Renovation Impact Index (RII), was developed and used for the assessment. The RII is defined as the performance gradient of indoor hygrothermal conditions over two annual periods, the year before and the year after the renovations. The performances of the two most critical parameters to artwork conservation – temperature (T) and relative humidity (RH) – were assessed with respect to conservation specifications. RII was defined over two windows: tight set points specified in the BS 5454 : 2000 Conservation Standard and a relaxed strategy for energy saving potential. ‘Global’ Performance Index was obtained as a combined effect of T and RH. A seasonal analysis was undertaken for detailed study of renovation impact on individual seasons. Results identified the positive effects of the renovation solutions, with the indoor environment then being less influenced by outdoor weather changes. In addition to energy savings of 27%, the positive RII estimate showed quantitative improvement in hygrothermal performance. The proposed methods can be extended to other renovation projects in similar buildings to assist building managers to target future improvements.