Spectral Relative Attenuation of Solar Radiation through a Skylight Focused on Preventive Conservation: Museo De L’almoina in Valencia (Spain) Case Study

Abstract

The aim of the present study was to evaluate the relative attenuation of VIS, UV and NIR solar radiation through a large pond skylight into the interior of the l’Almoina Archaeological Museum (Valencia, Spain), and to determine how relative attenuation varied throughout the year and time of day. Measurements were taken at 9:00 a.m., 12:00 p.m. and 3:00 p.m. during July 2019 and January 2020. Relative attenuation values were obtained from the measurement of spectral irradiance in the exterior and at different points in the interior by means of two Ocean Optics spectrometers: HR4000CG-UV-NIR for VIS (400–700 nm) and NIR (700–1000 nm) bands, and FLAME-S-UV-VIS for UV-A (280–315 nm) and UV-A (315–400 nm) bands. The central points of the skylight had relative attenuation at 520 nm, reaching a value of 50% in summer at noon and 38% in the afternoon. At noon in winter, there were two relative attenuation peaks above 33% at 520 nm and at 900 nm. For mean relative attenuation, in the UVB range, the highest relative attenuation (20%) was inside the ruins in the morning in both summer and winter, and the UVA band relative attenuation was quite constant throughout the museum, but lower than that of the UVB band, in the range 0–3%.

A Methodology for the Multi-Point Characterization of Short-Term Temperature Fluctuations in Complex Microclimates Based on the European Standard EN 15757:2010: Application to the Archaeological Museum of L’Almoina (Valencia, Spain)

“…According to the standard, it is convenient to investigate the reason for such fluctuations in order to try to reduce them. Based on previous investigations [43,44,53], the high daily variability is explained by the skylight covering the central area of the museum. It is located above data-logger B2 and nearby ones (i.e., B3, B4, A2, A3, and C3) as shown in Security limits according to EN 15757:2010 are depicted as horizontal lines in red.…”

Statistical Analysis of Visible and Infrared Radiation in The Museum of L'Almoina in Valencia (Spain)

“…Solar radiation were measured in three bands: UV (300-400 nm), Visible (400-700 nm) and Near Infrared, depending on the interval (700-900 nm), (published in Serrano el al. [39]), and the following tasks have been carried out in this work: Analysis of visible and infrared values; evolution of the spectral radiation for each measurement point in the museum; the comparison between series of measurements (between interior points in the summer). Determining associations of data distributions using the Q index.…”

Statistical Analysis of Ultraviolet Radiation in The Museum of L'almoina in Valencia (Spain)

“…The relative attenuations were obtained from the measurement of the spectral irradiance outside and at different points inside were made using an Ocean Optics spectrometer [40]: FLAME-S-UV-VIS for the UV-B (280-315 nm) and UV-A (315-400 nm) bands. The operation of this device is described in Figure 3, and technical specifications are shown in Table 1.…”