Evaluating the influence of mixture composition on the kinetics of salt damage in wall paintings using time lapse video imaging with direct data annotation

Sawdy, Alison; Heritage, Adrian

doi:10.1007/s00254-006-0496-6

Cited by 21 publications

(17 citation statements)

References 3 publications

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“…The range of RH variation (30-70 %) observed may induce the saline solution mobility and salt precipitation on the surfaces of the indoor walls subject to intense moisture [14,15,27,41,42], since the RH at the base of the nave is altered less by the heating than by the church's natural dynamics and the effect of its construction materials. The presence of efflorescence (Ca sulphates; gypsum) is attributable primarily to the natural variations in the indoor environment, spring time ventilation and the presence of certain materials such as gypsum and cement mortars wall covering, and, and to a lesser extent, the use of heating.…”

Section: Discussionmentioning

confidence: 99%

Fluctuations in the indoor environment in Spanish rural churches and their effects on heritage conservation: Hygro-thermal and CO 2 conditions monitoring

Varas–Muriel

Fort

Martínez-Garrido

et al. 2014

Building and Environment

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The indoor environment and its natural dynamics in small Spanish historical churches such as the studied here depend on the variations of outdoor climate and the moisture dynamics of walls, built with different materials. Such indoor environments are impacted by local factors, which may put at risk the conservation of a church's cultural assets. Natural ventilation in spring, the presence of people and especially the wintertime use of ageing heating system induce substantial fluctuations in indoor environments primarily affecting the stability of relative humidity (RH). RH is the physical parameter that can induce efflorescence as well as plaster blistering and detachment in its inside walls, drying and cracking in the timber and efflorescence and disgregation in the carved dolostone.Where the RH inside building is not high, as in the present case, natural and induced fluctuations may lower it considerably (<25 %), which is detrimental to conservation and human well-being both. Human presence partially counters the steep declines in RH attributable to heating in winter and warm, dry summer weather, although the trade-off is a rise in CO 2 levels inside the church.Heating induces substantial changes in the T and RH on the high altar and in the upper areas of the nave, while natural ventilation affects the RH at the base of the church and favours the elimination of CO 2 . The results obtained have allowed us to develop a series of recommendations that might be useful for the preventive conservation of such historic buildings, without compromising human comfort.

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Section: Discussionmentioning

confidence: 99%

Fluctuations in the indoor environment in Spanish rural churches and their effects on heritage conservation: Hygro-thermal and CO 2 conditions monitoring

Varas–Muriel

Fort

Martínez-Garrido

et al. 2014

Building and Environment

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“…The crystallization of salt mixtures occurs at lower humidities than expected in case of pure single salts [7]. The rate of deliquescence and crystallization of single salts is also affected by the presence of another salt [8]. In the presence of an additional salt, an increase of the rate of moisture uptake (deliquescence) and a decrease of the rate of moisture loss (crystallization) have been reported.…”

Section: Introductionmentioning

confidence: 95%

“…In the presence of an additional salt, an increase of the rate of moisture uptake (deliquescence) and a decrease of the rate of moisture loss (crystallization) have been reported. This is caused by the reduction of the solution vapor pressure in the presence of additional salts [8]. For a salt mixture, where the salts have one ion in common, the saturation concentration of the salts in the mixture may become lower than the saturation concentration of the salts individually.…”

Section: Introductionmentioning

confidence: 99%

The effect of ferrocyanide ions on sodium chloride crystallization in salt mixtures

Gupta

Pel

Steiger

et al. 2015

Journal of Crystal Growth

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“…In contrast, the literature about stone in the built environment has focused on practical approaches to addressing stone conservation (e.g., [5][6][7][8]). Fundamental questions, such as the mechanisms of crystallization and the development of crystallization pressure in porous media, remain open questions and active areas of research (e.g., [9][10][11][12][13][14][15][16][17][18][19]). Nevertheless, there is consensus that repeated cycles of crystallization and dissolution of hygroscopic salts is controlled by changing conditions in relative humidity (RH) and that repeated crystallization leads to the degradation of porous stone through the resulting weakening of intergranular bounds in the substrate.…”

Section: Introductionmentioning

confidence: 99%

NaCl-related weathering of stone: the importance of kinetics and salt mixtures in environmental risk assessment

et al. 2021

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Salt weathering is one of the most important causes of deterioration in the built environment. Two crucial aspects need further investigation to understand the processes and find suitable measures: the impact of different climatic environments and the properties of salt mixture crystallization. We demonstrate the importance of kinetics in quantifying crystallization and dissolution cycles by combining droplet and capillary laboratory experiments with climate data analysis. The results proved that dissolution times for pure NaCl are typically slower than crystallization, while thermodynamic modelling showed a lower RHeq of NaCl (65.5%) in a salt mixture (commonly found in the built heritage) compared to its RHeq as a single salt (75.5%). Following the results, a minimum time of 30 min is considered for dissolution and the two main RHeq thresholds could be applied to climate data analysis. The predicted number of dissolution/crystallization cycles was significantly dependent on the measurement frequency (or equivalent averaging period) of the climatic data. An analysis of corresponding rural and urban climate demonstrated the impact of spatial phenomena (such as the urban heat island) on the predicted frequency cycles. The findings are fundamental to improve appropriate timescale windows that can be applied to climate data and to illustrate a methodology to quantify salt crystallization cycles in realistic environments as a risk assessment procedure. The results are the basis for future work to improve the accuracy of salt risk assessment by including the kinetics of salt mixtures.

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Evaluating the influence of mixture composition on the kinetics of salt damage in wall paintings using time lapse video imaging with direct data annotation

Cited by 21 publications

References 3 publications

Fluctuations in the indoor environment in Spanish rural churches and their effects on heritage conservation: Hygro-thermal and CO 2 conditions monitoring

Fluctuations in the indoor environment in Spanish rural churches and their effects on heritage conservation: Hygro-thermal and CO 2 conditions monitoring

The effect of ferrocyanide ions on sodium chloride crystallization in salt mixtures

NaCl-related weathering of stone: the importance of kinetics and salt mixtures in environmental risk assessment

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