Integration model of hygrothermal analysis with decay process for durability assessment of building envelopes

Saito, Hiroaki; Fukuda, Kiyoharu; Sawachi, Takao

doi:10.1007/s12273-012-0081-8

Cited by 25 publications

(17 citation statements)

References 3 publications

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“…The fungus was able to continue degradation only at 100% RH; at lower RH the initial decay was obviously disrupted. This coincides fairly well with observations of Saito et al (2012), where ML of P. densiflora by F. palustris was detected below 100% RH.…”

Section: And Decay In Different Climatessupporting

confidence: 92%

“…After 16 weeks of exposure to C. puteana, the MC i exceeded FSP, which agrees with findings of Theden (1941) and Saito et al (2012), where MC i increment with increasing ML was seen because of water generation according to Eq. 1.…”

Section: And Decay In Piled Specimenssupporting

confidence: 90%

“…Furthermore, the MC i of specimens increased with increasing ML probably because of the water liberated according to Eq. 1 (Theden 1941;Saito et al 2012). Even if the MC i after incubation was corrected by the reduced oven-dry weight of the samples, there still would be a difference between the actual MC i after incubation and the theoretically expected MC i in equilibrium with ambient air.…”

Section: And Decay In Different Climatesmentioning

confidence: 99%

“…2% below the expected EMC and 7% below the FSP of Norway spruce (Picea abies). Saito et al (2012) conditioned Japanese red pine (Pinus densiflora) in small vessels at 93, 97, and 100% of RH and incubated the specimens with Fomitopsis palustris up to 12 months. No decay was observed below FSP at 100% RH.…”

Section: Introductionmentioning

confidence: 99%

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The minimum moisture threshold for wood decay by basidiomycetes revisited. A review and modified pile experiments with Norway spruce and European beech decayed by Coniophora puteana and Trametes versicolor

2017

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Abstract:To know the minimum moisture threshold (MMThr) in wood allowing for the initiation of the fungal decay by basidiomycetes is relevant both from a theoretical and a practical point of view. The present work summarizes the knowledge about MMThr and presents experimental data obtained by improved laboratory decay tests on Picea abies (Norway spruce) and Fagus sylvatica (European beech) with the fungi Coniophora puteana and Trametes versicolor under different exposure scenarios well suited for simulation in real applications. The three experimental set-ups, in which the pile tests play a pivotal role, differed in terms of external moisture supply and the inoculation strategies. It was confirmed that wooddestroying basidiomycetes are able to degrade wood at high relative humidity without any external source of available liquid water. The method of moistening the wood samples has an effect on the MMThr before initiation of the fungal decay, but different basidiomycetes were able to cause significant decay at moisture contents considerably below the fiber saturation point.

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Section: And Decay In Different Climatessupporting

confidence: 92%

Section: And Decay In Piled Specimenssupporting

confidence: 90%

Section: And Decay In Different Climatesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The minimum moisture threshold for wood decay by basidiomycetes revisited. A review and modified pile experiments with Norway spruce and European beech decayed by Coniophora puteana and Trametes versicolor

2017

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“…This methodology involves two major challenges, one being the need for quantifying the hygrothermal conditions of the wood product and the other being the need for relating the hygrothermal conditions that are present to the decay activity that occurs. The literature offers a variety of mathematical models for estimating the rate of decay on the basis of the hygrothermal conditions that are present (Viitanen et al 2010;Saito et al 2012;Isaksson et al 2013;Brischke and Meyer-Veltrup 2016). The hygrothermal conditions can be estimated numerically by modeling the moisture transport within the wood on the basis of climate data via moisture dynamics.…”

Section: Introductionmentioning

confidence: 99%

Moisture behavior of weathered wood surfaces during cyclic wetting: measurements and modeling

et al. 2018

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The effects of weathering on the in-service moisture behavior of wood have received only limited attention so far, with much focus being on the effect of photodegradation on the hydrophobicity of the wood surface. The objective of the present study was to examine the effect of weathering surfaces on the overall moisture behavior of wood specimens exposed to short-term cyclic spraying, with special emphasis on the surface conditions involved. Specimens cut from eight different species including hardwoods and softwoods were weathered for 8 years and continuously monitored during a single-sided cyclic spraying together with a set of axially matched controls. After each spray cycle, the duration of surface wetness was evaluated by resistance moisture sensors as well as an optical approach (colorimetric) based on time-lapse images. The moisture content in the core was monitored simultaneously by use of resistance moisture sensors. The optical method correlated well with the electrical resistance measurements and provided a simple and practical measure of the areal distribution of the surface wetness. The results showed specimens with a weathered surface to sustain a wet surface for about twice the duration of their axially matched control. A considerable, albeit smaller, effect was also observed deeper in the core. By adapting the length of the wet period on the exposed boundary, the corresponding response at the core of the Norway spruce specimens was reproduced numerically.

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Wood-water relationships and their role for wood susceptibility to fungal decay

Brischke¹,

Alfredsen

2020

Appl Microbiol Biotechnol

102

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Wood in service is sequestering carbon, but it is principally prone to deterioration where different fungi metabolize wood, and carbon dioxide is released back to the atmosphere. A key prerequisite for fungal degradation of wood is the presence of moisture. Conversely, keeping wood dry is the most effective way to protect wood from wood degradation and for long-term binding of carbon. Wood is porous and hygroscopic; it can take up water in liquid and gaseous form, and water is released from wood through evaporation following a given water vapour pressure gradient. During the last decades, the perception of wood-water relationships changed significantly and so did the view on moisture-affected properties of wood. Among the latter is its susceptibility to fungal decay. This paper reviews findings related to wood-water relationships and their role for fungal wood decomposition. These are complex interrelationships not yet fully understood, and current knowledge gaps are therefore identified. Studies with chemically and thermally modified wood are included as examples of fungal wood substrates with altered moisture properties. Quantification and localization of capillary and cell wall water – especially in the over-hygroscopic range – is considered crucial for determining minimum moisture thresholds (MMThr) of wood-decay fungi. The limitations of the various methods and experimental set-ups to investigate wood-water relationships and their role for fungal decay are manifold. Hence, combining techniques from wood science, mycology, biotechnology and advanced analytics is expected to provide new insights and eventually a breakthrough in understanding the intricate balance between fungal decay and wood-water relations. Key points • Susceptibility to wood-decay fungi is closely linked to their physiological needs. • Content, state and distribution of moisture in wood are keys for fungal activity. • Quantification and localization of capillary and cell wall water in wood is needed. • New methodological approaches are expected to provide new insights

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Integration model of hygrothermal analysis with decay process for durability assessment of building envelopes

Cited by 25 publications

References 3 publications

The minimum moisture threshold for wood decay by basidiomycetes revisited. A review and modified pile experiments with Norway spruce and European beech decayed by Coniophora puteana and Trametes versicolor

The minimum moisture threshold for wood decay by basidiomycetes revisited. A review and modified pile experiments with Norway spruce and European beech decayed by Coniophora puteana and Trametes versicolor

Moisture behavior of weathered wood surfaces during cyclic wetting: measurements and modeling

Wood-water relationships and their role for wood susceptibility to fungal decay

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