Water vapor properties of two hemp wools manufactured with different treatments

Collet, Florence; Achchaq, Fouzia; Djellab, Karim; Marmoret, Laurent; Béji, H.

doi:10.1016/j.conbuildmat.2010.06.069

Cited by 44 publications

(22 citation statements)

References 10 publications

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“…Moisture flow is a function of hygroscopic capacity, vapour permeability and rate of air flow. Since the vapour permeability of both insulations is similar, as also observed by Collet et al [30], and the cooler sides of the insulations were airtight, the managed response of Hemp insulation can mainly be attributed to its higher moisture adsorption capacity and to a limited extent to its relatively lower air permeability.…”

Section: Fig 7 Internal Surface Temperatures Of the Acrylic And Thesupporting

confidence: 75%

Quasi steady state and dynamic hygrothermal performance of fibrous Hemp and Stone Wool insulations: Two innovative laboratory based investigations

Latif

Tucker

Ciupala

et al. 2016

Building and Environment

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Moisture and heat management properties of Hemp and Stone Wool insulations were studied by mounting them between a hot and a cold climate chamber. Both insulations were exposed to identical hygrothermal boundary conditions. Quasi steady state and dynamic tests were carried out at a range of relative humidity exposures. The likelihood of interstitial condensation was assessed and equivalent thermal conductivity values of the insulations were determined. The adsorption-desorption isotherms of the insulations were also determined in a dynamic vapour sorption (DVS) instrument. It was observed that the likelihood of condensation was higher in Stone Wool insulation than in Hemp insulation. Hemp insulation performed better in managing moisture due to its high hygric inertia and water absorption capacity. It was observed that the equivalent thermal conductivity of Stone Wool insulation was dependent on enthalpy flow and phase change of moisture. The equivalent thermal conductivity of Hemp insulation was close to its declared thermal conductivity in dynamic conditions when high relative humidity exposures were transient. In quasi steady state boundary conditions, when the insulation was allowed to reach the equilibrium moisture content at ranges of relative humidity, there was a moisture dependent increase of thermal conductivity in Hemp insulation.

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Section: Fig 7 Internal Surface Temperatures Of the Acrylic And Thesupporting

confidence: 75%

Quasi steady state and dynamic hygrothermal performance of fibrous Hemp and Stone Wool insulations: Two innovative laboratory based investigations

Latif

Tucker

Ciupala

et al. 2016

Building and Environment

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show abstract

“…At lower relative humidity, 0-15% according to Hill, Norton and Newman [6] and 5-35% according to Collet et al [7], water molecules are adsorbed in a monolayer (solid solution) on to the internal surfaces of the cell wall. Multi-molecular layers of water are formed on the cell wall micro-capillaries at a relative humidity varying between 15% and 70%, while capillary condensation occurs at further higher relative humidity ranges.…”

Section: Adsorption-desorption Isothermmentioning

confidence: 99%

“…The GAB equation has been chosen for its higher coverage of activity range for monolayer sorption values (0.05<φ<0.8-0.9) [7] compared to that of BET equation…”

Section: Analysis Of Adsorption-desorption Isothermmentioning

confidence: 99%

Hygric properties of hemp bio-insulations with differing compositions

Latif

Tucker

Ciupala

et al. 2014

Construction and Building Materials

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The paper presents the results of a laboratory investigation on the hygric properties of five hemp insulation materials commercially available in the UK. The hemp fibre content varies between 30-95% in the total fibre content of the insulation materials examined. The adsorption-desorption isotherm, moisture buffer value, vapour diffusion resistance factor and water absorption coefficient were determined for the insulation materials investigated. The results showed that the hygric properties of the hemp insulation materials could vary widely depending on the constituents and fibrous structure. The considerable differences noted in the hygric properties of the insulation materials examined could potentially influence their hygrothermal performance as part of a building thermal envelope.

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“…Hygrothermal materials include natural fibres (Collet et al 2011), timber (Ku¨nzel et al 2004), earth and clays (D'Orazio andQuagliarini 2009, Hall and, natural and synthetic zeolites (Feng and Peng 2005), silica gels (La et al 2010) and molecular sieves (Dieng and Wang 2001). The limitations of these materials are that they have predefined microstructural characteristics resulting in set levels of heat and moisture uptake and storage.…”

Section: Introductionmentioning

confidence: 98%

Nanocomposite materials for rapid-response interior air humidity buffering in closed environments

Casey

Hall

Tsang

et al. 2013

Journal of Building Performance Simulation

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Three different mesoporous silica (MS) samples were selected as template materials for designing novel, highperformance desiccants to give rapid-response temperature and humidity buffering in closed environments. The aim was to investigate how the functional properties of the MS materials can be tuned to suit differing psychrometric conditions in closed environments, and to inform the design process by conducting sensitivity analysis using building performance simulation software. Their humidity buffering performance was compared with other materials using WUFI Pro v5.1 to conduct numerical hygrothermal simulations. The MS materials had more than two orders of magnitude greater humidity buffering than traditional interior building materials (e.g. painted gypsum plaster) due to their high vapour storage capacity and high dynamic vapour sorption (DVS) response rates. Analysis showed that the gradient of the w 50 -w 80 portion of the absorption branch isotherm is the most sensitive parameter when using the hygrothermal numerical model as a design tool for materials tuning.

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Water vapor properties of two hemp wools manufactured with different treatments

Cited by 44 publications

References 10 publications

Quasi steady state and dynamic hygrothermal performance of fibrous Hemp and Stone Wool insulations: Two innovative laboratory based investigations

Quasi steady state and dynamic hygrothermal performance of fibrous Hemp and Stone Wool insulations: Two innovative laboratory based investigations

Hygric properties of hemp bio-insulations with differing compositions

Nanocomposite materials for rapid-response interior air humidity buffering in closed environments

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