Air permeability of sugi (Cryptomeria japonica) wood in the three directions

Tanaka, Takashi; Kawai, Yasuo; Sadanari, Masanori; Shida, Satoshi; Tsuchimoto, Toshikazu

doi:10.4067/s0718-221x2015005000002

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…It is thought that NO 2 sorption volume is greatly affected by gas permeability. Generally, gas permeability in the longitudinal direction is much higher than that in the tangential or radial direction [17]. It is conjectured that the diffusion rate of NO 2 gas in discoid specimen was higher than that in the other specimen.…”

Section: Effect Of Aeration Condition On No 2 Sorption Abilitymentioning

confidence: 94%

Evaluation of NO2 sorption of cedar wood (Cryptomeria Japonica) with difference of the specimen size and contact condition between NO2 gas and specimen using new test system

et al. 2018

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We developed a new system for measuring the NO 2 sorption ability of Japanese cedar (Cryptomeria japonica) wood by referring to Japanese Industrial Standard for JIS R 1701-1 (Test method for air purification performance of photocatalytic materials, Japanese Standard Association, Tokyo, 2004). Aeration experiments were conducted using plated specimen, particle specimen, discoid specimen and wood powder with consideration of aeration condition and surface area which can contact with NO 2 gas. In the plated specimen, the NO 2 sorption ability was greatly affected by the thickness of longitudinal direction, and high NO 2 sorption ability of the transverse section was observed within a thickness range from the surface to ca. 3 mm. The average NO 2 sorption volume for discoid specimen for 5 h was approx. five times larger than that those for the plated and particle specimens, which the thickness of longitudinal direction was 1.5 mm. This means that the NO 2 sorption effect was especially high under the condition where the NO 2 gas passed through tracheid. Also, it was suggested that the interface area between NO 2 gas and specimen influenced to the NO 2 sorption ability. Furthermore, it was confirmed that the NO 2 sorption volume in discoid specimen and the grain size below 0.25-0.50 mm of wood powder reached the greatest.

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Section: Effect Of Aeration Condition On No 2 Sorption Abilitymentioning

confidence: 94%

Evaluation of NO2 sorption of cedar wood (Cryptomeria Japonica) with difference of the specimen size and contact condition between NO2 gas and specimen using new test system

et al. 2018

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“… The μ value denotes the water vapor diffusion resistance factor, and L represents the air permeability coefficient. The airflow rate Q v75Pa is determined at 75 Pa PD from the value of L. The U values of the walls and the Sd values of the vapor control layers and external layers are presented in the bottom part of the table. a Thickness of material layer is shown in parenthesis. b The maximum values for wind barrier products at 75 Pa according to the Finnish Ministry of Environment (2002) is 0.75 L/sm 2 and for continuous air barriers, the tightness limit is 0.02 L/sm 2 according to ASHRAE (2017). c Glass wool. d Wind barrier. e Fiberglass-based cardboard. f Stone wool. g DuPont ™ FireCurb breather membrane. h Exterior gypsum sheathing. i Pinus sylvestris sapwood in the radial direction (Tanaka et al, 2015). j Wood fiber board. k Low density polyethylene. l Bouma et al (1997). m After installation of WFB. …”

Section: Methodsmentioning

confidence: 99%

“…Starting from the second phase, the indoor chamber was humidified. In the third phase, a fan was used to increase the PD over the wall to 5.5 Pa, and the i Pinus sylvestris sapwood in the radial direction (Tanaka et al, 2015). j Wood fiber board.…”

Section: Experimental Arrangementsmentioning

confidence: 99%

Hygrothermal performance of highly insulated external walls subjected to indoor air exfiltration

Viljanen

Puttonen

Lü

2022

Journal of Building Physics

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The study comprises three laboratory tests in which typical Finnish highly insulated (HI) walls were exposed to concentrated leakages of indoor air under steady outdoor temperatures of 1–5°C. Airflows with a relative humidity of 50% and at rates of 1–3 L/min were directed close to the wooden frames inside the walls. The thermal resistance ratios between the exterior sheathing(s) and the whole wall (Γ) were 20%–22% and 1%–10% for the HI and baseline (BL) walls. The HI walls that presented Γ values of at least 20% were observed to be resistant to air exfiltration, and their durability was not affected by the addition of a gypsum sheathing outside the wooden frame or a more permeable vapor retarder. This is related to the negative linear correlation that exists between the moisture accumulation rate in wood-based material and the dew point depression (DPD) value. The developed approach, called the DPD method, shows that a significant degree of moisture accumulation does not occur even for DPD values of as low as −2°C if the exterior sheathing is vapor permeable. The airflow does not penetrate into the rigid mineral wool sheathing, which helps to avoid interstitial condensation. Regardless of thermal transmittance, the HI and BL walls with maximum Γ values of 1% were exposed to a high relative humidity and even interstitial condensation because the DPD values were often below −2°C. For these walls, the mold index analysis and visual observations confirmed the local risk for mold growth on the opposite side of the leakage point. In practice, long-term mold growth may be limited if the seasonal periods during which the outdoor temperature is 1–5°C last for a maximum of about 1 month every year.

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“…Several methods for measuring the air permeability of wood have been developed (Resch and Echlund 1964, Choong and Fogg 1968, Petty and Puritch 1970, Perré 1987, Siau 1995, Perré 2007, Ai et al 2017. Using these methods and similar methods, the air permeability of various wood species in various directions has been determined (Resch and Echlund 1964, Choong and Fogg 1968, Comstock 1970, Perré 1987, Matsumura et al 1994, Fujii et al 1997, Lihra et al 2000, Rayirath and avramidis 2008, Tanaka et al 2015, Poonia et al 2016, Taghiyari and Avramidis 2019.…”

Section: Introductionmentioning

confidence: 99%

A new method for determining air permeabilities of wood-based panels

Tanaka

2020

Maderas, Cienc. tecnol.

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In this study, a new apparatus for measuring the air permeability of wood-based panel specimens without using water displacement was developed with the aim of decreasing the influence of variation in atmospheric pressure on permeability measurement. Validation experiments were conducted using plywood, oriented strand board (OSB), particleboard, and medium-density fiberboard (MDF) panels and a control specimen sealed with an epoxy resin. The background (leakage) flow of the apparatus was evaluated based on the experimental results of the control specimen. A methodology for the determination of air permeability based on Darcy's law for gases and the evaluated background flow rate was proposed. The results of the current study were compared with those obtained in a previous study, indicating that the new method provides valid measurements for woodbased panels with high and low air permeability. No significant influence of variation in atmospheric pressure on the experimental results was observed, suggesting that the proposed method is suitable for a long-term continuous experiment for evaluating a specimen with extremely low permeability.

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Air permeability of sugi (Cryptomeria japonica) wood in the three directions

Cited by 9 publications

References 7 publications

Evaluation of NO2 sorption of cedar wood (Cryptomeria Japonica) with difference of the specimen size and contact condition between NO2 gas and specimen using new test system

Evaluation of NO2 sorption of cedar wood (Cryptomeria Japonica) with difference of the specimen size and contact condition between NO2 gas and specimen using new test system

Hygrothermal performance of highly insulated external walls subjected to indoor air exfiltration

A new method for determining air permeabilities of wood-based panels

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