scholarly journals Vapour resistance of wind barrier tape: Laboratory measurements and hygrothermal performance implications

2021 ◽  
pp. 174425912110571
Author(s):  
Ida-Helene Johnsen ◽  
Erlend Andenæs ◽  
Lars Gullbrekken ◽  
Tore Kvande
Keyword(s):  
Water Vapour ◽  
Barrier Layer ◽  
Building Envelope ◽  
Climate Impacts ◽  
Adhesive Tape ◽  
Laboratory Measurements ◽  
Vapour Permeability ◽  
Wind Barrier ◽  
Increasing Demand ◽  
Drying Conditions

In the building industry, the interest into adhesive tape to achieve a more tight and robust building envelope has increased rapidly in recent years. With an increasing demand for energy efficiency in buildings, national building authorities are strengthening building requirements to mitigate and adapt to future climate impacts. This paper studies the water vapour permeability of adhesive tape for building purposes. A water vapour permeable wind barrier is essential to enable drying of the external side of the building envelope. Laboratory measurements have been conducted to evaluate how the drying conditions of the wind barrier layer are affected by the use of wind barrier tape. The results show that all the wind barrier tapes tested can be defined as significantly more vapour tight than the wind barrier itself. The wind barrier used as reference was found to have an sd-value of 0.03 m while tape ranged between 1.1 and 9.24 m. To ensure adequate drying and minimize the risk of moisture damages, the wind barrier layer should be vapour open. In an investigated construction project, the amount of tape constitutes 13% of the area of the building’s wind barrier. Further simulations need to be conducted to accurately determine the drying conditions and the following consequences.

Using Control Chart to Detect Abnormal Changes in the Permeability

2013 ◽  
Vol 779-780 ◽  
pp. 319-322
Author(s):  
Ming Hung Shu ◽  
Jui Chan Huang ◽  
Thanh Lam Nguyen ◽  
Bi Min Hsu
Keyword(s):  
Water Vapour ◽  
Average Run Length ◽  
Stable Process ◽  
Critical Factor ◽  
Water Vapour Permeability ◽  
Control Signal ◽  
Process Mean ◽  
Vapour Permeability ◽  
Practical Applications ◽  
Printing Papers

Water-vapour permeability is a critical factor of writing/ printing papers in most of practical applications; but how to monitor the manufacturing process to keep the key characteristic of the paper in control is still understudied. Therefore, in this paper, in order to monitor the water-vapour permeability of writing/ printing papers, MaxGWMA chart is first suggested due to its best effectiveness in terms of average run length performance and its high capability of detecting small shifts in the process mean and variability as well as identifying the source and the direction of an out-of-control signal. By using MaxGWMA chart, assignable causes of any out-of-control signal should be deeply examined so as to have proper corrective actions undertaken to either eliminate them from the process or reduce the variability induced by them to make the papers consistently manufactured under a stable process.

scholarly journals Evaluation of Bed Cover Properties Produced from Double Fabric Based on Honeycomb

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
A. A. Salama ◽  
A. S. El-Deeb ◽  
I. M. El-shahat
Keyword(s):  
Thermal Comfort ◽  
Water Vapour ◽  
Thermal Insulation ◽  
Abrasion Resistance ◽  
Air Permeability ◽  
Weft Yarn ◽  
Vapour Permeability ◽  
Geometrical Properties ◽  
Fabric Structure ◽  
Air Pockets

This research aims to innovate a new fabric structure, which could be used as a bed cover based on double honeycomb fabric with self-stitching. The honeycomb air pockets were aimed at facing each other to form closed small air chambers which work to sequester the air. The double fabric increases fabric thickness. Thus, the opportunity to improve thermal comfort could be achieved. A number of samples were produced with different densities and counts of weft yarn. Thermal insulation and water vapour permeability were measured and compared with bed covers produced from reversible weft backed structure. Geometrical properties, abrasion resistance, and air permeability were also measured. The results showed that the innovated structure had higher values of thermal insulation than reversible weft backed structure at certain weft counts and densities.

scholarly journals Hygrothermal simulation of building performance: data for Scottish masonry materials

2021 ◽  
Vol 54 (4) ◽  
Author(s):  
P. F. G. Banfill
Keyword(s):  
Thermal Conductivity ◽  
Water Vapour ◽  
Material Properties ◽  
Simulation Software ◽  
Water Vapour Permeability ◽  
High Porosity ◽  
Water Absorption Coefficient ◽  
Vapour Permeability ◽  
Hygrothermal Simulation ◽  
Current Production

AbstractRetrofitting thermal insulation to solid masonry walls alters their hygrothermal behaviour, which can be modelled by hygrothermal simulation software. However, such software needs values of key material properties to ensure satisfactory results and until now data has not been available for Scottish masonry buildings. This work aims to contribute to a Scotland-specific dataset of material properties for use by designers working on such buildings. Thermal conductivity, water vapour permeability, sorptivity, water absorption coefficient, hygroscopic sorption, density and porosity were all determined experimentally for selected historic and contemporary masonry materials. Within the range of materials tested three groups of materials properties emerge. Natural hydraulic lime mortars, hot-mixed quicklime mortar and earth mortar all show comparatively low density, high porosity, low thermal conductivity, high water vapour permeability and variable but generally high hygroscopic sorption. Craigleith, Hailes and Giffnock sandstones, no longer available but obtained from conservation works on historic buildings, and Locharbriggs and Hazeldean sandstones, obtained from current production, all show intermediate values of these properties. Crathes granodiorite and Scottish whinstone (from current production) show high density, low porosity, high thermal conductivity, low water vapour permeability and low hygroscopic sorption. It is shown that these materials are all relevant to Scottish buildings constructed in traditional masonry and this paper presents the first comprehensive set of hygrothermal property data for them.

scholarly journals Improve of Footwear Comfort Sensation with Material Packages and Knitted Fabrics

2019 ◽  
Vol 27 (3(135)) ◽  
pp. 85-90 ◽  
Author(s):  
Wioleta Serweta ◽  
Zbigniew Olejniczak ◽  
Małgorzata Matusiak
Keyword(s):  
Water Vapour ◽  
Skin Surface ◽  
Phase Changes ◽  
Positive Information ◽  
Knitted Fabrics ◽  
Vapour Permeability ◽  
Temperature Changes ◽  
Grubbs Test ◽  
Microclimate Conditions ◽  
Footwear Comfort

The main goal of this paper was to analyse the hygienic properties of textile packages used for the construction of shoe uppers. Distance fabrics with varied hygienic properties were the basis of these packages. The discomfort indexes, which describe changes in footwear microclimate, were calculated according to the moisture absorbance capacity and temperature changes in the immediate surrounding of the foot skin surface. The experiment was done for a group of grain leather uppers, where the Grubbs test (a = 0.05) gave positive information about the outliers, describing such parameters as the water vapour permeability and water vapour coefficient. The phase changes of the shoe microclimate were detected via temperature and relative humidity sensors during simulation of the shoes used via an elliptical trainer for a group of 7 men. Statistically significant differences between the packages’ upper – lining confirmed the possibility of monitoring the circulation of biophysical mediums inside a footwear volume. The appropriate choice of package materials could raise the comfort conditions for users. For certain material configurations the microclimate conditions described by the discomfort index were improved.

scholarly journals DEVELOPMENT OF MULTILAYER TEXTILE STRUCTURES FOR FILTERING APPLICATIONS – A NEW SURGICAL MASK APPROACH

2021 ◽  
Vol 2021 ◽  
pp. 26-34
Author(s):  
R.V. Costa ◽  
C. Silva ◽  
T. Sousa ◽  
J. Bessa ◽  
F. Cunha ◽  
...  
Keyword(s):  
Water Vapour ◽  
Vapour Permeability ◽  
Water Vapour Diffusion ◽  
Surgical Masks ◽  
Community Transmission ◽  
Substrate Resistance ◽  
Level I ◽  
New Generation ◽  
The Web ◽  
Governmental Strategy

Universal mask use has emerged as one of the main strategies for reducing community transmission of the SARS-COV-2 virus. Due to the scarcity of material to produce disposable surgical masks, the governmental strategy was oriented to the community masks, even though performance levels were still not the same. This study intended to develop a new generation of surgical masks with different warp knit structures, evaluating the potential of multilayer gradient performance. The assembling methodology was also considered by modifying flat-bed calendering process parameters and manipulating final structures into a new origami design concept, and the overall mask filtration performance was reviewed. The overlapping of monolayers increased the substrate resistance to air and water vapour permeability, also influencing the water molecule's adhesion. The introduction of the web allowed a better layer assembling during the flat-bad process. Moreover, the breathability and water vapour diffusion are compromised since the adhesive web with temperature tends to merge and occupy the empty spaces between the layers. Moving forward, calendared structures without a web proved to be the best approach, meeting the certification criteria for surgical masks level I and II.

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