Experimental Tests of Water Vapour Permeability of Plasters

2016 ◽  
Vol 865 ◽  
pp. 151-156
Author(s):  
Šárka Nenadálová ◽  
Lukáš Balík ◽  
Milan Rydval ◽  
Tomáš Bittner
Keyword(s):  
Water Vapour ◽  
Experimental Tests ◽  
Water Vapour Permeability ◽  
Physical Parameters ◽  
Drying Process ◽  
Vapour Permeability ◽  
Resistance Factors ◽  
Diffusion Speed ◽  
Water Vapour Resistance ◽  
Diffusion Properties

In the paper there are summarized results of diffusion properties of mortars. Water vapour permeability represented by diffusion thicknesses and water vapour resistance factors are except mechanical properties the most important physical parameters of historic buildings. These parameters are influenced by border conditions among that mainly temperature, relative humidity and barometric air pressure belong. It is necessary to know these parameters to understand a material behaviour after a flood. They are decisive for a determination how quick a diffusion speed rate will be and a drying process will take. Everything depends on a type of binder, a material of a structure itself and primarily on properties of mortar and plaster and finishing. After a flood it is necessary to know when users of buildings can start to make rehabilitations and which of them are proper for particular material and when can return to their homes.

scholarly journals Correlation of Air Permeability to Other Breathability Parameters of Textiles

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 140
Author(s):  
Karel Adámek ◽  
Antonin Havelka ◽  
Zdenek Kůs ◽  
Adnan Mazari
Keyword(s):  
Water Vapour ◽  
Air Permeability ◽  
Water Vapour Permeability ◽  
Textile Material ◽  
Permeability Measurement ◽  
Smart Textiles ◽  
Vapour Permeability ◽  
Clothing Comfort ◽  
Strong Relation ◽  
Water Vapour Resistance

In the field of textile comfort of smart textiles, the breathability of the material is very important. That includes the flow of air, water and water vapours through the textile material. All these experiments are time consuming and costly; only air permeability is much faster and economical. The research is performed to find correlation between these phenomena of breathability and to predict the permeability based on only the air permeability measurement. Furthermore, it introduces a new way of expressing the Ret (water vapour resistance) unit according to SI standards as it is connected with the air permeability of garments. The need to find a correlation between air permeability and water vapour permeability is emphasised in order to facilitate the assessment of clothing comfort. The results show that there is a strong relation between air permeability and water vapour permeability for most of the textile material.

Thermal Comfort Properties of Knitted Fabrics Suitable for Skin Layer of Protective Clothing Worn in Extreme Hot Conditions

2011 ◽  
Vol 331 ◽  
pp. 184-189 ◽  
Author(s):  
Nazia Nawaz ◽  
Olga Troynikov ◽  
Chris Watson
Keyword(s):  
Body Temperature ◽  
Thermal Comfort ◽  
Water Vapour ◽  
Protective Clothing ◽  
Skin Layer ◽  
Water Vapour Permeability ◽  
The Body ◽  
Physical Parameters ◽  
Knitted Fabrics ◽  
Vapour Permeability

Key words: Physiological comfort, knitted fabrics, protective clothing Abstract. Thermal comfort of clothing is associated with the thermal balance between human body and the environment, and also a balance between the body heat production and the heat loss. During work activities performed in extreme hot conditions, the body produces substantial amount of heat energy which leads to raised body temperature. As a result the body perspires in liquid and vapour form to reduce the increased temperature. When this perspiration is transmitted to the atmosphere, the body temperature reduces. Thus the garments worn next to skin should allow the perspiration and heat to easily pass through them; otherwise the result will be a significant discomfort of the persons working in extreme hot conditions. Therefore, thermal properties and water vapour permeability of the fabrics used for the next-to-skin layer of protective clothing are very important for the maintenance of physiological comfort of workers. In the present study physical parameters, air permeability, porosity, thermal and water vapour permeability of six commercially available knitted fabrics of different fibre blends, different and knitted structures suitable for skin layer garments of protective clothing worn in extreme hot conditions were evaluated. The influences of fabric physical parameters, and optical porosity on thermal conductivity and water vapour permeability of fabrics were determined and correlation coefficients were calculated between these variables.

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 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.

Sign in / Sign up

Export Citation Format

Share Document