scholarly journals Influence of the Water Vapour Permeability of Airtight Sheets on the Behaviour of Facade

2020 ◽  
Vol 12 (24) ◽  
pp. 10480
Author(s):  
Joaquín Torres-Ramo ◽  
Purificación González-Martínez ◽  
Nerea Arriazu-Ramos ◽  
Ana Sánchez-Ostiz
Keyword(s):  
Water Vapour ◽  
Water Vapour Permeability ◽  
Vapour Permeability ◽  
Climate Zones ◽  
Insulating Material ◽  
Permeability Characteristics ◽  
Energy Demands ◽  
Air Tightness ◽  
Interior Face ◽  
Water Vapour Barrier

The air-tightness of the thermal envelope of buildings is one of the measures to reduce their energy demands in order to achieve global warming reduction targets. To this end, airtight sheets with different water vapour permeability characteristics are used. The different products studied are highly dispersed in terms of equivalent air thickness values, leading to confusion. After the analysis carried out, it is concluded that all airtight sheets are vapour barriers. To clarify whether or not these sheets are necessary as vapour barriers, a condensation analysis was carried out on 13 different facades for 3 climate zones with severe winters as defined in Spanish regulations. The results reveal that interstitial condensation occurs in only 7 of the 39 case studies, with the traditional facades of brickwork with render causing the greatest problems if the appropriate products are not used. In these cases, airtight sheets with water vapour barrier characteristics must be applied on the interior face of the insulating material. In all other cases (32), the airtight sheets must be permeable to water vapour if it is looked for a more breathable wall to water vapour and a better control of the interior humidity conditions.

Research on the Simulation of Hygrothermal Distribution of Stone Wool ETICS

2016 ◽  
Vol 858 ◽  
pp. 111-116
Author(s):  
Li Xin Sun ◽  
Zeng Feng Yan ◽  
Hui Zhou
Keyword(s):  
Moisture Content ◽  
Water Vapour ◽  
Thermal Insulation ◽  
Liquid Water ◽  
Composite System ◽  
Water Vapour Permeability ◽  
Outdoor Temperature ◽  
Vapour Permeability ◽  
Climate Zones ◽  
Stone Wool

Stone wool external thermal insulation composite system is used more and more in China now. Former studies in China simply consider that water vapour permeability of render coating should be equal to the water vapour permeability of stone wool. Neither is there any necessary indicator for the liquid water (wind-driven rain) for the system. Therefore, an important issue to be solved currently is how to propose reasonable indicators for water vapour and liquid water transfer performance in stone wool system for different climate zones in China. This research studied on the simulation of hygrothermal distribution of stone wool system. Simulations of stone wool systems were done under different outdoor temperature, humidity, wind driving rain and other conditions to analyze the moisture content in each layer of the system. Meanwhile, simulations of different render coating performances were also done to analyze the moisture content in each layer. Based on these, indicators for water vapour and liquid water were proposed, which provides a foundation for the stone wool external thermal insulation composite system standards in China.

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.

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