scholarly journals Hygrothermal assessment of internally insulated historic solid masonry walls with focus on the thermal bridge due to internal partition walls

2021 ◽  
Vol 2069 (1) ◽  
pp. 012079
Author(s):  
N F Jensen ◽  
C Rode ◽  
E B Møller
Keyword(s):  
Relative Humidity ◽  
Numerical Simulations ◽  
Masonry Walls ◽  
Test Field ◽  
Indoor Climate ◽  
Partition Wall ◽  
Interior Surface ◽  
Thermal Bridge ◽  
Hygrothermal Performance ◽  
Insulation Systems

Abstract This study investigated the hygrothermal performance of five insulation systems for internal retrofitting purposes. Focus was on the hygrothermal performance near partition brick walls compared to the middle of the wall. The setup comprised two insulated reefer containers with controlled indoor climate, reconfigured with several holes containing solid masonry walls with interior embedded wooden elements, an internal brick partition wall and different internal insulation systems, with and without exterior hydrophobisation. Relative humidity and temperature were measured over five years in the masonry/insulation interface and near the interior surface, in the centre of the test field and near the partition wall. In addition, calibrated numerical simulations were performed for further investigation of the thermal bridge effect. Findings for the masonry/insulation interface showed higher temperatures and lower relative humidity near the partition wall in comparison with the central part of the wall. Near the interior surface, measurements showed only minor differences between the two locations. The relative effect of the thermal bridge was smaller in the case of a high driving rain load on the exterior surfaces. The numerical simulations showed that the hygrothermal conditions were affected further away from the partition wall than what could be measured in the experimental setup.

Hygrothermal performance of six insulation systems for internal retrofitting solid masonry walls

2021 ◽  
pp. 174425912098874
Author(s):  
Nickolaj Feldt Jensen ◽  
Søren Peter Bjarløv ◽  
Carsten Rode ◽  
Birgitte Andersen ◽  
Eva B Møller
Keyword(s):  
Relative Humidity ◽  
Open Systems ◽  
Ph Value ◽  
Cell Structure ◽  
Fungal Growth ◽  
Masonry Walls ◽  
Indoor Climate ◽  
North East ◽  
Hygrothermal Performance ◽  
Insulation Systems

The study investigated the hygrothermal performance and risk of fungal growth in a phenolic foam system with a closed cell structure and a diffusion-open and capillary active lime-cork based insulating plaster, for internal retrofitting purposes. The setup comprised two 40-feet (12.2 m) insulated reefer container with controlled indoor climate, reconfigured with 24 holes (1 × 2 m each) containing solid masonry walls with embedded wooden elements on the interior side. Focus was on the conditions in the masonry/insulation interface and embedded wooden elements, and the performance of the two systems were compared to three diffusion-open insulation systems and one diffusion-tight. The effect of exterior hydrophobisation was also investigated. Relative humidity and temperature were measured in several locations in the test walls over 2½ years, and the risk of fungal growth was evaluated by on-site measurements and the VTT mould-growth model. The findings indicate that internally insulated walls with bare brick exterior surfaces performed poorly with high risk of fungal growth. The effect of exterior hydrophobisation was found to vary with the orientation and the installed insulation system, with a generally positive effect on walls facing south-west but limited effect for north-east. Furthermore, the more diffusion-tight insulation systems were found to perform better in combination with exterior hydrophobisation than the highly diffusion-open systems. The lime-cork insulating plaster showed high relative humidity and risk of moisture-induced problems. The on-site fungal tests showed no growth in the masonry/insulation interface inside the two insulation systems, probably due to high initial pH-value.

scholarly journals Internal insulation of solid masonry walls – field experiment with Phenolic foam and lime-cork based insulating plaster

2020 ◽  
Vol 172 ◽  
pp. 01003 ◽  
Author(s):  
Nickolaj Feldt Jensen ◽  
Carsten Rode ◽  
Birgitte Andersen ◽  
Søren Peter Bjarløv ◽  
Eva B. Møller
Keyword(s):  
Relative Humidity ◽  
Cell Structure ◽  
High Relative Humidity ◽  
Masonry Walls ◽  
Mould Growth ◽  
Indoor Climate ◽  
Phenolic Foam ◽  
Closed Cell ◽  
Insulation Systems ◽  
Positive Effect

The study investigated the hygrothermal performance and risk of mould growth in two thermal insulation systems for internal retrofitting purposes; a phenolic foam system with a closed cell structure, and a capillary active diffusion-open lime-cork based insulating plaster. The setup consisted of a 40-feet (12.2 m) insulated reefer container with controlled indoor climate, reconfigured with several holes (1x2 m each) containing solid masonry walls with embedded wooden elements on the interior side and different interior insulation systems, with and without exterior hydrophobisation. Focus was on the conditions in the interface between wall and insulation system, and in the embedded wooden elements. Relative humidity and temperature were measured in several locations in the test walls over two years, and the mould risk was evaluated by measurements and the VTT mould growth model. Findings for the interior phenolic foam system indicated that exposed walls experienced high relative humidity and high risk of moisture-induced problems. Exterior hydrophobisation had a positive effect on the moisture balance for the southwest oriented wall with phenolic foam. The lime-cork based insulating plaster showed high relative humidity and risk of moisture-induced problems, with and without hydrophobisation.

scholarly journals Timber Based Integrated Techniques to Improve Energy Efficiency and Seismic Behaviour of Existing Masonry Buildings

2021 ◽  
Vol 13 (18) ◽  
pp. 10379
Author(s):  
Matteo Busselli ◽  
Davide Cassol ◽  
Alessandro Prada ◽  
Ivan Giongo
Keyword(s):  
Masonry Walls ◽  
Masonry Buildings ◽  
Unsteady State ◽  
Heat Transmission ◽  
Nonlinear Analyses ◽  
Seismic Behaviour ◽  
Improve Energy Efficiency ◽  
Thermal Bridge ◽  
Hygrothermal Performance ◽  
Point To Point

The retrofit solutions studied herein aim to improve the seismic and energetic behaviours of existing masonry buildings to guarantee safety and the preservation of the building heritage. The retrofit consists of timber-based products (panels and strong-backs) fixed to the masonry walls using mechanical point-to-point connections; the durability and the hygrothermal performance of the solutions are guaranteed by insulation layers and membranes. The thermophysical properties of the retrofitted walls were evaluated by means of analytical and numerical analyses, considering the heat transmission in both steady and unsteady state conditions and the thermal bridge in correspondence with the corner of the wall. The in-plane seismic behaviour of the retrofitted walls was numerically investigated through nonlinear analyses. The influence of various parameters (such as masonry and insulation properties) on the performance of the retrofit solutions was analysed via parametric simulations.

scholarly journals Hygrothermal performance of internally insulated masonry walls with embedded wooden beam heads: a field study on the impact of hydrophobisation

2021 ◽  
Vol 2069 (1) ◽  
pp. 012019
Author(s):  
E Vereecken ◽  
S Roels
Keyword(s):  
Relative Humidity ◽  
Field Study ◽  
Open System ◽  
Frost Damage ◽  
Masonry Walls ◽  
Insulation System ◽  
Hygrothermal Performance ◽  
Potential Measure ◽  
Moisture Conditions ◽  
The Impact

Abstract Internal insulation remains often the only option to thermally upgrade massive masonry. Unfortunately, internal insulation can significantly change the wall’s hygrothermal performance, resulting in a higher risk on frost damage, wood rot of embedded beam heads, etc. The application of hydrophobisation is often put forward as a potential measure to avoid moisture problems, though more research on the impact of hydrophobisation is still required. Thereto, the current paper presents the results of a field study on the hygrothermal performance of internally insulated masonry with embedded wooden beam heads, exposed to wind-driven rain. Both a vapour open capillary active and a vapour tight insulation system are studied. Mainly the moisture conditions near the back of the wooden beam head are found to be influenced by hydrophobisation, which lowers the relative humidity. Closer to the masonry’s interior surface, the choice of the insulation system also influences the results. In case of a well-applied hydrophobisation, overall, the vapour tight system shows a better performance than the capillary active vapour open system. An exception to this is found for the first months after applying the hydrophobisation and the insulation system, where a longer drying period is needed in case of the vapour tight system.

Hygrothermal assessment of four insulation systems for interior retrofitting of solid masonry walls through calibrated numerical simulations

2020 ◽  
Vol 180 ◽  
pp. 107031 ◽  
Author(s):  
Nickolaj Feldt Jensen ◽  
Søren Peter Bjarløv ◽  
Carsten Rode ◽  
Eva B. Møller
Keyword(s):  
Numerical Simulations ◽  
Masonry Walls ◽  
Insulation Systems

Influence of Sulphate on the Moisture Movement of Calcium Silicate Brick Masonry Wall

2010 ◽  
Vol 133-134 ◽  
pp. 201-204
Author(s):  
Ibrahim Mohamad H. Wan ◽  
B.H. Abu Bakar ◽  
M.A. Megat Johari ◽  
P.J. Ramadhansyah
Keyword(s):  
Relative Humidity ◽  
Calcium Silicate ◽  
Masonry Wall ◽  
Sodium Sulphate ◽  
Brick Masonry ◽  
Masonry Walls ◽  
Moisture Movement ◽  
Moisture Expansion ◽  
Curing Period ◽  
Wet Condition

This paper presents the behaviour of moisture movement of calcium silicate brick masonry walls exposed to sodium sulphate environment. The walls were exposed to three sodium sulphate conditions with sulphate concentrations of5%, 10% and 15%. For comparison, some walls were also exposed to dry and wet condition which acts as a control conditions. All specimens were prepared and cured under polythene sheet for 14 days in a controlled environmental room and maintained at relative humidity and temperature of 80 ± 5% and 25 ± 2°C, respectively. After the curing period, the specimens were exposed to sodium sulphate as well as drying and water exposures, during which moisture movement was measured and monitored for a period of up to 7 months. As a result, the moisture expansion was observed and recorded for all masonry wall specimens after exposed to the sulphate condition.

scholarly journals Hygrothermal Analysis of Masonry Wall with Reed Boards as Interior Insulation System

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5252
Author(s):  
Kadri Keskküla ◽  
Tambet Aru ◽  
Mihkel Kiviste ◽  
Martti-Jaan Miljan
Keyword(s):  
Relative Humidity ◽  
Masonry Wall ◽  
Insulation System ◽  
Conservation Area ◽  
Heating Cable ◽  
First Case ◽  
Data Loggers ◽  
Insulation Systems ◽  
Institute Of Technology ◽  
Hygrothermal Analysis

When the masonry walls of buildings under heritage protection need to be restored and thermally improved, the only option is to use an interior insulation system. This is also the riskiest method of insulating walls in cold climates. Capillary active interior insulation systems have been proven to be the most reliable, minimizing the risk of mold growth and decay caused by condensation. They have also been proven to be less risky in wind-driven rain. The building studied is situated in a heritage-conservation area in downtown Tartu, Estonia, and therefore cannot be insulated from the exterior. This paper compares the hygrothermal performance of four different interior insulation systems with and without a heating cable and vapor barrier. In the first case, Isover Vario KM Duplex UV was placed between reed panels. In the second case, reed panels were used without the vapor barrier. Data loggers were applied between the reed panels and the original wall and inside the room to measure temperature and relative humidity in one-hour intervals. Exterior temperature and relative humidity values were taken from the Estonian University of Life Sciences Institute of Technology weather service station. In addition to the measurements taken in the case study building, calculations were made using heat-air-moisture (HAM) Delphin software to simulate the situation. The use of a smart vapor retarder (Isover Vario KM Duplex UV) with reed panels in the interior insulation system reduced the relative humidity level inside the wall. The vapor retarder improved the drying-potential compared to the interior insulation system without the vapor barrier.

scholarly journals Moisture transfer modelling in polystyrene mortar with consideration of sorption hysteresis

2019 ◽  
Vol 128 ◽  
pp. 07006 ◽  
Author(s):  
Maroua Maaroufi ◽  
Kamilia Abahri ◽  
Fares Bennai ◽  
Rafik Belarbi
Keyword(s):  
Air Quality ◽  
Numerical Analysis ◽  
Relative Humidity ◽  
Significant Influence ◽  
Moisture Transfer ◽  
The Other ◽  
Hysteresis Phenomenon ◽  
Indoor Climate ◽  
Sorption Hysteresis ◽  
Transfer Modelling

The walls of buildings experience heat, air and moisture transfers. These transfers have a significant influence on indoor climate, since they affect the value of temperature and relative humidity inhouses. High levels of humidity lead to pathologies in the buildings, and influence the air quality and the hygrothermal comfort of the occupants. In this work, a numerical analysis of the behaviour of polystyrene mortar under hydric solicitations was led. The simulations were held using ComsolMultiphysics and MATLAB. There were two different moisture transfer models used in this work: the first one took into account sorption hysteresis phenomenon, and the other one did not. The computed results showed that considering sorption hysteresis in modelling the hydric behaviour of the material allows obtaining more accurate results comparing to a model that does not consider hysteresis.

scholarly journals Modeling Indoor Relative Humidity and Wood Moisture Content as a Proxy for Wooden Home Fire Risk

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5050 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Moisture Sorption ◽  
Fire Risk ◽  
Cold Weather ◽  
Indoor Climate ◽  
Ambient Conditions ◽  
Wood Panel ◽  
Fire Disaster ◽  
Strong Winds

Severe wooden home conflagrations have previously been linked to the combination of very dry indoor climate in inhabited buildings during winter time, resulting in rapid fire development and strong winds spreading the fire to neighboring structures. Knowledge about how ambient conditions increase the fire risk associated with dry indoor conditions is, however, lacking. In the present work, the moisture content of indoor wooden home wall panels was modeled based on ambient temperature and relative humidity recorded at meteorological stations as the climatic boundary conditions. The model comprises an air change rate based on ambient and indoor (22 °C) temperatures, indoor moisture sources and wood panel moisture sorption processes; it was tested on four selected homes in Norway during the winter of 2015/2016. The results were compared to values recorded by indoor relative humidity sensors in the homes, which ranged from naturally ventilated early 1900s homes to a modern home with balanced ventilation. The modeled indoor relative humidity levels during cold weather agreed well with recorded values to within 3% relative humidity (RH) root mean square deviation, and thus provided reliable information about expected wood panel moisture content. This information was used to assess historic single home fire risk represented by an estimated time to flashover during the studied period. Based on the modelling, it can be concluded that three days in Haugesund, Norway, in January 2016 were associated with very high conflagration risk due to dry indoor wooden materials and strong winds. In the future, the presented methodology may possibly be based on weather forecasts to predict increased conflagration risk a few days ahead. This could then enable proactive emergency responses for improved fire disaster risk management.

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