Brick Cavity Wall Research Articles

Implementation of rainwater infiltration measurements in hygrothermal modelling of non-insulated brick cavity walls

The watertightness of solid masonry walls is generally based on the concept of buffering and afterwards drying out the absorbed rainwater. In cavity walls, on the contrary, the air layer provides a capillary break between the inner and outer leafs allowing drainage of rainwater and preventing infiltration to the interior wall surface. For assessing moisture-related risks, heat, air and moisture models have proven to be a valuable tool, but in the case of cavity walls two problems arise: the degree of water infiltration into the cavity is unknown, and no consensus is available on the method that should be used to implement these infiltrations in a simulation. For example, for the existing buildings, it is worthwhile to investigate whether injecting cavity wall insulation induces an increase or decrease in moisture-related pathologies, in contrast to adopting a fixed performance criterion for assessment. However, to complete a thorough analysis of a brick cavity wall, it is first useful to review the hygrothermal behaviour of cavity walls as it has been previously described in the literature. As such, this article provides a summary of experimental water infiltration results for cavity walls as described in the literature, discusses experimental results of four test walls subjected to four test protocols and extracts from these results the water infiltration rate for implementation in heat, air and moisture models. Finally, several methods for implementing the infiltrations in heat, air and moisture simulations are presented and evaluated based on different damage criteria. In general, the new modelling approaches are considered to provide realistic results. Nonetheless, an in situ investigation on whether mortar bridges occur in the cavity due to poor workmanship remains crucial to understanding the hygrothermal response as mortar bridges are found to have a dominant impact on the risk of mould growth at the interior wall surface.

Passive solar design for energy efficiency in buildings in composite climate

Renewable energy sources offer an unlimited supply of energy. Solar energy can be utilized to supplement energy needs of a building either passively or actively. It is feasible to reduce consumption of energy usage for heating, cooling and lighting requirements of a building by adopting a climate sensitive approach for design of building elements like static sunshade, wall and roof. To study the effect of passive building elements in composite climate zone, four rooms were designed with a different combination of type of static sunshade, wall and roof. The static sunshade and brick cavity wall with brick projections were designed using sunpath diagram and shadow angles. Air cavity was introduced in the reinforced cement concrete (RCC) roof by laying hollow stoneware pipes. This paper presents theoretical and simulation studies to compare thermal performance of the four rooms. Theoretically, the four rooms were compared by steady state method based on total heat load in every month and on representative days in different seasons throughout the year. The extreme and most frequently occurring temperature values (mode) in every season were identified by obtaining the frequency distribution of the outdoor air temperature with the software SPSS Statistics (IBM Corp. 2012). Results showed that room with designed passive elements gained minimum heat in summer and moderate summer, while it lost minimum heat in winter and moderate winter. This shows the effectiveness of the designed passive elements in insulating the room interiors from the extreme climatic conditions. The rooms were also simulated using software Autodesk Ecotect Analysis 2011 and their performance was compared on a typical day in each month. Results showed that this software can be helpful for preliminary design to get an idea about the room performance that can help to create thermally comfortable indoor environment for the well being of occupants.

Experimental investigation of seismic behavior of confined cavity walls retrofitted with reactive powder concrete overlays

AbstractBrick cavity wall structures are widely distributed in southeastern China; however, their integrity and seismic behavior are extremely poor. To solve this problem, a new technique is proposed to enhance the seismic behavior of brick cavity walls using steel fiber reactive powder concrete (SFRPC) overlays. Two unreinforced cavity walls and four cavity walls strengthened with SFRPC overlays (applied over the entire wall surface) were tested under cyclic loading. In this study, the damage and failure modes of the specimens were analyzed in terms of the load displacement curves; furthermore, a comparative investigation was performed considering the load capacity, ductility, stiffness degradation, and energy dissipation capacity to demonstrate the merits of brick cavity walls strengthened with SFRPC overlays. The effect of strengthening using different thicknesses of reinforcement was investigated. In addition, damage analyses of the walls were performed based on the modified Park–Ang damage assessment model.

The rising damp in two traditional clay-brick masonry walls and influence on heat transfer performance

This paper studies the law of capillary water rise in the brick solid wall and the brick cavity wall under the influence of high-humidity wall foundation. It is found that the rising height of the capillary water sharp front is proportional to the time to the 0.5 power, but the coefficient is related to the wall structure, and the speed in cavity wall is higher than that in the solid wall. The heat flow meter method was used to compare the influence of the capillary water to the heat transfer when it rises to different heights. It is found that the presence of capillary water has a direct impact on the heat transfer coefficient of the wall. The presence of capillary water may increase the heating load by 11.1% and the cooling load by 15% of a common historical building in hot summer and cold winter area of China.

Heat Transfer in Facade Systems and Energy Use: Comparative Study of Different Exterior Wall Types

AbstractThis research article discusses methods for designing high-performance facades with a focus on minimizing heat transfer and improving energy usage. The facade is one of the most significant contributors to the energy budget and comfort parameters of any building. Control of physical environmental factors, including methods for minimizing heat transfer, must be considered during the design process. High-performance facades need to block adverse external environmental effects and maintain internal comfort conditions with minimal energy consumption. The research was conducted by initially modelling conductive heat transfer in four different exterior wall types, including a brick cavity wall, a rain-screen facade with terracotta cladding, a rain-screen facade with glass fiber–reinforced concrete cladding, and a curtain wall, to compare their relative thermal performances. Then, heat-transfer modelling was conducted for three thermally improved systems, including curtain walls with thermally broken fra...

Building Operational Energy Optimization Technique Waste Filled Cavity Wall

Emerging crises for resources and energy has became one of the major global issues. Unstoppable population and urban growth is demanding shelter. The figure for estimated housing shortage across the world according to the internationally recommended standards is 428,700,000 units. By the year 2030, an additional 3 billion people, about 40 percent of the world’s population, will need access to housing. This translates into a demand for 96,150 new affordable units every day and 4000 every hour.(United Nation –Habitate:2005)(128). All this unstoppable global population growth is resulting in high demand supply gap between resources and thus present trend concentrate to satisfy and minimize this gap. This shooting urbanization problem is leading towards diversion for easy and fast construction methodology.Along with this the problems associated to it are also increasing globally. The problem of Urban Heat Island and Urban Canyon Effect, CO2 emission , Green House Effect , Resource depletion and all such problems are demanding global attention to overcome it and make habitant sustainable for safeguarding future generations to come. The major hurdle for application of sustainable construction is barrier of human mind who concentrates more on initial cost of construction and negligence towards operations energy cost and pay back period calculations.The aim of the paper is to show feasibility of application of waste in construction elements like wall by analysing thermo resistive property of such waste filled cavity wall and equivalence cooling effect calculations for conventional clay brick wall , AC sheets , cavity wall and various waste filled cavity wall by making model and process of simulation using Ansys Fluent .The results of research work shows feasibility of adopting cavity wall and waste fill cavity wall for construction of wall because of its high thermoresistive property so as to mitigate global problems like Urban Heat Islands and operational energy consumption.

Comparative thermal performance of static sunshade and brick cavity wall for energy efficient building envelope in composite climate

Energy efficient building technologies can reduce energy consumption in buildings. In present paper effect of designed static sunshade, brick cavity wall with brick projections and their combined effect on indoor air temperature has been analyzed by constructing three test rooms each of habitable dimensions (3.0 m ? 4.0 m ? 3.0 m) and studying hourly temperatures on typical days for one month in summer and winter each. The three rooms have also been simulated using a software and the results have been compared with the experimental results. Designed static sunshade increased indoor air temperature in winter while proposed brick cavity wall with brick projections lowered it in summer. Combined effect of building elements lowered indoor air temperature in summer and increased it in winter as compared to outdoor air temperature. It is thus useful for energy conservation in buildings in composite climate.

Annual Thermal Performance of a Hollow Roof in Combination with a Cavity Wall and Static Sunshade: Experimental Study of Energy-Efficient Rooms

AbstractEnergy consumption by the building sector constitutes a large portion of global energy use. Energy-efficient building technologies help to reduce heat gain in hot summer months, heat loss in cold winter months, and modify energy requirements in buildings. In the writers’ paper, the effect of a proposed hollow roof (independent of and combined with a designed brick-cavity wall with brick projections and static sunshade) on indoor air temperature has been analyzed experimentally by constructing four rooms of habitable dimensions (3.0×4.0×3.0-m high) and studying average hourly temperatures for 1 year. Each room has a different combination of type of roof, wall, and static sunshade; hence, the difference in indoor air temperature of the rooms will primarily be attributable to differences in heat transferred through these building elements. The proposed hollow roof combined with the designed brick-cavity wall with brick projections and static sunshade lessened indoor air temperature in summer and incr...

Effect of energy efficient building elements on summer cooling of buildings

Growing energy demands with an increasing population have reiterated the importance of energy conservation. Buildings share a large portion of energy use worldwide. Energy efficient building technologies help to maximize solar heat gain in winter, minimize it in summer and optimize energy requirements in buildings. In present paper, effect of ventilated brick cavity wall with brick projections (independently and combined with designed static sunshade and hollow roof) on indoor air temperature has been analyzed experimentally by constructing four rooms of habitable dimensions (3.0m×4.0m×3.0m high) and studying average hourly temperatures in summer. The combined effect of ventilated brick cavity wall with brick projections, designed static sunshade and hollow roof helped to lower indoor air temperature for hotter part of the day in the study period. It also lowered maximum and minimum indoor air temperature and swing in indoor air temperature although there was a large variation in outdoor air temperature. Combined effect of the energy efficient building elements is thus useful for summer cooling and energy conservation in buildings.

Design development and thermal performance evaluation of static sunshade and brick cavity wall: An experimental study

Energy efficient building technologies reduce energy requirements in buildings. It is possible to maximize solar heat gain in winter, avoid overheating in summer by proper design of building elements and bring indoor air temperature near comfort zone (18–27°C) to optimize energy needs. In present paper effect of proposed static sunshade, brick cavity wall with brick projections and their combined effect on indoor air temperature has been analyzed by constructing three rooms each of habitable dimensions (3.0m×4.0m×3.0m high) and studying average hourly temperatures for three months in summer and winter each. Performance of proposed static sunshade has been found to be better than horizontal static sunshade in winter while that of proposed brick cavity wall with brick projections is better than a solid brick wall in summer. Combined effect of proposed static sunshade and brick cavity wall with brick projections has been effective in keeping indoor air temperature less in summer mornings, more in winter nights and hence useful for energy conservation in buildings as per seasonal needs.

Brick Cavity Walls: A Performance Analysis Based on Measurements and Simulations

After world war two, cavity walls became a widespread external wall type in the cool but humid climate of North Western Europe. Moisture tolerance of the unfilled construction was excellent. Instead, calculation and testing underlined that the unfilled cavity walls of that era performed poorly from a thermal insulation point of view. After the energy crisis of 1973, cavity filling was therefore introduced as the main upgrade. Hence, extensive testing revealed upgrading was less simple than expected. Air in- and exfiltration through the wall, wind washing behind the fill, thermal stack induced air looping around the fill and thermal bridging all cooperated in lowering expected thermal quality of the filled walls. Anyhow, at the same time testing underlined that moisture tolerance remained outstanding in the cool, humid climate of North Western Europe also without cavity ventilation. That resulted in a set of recommendations how to construct high performing filled cavity walls.

Architectural Engineering Approach to Building Façade Design, Construction, and Evaluation

Whether you are looking at high performance facade components as part of building “green” or more traditionally from a weather barrier perspective, facade systems remain one of the most important aspects of a building design, and often one of the most problematic. Building facades involve a unique combination and integration of manufacturing, design, construction, and maintenance to perform as expected. Advances in technology and materials have made available an expanded number of system options that provide the owner and designer with additional cost and performance choices. While new choices are welcomed by the industry, the importance of proper design and execution remains as important as ever. This is true for all building types from single family residential construction with siding or brick cavity walls, to commercial and institutional construction with traditional masonry facades and punch through windows, to modern high performance curtain walls. While new buildings are important because they set the tone for the future, existing structures and their facades are subjected to a multitude of factors including aging, weathering, structural damage from severe environmental impacts, and, unfortunately, in some cases, mistakes of the past such as inadequate design and construction. Those who believe in an integrated architectural engineering AE approach to building design and construction will likely agree that AE as a profession is well situated to advance the art and science of design and construction of facades for new buildings, as well as investigation and repair of existing building facades. Unfortunately, as a profession, we do not always take full advantage of that potential. In addition to meeting the general requirements of model codes such as the International Building Code IBC and the required structural loads from ASCE-7 and similar standards, proper facade design for new or retrofit/repair situations necessitates a review of a number of important issues including, but not limited to, the following: 1. Overall energy issues including heat gain and loss and how they impact the design and control of the building’s mechanical systems. 2. Acoustics and sound control, especially in urban environments. 3. Natural ventilation as appropriate to the climate and location of the building. 4. Indoor air quality and the relationship to items such as ventilation quantities, vapor drive, and tightness of the envelope leakage rates . 5. Incorporation of a properly designed and constructed envelope including roof system that integrates best practice

Thermal properties of a variable cavity wall

An experimental investigation of heat transfer through a variable aspect ratio cavity wall has been conducted with the aid of a guarded hot box. A block and brick cavity wall measuring 1.2×1.2 m 2 was tested at cavity depths of 78, 60 and 40 mm. The influence of cavity flow upon the rate of heat transfer was established by correlation of convective cavity flows, measured by means of laser Doppler anemometry and by measuring surface temperatures on the four cavity faces. The experimental results show that with increasing aspect ratio, flow magnitude falls, circulation intensity reduces and the thermal resistance of the air cavity is thereby increased. Computational predictions were also used for the purpose of gaining an insight into cavity heat transfer and extrapolating models for further configurations.

Transmission of Sound through Tied Walls: An Experimental Study

Experimental work on the prediction of sound transmission loss, TL, of brick cavity walls, plastered on both faces, is presented. First double brick walls having either 2 cm or 5 cm cavity widths were subjected to a diffuse sound field. Then tied walls were tested. In order to assess the effect of the wall ties on TL values, two types of ties, namely unit and continuous reinforcement, were investigated. The low frequency TL of the walls was observed to be highly affected by the presence of ties. High frequency TL values were not strongly influenced by the ties. When the leaves of the double brick walls having 5 cm cavity depth were tied, regardless of the type of tie used, their Sound Transmission Class was decreased by 5 points.

Reinforcement of Brick Walls Spanning Vertically

A vertical shear connector suitable for manufacture by automated sheet metal processes from steel coil is developed in an experimental program involving 90 small area bearing tests, 18 shear tests, and 6 tension tests. A comparison of three full‐scale wall panel tests (standard cavity wall, cavity wall with an unbonded steel mullion, and cavity wall with a vertical shear connector) demonstrate that the connector significantly increases both the post‐ and pre‐cracking strength and stiffness of a vertically spanning brick masonry cavity wall under out‐of‐plane loads.

Transmission Loss of Partition Walls

ABSTRACTResults of the measurement on sound insulation of a few partition walls are presented. The sound insulation has been measured in the transmission-reverberation chamber of this Institute. The results are compared with theoretical predictions. A simplified method is adopted to obtain approximate theoretical values of the transmission loss (T.L.).Three types of partition walls, a solid brick wall, brick cavity wall and a double wall plywood panel have been tested. The experimental values of transmission loss of the brick cavity wall is found to be lower than the computed values. This is due to sound transmission through the wire-ties bridging the two panels. The transmission loss of a single thin panel of plywood is too low to meet the insulation requirements. Sound insulation of such panels can be increased by using two panels with a little air space in between. An absorbent material loosely filled in the cavity further improves the transmission loss.