Building Research Establishment BRE

The high kaolinite content of metakaolin makes it valuable to other industries, thereby affecting its availability and affordability for the production of limestone calcined clay cement (LC3). This work presents a study on the potential utilization of low-grade clay in place of pure metakaolin in the preparation of LC3 for mortar formulations. CEM I was partially substituted with calcined clay and limestone by 20, 30, 40, and 50 wt.%. The weight ratio of calcined clay and limestone was maintained at 2:1 for all mixes and the water-to-binder ratio was 0.48. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and isothermal conduction calorimetry were used to study the hydration process and products after 28 days. Mechanical and durability assessments of the LC3 mortar specimens were conducted. LC3 specimens (marked LC20%, LC30%, LC40%, and LC50%) trailed the control sample by 1.2%, 4%, 9.8%, and 18%, respectively, at 28 days and 1.6%, 2.3%, 3.6%, and 5.5%, respectively, at 91 days. The optimum replacement of OPC clinker, calcined clay, and limestone was 20% (LC20%).

In 1937 the investigation of the failure during construction of Chingford No 2 embankment dam brought the concepts of modern soil mechanics to bear on the construction of British embankment dams. Effective stress theory highlighted the crucial significance of pore water pressure in understanding embankment stability and it became standard practice to monitor pore pressures during embankment construction using twin-tube hydraulic piezometers. By the 1980s embankment stability might have seemed assured, with embankment design utilising limit equilibrium stability analyses that incorporated strength parameters of fill and foundation materials determined by laboratory testing. However, in 1984 the upstream slope of Carsington dam suffered a major slip in the final stage of construction. Recently developed advanced finite element analyses were able to demonstrate that progressive failure was a major factor in the slope instability, but the failure was also a reminder of the continuing need for experience-based judgement in design.

Background The health and well-being of older people is significantly affected by housing, representing an essential aspect of preventative healthcare in the community. Good quality housing is an important factor in a person’s ability to maintain mental and physical health, as well as sustain optimal quality of life. This is particularly true for older people who may spend more time at home than other demographic groups. This study explores the linkages between housing conditions and the health and wellbeing of older people with the aim to inform housing designers, providers, and policy makers about the key aspects of healthy homes and common housing hazards, affecting older people. Methods The qualitative research programme involved an in-depth stakeholder engagement strategy, with activities including focus groups, diaries, and interviews to place the perspectives of older people at the centre of the work. The research also included a series of case study visits to the homes of patients of an Integrated Care Programme for Older People, where the research team conducted a series of qualitative semi-structured interviews with the patient, as well as a technical and quantitative survey of the home. Results Key themes identified throughout the research programme include overarching themes such as healthy ageing and housing and ageing in place; themes related to the hospital and integrated care, and the local authority; housing conditions and hazards; and built environment issues across the key spatial scales. Conclusion There is a need for better, more accessible data on the housing issues, conditions, and hazards for older people throughout Ireland. Additionally, it is essential to consider the needs of patients with additional care requirements, such as those living with dementia, as the built environment greatly impacts them.

Over the last decade growing concern has been voiced about the fire hazards of cellular polymers used in building and transport applications. Some of this concern is justified as illustrated by recent fires and experimental simulations where rapid fire development has occurred with potential for death or injury from the spread of combustion products within very short periods of time. Many technical difficulties have arisen in the use of synthetic foams. Their introduction has presented problems since the test methods used traditionally to assess performance have been somewhat inadequate to cope effectively with the new properties of polymers and polymer composites. Major progress is being made in understanding the fire behaviour of cellular polymers. This involves studies of ignitability, flame spread, heat release, and the production of smoke and toxic gases. In parallel to this, important technical advances have been made by industry in the development of new formulations of cellular materials and composites with improved fire behaviour. It is now time to bring together the current knowledge of all aspects of cellular polymers in fire so that further applications of these materials can continue safely allowing full use of their potential for improving the comfort and efficiency of our lives. This paper examines the basic problems which have occurred during the use of cellular polymers with regard to fire. Recent fire scenarios which have attracted attention to cellular materials and the ways the hazard is being addressed and mitigated are discussed. To aid this the paper also examines the basic mechanisms of burning of the polymers and the associated hazard to life. Finally it should be emphasised that much of this paper is directed, intentionally, to understanding circumstances where untoward events may occur to place life in jeopardy. This approach is necessary for the elimination of potentially hazardous situations and to enable the continuing use of cellular polymers in a safe way.

Scammonden dam has been described as a unique structure with its large embankment not only forming part of the M62 motorway but also impounding a reservoir. This paper presents the recollections and reflections on this huge project from the viewpoint of its two authors who were present on the site for most of the construction period; one of the authors, who is a Highway Engineer, was the Materials Engineer for the main contractor, Sir Alfred McAlpine & Son, and the other author, who is a Geotechnical Engineer, was much involved with some of the instrumentation. The important role of the contractor in sourcing materials for the embankment is described. Each author made a significant contribution in a sequence of events which arose towards the end of embankment construction. This began with identifying an issue relating to the extremely high pore-water pressures in the clay core and then in a preliminary assessment of the effect of this on upstream slope stability during the early stages of reservoir impounding.

The availability of some supplementary cementitious materials, especially fly ash, is of imminent concern in Europe due to the projected closure of several coal-fired power generation plants. Pure kaolinitic clays, which arguably have the potential to replace fly ash, are also scarce and expensive due to their use in other industrial applications. This paper examines the potential utilisation of low-grade kaolinitic clays for construction purposes. The clay sample was heat-treated at a temperature of 800 °C and evenly blended with Portland cement in substitutions of 10–30% by weight. The physical, chemical, mineralogical and mechanical characteristics of the blended calcined clay cement were determined. The Frattini test proved the pozzolanic potential of the calcined impure clay, as a plot of its CaO and OH− was found below the lime solubility curve. The 28 days compressive strengths trailed the reference cement by 5.1%, 12.3% and 21.7%, respectively, at all replacement levels. The optimum replacement level between the three blends was found to be 20 wt.%.

Daylight is an important component in maintaining human health and wellbeing and plays a key role in physiological, psychological, and behavioural regulation. Understanding the complexity of daylight perception is vital since the degree of satisfaction with daylight conditions could greatly impact individual mood, behaviour and cognitive performance. This paper aims at (1) presenting an overview of current knowledge on methods for assessing daylight perception and (2) establishing a methodology for assessing daylight perception in the context of cultural background. An experiment was conducted with 50 students who were instructed to select the best and worst seats, describe the best desks’ daylight conditions and draw boundary lines between perceived daylit and non-daylit spaces in a library. The study showed that subjective rating and seat preference methods were consistent with actual daylight levels. However, participants’ boundary lines did not represent the actual daylight availability in the space. The study suggests that individual daylight perception in the context of cultural background can be assessed using the subjective rating and seat preference methods.

New technologies brought about by digital transformation in the construction sector will inevitably lead to a change in the traditional ways of dealing with health and safety risk management as has occurred with other specialties such as architecture, structural, mechanical, electrical, heating and ventilation. Existing procedures will need to be adapted, and new routines are created. The technical and soft skills of employees will need to be updated, enhancing competitiveness and sustainability. Based upon ongoing research studies, this chapter aims to explain how health, safety and well-being (HSW) risk management and associated skills can be dealt with using technologies such as building information modelling, virtual and augmented reality, Internet of Things, teleoperation, soft skills, artificial intelligence applied to big data and cybersecurity. Fields where these key technological developments (KTD) can be applied include: technical training; documental/contractual management; hazards identification; on-site monitoring and implementation; emergency planning; and accident investigation. High-level risks including pedestrian/vehicle collisions and falls from heights will also be covered. Based on a review of the relevant literature, an analysis of the application of KTDs to the main fields indicated in EU directive 92/57/CE has been conducted. The main conclusions are that if correctly implemented, these new ways of handling risk management will enable a better perception of risks and enhanced preventive measures, allow improvement of training levels, logistic and financial management and, promote improved integration of prevention measures into work planning. Raising, the skills levels of HSW will be a key enabler for teams to increase their knowledge and understanding of KDT in HSW contexts.

This paper presents the technical performance results of a measurement campaign from a 5G indoor millimeter Wave (mmWave) and Visible Light Communications (VLC) multi component carrier system, which was developed in a Horizon 2020 research project called Internet of Radio-Light (IoRL). The measurement campaign was performed in the famous Integer House laboratory at the Innovation Park in Building Research Establishment in Watford, U.K., which represents a typical European home environment. It includes four field test results: 1) VLC received signal quality measured as Error Vector Magnitude (EVM) against coverage, 2) mmWave received signal quality measured as EVM against coverage, 3) VLC location accuracy against a prescribed grid using received signal strength, 4) Comparison of measured and simulated Electromagnetic Field (EMF) strength against coverage. This measurement campaign not only tests the system concept in a realistic indoor home environment but also provides analysis of the results with practical recommendations on further technical enhancements required to improve the system performance and insights into viable commercial solutions and applications. Other environments in which this technology could be deployed were envisaged as: underground train platforms and tunnels, museums and supermarkets.

Durability-based designs with timber require reliable information about the wood properties and how they affect its performance under variable exposure conditions. This study aimed at utilizing a material resistance model (Part 2 of this publication) based on a dose–response approach for predicting the relative decay rates in above-ground situations. Laboratory and field test data were, for the first time, surveyed globally and used to determine material-specific resistance dose values, which were correlated to decay rates. In addition, laboratory indicators were used to adapt the material resistance model to in-ground exposure. The relationship between decay rates in- and above-ground, the predictive power of laboratory indicators to predict such decay rates, and a method for implementing both in a service life prediction tool, were established based on 195 hardwoods, 29 softwoods, 19 modified timbers, and 41 preservative-treated timbers.

Service life planning with timber requires reliable models for quantifying the effects of exposure-related parameters and the material-inherent resistance of wood against biotic agents. The Meyer-Veltrup model was the first attempt to account for inherent protective properties and the wetting ability of wood to quantify resistance of wood in a quantitative manner. Based on test data on brown, white, and soft rot as well as moisture dynamics, the decay rates of different untreated wood species were predicted relative to the reference species of Norway spruce (Picea abies). The present study aimed to validate and optimize the resistance model for a wider range of wood species including very durable species, thermally and chemically modified wood, and preservative treated wood. The general model structure was shown to also be suitable for highly durable materials, but previously defined maximum thresholds had to be adjusted (i.e., maximum values of factors accounting for wetting ability and inherent protective properties) to 18 instead of 5 compared to Norway spruce. As expected, both the enlarged span in durability and the use of numerous and partly very divergent data sources (i.e., test methods, test locations, and types of data presentation) led to a decrease in the predictive power of the model compared to the original. In addition to the need to enlarge the database quantity and improve its quality, in particular for treated wood, it might be advantageous to use separate models for untreated and treated wood as long as the effect of additional impact variables (e.g., treatment quality) can be accounted for. Nevertheless, the adapted Meyer-Veltrup model will serve as an instrument to quantify material resistance for a wide range of wood-based materials as an input for comprehensive service life prediction software.

The summer 2018 saw temperatures far above the long-time average in the Northern Hemisphere. It was England's hottest ever summer, with temperatures typical of those expected of the 2050s. In the largest and most comprehensive study of overheating in English homes to date, overheating in 750 homes was assessed through both monitoring and questionnaires. Overheating determined using adaptive thermal comfort criteria invariably produced patterns of overheating with dwelling and household characteristics, comparable with self-reported results for both living rooms and bedrooms. However, households with members aged over 75 significantly under-reported the prevalence of overheating compared with monitored results. A static overheating criterion produced implausible estimates for the prevalence of overheating in bedrooms. Weighting the results to the national stock, revealed that in 2018 4.6million English bedrooms (19% of the stock) and 3.6million living rooms (15%) may suffer from overheating. Overheating was more prevalent in bedrooms at night than in living rooms during the day. The occurrence of living room overheating was significantly greater in flats (30%) than other dwelling types. Improved fabric energy efficiency did not significantly increase the risk of overheating. The prevalence of monitored overheating was greater in households living in social housing, with low incomes or with members aged over state pension age. Recommendations are made about the measurement of overheating and the formulation of policies aimed at mitigating the risk of overheating in existing homes.

Moisture is one of the major causes of damage to building systems, affecting the hygrothermal performance and durability of building envelopes. Surface treatment products are available in the market that can influence the hygric performance of masonry facades under water exposure. These are of a wide range of chemical compositions, and they claim to waterproof the masonry surfaces while not diminishing breathability. This paper presents and discusses the findings from a series of benchtests carried out to measure hydrophobicity, water absorption and water vapour transmission following the relevant codes for an appraisal of the hygric behaviour change in brick masonry induced by waterproofing through three distinct phases of the life-cycle of moisture exposure, i.e. first contact with water, wetting and drying. To this end, 4 waterproofing products including silane/siloxane blend liquid and cream, and acrylic and stearate-based liquids were selected for testing, along with 3 brick types common in the 50s and 60s to be representative of the majority of the UK building stock. The findings show that the treatment products indeed enhance the surface hydrophobicity and reduce water absorption while allowing water vapour permeability, to differing degrees: silane/siloxane blend cream, despite application difficulties leading to inconsistencies in performance, overall was found the most effective throughout the moisture-exposure life-cycle, with an average of ∼96% reduction in water absorption and 18% of increase in water vapour resistance in comparison to the untreated case, followed by the stearate-based liquid with 57% reduction in water absorption and 12% increase in water vapour resistance. The acrylic-based product demonstrated good performance in hydrophobicity and water vapour transmission tests, however led to a comparatively higher water absorption capacity than the other treatment products with only ∼40% reduction in comparison to the base-case. Finally, silane/siloxane blend liquid was found to lead to the lowest contact angle, demonstrating a lower-than-others capacity to developing surface hydrophobicity, and led to 35% reduction in water absorption and 28% increase in water vapour resistance, making it the poorest product in the dataset to lead to watertight and vapour open systems under water exposure. Based on the test results it was also deemed beneficial to use masonry specimens to account for its composite nature, rather than using results obtained from brick and mortar separately to infer the wall response under exposure.

Prolonged overheating has severe consequences for the future habitability of buildings. Building Performance Simulation (BPS) is increasingly used to identify the propensity of buildings to overheat, however the reliability of this approach has been repeatedly questioned. A new overheating risk-assessment methodology, Technical Memorandum (TM)59 was developed by the Chartered Institution of Building Services Engineers (CIBSE), to address this problem by providing a consistent framework for the evaluation of overheating risks in new homes. To date, little empirical research has been carried out to validate this approach in comparison to real buildings. This study aims to bridge the gap between theory and praxis by investigating the potential challenges, limitations, and implications of implementing this standardised methodology. This was achieved by comparing BPS simulations, based on the application of TM59, with empirically measured data from three recently constructed energy-efficient flats located in London. The flats were monitored during the late autumn in order to assess their propensity to chronic year-round overheating, outside of the summer season. Distinct user scenarios, based on different modes of ventilation and window/shading operation, were analysed in relation to the CIBSE TM59 overheating thresholds. The results showed that the TM59 criteria were extremely difficult to satisfy. Under a mechanical ventilation assessment mode (with windows closed) 30–67% of the total occupied hours exceeded the overheating thresholds. This analysis has highlighted the need to further improve overheating methodologies, by considering the assessment of risks in discrete temporal bands as well as incorporating methods to assess mixed-mode purge-ventilation strategies.

Prolonged overheating can have serious cumulative effects on human health, resulting in heat exhaustion, heatstroke and even death. The frequency and severity of heatwaves will increase considerably in the future as a result of accelerating climatic changes compounded by increasing urbanisation. A recent overheating risk-assessment methodology, Technical Memorandum (TM)59: 2017 was developed by the Chartered Institution of Building Services Engineers (CIBSE) to address this problem, by providing a consistent framework for the evaluation of overheating risks in new homes. TM59 has for the first time highlighted the importance of including corridor heat transfer effects in the dynamic modelling of multi-residential dwellings. This paper investigates the strengths and limitations of current approaches to the modelling of corridors, based on a case study of three energy-efficient flats located in London. The results of modelling in accordance with TM59 guidance are compared with alternative approaches, using more realistic occupancy and weather information, and compared to empirically measured data. The findings of this study indicate that current practices in Building Performance Simulation (BPS) are likely to under-estimate the actual air temperatures in corridors. This study highlights the need for further research into the way in which corridors, flats and their interconnecting ventilation and heat transfer networks are commonly discretised in BPS models.

Radon ( ²²² Rn) is a natural radioactive gas that occurs in rocks and soils and can only be detected with special equipment. Radon is a major cause of lung cancer. Therefore, early detection is essential. The British Geological Survey and Public Health England have produced a series of maps showing radon affected areas based on underlying geology and indoor radon measurements, which help to identify radon-affected buildings. Many factors influence how much radon accumulates in buildings. Remedial work can be undertaken to reduce its passage into homes and workplaces and new buildings can be built with radon preventative measures.

Several attempts have been made in the past to develop a European harmonized testing and assessment method for façades before the European commission decided to publish a call for tender on the topic. A project consortium from five countries (Sweden, UK, France, Germany and Hungary) applied to the call for tender and was contracted to develop a European approach to assess the fire performance of façades. 24 sub‐contractors and 14 stakeholder entities were part of the project. The objective of the European project was to address a request from the Standing Committee of Construction (SCC) to provide EC Member States regulators with a means to regulate the fire performance of façade systems based on a European approach agreed by SCC. The initial stages of this project were focused on establishing a register of the regulatory requirements in all Member States in relation to the fire performance of façade systems, and to identify those Member States who have regulatory requirements for the fire performance façade systems which go beyond the current EN 13501 (reaction to fire and fire resistance) classification systems and to collate the details of these additional requirements. After having confirmed the regulatory needs a testing and classification methodology based on BS 8414 and DIN 4102‐20 was developed to address the identified key performance and classification characteristics. This paper is a short overview of results the two‐year development work, which Final Report published by the European Commission in 2018.

Energy used by domestic refrigerators can be a large part of household energy use. In most countries, consumers are informed of the energy used by their appliance through energy labels or manufacturers data provided with the appliance. Work was carried out to ascertain whether the information provided to consumers provided an accurate reflection on the energy used in real life. Data was extracted from a large-scale survey of the performance of domestic cold appliances. Information on temperature control and electricity consumption as well as information about the appliances was collected in the survey. In total 998 appliances were examined, of which 124 were used for the analysis in this paper. For each of these appliances, the electricity measured by the appliance manufacturer in a test laboratory was compared to the energy consumed in the home. Sixty-one percent of appliances consumed more energy in the home than the laboratory. The rank order of energy used by appliances was also assessed and found to vary considerably between the laboratory and the home. A more transparent test method to assess performance of refrigerated appliances in the home is suggested.

With the help of building diagnostics, the causes and solutions to complex problems in buildings can be determined. In central and greater London, an increasing number of cases of chronic, year-round, overheating in buildings have been reported. We present three cases of unexpected temperatures in multi-storey residential buildings. Detailed analysis and modelling of these scenarios have led to an investigation of whether the way in which infiltration is currently modelled in building performance simulation may be exerting a pronounced effect on the results of overheating studies. An EnergyPlus model, of one of the dwellings in a multi-residential building in London, was created to investigate the influence of infiltration and exfiltration pathway assumptions on the prediction of overheating. The simulation results were compared to empirical data and show that the predicted indoor temperatures are highly sensitive to how the infiltration airflow network is modelled. The findings of this study have been used to provide practical guidance for modellers and building designers on critical aspects to consider when creating building performance simulation models to ensure more reliable outcomes. Overheating in buildings is an emerging topic of critical importance to the future of the built environment. The importance of understanding infiltration pathways in assessing and modelling overheating risks in flats and multi-residential buildings has been hitherto underestimated or simply ignored. In this paper, examples are given which highlight the need for a fuller understanding of internal air movement where accurate predictions of internal temperatures are required. At present, common building simulation practices and existing technical memorandum (TM) standards are masking the problem and do not provide a basis from which typical or worst-case scenarios can be adequately considered.