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Natural ventilation is particularly important for residential high-rise buildings as it maintains indoor human comfort without incurring the energy demands that air-conditioning does. To improve a building’s natural ventilation, it is essential to develop models to understand the relationship between wind flow characteristics and the building’s design. Significantly more effort is still needed for developing such reliable, accurate, and computationally economical models instead of currently the most popular physics-based models such as computational fluid dynamics (CFD) simulation. This paper, therefore, presents a novel model developed based on physics-based modelling and a data-driven approach to evaluate natural ventilation in residential high-rise buildings. The model first uses CFD to simulate wind pressures on the exterior surfaces of a high-rise building. Once the surface pressures have been obtained, multizone modelling is used to predict the air change per hour (ACH) for different flats in various configurations. Data-driven prediction models are then developed using data from the simulation and deep neural networks that are based on mean absolute error, mean absolute percentage error, and a fusion algorithm respectively. These data-driven models are used to predict the ACH of 25 flats. The results from multizone modelling and data-driven modelling are compared. The results imply a high accuracy of the data-driven prediction in comparison with physics-based models. The fusion algorithm-based neural network performs best, achieving 96% accuracy, which is the highest of all models tested. This study contributes a more efficient and robust method for predicting wind-induced natural ventilation. The findings describe the relationship between building design (e.g., plan layout), distribution of surface pressure, and the resulting ACH, which serve to improve the practical design of sustainable buildings.

Sustainability analysis should include the assessment of the environmental, social, and economic impacts throughout the life cycle of a product. However, the social sustainability performance assessment is seldom carried out during materials selection due to its complex nature and the lack of a social life cycle assessment tool. This study presents a single score-based social life cycle assessment methodology, namely social sustainability grading model, for assessing and comparing the social sustainability performance of construction materials using a case study on recycled and natural construction materials. The proposed method is developed based on the methodological framework provided by the United Nations Environment Programme/Society of Environmental Toxicology and Chemistry guidelines published in 2009 and the methodological sheets published in 2013, the indicators and sustainability reporting guidelines provided by the Global Reporting Initiatives and ISO 26000 for social responsibility of products, and the indicators provided by the Hong Kong Business Environment Council Limited for construction sustainability. A twofold research approach is proposed in this model: the first one is the qualitative research based on expert interviews to identify, select, and prioritize the relevant subcategories and indicators, and the second one is the operational research based on the case-specific survey to collect the required data. A social sustainability index was proposed for the interpretation of the results effectively. A case study on construction materials was conducted to illustrate the implementation of the method using case-specific first-hand data. The major outcome of this study is the systematic development of a social sustainability assessment tool based on the established standards and guidelines. The case study showed that four subcategories are crucial social concerns for construction materials (i.e., health and safety issues of the materials, health and safety of workers, company’s commitment to sustainability, and company’s policies on energy and water consumption). Based on the sustainability index proposed, using recycled aggregates from locally generated waste materials scored higher (about 31–34%) social sustainability than using imported natural aggregates. In addition, recycled aggregates and natural aggregates achieved “sustainable” and “neutral” rating sustainability levels, respectively. However, several subcategories (e.g., health and safety, working hour, forced work, training and social benefits of workers, and quality of the materials and information disclosing to public) are still needed to improve the social sustainability performance of recycled aggregates. An integrated social life cycle assessment method is presented in this study for assessing the social sustainability of construction materials. In addition, the reported case study in this paper is one of the first attempts for social sustainability assessment of recycled construction materials, and the method can be applied to other recycled materials/products for comparative analysis. However, several critical factors, such as integration in other life cycle methods and software, sensitivity analysis, and more case studies, are still needed for further improvement of the developed method.

The demand for green construction materials and eco-products is burgeoning globally due to the shortage of natural materials and the relevant environmental consequences of natural materials. In addition, the management of rapidly increasing construction and demolition (C&D) waste and waste glass is in serious concern due to the shortage of landfills and associated environmental burdens for landfill disposal. Concrete paving eco-blocks using recycled materials derived from locally generated C&D waste and waste glass have been developed in Hong Kong and achieved its current advanced form with the continuous improvement. Therefore, this study aims to assess and compare the environmental impacts and sustainability associated with the natural blocks manufactured with virgin materials and three generations of the eco-blocks manufactured with recycled C&D waste and waste glass by the lifecycle assessment (LCA) techniques. For evaluating the environmental performance of concrete paving blocks, the IMPACT 2002+ method was used for lifecycle impact assessment with the functional unit of 1 t of blocks production. This study considered the “cradle-to-site” system boundary, which includes raw material extraction/production, raw material collection and transport to blocks manufacturing site, blocks manufacturing, and transport of the produced blocks to use sites. First-hand data were collected from a local eco-block manufacturer. Sensitivity analysis was conducted for different raw material inputs to investigate the variation of the results. The findings demonstrated that as compared to the natural blocks, the eco-blocks consumed 26–32 % lower energy, emitted 17–20 % lower greenhouse gases (GHG) in CO2 eq. as global warming potential, 22–29 % lower SO2 eq. as acidification potential, and 20–26 % lower PM2.5 eq. as respiratory inorganics potential, depending on the types of eco-blocks. The proposed manufacturing process has the higher savings for all impacts categories for the eco-blocks. In addition, second generation eco-blocks induced the lowest impacts compared to other two types of eco-blocks. In summary, the eco-blocks have significant environmental gains which could help minimize the waste management problem, reduce natural resource depletion, and promote green consumption. The paper provides a method to facilitate the construction industry to choose sustainable materials to minimize environmental damages and promote the sustainable management of wastes. In addition to establishing a basis for choosing materials, the paper compares alternative manufacturing processes of concrete paving blocks for promoting green construction.

Food waste is the largest constituent of municipal solid waste in Hong Kong, but food waste recycling is still in its infancy. With the imminent saturation of all landfill sites by 2020, multiple technologies are needed to boost up the food waste recycling rate in Hong Kong. Conversion of food waste into animal feeds is prevalent in Japan, South Korea, and Taiwan, treating over 40 % of their recycled food waste. This direction is worth exploring in Hong Kong once concerns over food safety are resolved. Fortunately, while feeding food waste to pigs and chickens poses threats to public health, feeding it to fish is considered low risk. In order to examine the feasibility of converting food waste into fish feed in Hong Kong, this paper investigates the market demand, technical viability, feed quality, regulatory hurdles, and potential contribution. The results show that a significant amount of food waste can be recycled by converting it into fish feed due to the enormous demand from feed factories in mainland China. Two conversion technologies, heat drying and black soldier fly bioconversion, are studied extensively. Black soldier fly bioconversion is preferable because the end-product, insect powder, is anticipated to gain import approval from mainland China. The authors suggest further research efforts to speed up its application for food waste recycling in urban cities.

Purpose The construction sector was the second largest contributor of Hong Kong carbon emissions, and 85 % of the emission from construction was external in nature. The carbon footprint embodied in each building construction material varies considerably under different conditions. This study aims to quantify the embodied carbon footprint of building construction materials used in Hong Kong with the consideration of local factors and to investigate how the region-specific characteristic would affect the result.

Increasingly, taxonomies are being developed and used by industry practitioners to facilitate information interoperability and retrieval. Within a single industrial domain, there exist many taxonomies that are intended for different applications. Industry specific taxonomies often represent the vocabularies that are commonly used by the practitioners. Their jobs are multi-faceted, which include checking for code and regulatory compliance. As such, it will be very desirable if industry practitioners are able to easily locate and browse regulations of interest. In practice, multiple sources of government regulations exist and they are often organized and classified by the needs of the issuing agencies that enforce them rather than the needs of the communities that use them. One way to bridge these two distinct needs is to develop methods and tools that enable practitioners to browse and retrieve government regulations using their own terms and vocabularies, for example, via existing industry taxonomies. The mapping from a single taxonomy to a single regulation is a trivial keyword matching task. We examine a relatedness analysis approach for mapping a single taxonomy to multiple regulations. We then present an approach for mapping multiple taxonomies to a single regulation by measuring the relatedness of concepts. Cosine similarity, Jaccard coefficient and market basket analysis are used to measure the semantic relatedness between concepts from two different taxonomies. Preliminary evaluations of the three relatedness analysis measures are performed using examples from the civil engineering and building industry. These examples illustrate the potential benefits of regulatory usage from the mapping between various taxonomies and regulations.