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The building sector significantly contributes to embodied carbon (EC) emissions. Usually, a pre- or post-construction assessment is conducted for analysing prefabricated buildings' EC. However, actual EC may differ from estimated values, and a lack of real-time EC monitoring method makes it difficult to determine the causes and take prompt actions if an unexpected deviation is found after construction. Therefore, this paper develops an EC monitoring system for tracking and visualising prefabricated buildings' EC at multiple spatiotemporal levels by integrating the Internet of Things (IoT) and Building Information Modelling (BIM). Infrastructure, computing, and application layers were designed to form the system. The developed system proved effective and efficient in formulating prompt and reasonable carbon control measures and conducting comprehensive carbon analysis using a real-life prefabricated building in Hong Kong. Feedback provided by the system indicates that construction material is the most significant carbon source, whereas EC generated from transportation and electricity consumption of equipment should not be underestimated. The system advances knowledge in achieving carbon traceability and visibility and depicts a comprehensive carbon distribution map, which should help project managers and government authorities with effective carbon strategies. • Integrating IoT and BIM is found to enhance buildings' carbon traceability and visibility. • An embodied carbon (EC) monitoring system for prefabricated buildings is developed. • Prefabricated buildings' EC is examined at multi-spatiotemporal levels. • Material is identified as the largest carbon source for constructing precast elements. • EC generated from transportation and equipment should not be underestimated. [ABSTRACT FROM AUTHOR]

Building information modeling (BIM) has been leveraged to reduce manual efforts in the life cycle assessment (LCA) of buildings. However, data interoperability between BIM and LCA tools remains a significant challenge because of disparate data structures, leading to a deficiency in automatic data mapping methods. Few studies have adopted professional BIM and LCA tools to evaluate the embodied carbon of prefabricated buildings at multiple spatial levels. Thus, this paper developed a BIM-integrated LCA solution to automate the embodied carbon assessment of prefabricated buildings based on a five-level framework: material, component, assembly, flat, and building. The solution framework involved three modules: (1) BIM data preparation, (2) data extraction and integration, and (3) embodied carbon assessment. An Industry Foundation Classes (IFC)-enabled data transfer tool was developed to adapt BIM data to the LCA data structure automatically. A real-life prefabricated building in Hong Kong was used to validate the feasibility of the developed solution by comparing it with the traditional LCA method. Embodied carbon was reported in five levels. The cradle-to-end-of-construction embodied carbon of the case building was calculated as 561 kg CO 2 /m2, showing an acceptable 1% discrepancy with traditional LCA results owing to inevitable quantity differences between design and construction. The results also indicate a dramatical time reduction in the LCA modeling process from 729 min to 62 min, achieving a 91.5% efficiency improvement. It can thus practically increase practitioners' willingness to conduct LCA at an early design stage with quick feedback. The developed solution also extends the knowledge on automatic BIM-integrated LCA methodologically by addressing data interoperability using the IFC standard. Further, it provides systematic insights into the embodied carbon emissions of prefabricated buildings based on the five-level theoretical framework, guiding low-carbon designs for prefabricated buildings. • Embodied carbon assessment is automated by integrating BIM into LCA. • A tool named BIMToSimaPro is developed to automate data transfer from BIM to LCA. • Data interoperability between BIM and LCA is enhanced using the IFC standard. • A five-level framework is proposed for standardized embodied carbon evaluations. • The solution achieves consistent carbon results with a 91.5% efficiency improvement. [ABSTRACT FROM AUTHOR]

The study reviewed coping and help-seeking behaviour among Hong Kong Chinese family care-givers of older people diagnosed with dementia. A convenience sample of those caring for family members with dementia (N=11) was recruited in Hong Kong. Semi-structured interviews were conducted, transcribed and analysed using NVivo. The study found evidence of distinct Chinese coping strategies that focused upon internal self-regulation, forbearance and family obligations. In terms of help-seeking behaviour, these care-givers expressed great concern about bothering their family members. When there is a desperate need for help, they turn to community services. Results are discussed in the context of both traditional Chinese cultural values as well as the modern transformations of the Chinese society. In particular, Eastern philosophical teachings tend to focus on changing personal inner perception and thoughts rather than attempting to change the environment. Although family obligations have been traditionally upheld, many modern Chinese societies are undergoing social and demographic changes, resulting in marked decline in multi-generational households. Our findings can have applications not only for Chinese cities but also may have implications to the West as strong well-established Chinese communities are widespread. [ABSTRACT FROM PUBLISHER]

Carbon emissions associated with high-rise buildings are expected to grow with the increasing population in high-density cities. As an environmentally friendly construction method, prefabrication should lead to reduced buildings' emissions. However, few studies have considered the uncertainty caused by errors in input parameters, scenario assumptions and choices of analytical uncertainty models when examining the embodied carbon of prefabricated high-rise buildings, leading to the misinterpretation of results. To address this, a five-level framework is developed for assessing the deterministic embodied carbon of prefabricated buildings using the process-based method. A Data Quality Index based Monte Carlo Simulation is applied for the uncertainty analysis using SimaPro 9.0 software. A typical prefabricated high-rise residential building in Hong Kong is examined. Seven scenarios are developed by varying system boundaries, materials used, partition wall thickness, waste rate, prefabrication rate, transportation distance, and analytical uncertainty model's transformation coefficients, to examine the influences of the scenario and model uncertainty. Results indicate that the embodied carbon of the case averages 561 kg CO 2 /m2. When considering both deterministic results and parameter uncertainty, the key processes are identified as being the production of concrete, steel and timber, as well as transportation activities. The results reveal that 31.6% of the embodied carbon can be possibly reduced by combining the pre-defined scenarios. The selection of transformation coefficients in analytical uncertainty model significantly affects the variances of the results and should be carefully examined. This paper can better facilitate the uncertainty measurement of prefabricated buildings' embodied carbon assessment for improving the reliability of results. • A five-level framework facilitates carbon calculation and meaningful comparison. • A DQI-based MCS uncertainty analysis helps to avoid misinterpretation of results. • Decisions on material selection affect buildings' embodied carbon significantly. • Reliability of carbon estimation results is highly correlated with analytical uncertainty models. • Prefabricated high-rise buildings' embodied carbon in HK can be reduced by up to 31.6%. [ABSTRACT FROM AUTHOR]

Buildings contribute significantly to carbon emissions worldwide. Prefabrication is regarded as a cleaner production and sustainable construction approach, which has been utilized for public residential building construction in Hong Kong to achieve more productive, safer and higher-quality construction process with less negative impacts on the environment. Previous studies explored the life cycle carbon assessment of prefabricated buildings, but no unified embodied carbon assessment model or reporting format has been established in Hong Kong. This paper aims to contribute a better systematic understanding of the embodied carbon of prefabricated high-rise public residential buildings at different levels of unit of analysis and to identify appropriate measures for effective embodied carbon reduction. The research was carried out through a case study using a typical 30-storey public residential building in Hong Kong. The embodied carbon was calculated and reported at five levels of unit of analysis, i.e. material, component, assembly, flat and building. The cradle-to-end of construction embodied carbon of the case building was found to be 561 kg CO 2 /m2. Off-site activities accounted for 27.3% of the total embodied carbon, most of which were contributed by the production of façades (6.9%), bathrooms (6%), kitchens (4.5%) and slabs (4.2%). Embodied carbon from the manufacturing of materials was mainly attributed to concrete (59.2%) and steel (20.1%). The results reveal that the embodied carbon could be reduced significantly by adopting low carbon concrete such as replacing the ordinary Portland cement with blast furnace slag cement (with 22.8% reduction potential) and utilizing cement substitutes (25% pulverized fly ash (PFA)) (with 9.8% reduction potential). However, other measures were revealed to only impose marginal effect, such as decreasing the thickness of walls (with 1.9% reduction potential) and optimizing prefabrication rate (with 1.5% reduction potential), which was believed to be hindered by the high transportation carbon to and in Hong Kong. The developed five-level analytical framework paves the foundation for future standardization and benchmarking of prefabricated buildings' embodied carbon and the findings provide strategies for the most effective carbon reduction of prefabricated buildings in cities. • Embodied carbon of typical precast concrete housing blocks in HK is 561kgCO 2 /m2. • A five-level analytical framework is developed for benchmarking and standardization. • Embodied carbon can be reduced significantly by adopting low carbon materials. • The use of prefabrication helps to reduce embodied carbon of HK high-rise buildings. • To establish precast database at the five levels helps to achieve efficient comparisons. [ABSTRACT FROM AUTHOR]