Please cite this article in press as: Omar, W. M. S. W., et al. Assessment of the embodied carbon in precast concrete wall panels using a hybrid life cycle assessment approach in Malaysia. Sustainable Cities and Society (2013), http://dx. a b s t r a c tThere is currently growing interest in quantifying the direct and indirect carbon emissions embodied in construction materials and their components production. Previous research shows that indirect emission could be higher than direct emission for energy intensity materials such as cement and steel reinforcement. Quantifying direct emissions alone would underestimate the carbon emissions associated with a material and in turn its environmental impact. The assessment of indirect emissions is a challenging task involving upstream processes of material production. This paper investigates the existing literature on the quantification of embodied carbon by both direct and indirect emissions as well as demonstrating the application of a hybrid life cycle assessment method in building construction. The focus of this paper is the Malaysian context however the principles apply universally. A typical 2-storey residential building has been investigated to determine the total carbon emissions when comparing two construction techniques: conventionally reinforced concrete and precast concrete panels. This paper demonstrates the application of hybrid life cycle assessment by expanding the boundaries of process methods and reducing the sensitivities of I-O life cycle assessment to the raw material price fluctuation for product manufacturing.

Identification of parameter variation allows us to conduct more detailed life cycle assessment (LCA) of energy and carbon emission material over their lifecycle. Previous research studies have demonstrated that hybrid LCA (HLCA) can generally overcome the problems of incompleteness and accuracy of embodied energy (EE) and carbon (EC) emission assessment. Unfortunately, the current interpretation and quantification procedure has not been extensively and empirically studied in a qualitative manner, especially in hybridising between the process LCA and I-O LCA. To determine this weakness, this study empirically demonstrates the changes in EE and EC intensities caused by variations to key parameters in material production. Using Australia and Malaysia as a case study, the results are compared with previous hybrid models to identify key parameters and issues. The parameters considered in this study are technological changes, energy tariffs, primary energy factors, disaggregation constant, emission factors, and material price fluctuation. It was found that changes in technological efficiency, energy tariffs and material prices caused significant variations in the model. Finally, the comparison of hybrid models revealed that non-energy intensive materials greatly influence the variations due to high indirect energy and carbon emission in upstream boundary of material production, and as such, any decision related to these materials should be considered carefully.

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Abstract. Effectiveness of management in maintenance aspect holds the key element in influencing the performance of overall maintenance management. Similarly, public hospital building needs an effective maintenance management as this type of building in nature is one of the most complex issues in the field of maintenance. Improper building maintenance management adopted by the organization significantly will interrupt the overall operation of the building. Therefore, this paper is aim to identifying the key performance indicator (KPI) of effectiveness of maintenance management for the public hospital building. A total of 32 set of questionnaires were distributed to the maintenance manager for each hospital in the northern region of peninsular Malaysia by using selfadministration strategy. The survey answer was analyzed by performing descriptive analysis in SPSS. Overall, the result of descriptive analysis shows that all the ten factors of effectiveness of maintenance management are accepted as KPI since the mean value is at least 3.93 which classified as important and significant. The most significant factor of effectiveness of maintenance management is task planning and scheduling with the mean score of 4.35. While less significant factor is identify as maintenance approach with the value of mean score is 3.93. The both results indicates that the management need to have well-structured planning for the maintenance works and also need to embrace the exact strategy of maintenance approach in order to achieved better overall performance of maintenance management. This study may draw a standard practice for the government in assessing the performance of public facilities in terms of maintenance management.