• Carbon Emission Estimation

    To seek carbon emission reduction opportunities for housing developments at the planning and design stages, a life cycle Carbon Emission Estimation (CEE) method has been developed to estimate the carbon dioxide emission from buildings throughout their life cycle. This methodology applies a Life Cycle Assessment framework to estimate the Greenhouse Gas emissions in terms of carbon dioxide equivalent (CO2-e) of a public housing block from cradle to grave. This also enables the establishment of the benchmarks of emission level for a housing block and a housing estate throughout the project life cycle stages to facilitate comparison and to set achievable goals for improvements. The estimated result is presented in terms of CO2-e emissions per flat and per square metre of gross floor area (GFA) and construction floor area (CFA) of the building. In principle, the CEE covers the following six major aspects:

    Construction Stage

    1. Materials Consumed during Construction

    2. Materials for Structure

    Occupation Stage

    3. Electricity Consumption by Communal Building Services

    4. Carbon Reduction by Renewable Energy Installations

    5. Carbon Absorption by Trees

    Demolition Stage

    6. Demolition

    With the benchmarks established, the carbon emission level of a new housing block can be compared to determine its positioning in terms of environmental impact. The benchmark can also help improve public communication about carbon emissions and, more importantly, serve as a minimum standard to facilitate carbon mitigation through different design alternatives. Since February 2011, the estimation of carbon emissions for the above six aspects during the design stage have been adopted in all our new development projects with domestic blocks design.

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    Kai Tak Site 1A project design with the application of Carbon Emission Estimation method to benchmark the carbon emission levels throughout the project life cycle

  • Life Cycle Assessment and Life Cycle Costing Study of Building Materials

    The selection of building materials has significant impact both in environmental and monetary terms. If better alternatives are used, huge potential benefits can be realised over the life span of a building. Conscious of our environmental responsibility to the community and the need for cost effectiveness, we have pioneered evaluation methodologies for appraising building materials and products on a life cycle basis for better sustainable solutions.

    The main objective of the study is to appraise building materials commonly used in our New Harmony 1 (NH1) blocks and to explore how their sustainability can be enhanced.

    Combining LCA Indices with LCC Price Mechanisms as a Decision Making Tool

    Combining LCA Indices with LCC Price Mechanisms as a Decision Making Tool

    Following are some key findings of the study:

    • The ratio of capital cost to maintenance cost is 1:4 while the ratio of initial impact to operational environmental impact is about 1:10. This means more emphasis should be placed on the maintenance regime.
    • Initial environmental impact generated from architectural items is low, while the recurring impact generated from regular maintenance is comparatively high.
    • It has been validated that the NH1 domestic block has reached the optimum level in terms of positive environmental impact and life cycle cost effectiveness.

    Applications:

    • A number of elements have been evaluated with the aim to enhance the design standard.
    • The developed computer model and data generated can be used for comparing the cost and environmental performance of some new/alternative materials.
    • The whole study report has been uploaded onto HA website for access by general public.
  • Micro-climate Studies

    To create quality living environment and improve the environmental performance of our new building projects, micro-climate studies and Air Ventilation Assessments are conducted during the planning and design stages. With the use of computerised simulation models, we can optimise our design to enhance wind environment of the site, natural ventilation and daylight for the domestic flats, thermal comfort of external areas and energy efficiency. Since 2004 we have been applying the studies in all public housing projects. Encouraging feedback from residents on environmental performance was collected in resident survey conducted in recently completed projects. In 2018/19, we continued to carry out micro-climate studies for 31 on-going projects, in addition to Air Ventilation Assessment for 19 on-going projects.

    Study of vertical daylight factor and outdoor sunshading pattern

    Study of vertical daylight factor and outdoor sunshading pattern

    Study of vertical daylight factor and outdoor sunshading pattern

    Study of vertical daylight factor and outdoor sunshading pattern

    Study of vertical daylight factor and outdoor sunshading pattern

    Wind environment study for different seasons

    Wind environment study for different seasons

    Wind environment study for different seasons

    Wind environment study for different seasons

    Wind environment study for different seasons

  • Use of Green and Sustainable Materials and Components

    • Usage of Green Materials and Components

      We completed the development of an accelerated test for resistance to fungal and algae growth for multi-layer acrylic paint which was applicable in the Hong Kong environment. A new specification including relevant requirements was published and implemented in the third quarter of 2011. Our project team had closely examined the application of synthetic macro-fibre reinforcement in ongrade slabs as a replacement to steel reinforcement. The application was found to be technically feasible. We have incorporated this technology in the design of various projects, including Shui Chuen O Estate and On Tat Estate.

      We endeavoured using recyclable materials to reduce the consumption of cement (a source of carbon emission) in projects. For instance, the ground granulated blastfurnace slag (GGBS) has been used as a partial replacement of cement in precast façades in all building projects and it has been further extended to precast staircase since January 2016. There will be a saving of about 300 tonnes of cement for each 41-storey domestic block when GGBS is applied to the precast façades and staircase. Wider use of GGBS concrete in semi-precast slabs are being explored.

      Green Materials and Components

      Green Materials and Components

    • Sustainable Timber

      We have stopped using tropical hardwood in temporary construction works since mid-2003. We have also promulgated specification requiring contractors to use timber from sustainable source for temporary works including formwork, protective canopy, catch fan, walkway, toe board, timber mock-up, signboards etc. during construction. We continue to apply specifications for the use of timber from certified sustainable source for manufacturing of doors. In August 2014, we implemented a new specification allowing the use of finger and composite joints for manufacturing door-sets, which help reduce the use of raw materials in the manufacturing process.

      Sustainable timber

      Sustainable timber

  • Greening in Housing Estates

    • Estate Ecology

      We protect the ecology nearby our housing estate carefully by applying balanced ecological planning and design principles in all suitable projects. We set out green design guidelines for public housing developments. The overall greening coverage target is to have at least 20% greening ratio in new estates and 30% for sites over two hectares. As a rule of thumb, the tree planting ratio is not less than one tree per 15 flats. In addition, we continued to closely monitor the cost effectiveness of the greening design and provisions in our new estates. We co-ordinate with the Development Bureau on tree preservation and management works.

    • Greening for Newly Formed and Existing Slopes

      To create aesthetic values for residents, we proactively provide green treatment to newly formed slopes and existing slopes by hydroseeding, planting or other appropriate methods.

      Hydroseeding at slopes in So Uk Estate Phase 2

      Hydroseeding at slopes in So Uk Estate Phase 2

      Hydroseeding at slope in Shui Chuen O Estate

      Hydroseeding at slope in Shui Chuen O Estate

    • Soft Landscaping

      Starting from April 2000, our policy has been to plant at least one tree for every 15 flats in a newly built estate.

      To enhance greening in estates, we have established the overall target of 30% green coverage for all new housing projects, with a minimum of at least 20%. We are implementing initiatives of roof greening, vertical greening and grass-paving system for some vehicular areas, in addition to traditional greening at grade and slopes.

      Soft landscaping in open area

      Soft landscaping in open area

      Soft landscaping under covered walkway

      Soft landscaping under covered walkway

      We completed a study on the environmental benefits of green roof at two selected residential blocks at Shin Ming Estate in October 2013. Some of the recommendations from the study have been incorporated into the Green Design Guide in 2015/16.

  • Green Living Environment

    • Promoting Electric Vehicles

      To support Government's policy to promote the wider use of electric vehicles (EVs) for environmental protection, we have provided EV charging facilities in the new carparks and at some parking spaces in the existing carparks on need basis. In the year of 2019, we already have some 1000 parking spaces equipped with EV charging facilities. A maximum of two hours free parking were offered for EVs during charging with free electricity as an incentive.

      EV Charging Station

      EV Charging Station

    • Green Living Environment

      Under the programme "Action Seedling", participants from residents, schools and community organisations were required to nurse seedlings plants given by the Housing Authority and its building contractors until they are fit for transplanting into the planters of new public housing estates. The programme aims to unify the inputs from our contractors, tenants and general community in bringing new public housing estates to a greener living environment.

      Residents participated in “Action Seedling”

      Residents participated in "Action Seedling"

      School Students joined the planting activity in the estate

      School Students joined the planting activity in the estate