Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) Tool. for Commercial Building Developments in Hong Kong

Transcription

1 Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) Tool for Commercial Building Developments in Hong Kong

2 FORWARD

3 Forward 2002, the Electrical and Mechanical Services Department In (EMSD) of the HKSAR Government initiated a consultancy study titled Life Cycle Energy Analysis of Building Construction. Ove Arup & Partners Hong Kong Ltd, in association with the sub-consultants, were commissioned to undertake the Consultancy Study. Recommended by the Construction Industry Review Committee (CIRC) in 2001, the study aims to develop an assessment tool with model and data that appraises life cycle costs and life cycle performances of building materials and components; and provides guidelines on the use of alternative materials and systems that help to improve the environmental, energy and economic performances of buildings. The study also aims to promote the concept of sustainable construction and to solicit a broad base of public support in ensuring the need for sustainability to the community. This pamphlet provides general information on the concept of Life Cycle Assessment (LCA), and an outline of the established LCA tool which was developed based on extensive research work, survey of commercial buildings and consultation forums to the local construction industry. With the integration of life cycle philosophies, the LCA tool features a user-friendly processing template, with design-oriented data-entry sheets and informative reporting documents for the application of the construction industry in Hong Kong. 1

4 TABLE of CONTENTS 2

5 Content Page 1 Introduction of LCA 4 Buildings and Sustainable Development Background of LCA 2 Life Cycle Inventory 6 Inventory (LCI) Process Impact Assessment (LCIA) Life Cycle Cost 3 LCA/LCC Tool Development 10 The Need of LCA/LCC Tool for Hong Kong Establishment of LCA/LCC Data The LCA/LCC Database for Hong Kong Buildings Key Features of the LCC/LCA Tool 4 A Simple Wood Shed Example 14 An Introductory Example of LCA 5 Further Information 16 3

6 Buildings and Sustainable Development INTRODUCTION of LCA Buildings are climate modifiers that provide indoor environments suitable for habitation and various economic and social functions. However, the cost of having buildings to fulfil our needs involves enormous amount of resources consumption during construction, operation and maintenance of the buildings, from which large quantities of wastes and pollutants are also generated. Sustainable Development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs (The World Commission on Environment and Development, 1987). In Hong Kong, buildings are responsible for a major portion of the city s overall energy use. Demolition of buildings generates huge amount of solid waste, which is becoming a major load on our landfills. Enhancing sustainability of building development is paramount important to the sustainability of Hong Kong. To achieve this goal, developing a reliable tool for quantifying environmental impacts of buildings is necessary. Sustainable development is a key issue for the building industry in Hong Kong Life Cycle Assessment (LCA) is an objective method to evaluate the environmental burdens associated with a product, process or activity by identifying and quantifying energy and material uses and releases to the environment, and to evaluate and implement opportunities to influence environmental improvements. The method assesses the entire life cycle of the product, process or activities, encompassing extracting and processing material; manufacturing, transporting and distribution; use, reuse and maintenance; recycling and final disposal (The Society of Environmental, Toxicology and Chemistry, 1993). 4

7 Background of LCA Originated from the industrial sector of Western Europe and North America for quantification of the environmental impacts in producing, using and disposing of manufactured products, LCA is adopted in providing advice on production processes improvement, and more recently as a basis for environmental performance labelling of products. At present, application of LCA to building design remains embryonic. Internationally, the idea of LCA has been raised in: Earth Summit at Rio de Janeiro Kyoto Protocol United Nations Environment Programme Earth Summit at Johannesburg Life cycle ISO assessment framework Goal and scope definition Inventory analysis Impact assessment Interpretation Applications Framework of Life Cycle Assessment under ISO The series of ISO Standards provides an internationally accepted framework for LCA. Stages of LCA under ISO Goal and Scope Definition: State intended application, reasons for doing LCA and to whom the LCA results are communicated; and define system boundary, a s s e s s m e n t m e t h o d, d a t a requirement, functional units, assumptions, limitations, etc. Inventory Analysis: Collect the economic flows and environmental intervention data for each unit process within the system boundary. The analysis yields a list of resources input and emissions from the involved processes. Impact Assessment: Include: (1) Section of impact categories and indicator; (2) Classification of inventory data i n t o i m p a c t c a t e g o r i e s ; ( 3 ) Characterization of inventory data within each category, and optionally (4) Normalization; (5) Grouping; and (6) Weighting the characterised results. Interpretation: Include: making observations from the results to identify improvement opportunities or compare alternative processes. 5

8 Inventory (LCI) Process LIFE CYCLE INVENTORY 6 Inventory (LCI) Analysis yields a long list of quantities of all the natural resources consumed and the emissions produced in various stages of the complete life cycle of a product, from cradle to grave. The LCI result depends on the types and quantities of natural resources (including fossil fuels) and other materials used during the production of goods; the modes and distances of transportation involved; the way in which the product is used and its lifespan; and how the product is finally disposed. These factors vary from one country or region to another, dependent on the availability of the required resources in the region, the technologies employed in the production processes, and whether the consumed product is locally produced or imported. Whilst the LCI result is a complete account of the quantities of resources consumed and emissions incurred during the life cycle of a product, the long list of quantities is difficult to interpret. LCI Analysis Steps of LCIA Impact categories in CML Baseline method: 1. Abiotic depletion 2. Global warming 3. Ozone depletion 4. Human toxicity 5. Fresh water ecotox. 6. Marine aquatic ecotox. 7. Terrestrial ecotox. 8. Photochemical smog 9. Acidification 10. Eutrophication Categorization Characterization Normalization * Grouping * Weighting * * Optional under ISO 14042

9 Impact Assessment (LCIA) The assessment follows the LCI analysis first Categorises the impacts (resources consumption and emissions) into a range of impact categories. The Characterization step is then performed, which converts the quantities of various types of impacts under each category into equivalent quantities of a reference impact (e.g. methane into an equivalent amount of CO 2 under the global warming category), yielding one single impact indicator for each impact category. Each impact indicator retains the unit of measurement of the quantity. The Normalization step converts the impact profile (the set of impact indicators, one for each impact category), into a set of dimensionless numbers. Typical normalization factors used are the total quantity of each type of impact incurred in a region or the whole world in a year, on the whole or per capita basis. A normalised impact indicator reflects the proportional contribution of the product to the total impact of the same type in the region, and hence the seriousness of the impact the product would incur. An effective Grouping step is required for the convenience of further study and data analysis. To facilitate decision making, the normalised impact indicators may be Weighted to yield a single, all-embracing impact indicator, through the use of a set of weighting factors. Derivation of the weighting factors is typically through solicitation of expert opinions. In this study, the CML Baseline 2000 LCIA method is employed. In addition to the ten impact categories embraced by the method, two additional impact indicators are provided for reference: life cycle energy use (including embodied and operating energy use) and solid waste generation. The normalization factors used are based on 1995 World data. 7

10 The relationship between the Impact Analysis a Life Cycle Cost (LCC) LIFE CYCLE INVENTORY Like any other investments, attempts to minimise environmental impact of building developments should take into account the associated costs. Life cycle cost (LCC) yields the present value of the current and future expenditures for the procurement of the building and the operation and maintenance throughout its useful life. This allows the financial implications of future savings due to additional investments made at present for enhancing performance (e.g. energy efficiency or durability of materials) which should be assessed for decision making. Development Tool and LCI Database: There are several LCA tools available in the market that can be used to implement the above processes. The detailed LCA Tool Sima Pro has been employed in establishing a LCIA profile database in the study. LCI data for various processes have been extracted from proprietary databases and modified to reflect local construction practices. Life Cycle Inventory Analysis 8

11 Acidification Photochemical Photochemical Smog Smog Resources Depletion Acidification Global Warming Global Warming Ozone Depletion Ozone Depletion Eutrophication Fresh Water, Marine and Fresh Water, Marine Terrestrial Ecotoxicity Human Toxicity and Terrestrial Toxicity Ecotoxicity Life Cycle Impact Analysis Life Cycle Cost Analysis Life Cycle Inventory Analysis, Life Cycle nd Life Cycle Cost Analysis 9

12 The Need of a LCA/LCC Tool for Hong Kong LCA/LCC TOOL DEVELOPMENT Given that conducting LCA and LCC of buildings is a complicated process, equipping designers with an appropriate tool is a key step in promoting sustainable building development. There are at present a few tools that have been developed specifically for assessing buildings. These tools, however, vary in scopes and methods of assessment and are embedded with data specific to construction practices in either the West Europe or North America. Therefore they can neither be used directly for buildings in Hong Kong nor can the embedded data be amended. To make it meaningful, LCA and LCC of buildings must be based on data that reflect the impacts incurred by consuming the resources in the local Life Cycle Cost context, including local practices of construction and operation and maintenance of buildings. Such data are, until now, unavailable in Hong Kong. This consultancy study includes development of a LCA and LCC tool suitable for application to commercial building developments in Hong Kong. The work involved the establishment of an impact and cost database for the dominant range of building services systems and components, and materials that can be found in commercial buildings in Hong Kong. Well-known LCA programs for buildings currently available include: - ATHENA (Canada) - BEES (US) - EcoQuantum (The Netherlands) - ENVEST (UK) 10

13 Establishment of LCA/LCC Data The consultancy study includes surveys of components and materials that can be found in 28 recently completed commercial buildings in Hong Kong, the survey helped to identify the range of Environmental Impacts components and materials that would dominate the total environmental impacts of buildings. Surveys are also conducted to find out additional impacts that would be incurred during the construction stage; and the countries from which building m a t e r i a l s a n d s e r v i c e s equipment are imported into Hong Kong for building construction. Other supporting data are also collected from different sources, such as the type of fuel used for producing heat during the production processes, the fuel used in various countries for electricity generation and the mode and distance of transportation involved for importing building and system components and materials from these countries, etc. Top 20 dominant building materials in respect of LCI in the database: 1. Concrete 2. Reinforcing Bar 3. Plaster, Render and Screed 4. Galvanised Steel 5. Tiles 6. Stones 7. Aluminium 8. Structural Steel 9. Access Floor Panel 10. Stainless Steel 11. Plasterboard 12. Glass 13. Bricks and Blocks 14. Plywood 15. Formwork 16. Structural Pre-cast items (Floor Planks, Beams, Staircase) 17. Acoustic Tiles 18. Plastic, Rubber, Polymer 19. Plastic Laminate 20. Thermal Insulation List top 40 building services systems & components with greatest LCI in the database: 1. Power cables 2. Busbar trunking or busducts 3. Chillers 4. Air conditioning duct work & fitting and insulation 5. C h i l l e d w a t e r systems including pipework excluding chiller 6. M c b a n d m c c b distribution boards 7. Sprinkler systems including pipework 8. AHU/ PAUs 9. Submain conduits and trunkings 10. Luminaries 11. Escalators 12. FCU 13. Lift 1 4. F r e s h w a t e r systems 15. Ventilation fans 16. Fire hydrant and hose reels systems 17. Condensate drain systems 18. Diesel generators 19. Plumbing and drainage systems 20. LV switchboards 21. etc 11

14 The LCA/LCC Database for Hong Kong Buildings LCA/LCC TOOL DEVELOPMENT Based on the data collected in building surveys and other global LCA program, adjustments were made to the LCI data sourced from proprietary LCI databases to make them the representative of the impacts that would be incurred due to consumption of building and services components and materials for construction of buildings in Hong Kong. The detailed LCA program was then used to produce LCIA profiles (by implementing the characterization process) for each material that appeared in the list of dominant materials ascertained in the building survey. The produced LCIA profiles are key data in the database and with which LCA of commercial buildings can be performed. Other data in the database include unit price data compiled from tender prices by the Quantity Surveyor in the project team, and physical properties of the materials, including density, thermal conductivity and specific heat. Aggregation of the LCIA results (a list of impact indicators) into a single and all-embracing impact indicator requires a set of weighting factors; likewise for weighting between total impact and life cycle costs. A forum was conducted to solicit subjective evaluations from the building professionals based upon which a set of weighting factors has been derived. A user-friendly data-entry platform facilitates the building designers to input the required data 12

15 Key Features of the LCA/LCC Tool The LCA/LCC tool developed from the study is a computer program that can facilitate building designers to input the required data to model the building designed; perform calculations of the environmental impacts and life cycle cost of the building; and to compare the impacts and costs of alternative designs. The program can output calculated results for different stages in the life cycle of a building, including up to the as-built stage, the operating stage and the endof-life stage. Separate results can also be retrieved for different parts of a building, such as the impacts of the foundation, the building fabric and the services. Facilities are provided to allow the user to compare results down to individual elements level. In addition to data outputs, graphical outputs that show a comparison between alternative designs and a breakdown of the total impact by individual impact c a t e g o r i e s c a n b e p r o v i d e d. T h e LCA/LCC tool and the database will be made publicly available as an enabling mean in promoting sustainable building development. Breakdown of the impacts can be displaced in numerical or graphical form The LCA / LCC Tools will soon be released to the general public for trial run! 13

16 An Introductory Example of LCA A SIMPLE WOOD SHED EXAMPLE The idea of LCA can lively be illustrated in the following example about the construction of a simple wood shed. At the beginning, we need materials including Wood Plank, Nails and other Metal Parts. Process 1 Process 2 Process 3 Process 4 To make the wood planks, some trees need to be fell first Felling trees requires the use of chainsaws Use of chainsaws requires: Petrol input Felling tree generates: Sawdust Branches left in the forest Emissions form the chainsaw Up to this stage, we can first consider the tree felling unit process. In cutting the trees, petrol is burnt for the process where branch sawdust and exhaust gas emitted are considered as waste. Logs are the process product for the next unit process. Output of other processes Petrol Tree Treefelling with a chainsaw Logs Branches Sawdust Emissions Output of other processes Emissions to land and air from the process 14

17 Process 5 After the tree felling process, the logs are collected and transported to the mill. Hence, transportation is the next unit process to be considered. At this time, diesel is the fuel for the tracker while delivered logs are the products in the process. Logs in Forest Output of other processes Diesel Transporting logs to a sawmill Emissions Emissions to air from the process Delivered Logs Output of other processes Process 6 Finally, planks are produced in the mill by sawing. This is another unit process. Output of other processes Electricity Logs Sawmill Sawdust Bark By-products and Emissions to air from the process Planks Output of other processes Process 7 By connecting the unit processes together, we can form a life cycle inventory accumulating the inputs and outputs of the entire process To be accumulated Natural materials Products & energy Natural materials Products & energy Natural materials Products & energy Product Product Final Product Unit process Unit process Unit process Wastes and emissions Wastes and emissions Byproducts Byproducts Byproducts Wastes and emissions To be accumulated 15

18 FURTHER INFORMATION Where Can I Get More Information? For further information, please contact Energy Efficiency Office, Electrical and Mechanical Services Department. Contact details are: Address: 11/F, 111 Leighton Road, Causeway Bay, Hong Kong Tel: , Fax: [email protected] Homepage: 16

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