Life Cycle Assessment Of Bamboo/Wood Structure Village House

In the National Guideline on Medium-and Long-Term Program for Science andTechnology Development(2006-2020), green building,energy saving and consumptionreducing,biomass resources developing and utilizing have been listed as the key areas and theprior development subject. Use bamboo or wood to substitute conventional building materialsaccords with the strategy demands of China.Howerever, there are still some doubts about bamboo/wood structure house:1, Shortage ofland resources makes the application and extension of bamboo/wood structure house impossible.2, As main forest resources, bamboo and wood itself can protect our environment, regulateclimate, retain soil and water, so built bamboo/wood house would also destroy our environment.3, Bamboo/wood must be produce and modify to become structure members, in these proceses,environment pollution and energy consumption still exist.4, The cost of bamboo/woodstructure house is high than the expection of ordinary people.For the above reasons, our research restrict the use bondary of bamboo/wood structurehouse in rural areas, adopts the method of Life Cycle Assessment as the basic framework,analyzes the carbon balance and ecological efficiency of the three types of residentialhouses--the bamboo structure, wooden structure, and brick structure. We attempts to explorethe comparative advantages and shortcomings of the bamboo structure houses, in order toprovide a analytical support for the government to formulate relevant policies and decisionmaking. In the life cycle assessment process, this thesis has taken a series of analyticalmeasures in each of the following standard procedures: ISO14044.(1) Goal and scope definition. The research objective is defined to establish an inventoryof the resources, energy and environmental emissions of three types of structures of houses, andconduct a comparative evaluation of the three. As a new phenomenon, the bamboo structurehousing has not been put into official practices,nor "a report as worthless" case of it can befound. In this circumstance, this study defines the scope of the evaluation as such, fromresource extraction to the construction process. In order to present the study differences in thefunctional area and to improve comparability, the functional units of this study is defined as onesquare meters of houses.(2) Inventory analysis. The inventory analysis is the most important part of the LCAmethod, mainly due to data acquisition and data quality issues. In accordance with theinternational practice in the field of life cycle assessment, this study has taken the approach offield research (bamboo scrimber, bamboo laminated timber, bamboo plywood, gravel life cycleinventory data) and literature data (steel, cement, wood laminated timber, OSB board, wood preservative, concrete, porous brick, electricity, coal, fuel oil, diesel and natural gas productionand combustion), to integrate into a main input materials and semi-finished products inventoryof the three types of houses, and established a life cycle inventory database.(3) Impact assessment. From the list of data, it involves the following types ofenvironmental impact: non-renewable resources (ADP), the greenhouse effect (GWP),photochemical consequences of potential (POCP), acidification (AP), eutrophication (EP),water pollution (WTP) and human toxicity (HTP). In order to improve the comparability of theresults, the equivalent material selection and the normalized weighting, have adopted therecommendation by the "manual of international standard of life cycle assessment".(4) Interpretation. For the three types of houses, we interprete the LCA result from theangle of the main pollutants' contribution size in the environmental impact, as well as wherethey are generated.Based on the comparative evaluation of life cycle inventory and evaluation of the threetypes of houses, we draw the following conclusions:(1) with bamboo structure as a benchmark,the consumption of fossil resources each square meter of wood structure is48.8%of that of thebamboo structure, while the brick-concrete structure consumes714.6%of that of bamboostructure;(2) the energy consumption per square meter of wooden structure accounts for51.7%of that of the bamboo structure, while the brick-concrete structure accounts for322.2%of that ofthe bamboo structure;(3) the total environmental load per square meter of wood structure is70.6%of that of the bamboo structure, while the brick structure accounts for696.8%of that ofthe bamboo structure;(4) in term of the types of environmental impact, the three structures ofhouses all demonstrate great impact in ADP, GWP and AP. The ratios of the impact of the ADP,GWP and AP of the wooden structure to the bamboo structure are respectively49.3%,81.3%and76.7percent; likewise, the ratios of the brick structure to the bamboo structure arerespectively712.3%.418.8%and1333.3%;(5) from the carbon balance point of view, thebamboo structure house demonstrates positive carbon balance because its carbon sequestrationin the building materials is greater than that of its carbon emissions, while the wood structurehouse shows negative carbon balance, and the brick-concrete structure does not have thefunction of carbon sequestration.(6) Regarding the ratio of economic costs to ecological cost,wooden structure house has the highest eco-efficiency, accounts for1.16times of that of thebamboo structure, and the brick structure accounts for0.15times of that of the bamboostructure.After a comparative life cycle assessment, it can be drawn that the bamboo structure housesare better than brick structure in terms of resources, energy, environmental emissions andeco-efficiency, but not as good as the wooden structure houses. The major reasons are two:(1)the amount of foundation concrete usage of bamboo structure houses is2.24times of that of the wooden structures, and the usage of beams and columns that connect the pieces of bamboostructure is1.34times of that of the wooden structure;(2) in the survey data, materials andenergy consumption of the bamboo structure may be higher, and the emission data may be lowerthan reality.The nature of the contribution of this thesis lies in twofold:(1) it established a life cycleinventory database for bamboo structure, wood structure and brick-concrete structure houses;especially, this is the first original work of such kind for the bamboo structure houses;(2) itintroduced carbon balance and eco-efficiency into the life cycle assessment of buildingmaterials.