Skip to main content

A system boundary identification method for life cycle assessment



Life cycle assessment (LCA) is a useful tool for quantifying the overall environmental impacts of a product, process, or service. The scientific scope and boundary definition are important to ensure the accuracy of LCA results. Defining the boundary in LCA is difficult and there are no commonly accepted scientific methods yet. The objective of this research is to present a comprehensive discussion of system boundaries in LCA and to develop an appropriate boundary delimitation method.


A product system is partitioned into the primary system and interrelated subsystems. The hierarchical relationship of flow and process is clarified by introducing flow- and process-related interventions. A system boundary curve model of the LCA is developed and the threshold rules for judging whether the system boundary satisfies the research requirement are proposed. Quantitative criteria from environmental, technical, geographical and temporal dimensions are presented to limit the boundaries of LCA. An algorithm is developed to identify an appropriate boundary by searching the process tree and evaluating the environmental impact contribution of each process while it is added into the studied system.

Results and discussion

The difference between a limited system and a theoretically complete system is presented. A case study is conducted on a color TV set to demonstrate and validate the method of boundary identification. The results showed that the overall environmental impact indicator exhibits a slow growth after a certain number of processes considered, and the gradient of the fitting curve trends to zero gradually. According to the threshold rules, a relatively accurate system boundary could be obtained.


It is found from this research that the system boundary curve describes the growth of life cycle impact assessment (LCIA) results as processes are added. The two threshold rules and identification methods presented can be used to identify system boundary of LCA. The case study demonstrated that the methodology presented in this paper is an effective tool for the boundary identification.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9


  • Clift R, Frischknecht R, Huppes G et al (1998) Towards a coherent approach to life cycle inventory analysis. SETAC, Brussels

    Google Scholar 

  • Crawford RH (2008) Validation of a hybrid life-cycle inventory analysis method. J Environ Manage 88(3):496–506

    Article  Google Scholar 

  • Dodbiba G, Takahashi K, Sadaki J et al (2008) The recycling of plastic wastes from discarded TV sets: comparing energy recovery with mechanical recycling in the context of life cycle assessment. J Clean Prod 16:458–470

    Article  Google Scholar 

  • Ekvall T, Weidema BP (2004) System boundaries and input data in consequential life cycle inventory analysis. Int J Life Cycle Assess 9(3):161–171

    Article  Google Scholar 

  • Environmental Protection Agency (EPA) (2006) Life cycle assessment: principles and practice. EPA/600/R-06/060. Cincinnati, OH, USA

  • Feng C, Ma XQ (2009) The energy consumption and environmental impacts of a color TV set in China. J Clean Prod 17(1):13–25

    CAS  Article  Google Scholar 

  • Finnveden G, Hauschild MZ, Ekvall T et al (2009) Recent developments in life cycle assessment. J Environ Manage 91(1):1–21

    Article  Google Scholar 

  • Gentil EC, Damgaard A, Hauschild M et al (2010) Models for waste life cycle assessment: review of technical assumptions. Waste Manage 30(12):2636–2648

    Article  Google Scholar 

  • Guinée JB (ed) (2002a) Life cycle assessment: an operational guide to the ISO standards (Eco-Efficiency in Industry and Science), part 2b. Kluwer, Dordrecht

    Google Scholar 

  • Guinée JB (ed) (2002b) Life cycle assessment: an operational guide to the ISO standards (Eco-Efficiency in Industry and Science), part 3. Kluwer, Dordrecht

    Google Scholar 

  • Heijungs R, Suh S (2001) The computational structure of life cycle assessment. Centre of Environmental Science, Leiden University, Holland

    Google Scholar 

  • Heijungs R, Guinee JB, Huppes G et al (1992) Environmental life cycle assessment of products: guide and backgrounds. CML, Leiden University, Leiden

    Google Scholar 

  • Hochschorner E, Finnveden G (2003) Evaluation of two simplified life cycle assessment methods. Int J Life Cycle Assess 8(3):119–128

    CAS  Article  Google Scholar 

  • International Standard Organization (ISO) (2000) Environmental management–life cycle assessment—examples of application of ISO 14041 to goal and scope definition and inventory analysis, ISO14049, BSI, ISO

  • International Standard Organization (ISO) (2006) Environmental management–Life cycle assessment—principles and framework. ISO14040, BSI, CEN

  • International Standard Organization (ISO) (2006) Environmental management–Life Cycle Assessment—requirements and guidelines, ISO 14044, BSI, CEN

  • Jacquemin L, Pontalier P-Y, Sablayrolles C (2012) Life cycle assessment (LCA) applied to the process industry: a review. Int J Life Cycle Assess 17(8):1028–1041

    CAS  Article  Google Scholar 

  • Kulkarni R, Zhang HC, Li JZ et al (2005) A framework for environmental impact assessment tools: comparison validation and application using case study of electronic products. Proc IEEE Int Symp Electron Environ, pp 210–214

  • Lindfors L-G, Christiansen K, Hoffman L et al (1995) Nordic guidelines on life-cycle assessment. Nord. Nordic Council of Ministers, Copenhagen

    Google Scholar 

  • Malmodin J, Oliv L, Bergmark P (2001) Life cycle assessment of third generation (3G) wireless telecommunication systems at Ericsson. In: Proceeding of environmentally conscious design and inverse manufacturing. Proc EcoDesign 2001

  • Marvuglia A, Cellura M, Heijungs R (2010) Toward a solution of allocation in life cycle inventories: the use of least-squares techniques. Int J Life Cycle Assess 15(9):1020–1040

    Article  Google Scholar 

  • Merrild H, Damgaard A, Christensen TH (2008) Life cycle assessment of waste paper management: the importance of technology data and system boundaries in assessing recycling and incineration. Resour Conserve Recy 52(12):1391–1398

    Article  Google Scholar 

  • Ny H, MacDonald JP, Broman G et al (2006) Sustainability constraints as system boundaries—an approach to making life-cycle management strategic. J Ind Ecol 10(1–2):61–77

    Google Scholar 

  • Raynolds M, Fraser R, Checkel D (2000) The relative mass-energy-economic (RMEE) method for system boundary selection. Int J Life Cycle Assess 5(1):37–46

    Article  Google Scholar 

  • Shrivastava P, Zhang HC, Li JZ et al (2005) Evaluating obsolete electronic products for disassembly, materials recovery, and environmental impact through a decision support system. Proc IEEE Int Symp Electron Environ, pp 221–225

  • Suh S, Lenzen M, Treloar GJ et al (2004) System boundary selection in life-cycle inventories using hybrid approaches. Environ Sci Technol 38(3):657–664

    CAS  Article  Google Scholar 

  • Tillman A-M, Ekvall T, Baumann H et al (1994) Choice of system boundaries in life cycle assessment. J Clean Prod 2(1):21–29

    Article  Google Scholar 

  • Todd JA, Curran MA (1999) Streamlined life-cycle assessment: a final report from the SETAC North America streamlined LCA workgroup. Society of Environmental Toxicology and Chemistry (SETAC) and SETAC Foundation for Environmental Education. Pensacola

  • Wenzel H, Hauschild MZ, Alting L (1997) Environmental assessment of products: Col. 1/ Methodology, tools and case studies in product development. Chapman & Hall, London

    Book  Google Scholar 

  • Williams E (2004) Energy intensity of computer manufacturing: hybrid assessment combining process and economic input–output methods. Environ Sci Technol 38(22):6166–6174

    CAS  Article  Google Scholar 

  • Yang JX, Nielsen PH (2001) Chinese life cycle impact assessment factors. J Environ Sci 13(2):205–209

    CAS  Google Scholar 

  • Yang JX, Xu C, Wang RS (2002) Methodology and application of life cycle assessment. China Meteorological Press, Beijing (In Chinese)

    Google Scholar 

Download references


The authors would like to thank National Basic Research Program of China (973 Program: 2011CB013406) for supporting the investigations.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Tao Li.

Additional information

Responsible Editor: Andreas Ciroth

Electronic supplementary material

Below is the link to the electronic supplementary material.


(DOC 43 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Li, T., Zhang, H., Liu, Z. et al. A system boundary identification method for life cycle assessment. Int J Life Cycle Assess 19, 646–660 (2014).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Life cycle assessment
  • Process tree
  • Search algorithm
  • System boundary
  • Threshold rule