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Streamlined Life-Cycle Assessment:A Final Report from the SETAC North America

Streamlined LCA Workgroup

Edited by:Joel Ann TJoel Ann TJoel Ann TJoel Ann TJoel Ann Todd and Marodd and Marodd and Marodd and Marodd and Mary Ann Cy Ann Cy Ann Cy Ann Cy Ann Currurrurrurrurrananananan

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July 1999

Society of Environmental Toxicology and Chemistry (SETAC)and

SETAC Foundation for Environmental Education

Streamlined Life-Cycle Assessment

©1999 Society of Environmental Toxicology and Chemistry (SETAC).Photoduplication of this document is encouraged. Please give proper credit.

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Preface

Under the auspices of the Life-Cycle Assessment (LCA) Advisory Group, a SETAC North America workgroup onStreamlining LCA was initiated in April 1994 along with other workgroups sharing an objective of providingdetailed information on various aspects of life-cycle assessment applications and methodology. Today, the activi-ties of the LCA Advisory Group include Environmental Decision-Making Tools and Techniques (formerly calledConceptually Related Programs), Life-Cycle Impact Assessment, and a short course on LCA methodology, alongwith the Streamlined LCA effort.

The original goal of the Streamlined LCA workgroup was to define and document a process for a shortened form ofLCA. At the time, because of the large amount of data needed to do a cradle-to-grave evaluation, it was believedthat in addition to such a “full” LCA approach there was also a way to conduct a simplified process called “Stream-lined LCA.” However, it was recognized by the workgroup early in the process that streamlining is an inherent partof any LCA. The key is to link the streamlining activities closely with the goal and scope definition process. That is,streamlining is a routine element of defining the boundaries and data needs of a study and is not in itself a differentapproach or methodology for LCA.

Further, the workgroup acknowledged that often the goal for conducting an LCA is not given much thought orcareful attention by the person conducting the study or by the requestor of the study. While the parties involvedmay have a general idea of what is wanted, the reason for the LCA is not explicitly stated, leaving it open for theresults to be used or interpreted in a manner that was not originally intended.

With these considerations in mind, the workgroup then established a slightly revised objective of more clearlydocumenting the different possible goals of LCA studies and how these different uses can affect streamlining.Because all LCAs are streamlined to varying degrees, this document is more a description of carefully planning andstating an LCA’s goal than it is about Streamlined LCA methodology.

The report consists of 4 chapters. Chapter 1 is a short introduction to LCA and the issues surrounding simplifyingthe process. Chapter 2 describes the important role of the goal-and-scope definition process in streamliningdecisions. It includes a useful checklist that study practitioners can use to address key considerations involved insetting the goal and scope. Chapter 3 describes approaches to streamlining and offers 2 examples of how stream-lined LCA has been used to evaluate pollution-prevention activities and product improvement. Finally, Chapter 4offers some concluding thoughts on streamlined LCA methods.

This report concludes the efforts of the Streamlined LCA workgroup. The issue of streamlining LCA has evolvedinto other aspects of methodology development. It is hoped that the thoughts contained here will contributetoward the development of other frameworks by using the life-cycle concept.

Information in this report was obtained from individual experts and highly regarded sources. It is the publisher’sintent to print accurate and reliable information, and numerous references are cited; however, the authors, editors,and publisher cannot be responsible for the validity of all information presented here or for the consequences of itsuse. The content of this publication does not necessarily reflect the position or the policy of any organization or ofthe United States government, and an official endorsement should not be inferred.

3A Final Report from the SETAC North America Steamlined LCA Workgroup

©1999 Society of Environmental Toxicology and Chemistry (SETAC). Photoduplication of this document is encouraged. Please give proper credit.

CCCCCH A P T E RH A P T E RH A P T E RH A P T E RH A P T E R 1 1 1 1 1

Introduction

Environmental life-cycle assessment (LCA) provides a framework, an approach, and methods for identifying andevaluating environmental burdens associated with the life cycles of materials and services, from cradle-to-grave (or,as preferred by some, “cradle-to-cradle,” which captures the recyclability of materials). Since the 1970s, there havebeen efforts to develop LCA methodology. In the 1990s, the Society of Environmental Toxicology and Chemistry(SETAC) in North America and the U.S. Environmental Protection Agency (USEPA) sponsored workshops andother projects designed to develop and promote consensus on a framework for conducting life-cycle inventoryanalysis and impact assessment. Similar efforts have been undertaken by SETAC in Europe, other internationalorganizations (such as the International Standards Organization), and LCA practitioners worldwide. As a result ofthese efforts, consensus has been achieved on an overall LCA framework and a well-defined inventory methodology.Further, the art and science of impact assessment have been advanced by SETAC through publication of Life-CycleImpact Assessment: The State-of-the-Art in North America and Toward a Methodology for Life-Cycle Impact Assessmentin Europe.

A continuing concern that has followed these activities is the cost and time required for LCA. Some have ques-tioned whether the LCA community has established a methodology that is, in fact, beyond the reach of mostpotential users. Others have questioned the relevance of LCA to the actual decisions that these potential users mustmake. These concerns have encouraged some practitioners to investigate the possibility of “streamlining” LCA tomake it more feasible and more immediately relevant without losing the key features of a life-cycle approach.1

When the concept of streamlining was first introduced, many LCA practitioners were skeptical, stating that LCAcould not be streamlined. Over time, however, there has been growing recognition that “full-scale” LCA and“streamlined” LCA are not 2 separate approaches but rather are points on a continuum. Most LCA studies will fallsomewhere along that continuum, in between the 2 extremes. As a result, the process of streamlining can beviewed as an inherent element of the scope-and-goal definition process. For example, as the study team decideswhat is and is not to be included in the study, they are engaged in streamlining. In addition to determining whatwill and will not be included, the study team will determine how to best achieve these requirements. The key is toensure that the streamlining steps are consistent with the study goals and anticipated uses, and that the informa-tion produced will meet the users’ needs. From this perspective, the scope-and-goal definition process involvesdetermination of what needs to be included in the study to support the anticipated application and decision.

It is clear that the scope-and-goal definition process is critical. The conclusions of the SETAC document on impactassessment support this view: “The study goal and scope are crucial to managing and coordinating a life-cycle studyby bringing together the LCA information needed to make an identified decision and an understanding of thereliability and representativeness of the LCA.” (Barnthouse et al. 1997, p. 47). Yet previous efforts to define LCAmethodology have provided little guidance on how scope-and-goal definition should be performed.

The purpose of this report is to• redefine streamlining as an inherent part of any LCA approach that involves deciding what is and what is not

to be included in a study;• emphasize that streamlining steps must be consistent with the original study goals and anticipated uses;• describe various ways that streamlining LCA has been attempted and investigated and the possible implica-

tions in different decision-making contexts; and

1 In this report, “streamlining” and “screening” are not considered synonymous. Streamlining refers to the design of the LCA, particularlydecisions concerning what is included in the study and what is not. Screening, on the other hand, is the use or application of LCA results,primarily to determine whether additional study is needed and where that study should focus (Todd 1996).



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• provide recommendations on how the goal-and-scope definition process can be used to design and stream-line an LCA study.

This report is the culmination of a multi-year effort of the SETAC North America Workgroup on Streamlining LCA.This effort has been enhanced and informed by several projects sponsored by the USEPA. During the first year ofits activities, the workgroup suggested that it needed to know more about the current state-of-the-practice ofstreamlining. The USEPA sponsored a survey of practitioners to explore their definitions of streamlining and theapproaches they used to streamline studies. The USEPA also sponsored 2 conferences, in 1995 and 1997, to bringtogether LCA practitioners to discuss their use of streamlining and the lessons learned. We have also benefittedfrom the work of the SETAC Europe Workgroup on Streamlining and their recent report Simplifying LCA: Just a Cut?

The remainder of this report is organized as follows:• Chapter 2 discusses the essential linkage between the goal-and-scope definition phase of LCA and decisions

on streamlining.• Chapter 3 explores the implications of various approaches to streamlining.• Chapter 4 suggests an approach for communicating streamlining decisions to users of the study.

ReferencesBarnthouse L, Fava J, Humphreys K, Hunt R, Laibson L, Noesen S, Owens J, Todd J, Vigon B, Weitz K, Young J. 1997. Life-cycle

impact assessment: the state-of-the-art. Pensacola FL: Society of Environmental Toxicology and Chemistry (SETAC).Udo de Haes HA, editor. 1996. Towards a methodology for life-cycle impact assessment. Brussels, Belgium: Society of

Environmental Toxicology and Chemistry (SETAC).Christiansen K, editor. 1997. Simplifying LCA: just a cut? Brussels, Belgium: Society of Environmental Toxicology and

Chemistry (SETAC).Todd JA. 1996. Streamlining. In: Curran MA, editor. Environmental life-cycle assessment. New York: McGraw-Hill.Curran MA, Young S. 1996. Report from the EPA conference on streamlining LCA. International Journal of Life-Cycle Assessment

1(1)57-60.[USEPA] U.S. Environmental Protection Agency. Unpublished. Streamlining life cycle assessment II: a conference and

workshop. Proceedings from 24–25 September 1997 workshop in Cincinnati, Ohio, USA. Contact Mary Ann Curran 513-569-7782.




Role of the Goal-and-Scope Definition Process in StreamliningDecisions

Background and PurposeWhen starting a Life-Cycle Assessment (LCA), it is vital that the study team 1) identifies the decisions or applica-tions for which the study results will be used, (2) determines what information is needed for those decisions orapplications and what part of this information can be provided by LCA, and 3) defines the goal and scope of thestudy. Too often, these steps are given only casual thought by the LCA practitioner, and a life-cycle inventory islaunched immediately. Without the proper level of attention to defining the goal of a given study, it is difficult ifnot impossible to determine if the study was successful. This goal definition process determines the intended usesof the study results and, therefore, the type of analysis needed and the manner in which the results are to bepresented. The scope of the study describes the system to be studied and directs how much information is to becollected, in what categories, and to what level of detail and quality. Barnthouse et al. (1997) urge LCA designteams to “...use the study goal and scope definition to clearly establish the needs that drive the study. What are theissues, questions, and decisions that need to be made? What levels of data, data quality, model accuracy, etc. arerequired? Who is the anticipated audience, and what is the anticipated use of the study?” ( p. 13).

This chapter further defines and describes the goal-and-scope definition process; the decisions made during theprocess; and the implications for streamlining, and provides guidance on improving the process.

Linkages Between the Goal-and-Scope Definition Processand LCA Streamlining

In the original LCA framework, developed at the first SETAC-sponsored LCA workshop, Fava et al. (1991) providethe following definitions:

The goal definition element of an LCA identifies the purpose for the study and its intendedapplication(s). This step will present reasons why the study is being conducted and how theresults will be used.

Scoping defines the boundaries, assumptions, and limitations of a particular LCA. It defineswhat activities and impacts are included or excluded and why. . . . Scoping should be attemptedbefore any LCA is conducted to ensure that:

• The breadth and depth of analysis are compatible with and sufficient to address the goal of theLCA.

• All boundaries, methodologies, data categories, and assumptions are clearly stated, comprehensible, and visible.

The goal-and-scope definition process is an integral part of any LCA study. At the outset of an LCA, before any dataare collected, key decisions must be made regarding the scope and boundaries of the system being studied. Thesedecisions are mainly determined by the goal, i.e., the defined reasons for conducting the study, its intendedapplications, and the target audience.

Examples of generic goals and applications of LCA by public and private sector organizations include the following(Barnthouse et al. 1997):

• education and communication,• product design (design for the environment),• product development and improvement/R&D,



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• pollution prevention,• assessment and reduction of potential liability,• strategic planning,• assessing and improving environmental programs,• development of policy and regulations,• individual and organizational purchasing/procurement,• labeling,• developing market strategies, and• environmental management systems/environmental performance evaluation.

Life-Cycle Assessment cannot provide a truly comprehensive and all-encompassing assessment. For one thing,industrial processes are so extensively interconnected globally that complete consideration of all these interdepen-dencies is prohibitive. Also, the results of an LCA are approximations and simplifications of aggregated loadings tothe environment and resources used. Therefore, the LCA process does not directly measure actual environmentalimpact, predict effects, or represent causal linkages with specific effects. As a result, to meet the needs of the studyusers, it may be necessary to supplement the LCA with other tools or methods to provide a basis for decision-making. These tools include risk assessment, site-specific environmental assessment, and others. As a part of thescoping process, it is useful to identify where and how these other tools will be used to augment the findings of theLCA.

An understanding of the study goal and intended applications provides the basis for the scoping process, duringwhich the most appropriate approach for the study is identified. During the scoping process, the study boundaries,assumptions, and limitations are defined. The scoping process involves a balancing of breadth and depth of datacollection with efficient use of resources available for the study. When the goal of the study has been clearlyarticulated, study designers can then identify the relevant categories of information that should be included as wellas the appropriate level of detail within each category. In this way, an LCA study selects an approach, or refines anexisting practice, that is appropriate to the intended end-use.

A published report on LCA impact assessment (Barnthouse et al. 1997) emphasized the importance of the goal-and-scope definition phase in planning the study. This report listed several “strategic tasks” that are performedduring goal-and-scope definition:

• develop a detailed understanding of the decisions to be made,• design and direct the study based on the organization’s principles,• discern how LCA can assist these decisions, i.e., the degree to which both inventory and impact assessment

can provide the information needed,• tailor the LCA study to these decisions, and• undertake the process of making value decisions and information limitations explicit to the study users and

audiences.

Barnthouse et al. (1997) also listed decisions that should be addressed during goal-and-scope definition (p. 48):• evaluate the necessity to conduct certain LCA steps,• include or exclude specific categories or issues,• select the level of rigor and detail for particular categories,• choose the indicators and models,• designate the areas and methods to conduct sensitivity and uncertainty analyses,• designate the need for non-LCA data and techniques to analyze indicator results, and• designate the use of and choice of valuation approaches or weighting methods.

The report stressed the importance of considering the life-cycle impact assessment (LCIA), when one is contem-plated, as well as the inventory during initial goal-and-scope definition. This is essential because the requirementsof the impact assessment will drive the design of the inventory, not vice versa as had been the assumption to date.



In other words, the requirements of the decisions or actions for which the study is undertaken dictate the types ofimpact assessment to be included. The data requirements for the impact assessment are, then, the major driversfor the inventory. As noted by Barnthouse et al. (1997), “...the selection of LCIA categories determines the need forspecific inventory data collection activities. These directions may include levels of data speciation, quality, andaccuracy, thereby directing specific inventory items and data quality requirements.” (p. 24).

This discussion of inventory versus impact assessment has been updated with the development of the InternationalStandards Organization (ISO) document, “Environmental Management—Life-Cycle Assessment—Principles andFramework,” which was published in October 1998. In this document, the definition of life-cycle inventory isexpanded beyond mass balance inputs and outputs (e.g., tons of mined ore) to include data that are needed in theimpact assessment phase (e.g., acres of land used in mining). ISO 1998 states the following:

Inventory analysis involves data collection and calculation procedures to quantify relevant inputsand outputs of a product system. These inputs and outputs may include the use of resources andreleases to air, water, and land associated with the system. . . . These data also constitute theinput to the life-cycle impact assessment.

The minimal requirements set forth in ISO 1998 state that LCA shall include definition of goal-and-scope, inven-tory analysis, impact assessment, and interpretation of results. The result is that LCA methodology is no longerviewed as beginning with an inventory of mass inputs and outputs that may or may not lead to an impact assess-ment.

Guidance for Goal-and-Scope Definition

Establishing the goal of the studyThe reasons for conducting the study, intended applications, and target audience define the questions that are to beaddressed by the study. These reasons range from establishing a baseline of environmental performance tocomparing alternative product systems. Typically, an LCA is performed in response to a specific question. Thequestion being answered determines, in essence, the goal of the study.

During the goal definition process, the following issues should be considered:• Why is the study being conducted (i.e., what decision, action, or activity will it contribute to or affect)?• Why is LCA needed for this decision, action, or activity? What, specifically, is it expected to contribute?

What additional analytical tools are needed and what will they be expected to contribute?• Who is the primary target audience for the study (i.e., who will be making the decision, taking or directing

the action, or organizing or participating in the activity)?• What other audiences will have access to the study results? What uses might these audiences make of the

study findings?• What are the overall environmental goals, values, and principles of the sponsoring organization and in-

tended audience? How does the intended application of the study relate to these goals, values, and prin-ciples?

Some examples of applications and audiences include1) A government agency that wants to• acquire an overview of the environmental performance of a selected range of products to guide procurement

officials,• evaluate environmental regulations and standards as they are developed to achieve overall pollution preven-

tion,• support environmental protection policies such as sustainability, and• develop a product certification program to guide consumer purchasing.

2) A product manufacturer that wants to• determine and demonstrate environmental preferability of a product,



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• acquire an overview of the environmental performance of a specific product or system to identify wheresignificant impacts may be occurring,

• evaluate the environmental impact that may result if a change to a given product or process is implemented,and

• compare sources or supply alternatives.

3) Consumers that want to• compare environmental profiles of products to guide purchasing and• assess the effects of potential life-style changes on the environment.

The goal definition process establishes the breadth, depth, and scope of the system and the proper types of dataneeded for the assessment. The study should be designed to include all information that will be relevant to thedecision or activity, and it might be able to eliminate information that is irrelevant. These decisions should beconscious, deliberate, and documented.

System function and functional unitAt the outset of an LCA, the system that will be the subject of the study and its function must be clearly identified.The function is related directly to the questions that the study is designed to answer, and the functional unit mustbe selected as the basis for the study. One of the primary purposes for a functional unit is to provide a reference forthe system inputs and outputs. A well-defined functional unit that assures equivalence also allows for moremeaningful comparisons between alternative systems. The study team should carefully define the functional unitto be meaningful to the goal of the study. It should include all of those factors that will be involved in the decision,action, or activity that will be affected by the study. If the functional unit is not chosen appropriately, it is likelythat the final study results will not be sufficient for answering all of the questions posed by the users or providingthe guidance needed.

Definition of the functional unit will enable the study team to identify elements that all of the items under studyhave in common. If the purpose of the study is to compare 2 or more items, it might be possible to eliminateelements that are identical between or among the functional units. If inclusion of these elements would have noeffect on the preferability of the items and if the study results are not to be presented as a complete environmentalanalysis of the items, then the study team could consider eliminating the identical components.

Definition of system boundariesThe scope of an LCA describes the boundaries which define the system being studied. The scope should be well-defined to ensure that the breadth and depth of the study are compatible with the stated goal. For example, in acomparison of virgin and recycled systems, removal of downstream stages may not affect comparative rankingssignificantly. However, if objectives go beyond comparative rankings to assessing environmental burdens through-out the life cycle, eliminating the downstream stages may exclude some environmental impacts that are unique torecycled systems and that have comparatively high burdens in the downstream stages.

System boundaries define the unit processes or activities that will be included in the system under study. Decisionsmust be made on which processes or activities will be included. As noted above under consideration of thefunctional unit, it might be possible to eliminate those processes that are identical for all items under study. Or, itmight be possible to eliminate elements of the system that are beyond the purview of the study goal and purpose,i.e., those components of the system that cannot be affected by the decisions, actions, or activities that are drivingthe study.

The basis for the decisions should be clearly understood and described and should be consistent with the statedgoal of the study. At the outset of an LCA, all life-cycle stages should be considered. Upon careful review, it may bepossible to eliminate the need to collect data from some of these stages or subprocesses. The study team shouldkeep in mind, however, that Barnthouse et al. (1997) noted several features that are crucial to LCA (p. 22):

• a system-wide perspective embodied in the term “cradle-to-grave” that implies efforts to assess the multipleoperations and activities involved in providing a product or services;

• a multimedia perspective that suggests that the system include resource inputs as well as wastes and emis-sions to all environmental media, i.e., air, water, and land; and



• a functional unit accounting system that normalizes energy, materials, emissions, and wastes across thesystem and media to the service or product provided.

Any decisions that affect these features should be carefully documented.

Data categories and requirementsThe data used in an LCA are dependent on the goal of the study. The goal may require that facility- or company-specific data be collected, or secondary data from published sources may be sufficient. In practice, all datasetscontain a mixture of measured, calculated, and estimated data.

The decisions on data requirements for the study, in terms of data quality, level of detail, and specific data ele-ments, are a key component of the scoping process. There has been growing recognition that the specification ofinventory data to be collected should be based on the analyses that will be performed using these data. Specifically,the impact assessments that are planned for the study should dictate the categories and data elements as well astheir level of detail. It is only by tracing the use of the data through the analysis stage that we can ensure thatrelevant and appropriate data will be available. It should be stressed that design of the LCIA should be performedduring initial scoping, not after the inventory data collection has been completed. By designing the impactassessment during initial stages, the study team will direct the inventory to gather appropriate data and willbalance the feasibility of the planned analyses with the effort required to gather and analyze the informationneeded for those analyses. If modification of the design is required, it can occur before the study gets underway,thus reducing the likelihood of wasted effort.

Elements of the Study Design

As noted above, during the goal-and-scope definition process, the study designers and sponsors consider numerouselements of the study design. The following questions are considered during this process.

• Depth and detail—What level of depth and detail of data does the application require? Are these require-ments greater for some data categories and issues than for others?

• Breadth and completeness— Does the application require that all aspects of the life cycle be included, or cansome be eliminated or examined less exhaustively? What inventory and impact-category indicators must beincluded to meet the purpose of the study? Where are the systems boundaries drawn and why?

• Transparency—What degree of openness and comprehensiveness is required in the presentation of data orstudy results? Who will see the products of the study, including underlying data as well as results, and howmuch transparency will they require? Will proprietary data be used that must be shielded from some users?

• Data sources—Where are the data to be collected? Are publicly available data sources appropriate for thestudy? Are primary data required? Is a mix of approaches appropriate for the study?

• Data quality—How much confidence should the potential users have in the data and in the study’s conclu-sions? How much uncertainty can they tolerate?

• Modeling allocation conventions—How is recycling to be treated? How are burdens of a process to beallocated among coproducts?

• Site specificity—Does the application require that the study produce information about specific sites orfacilities? Is site-specific information needed for any of the planned supplemental analyses, such as riskassessment?

• Scale—Does the application require data on a global, continental, regional, and local scale? Which biologi-cal scales are most relevant—ecosystems, populations, individual organisms, physiological systems, ormolecular systems? Are users of the study interested only, or primarily, in impacts that occur at a particularscale?

• Level of aggregation—What level and types of aggregation are most appropriate to support the studydecision needs? Will the traditional LCA approach of aggregating all data throughout the life cycle byfunctional unit be sufficient, or will the user require some data to be retrievable in a disaggregated form (e.g.,by industrial process)?



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• LCA limitations—How environmentally relevant is the modeling that was used in the impact assessment?Does the intended application require more precise modeling of risk or hazard?

• Temporal specificity—Does the application require that the study produce information on the time framefor when potential impacts or their associated inventory items occurred?

Each of these elements can be represented by a continuum, ranging from a low value to a high value. The highervalues produce a higher degree of rigor in the study or, in some cases, indicate the need for supplementary tools.While higher degrees of rigor are needed for some applications and often allow more versatility in the applicationof the results, high degrees of rigor are not always required. One rule of thumb is that the more ultimate influencethe study will have on decision-making, the higher the degree of rigor that should be demanded. Similarly, supple-mentary tools might not be needed for the intended application. Life-Cycle Assessment applications range fromquick screening analyses that are used to identify potentially important issues for further study and to help audi-ences “see” or “map” a system whose issues might be hard to comprehend or hidden, to rigorous, detailed studiesthat are intended to provide authoritative information for a public decision. The requirements of these and manyother applications differ significantly. The goal-and-scope definition process involves determining the appropriatedegree of rigor for each of the elements, given the intended use of the study and the resources available, in terms oftime and money.

The study team might find that the optimal level of depth, rigor, etc., is not achievable in practice. The coverage ofall operations involved in complex, interrelated industrial systems with complete accounting of all emissions andactivities for each is often impossible. For example, emissions from a facility may be limited to regulated com-pounds for which records must be kept. Often, companies consider data to be too confidential to be released forexternal use. Such difficulties in accounting for inputs and outputs have led to the inevitable streamlining of LCA.

As the study proceeds, there should be continuous interplay between the inventory and impact assessment as theinformation develops to ensure that the original goals will be met. If there are too many data constraints, theoriginal goal might have to be abandoned or a new goal may be defined. A sensitivity analysis might also providethe basis for streamlining, as elements of the study are identified that appear not to influence the final results andtherefore might be omitted in some cases. In this way, the scoping process becomes an iterative one.

Implications of Goal-and-Scope Definition Decisions

For all practical LCA studies, some form of streamlining is essential for feasibility. The benefits of streamlining, interms of saved resources, must be balanced against maintaining utility of the results.

Streamlining can be thought of in the context of goal-and-scope definition in much the same way as we think of aglass as “half-full or half-empty.” Streamlining can be viewed as “What can be eliminated from a full-scale LCAdesign and still meet the study goals?” or “Starting with a blank slate, what should be included to meet the studygoals?” The study-design team might reach the same point on the LCA continuum, but the thinking process isdifferent.

Guidance for improving the goal-and-scope definition phase of LCA cannot use a “one-size-fits-all” approach.Instead, we have listed and discussed some of the major goal-definition-and-scoping considerations that arecommon to most LCAs. Information from USEPA’s streamlining LCA research (1997) and from Curran (1996) wasused to develop these considerations.

Table 2-1 and Table 2-2 summarize the considerations in the goal-and-scope definition process that can lead tostreamlining. These tables may be useful in reporting because system boundaries, data categories, and assump-tions should be obvious to any reader of the completed study. In Table 2-1, the last column summarizes somecomments related to the value of streamlining or recommendations in that particular instance. Table 2-2 providesan alternative presentation format that visually illustrates the appropriateness of streamlining. The differentconsiderations need to be looked at collectively and the effectiveness of streamlining cannot be judged on the basisof a single consideration.

Any kind of streamlining will add varying amounts of uncertainty to the LCA results. Consideration of the factorsin Table 2-1 reflects the importance of asking whether the results from a streamlined LCA will adequately address



your objectives. For example, if the study objective is to compare 2 alternative products to determine overallenvironmental superiority of one over the other, then streamlining should be limited as much as possible.

ReferencesBarnthouse L, Fava J, Humphreys K, Hunt R, Laibson L, Noesen S, Owens JW, Todd JA, Vigon B, Weitz K, Young J, editors.

1997. Life-cycle impact assessment: the state-of-the-art. Pensacola FL: Society of Environmental Toxicology and Chemistry(SETAC).

Fava J, Consoli F, Denison R, Dickson K, Mohin T, Vigon B, editors. 1991. A conceptual framework for life-cycle assessment.Pensacola FL: Society of Environmental Toxicology and Chemistry (SETAC).

[ISO] International Standards Organization. October 1998. Environmental management—life cycle assessment—principlesand framework. Geneva, Switzerland: ISO . ISO 14040.

Todd JA. 1996. Streamlining. In: Curran MA, editor. Environmental life-cycle assessment. New York: McGraw-Hill.[USEPA] U.S. Environmental Protection Agency. 1997. Streamlining life-cycle assessment: concepts, evaluation of methods,

and recommendations. Washington DC: USEPA Office of Research and Development.



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TTTTTable 2-able 2-able 2-able 2-able 2-11111 Checklist of key goal-and-scope definition considerations

This table is intended to help users evaluate a list of considerations that should be addressed during the goal-and-scope definition process;this process will provide indications of areas in which streamlining might be more appropriate or less appropriate. A check on [1] indicatesthat streamlining success is more likely (based on that particular consideration), and conversely higher values ([2] and [3]) indicate lowersuccess or potential problems with streamlining. This checklist is designed strictly to provide helpful hints and suggestions. Higher scoresare indicators that the study should be designed so that it falls closer to the “full-scale” end of the continuum. This table is based on asimilar exhibit in USEPA 1997, a report for the USEPA prepared by Research Triangle Institute. Some of the guidance in this table is basedon “Streamlining,” by Joel Ann Todd, in Mary Ann Curran, editor (1996), Environmental Life-Cycle Assessment.

GOAL STATEMENT: The more clearly the purpose can be defined, the more likely it is that appropriatestreamlining steps can be chosen. If you are unclear about your goals and the decisions oractions that will be influenced by the study, the study team should clarify these elements aspart of goal definition. With clearly defined goals, it will be easier for the design team todetermine which parts, if any, of the study can be streamlined.

DEPTH AND DETAIL

How do you intend to use theinformation derived in the study?

G Do a general investigation/ Do ascoping or screening exercise/Identifypotential environmental concernsG Get rough estimate of relativedifference /Obtain specific intermediate conclusions G To weigh performance of products/to quantify flows throughout life-cycle/Do a detailed impact assessment orvaluation

Less precision is generally required in screening or scoping studies. Less-quantitative or less-qualitative information might suffice when information is primarily to be used for furtherdeveloping corporate goals and strategies or for identifying areas for further study

Streamlining can also be considered when obtaining rough estimates of differences forpurposes of targeting further study. For example, in design application, stages could beeliminated if they are static or not affected by a new design. One should avoid streamliningthe LCA components that affect the intermediate conclusions of interest.

Caution should be taken so that the LCA is not altered so significantly that the study could nolonger be considered “LCA.” (Such as limiting a study to a “gate-to-gate” analysis of afacility.) Applications that demand use of LCA methodology and quantified flows throughthe entire life cycle, such as claims of overall environmental preferability among products, arenot amenable to drastic streamlining.

BREADTH AND COMPLETENESS

Is there a dominant stage in the life cycleof the product being studied?

G Yes, there is a very dominant stage

G There is a somewhat dominant stage

G No, there is not a dominant stage

If one stage of the life cycle, such as the manufacturing operation or the use stage, is verydominant (i.e., has significantly higher inputs and outputs) as compared to other stages,streamlining (by removing other stages) may not have as great an impact on conclusions.Durable products can typically be expected to have higher flows (inputs and outputs) in theuse/reuse stage as compared to consumable products. If similar characteristics can be foundamong durable products, certain portions of the life cycle could be highlighted for study.Consumables, in general, can be expected to have higher flows in the upstream anddownstream stages. Thus, certain types of streamlining techniques may be chosen if yourstudy compares consumables alone or durables alone. However, comparing different types ofproducts by removal of stages could eliminate the advantages of one product or mask thedisadvantages of another.

TRANSPARENCY

What audience or context are the studyresults going to be released or applied to?

G Internal G Both external and internalG External

If the study is internal rather than to be used to substantiate external product or marketingclaims, it is more likely that streamlining options can be chosen. This is because the latter aretypically more controversial, requiring more documentation and precision. If the results areto be released externally, the detail to be provided, sensitivity of results, and purpose can allplay a role in determining whether or not streamlining can be detrimental to project goals.

DATA QUALITY OBJECTIVES



Table 2-1 continued

DATA QUALITY OBJECTIVES

What is your threshold for uncertainty?

G High (data quality not a priority)G MediumG Low (high data quality needed)

Data quality objectives include documentation, precision, bias, completeness,representativeness, comparability, and compatibility. Streamlining adds varying amounts ofuncertainty to LCA results, and there is currently no established methodology to measure thisuncertainty. The intended use of the study will determine how much uncertainty can betolerated. In addition, questions such as the ability of the study to handle secondary datathat do not permit aggregation or comparison (due to differences in the studies from whichthey are collected) need to be considered.

ALLOCATION CONVENTIONS

What is the role of recycling for one ormore products being studied?

G Virgin OR recycled/reusedproductsG Virgin AND reused productsG Virgin AND recycled products

Use of virgin materials requires a more complete upstream study, whereas use of recycled orreused material greatly reduces upstream effects. If upstream stages are removed in a studycomparing virgin and recycled products, the comparative advantages of the recycling systemin the upstream stages are lost. Closed-loop recycled systems greatly reduce upstream effects;thus, removing these stages would affect results, especially when comparing with virginsystems. Open-loop recycled systems also reduce upstream effects, although generally bysmaller amounts.

PRODUCT SPECIFICITY

How narrowly is the product or processunder study defined?

G Generic category (e.g., shop towels)G Specific product-type (e.g, cottonshop towelsG Specific product (e.g., towelsmade by vendor X)

A company that wants to improve its own production system would require informationspecific to its own operation. A company that wants to compare several vendors would needinformation specific to those vendors. A comparison of two generic products would permituse of industry-level or more generic averages. Studies of generic categories of products ormaterials can often be streamlined because they are not amenable to being preciselyquantified.

LEVEL OF KNOWLEDGE ANDINFORMATIONWhat is your level of knowledge aboutthe product/processes being studied?

G High level of knowledge for entire lifecycleG High level of knowledge for somestagesG Low level of knowledge

The more analysts know about the product or process under study, the more confidence theycan have in making streamlining decisions. For example, knowledge that two alternatives usethe same types and quantities of certain raw materials could enable the exclusion of these rewmaterials for a comparative study.



14

TTTTTable 2-able 2-able 2-able 2-able 2-22222 LCA continuum

This table illustrates the concept that LCA goal and scope definition is a process of locating the most appropriate point on a series ofcontinuums.

Goal and scopeconsiderations

More opportunity for streamlining Less opportunity for streamlining

How will results be used?

Scoping, screening, Estimate relative Marketing,identify hot spots difference labeling, public policy

Is there a dominant life-cycle stage?

Very dominant Somewhat dominant No dominant stage

Who is the study audience?

Internal Internal and external ExternalWhat is the threshold foruncertainty?

High uncertainty Moderate Low uncertaintyTo what extent arerecycled/reused materialsused? Recycled/reused materials Virgin and reused materials Virgin and recycled

materialsHow narrowly is theproduct defined?

Generic product Product type Specific productHow much is alreadyknown about the product?

High knowledge of High knowledge of Low knowledgeall life-cycle stages some life-cycle stages of all life-cycle stages




Approaches to Streamlining

How Are Streamlined Approaches Developed?

The use of streamlined approaches to Life-Cycle Assessment (LCA) appears to be increasing as practitioners seekless expensive methods that will yield more timely information. As defined in Chapters 1 and 2, an inherent part ofthe goal-and-scope definition process is the identification of the level of effort that is required for a study while stillproviding the detail and information needed by the study users. Consensus has not been reached, however, on theexact methods and procedures that can be used in a streamlined LCA or on appropriate uses of a streamlined LCA.

As stated previously, all LCAs can be considered streamlined to varying degrees. Life-Cycle Assessment practice iscurrently performed along a spectrum of detail. At one end of the spectrum is the more complete LCA model thatprovides detailed coverage of life-cycle stages, product system components, and projected multi-media environ-mental impacts. Moving along the continuum, streamlining of the scope or modeling is undertaken. However, apoint is eventually reached on the continuum where the study loses its life-cycle distinction. Such studies stillprovide useful information to stakeholders for specific study goals but should more appropriately be calledenvironmental assessment, environmental audit, or another more descriptive term than “life-cycle assessment.”

The purpose of this chapter is to present some approaches that are currently being used to streamline the LCAmethodology or process and the pros and cons of each approach as compared to what is traditionally considered tobe a “full” LCA. The streamlined approaches are grouped in 2 main categories for purposes of discussion. Thesecategories are 1) streamlining within the existing LCA framework and 2) alternative streamlining approaches basedon life-cycle concepts.

Streamlining Within the Current LCA Framework

Streamlining within the existing LCA framework can occur at 2 levels: 1) the methodology for conducting an LCA(the “what to do”); and 2) the process for conducting an LCA (the “how to do it”). Streamlining the LCA methodol-ogy generally can be accomplished by limiting the scope of the study or simplifying the modeling procedures,thereby limiting the amount of data or information needed for the assessment. As discussed in Chapter 2, thedecision should be made in the initial goal-and-scope definition stage. Streamlining the process of conducting LCAcan be accomplished by making life-cycle data or tools, such as software with embedded databases, more readilyavailable.

Typically, approaches to streamlining have entailed simplification of the life-cycle inventory (LCI) through theelimination of life-cycle stages (e.g., cradle-to-gate studies that ignore activities after the production stage) orreducing the data required on the unit process networks (e.g., by applying thresholds or cutoff criteria or bylimiting the analysis to first tier contributions). This section discusses a variety of possible approaches for simplify-ing the LCI methodology and reducing the amount of data required.

Streamlining approaches testedMany different approaches to streamlining LCA have been suggested and used by different organizations (seeHuang et al. 1995; Weitz et al. 1996). The main reason that there is such a broad range of LCA practice is thatorganizations need to apply LCA in a practical manner to make a large variety of decisions. Those wishing toconduct an LCA or some type of life-cycle study will most likely review the current literature on LCA concepts andmethods and then tailor those concepts or methods in some manner to fit their decision-making needs andconstraints (e.g., resources, time). Therefore, because there are countless ways to scope a life-cycle study, there alsohave been countless approaches used to streamline.



16

Despite the widespread practice of and great interest in streamlining LCA, there is not a clear understanding of theeffects that streamlining may have on LCA results. How is decision-making affected by using various streamliningapproaches versus full LCA results? To help answer these questions, the Research Triangle Institute (RTI) workedwith the USEPA to evaluate predefined streamlining methods that were identified through previous discussionswith LCA practitioners. The objective of these case studies was to identify whether streamlining methods yieldedsimilar results or conclusions to more complete LCI’s.

Through discussions with a number of LCA practitioners and researchers, a variety of approaches were identified ascurrently used to streamline LCI (see Weitz et al. 1996 and USEPA 1997). The approaches were grouped into 9categories for comparing to more complete LCAs in product case studies. These categories are each described inthe following sections and are presented in Table 3-1. The table also summarizes how the streamlining approacheswere applied in the case studies.

Limiting or eliminating all or some upstream stagesIn some studies, it seems that the tracing of materials can go back through an infinite number of steps. In themanufacture of bar soap, for example, tracing the constituent tallow back through meat packing and rendering,cattle raising and feedlot management, harvesting and processing of feed, and soil preparation (i.e., seeds, fertiliz-ers, and pesticides) leads to another major effort to trace the fertilizers and pesticides back to their chemicalconstituents, and so forth. As a result, this research begins to feel very distant from the product that is the target ofstudy.

All LCAs must set upstream boundaries. One approach to streamlining, then, sets the study boundaries within aprescribed number of stages, such those processes that are within 1 or 2 steps of the primary manufacturing

TTTTTable 3-able 3-able 3-able 3-able 3-11111 Streamlining approaches tested by RTI/FAL (USEPA 1997)

Streamlining appro ach Application pro cedure

Removing upstream co mponents All processes prior to final material manufacture are excluded. Includes fabrication intofinished product, c onsumer use, and po st-co nsumer waste management.

Partially removing upstreamco mponents

All processes prior to final material manufacture are excluded, with the exception of the stepjust preceding final material manufacture. Includes raw materials extraction andprecombustio n pro cesses for fuels used to extract raw materials.

Removing dow nstream components All processes after final material manufacture are excluded.

Removing up- and downstreamco mponents

Only primary material manufacture is included, as well as any precombustio n proc esses forfuels used in manuf ac turing. Sometimes referred to as a “gate-to-gate” analysis.

Using specific entries to representimpacts

S elec ted entries are used to approximate results in each o f 24 impact catego ries, based onmass and subjective decisions; other entries within each c atego ry are excluded.

Using specific entries to represent LCI S pecific entries from the individual processes comprising the LCI that correlate highly withfull LCI results are searched fo r; other entries are excluded.

Using " sho wsto ppers" or "knocko utcriteria"

C riteria are established that, if encountered during the study, can result in an immediatedecision.

Using qualitative or less accurate data Only dominant values within each of 6 process groups (raw materials acquisition,intermediate material manufacture, primary material and product manufacture, c onsumeruse, waste management, and ancillary m aterials) are used; other values are excluded, as areareas where data can be qualitative, o r otherwise o f high unc ertainty.

Using surrogate process data S elec ted proc esses are replaced with apparently similar pro cesses based on physical,c hemic al, or functio nal similarity to the datasets being replaced.

Limiting raw materials Raw materials comprising less than 10 % by mass of the LCI totals are excluded. Thisapproach was repeated using a 30 % limit.



process. In the example of the manufacture of a bar of soap, this could limit the studied upstream steps to cattleraising and feedlot management. The stages of harvesting and processing feed, preparing the soil, seeding,fertilizing, applying pesticide and analyzing the fertilizers and pesticides could be omitted.

In some cases, all upstream stages are eliminated so that the study looks only at the manufacturing stage and thedownstream stages (i.e., use and disposal). Some companies with product stewardship programs have chosen thisapproach, focusing on maintenance requirements and reducing downstream environmental considerations of theirproducts by building in recyclability or reusability and developing “take-back” programs in which the user canreturn the product to the manufacturer at the end of its useful life. They may become concerned with upstreamstages of the life cycle only insofar as these stages affect downstream stages. For example, the use of hazardousconstituents in the manufacture of a feedstock may complicate efforts to recycle or take back a used product.

The benefit of eliminating upstream stages is that clear boundaries are set and all of the products and processesthat are immediately involved in producing the item under study are included. From the manufacturers perspec-tive, this approach focuses on those issues that are most under his or her control—feedstocks and processes withinthe plant gates and immediate vendors or suppliers. It also eliminates the issue of proprietary vendor data, one ofthe more difficult data collection problems in LCA.

The disadvantage of this approach is that important environmental consequences of raw material extraction orproduction may be eliminated from consideration, causing a skewed picture to emerge. This could lead to conclu-sions that are erroneous and that would contradict those of a full-scale LCA. Unfortunately, the researcher has noinformation on which to estimate whether the streamlined study fairly represents the entire life cycle; before it canbe determined whether the omission of stages will affect the validity of the study, those stages must be evaluated.

Limiting or eliminating downstream stagesSome practitioners limit or eliminate the downstream stages and focus on the materials coming into the plant andthe processes within the plant gates. These users might be looking for alternative materials or processes that haveimproved environmental profiles.

The advantage of this approach is that it captures some of the important environmental concerns within the lifecycle that can be used in product improvement. Another benefit is that it can be used to encourage vendors andsuppliers to provide materials that have improved environmental profiles.

As with the previous approach, the disadvantage of this method is that it ignores important stages in the life cycle.In particular, the use stage for some products is the most critical (e.g., given the long lifetime of many buildingmaterials, their effects on building performance can overshadow environmental effects during other stages). Forothers, final disposal is an important issue.

Limiting or eliminating upstream and downstream stagesIn a few cases, manufacturers have applied the LCA template to only their own operation. This gate-to-gate ap-proach uses the LCA template to assist in organizing and analyzing data gathered within the facility. While severalpractitioners call this approach streamlined LCA, many would consider that it is more appropriately called anenvironmental assessment.

The advantage of this approach is that the data can be gathered, and the processes under the study can be affected,directly by the user. The results of the study are likely to be useful to the sponsor. The disadvantage is that thebenefits of looking at the life cycle of the material are lost.

Focusing on specific environmental impacts or issuesIn this approach, the study sponsor or the researcher selects high priority issues as the focus of the study andfollows these issues throughout the life cycle. These could include issues of particular importance to the environ-ment or to the study sponsors, such as a contribution to catastrophic or irreversible environmental impacts, acutehazards to human health, depletion of endangered resources or species, generation of one or more highly toxicpollutants, or life-cycle energy consumption. Some practitioners use a group of in-house or external experts toidentify these issues.



18

The advantage of this approach is that it focuses on the issues of importance to the user and is likely to produceinformation that the user will find helpful. This approach can be particularly useful when regional considerationsare of critical importance. This approach also addresses one of the problems involved in using the results of LCAstudies to compare alternative processes or products: it is likely that no single product or process will be superioron all environmental parameters. If the user has decided in advance which parameters are of greatest importance,the decision-making process will be facilitated.

The obvious disadvantage of this approach is that important environmental considerations will be excluded, andthe decisions made as a result of the study may not be the best overall for the environment or human health.

In a variation on this approach, some studies limit their focus to those issues for which data are available andquantifiable and which are of interest to the study sponsors. For example, environmental factors that are difficultto quantify, such as habitat loss and loss of biodiversity, are explicitly excluded. Energy-related factors and airemissions are elements that are more readily quantifiable.

The advantages of this approach are feasibility and quality of data. The results are less vulnerable to attack ongrounds of subjectivity. The disadvantages are similar to those cited in the previous example: important environ-mental factors may be excluded.

Establishing criteria to be used as “showstoppers” or “knockouts”This approach is related to the focus on specific issues of importance. In this approach, however, criteria areestablished that, if encountered during the study, can result in an immediate decision. Proponents of this approachbelieve that because these criteria are so important, other elements of the life cycle pale in comparison and becomeirrelevant. These criteria must be based on the values of the researcher or client. The criteria can include any of theissues listed under the previous approach—a product’s contribution to catastrophic or irreversible environmentalimpacts (e.g., ozone destruction or species extinction), acute hazards to human health, depletion of endangeredresources or species, generation of one or more highly toxic pollutants or life-cycle energy consumption—or others.Using this approach, the inventory shifts from a methodical exploration of all constituents to an examination ofquestions such as: “During the life cycle of product A, are any petroleum-based chemicals used?” or “During thelife cycle of product B, are any ozone depleting substances released?” If the answer to the relevant question isnegative, the inventory proceeds according to established guidelines.

Using qualitative as well as quantitative dataA major expense in conducting a full-scale LCA is collection of reliable quantitative data. Obtaining these data forthe inventory can be an enormous task; preparing a quantitative impact assessment or improvement assessment atthis point goes beyond the current state of the art. There are several problems that the researcher encounters incollecting quantitative data for an LCA. Many manufacturing facilities produce more than one product line, and itmay be difficult to assign energy consumption or waste generation values to separate products. Further, manycompanies consider the data needed for LCA to be proprietary and are reluctant to divulge this information tooutside researchers.

In this approach, qualitative information is gathered when quantitative data are not available. The materials-flowdiagrams that are constructed for the studies include processes and materials, but they are not true mass balancesbecause they do not include quantities at each step.

The benefit of using this approach is that all potential environmental issues are detected at each stage of the lifecycle. Another benefit of using qualitative as well as quantitative data is that some environmental factors, such asbiodiversity and habitat issues, are not readily amenable to quantification. If the study design requires quantifica-tion, these issues may be simply eliminated from consideration because they are not quantifiable, resulting in adistorted picture.

The major drawback of this approach is the difficulty in assessing the importance of each environmental concern inthe overall life cycle and in comparison to other products. For example, this approach may not allow the user tocompare 2 alternative products in terms of their contribution to ozone depletion or release of a particular carcino-



gen. This technique may not provide enough information to enable manufacturers to choose one process orfeedstock over another.

Using surrogate process dataSometimes it is difficult or impossible to obtain data on a particular product or process; however data on a similarproduct or process may be more readily available. Similarly, data on a material in one application may be moreavailable than are data on the material in another application. The more readily available data can be used as asurrogate for other information if the differences between the products, materials, or processes are minor and ifthese differences do not have significant environmental consequences. It is crucial in selecting a surrogate product,material, or process to analyze all key elements to ensure comparability.

The advantage of this approach is that estimates can be developed for data that would otherwise be unavailable.The caution is that the surrogates must be chosen very carefully to ensure that the surrogate truly represents theproduct, material, or process under the study.

Limiting the constituents studied to those meeting a threshold volumeSome studies eliminate those constituents that comprise less than a specified percentage of the product or process.A threshold of 1% is sometimes used in full-scale LCAs; a larger percentage could result in a “streamlined” LCA.

This approach has the advantage of limiting the number of items that must be studied and focuses on those that arelikely to be most important for the product under study. It is also easy to define clearly and does not have aninherent bias. The disadvantage of this strategy is that, by focusing only on volume and disregarding hazard ortoxicity, important environmental effects may be overlooked.

Case study evaluation proceduresThere is no objective standard against which to compare the streamlined approaches to determine their validity.Therefore, “full” LCI data for 26 different products in 10 different product categories were developed by FranklinAssociates, Ltd. (FAL) and RTI to serve as a proxy for the “full-scale” LCA. Comparative conclusions (i.e., productrankings) were then developed for the product systems in each category. Streamlining methods were then appliedto each product system and new conclusions were developed based on the streamlined LCI results. The success ofeach streamlining method was then measured in terms of how well the rankings based on the streamlining methodmatched those based on the full LCIs. Any deviation from the ranking produced by the full LCI was considered afailure; no distinction was made between major shifts in rank (e.g., from top to bottom) versus minor shifts (e.g.,switches in ranking between 2 products in the middle of the list).

This approach has several important limitations:• Although the data generated by Franklin Associates and RTI are as complete as was possible, all LCA studies

use some modeled or estimated data. Therefore, the standard against which the streamlined studies weremeasured is not perfect.

• By defining any deviation from the ranking as a failure, the study could not distinguish a major differencefrom a minor one. A shift from first to last would be a significant difference; a shift from third to fourth orsecond to third, based on only a few points, might not be a significant difference, particularly when uncer-tainty in the data is considered.

• There was no consideration of the extent to which the studies met the needs of users. The streamlined studymight have yielded excellent and highly accurate information for the purposes of the study and yet would bedefined as a failure if it failed to match the Franklin/RTI standard for all categories.

It is important to note that the RTI study did not examine the usefulness of the results to the user or the ability ofthe streamlined approaches to meet the study goals. The study, instead, examined streamlining approachesindependent of the decision-making context and the goal-and-scope definition process.

It is also important to note that an assumption was made regarding the “goodness” of the Franklin data. In makingthe comparisons, it was assumed that the more comprehensive life-cycle inventories provided by Franklin representthe “correct” results.



20

Summary of findingsIn general, none of the streamlining methods produced rankings identical to the full life-cycle studies. It was notsurprising to find that

• streamlining methods that excluded the least amount of data (or processes) were, rather predictably, themost successful in producing identical rankings, and

• excluding processes and data that were dominant in the LCI totals was less likely to give identical results.

It is important for an LCI to include all processes and data that are significant contributors to LCI totals in order toproduce results that will be identical to a full LCI. In applications when the equivalent of a full LCI is not required,this is less important.

A systematic and logical analysis based upon detailed knowledge of the product systems will indicate areas inwhich streamlining might be appropriate. For example, if all products to be compared have one life-cycle stage thatrequires large amounts of resources and produces large amounts of emissions, then upstream and/or downstreamcomponents are candidates for elimination.

The approach tested by EPA that produced results most like a full LCI was the historical “sensitivity analysis”approach. This requires that a complete flow diagram be developed, with materials-flow quantities in place, basedon estimates, secondary data, or generic data from commercial databases. A preliminary LCI using rough data, butcovering all major life-cycle stages, is performed at this point. Sensitivity analysis can then be applied. In thisprocess, each LCI entry is examined and the percent contribution of each process to the total is calculated. Forthose processes that contribute a large percentage of the total, the best data possible is required. For those pro-cesses that contribute very little to the total, estimates or surrogates are acceptable. This process also leads to ananalysis of product system structure, which is also an aid to selecting appropriate streamlining methods.

Streamlining will always incur the risk of obtaining a result that is different than that for a full LCA. However, ifsome level of risk is acceptable, there are some general rules that can be used to select a streamlining method thatwill reduce the risk of serious error. In addition, the goal-and-scope definition phase might indicate that a full LCIis not needed, as discussed in Chapter 2.

Streamlining Impact Assessment: P2 Factors

This method is derived from the notion that a relative comparison of alternatives (pollution-prevention technolo-gies or practices in this instance), based on a selected number of criteria spanning the life-cycle stages of therespective systems, can give process designers or facility engineers a useful picture of potential consequences ofthese alternatives; in fact, this approach might be more complete and realistic than analysis of selected emissionsduring a single life-cycle stage (USEPA 1994).

The Pollution-Prevention (P2) Factors methodology was developed to accommodate calculation of both an industryaverage and a site-specific value for an individual company in order to determine which P2 activities result in thegreatest environmental improvement. This information can be used along with other factors, such as cost,manufacturability, and performance, to choose among similar P2 alternatives.

Pollution-Prevention Factors are designed to quantify the environmental improvement in the form of a ratio, wherethe denominator is the summed score for criteria after implementation of that P2 activity. A P2 Factor calculatedfor a specific P2 activity in a given industry can be compared on a relative basis with other P2 Factors calculated forthe same industry. The report notes that a P2 Factor should not be used to claim that a specific alternative is goodor bad for the environment since this exceeds the goal of the study.

The P2-Factors approach is basically a streamlining of the impact assessment phase. The first step is to identifywhich impact categories are likely to change as a result of implementing a P2 activity. This is accomplished withthe help of stressor/impact chains. It also begins with a “master” list of impact categories from which a smaller listis formed (Table 3-2).

Scoring criteria were developed to assess each of the impact categories. They consist of 5 levels that indicatedecreasing environmental impact by the numbers 1, 3 ,5, 7, and 9, with 9 indicating the least environmental



impact. Table 3-3 provides examples of evaluation criteria and scoring ranges that were used in the pilot study ofsolvent replacement in lithographic printing. The results of applying the P2-Factors framework at 3 printingfacilities are presented in Table 3-4.

Key elements of this approach include:• Relative performance metrics—This method selects criteria based on the construction of networks connect-

ing inputs and outputs to possible environmental consequences that are relevant to differentiating thealternatives and the use of simplified scoring metrics for measuring each. Further, the absolute values of the

Scoring c riteria Raw materialacquisition

Manufacturing Use, resuse, andmaintenance

Rec ycle/wastemanagement

Habitat alteration X

Industrial accidents X X

Resource renew ability X

Energy use X X X X

Net water consumption X X X X

Preco nsumer w aste recycle percent X

Airbo rne emissions X X X X

Waterbo rne effluents X X X X

Solid waste generatio n rate X

Recycle content X

Source reductio n potential X

Produc t reuse X

Pho to chemic al o xidant creation potential X X X X

Ozone depletion potential (ODP) X X X X

Glo bal warming potential X X X X

Surrogate for energy/emissio ns to transportmaterials to recycle

X X

Recyclability potential (Postc onsumer) X

Produc t disassembly potential X

Waste-to-energy value X

Material persistence X

Toxic material mobility after disposal X

Toxic content X X

Inhalatio n toxicity X X

Landfill leachate (aquatic) to xic ity X

Incineratio n ash residue X

TTTTTable 3-able 3-able 3-able 3-able 3-22222 List of potential scoring criteria for determining P2 factors, with relevant life-cycle stages indicated by an “X” (USEPA 1994)



22

criteria scores are not used; instead, there is a relative comparison of performance prior to and subsequent toimplementation of the technology or practice. There is no explicit data uncertainty analysis with thisapproach, although sensitivity analysis can be performed on the criteria scores.

• Criteria tailoring—The P2-Factors method is designed so that it can be used to assess the relative perfor-mance of an action by a single company or by an industry as a whole. This is accomplished through selec-tion of the relevant criteria and by combining the scores from the individual criteria.

• Interpretation—The criteria represent a mixture of attributes that are amenable to summation across stagesand those that are not. For example, the criterion “recyclability potential,” which measures the feasibility ofrecovering materials from the product following its useful life, is not relevant in all of the life-cycle stages.

Habitat alterationC riteria ranges fo r habitat alterat ion

Score

9 F ew acres altered; habitat recovery < 5 years (e.g., natural gas or oil extractio n)

7 Moderate number of acres altered; recovery 5 -25 years (e.g., temperate forestry,underground mining)

5 Moderate number of acres altered; recovery 2 5-100 years (e.g., tropical forestry)

3 Many acres (hundreds) altered; recovery 25-10 0 years (e.g., strip mining)

1 Many acres altered; recovery 100 + years

* Insufficient data

Resource renew abilityC riteria ranges fo r reso urce renewability

Score

9 Renewability < 1 year (e.g., biomass feedstock s)

7 Renewability 1-2 5 years (e.g., temperate so ftwo ods)

5 No nrenewable, sustainability > 50 0 years (e.g., co al, oil, natural gas)

3 No nrenewable, sustainability 50-5 00 years (e.g., aluminum)

1 No nrenewable, sustainability < 50 years

* Insufficient data

Energy usageC riteria ranges fo r energy usage per unit output

Score

9 < 5 00 0 BTU/lb

7 5 00 0-10,000 BTU/lb

5 1 0,00 0-20,000 BTU/lb

3 2 0,00 0-30,000 BTU/lb

1 > 3 0,00 0 BTU/lb

* Insufficient data

TTTTTable 3-able 3-able 3-able 3-able 3-33333 Example evaluation criteria and scoring ranges for calculation of P2 factors for P2 activities used bylithographic printers (USEPA 1994)



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Streamlined Life-Cycle Assessm

ent

©1999 Society of Environm

ental Toxicology and Chemistry (SETAC).Photoduplication of this docum

ent is encouraged. Please give proper credit.

24

Table 3-4 continued

1Raw scores are initially assigned to a chemical based on the impact criteria scoring range with the best fit.2The raw score may be decreased to a modified score for selected impact criteria based on the quantity, characteristics, or release locationof the chemical available to cause the potential impact.

COMPANY Energy AirbornWater-

borne

Photo-chemical

oxidantcreation Inhalation

Ozonedepleting

Globalwarming

Individual solvent

mixture

Averagecon-

currentsolvent mixture

Inter-mediate

P2Overall

P2Combined Solvent use emissions emissions potential toxicity potential potential score score factor factor

INTELLIGENCER PRINTING COMPANY, LANCASTER, PAVT3-A raw score 2.7 5.9 5.9 3.9 7.7 9.0 9.0

modifiedscore

2.7 5.9 5.9 1.9 7.7 9.0 7.0 40.0

39.4Power Kleen XF Plus raw score 2.8 5.8 5.1 4.0 6.8 9.0 8.9

modifiedscore

2.8 5.8 5.1 2.0 4.8 9.0 8.9 38.6 1.05

IP Wash raw score 3.0 6.0 5.0 4.4 7.0 9.0 9.0modifiedscore

3.0 6.0 5.0 2.4 7.0 9.0 9.0 41.4 41.4

AVERAGE P2 RATIO: 1.00



• Criteria characteristics—P2-Factors criteria consist of a composite of conventional inventory items, such aswaterborne effluents; impact groupings, such as ozone depletion potential (ODP); and managementpractices, such as product disassembly potential. There is no established standard against which to com-pare the selection of impact categories to determine the validity of the P2-Factors master list; however,because the basis of interpreting the overall performance profile is a scored value, the inclusion of thesedifferent types of indicators may be appropriate in this application. In fact, this approach offers flexibility tothe method and makes the criteria much more relevant to the issues of concern to the user.

• Compatibility with other metrics—Factor scores may be used with or without a relative weighting factor andmay be combined with established performance metrics, e.g. relative print quality or cost, provided theseother attributes can be expressed in an ordinal fashion or interpreted outside of the environmental assess-ment altogether.

Streamlining Based on the Life-Cycle Concept

Some practitioners have developed streamlined approaches that challenge the need for a complete inventory ofmaterial and energy flows associated with the system of interest. Using the life-cycle concept through what hasbecome known as “life-cycle thinking” is a unique way of addressing environmental problems from a systems orholistic perspective.

In this way of thinking, a product or service system is evaluated or designed with a goal of reducing potentialenvironmental impacts over its entire life cycle. Life-Cycle Assessment should not be confused with life-cyclethinking: these terms are not synonymous. The essential difference is that life-cycle thinking does not normalizethe results to a functional unit, a step that is conducted as part of an LCA study. Additionally, with life-cyclethinking the results may be expressed qualitatively or quantitatively. In an LCA, the results are generally quantita-tive in nature (Fava 1999).

Although one of the fundamental tenets of LCA practice has been that there must be a complete accounting ofthese flows in order to constitute a valid description of the environmental characteristics of the system, anotherschool of thought regarding the goal-and-scope definition process might indicate that this is not the case for aparticular study. Prospective users of LCA information generally are not interested in the detailed quantitiesthemselves, but rather in the relative difference among the possible alternatives under consideration. Further,some of the data content of LCIs is unusable because designers and process engineers have no way to incorporate itinto their decision-making procedures and tools.

One such alternative approach developed in recent years may serve to illustrate the evolution of these concepts: theAT&T Abridged Life-Cycle Assessment. This approach is described briefly in the following sections.

AT&T abridged life-cycle assessmentAT&T (Graedel et al. 1995) has developed a technique that allows them do LCAs rapidly (in about 2 days for atypical product or a week for a typical facility) and produce improvement analyses that can be expeditiouslyimplemented. The central feature of their approach is a 5 X 5 assessment (Figure 3-1). One dimension consists ofthe 5 basic life-cycle stages (pre-manufacturing, product manufacture, packaging and transport, use, and disposal).The other dimension is environmental concern (materials choice, energy use, solid residues, liquid residues, andgaseous residues). Each cell in the matrix is assigned an integer from 0 (highest impact) to 4 (lowest impact), whichis established by the assessor to represent the estimated result of a more formal LCA. The assessor is guided by acombination of experience, a design and manufacturing survey, appropriate checklists, and other information.AT&T reports that although this process seems to be highly subjective, different assessors, provided with checklistsand protocols, produced results that differed by less than 15%.

Once an evaluation is done using the matrix approach, an overall environmentally responsible product rating canbe computed as the sum of the matrix elements:

Rerp = G i G jMij



26

Because there are 25 cells in the matrix (with values of 0 to 4), a maximum rating of 100 can be obtained.

AT&T feels that the matrices provide a useful overall assessment of a product design, but “target plots” provide amore effective display of the results. Each plot is constructed using the 25 elements around the circumference of acircle. Points on the circumference represent a value of zero. A good product then has more points toward thecenter of the circle. These plots make it easier to single out areas that may need special attention. Further, itpermits quick comparison between product and process designs to move toward improvement. Completedmatrices for generic 1950s and 1990s automobiles are illustrated in Figure 3-2. The overall rating of the 1950s car is46, far below what might be desired by today’s environmental standards. The overall rating for the 1990s car, 68, ismuch better than the earlier vehicle but identifies opportunities for further improvement (Graedel et al. 1995).

Key elements of this approach include• Relative performance metrics—All of the directional and intensity information in the matrices is relative.

However, the baseline for the assessment of relativity is less well-defined than is the case with the P2-Factorsmethod. It is up to the user to be transparent about the basis for the relative comparison.

• Criteria tailoring—Criteria may be judged to be inapplicable for a given stage.• Interpretation—The criteria represent a mixture of attributes that are amenable to summation across life-

cycle stages and/or environmental concern. For example, the environmental concern “materials choice”identifies the material resources in each life-cycle stage that present a high or low environmental impactpotential. Scores for material choice in each life-cycle stage could be summed to produced an overallmaterials choice score.

• Criteria characteristics—The matrix includes one dimension of 5 life-cycle stages and the other as 5 catego-ries of environmental concerns. The environmental elements include materials choice, and more traditionalLCA type elements (energy use and air, water, and solid emissions). Matrix elements are scored from 0highest impact potential) to 4 (lowest impact potential) and are summable to produce a single score or to bemapped on a target plot.

• Compatibility with other metrics—Matrix scores are typically used without a relative weighting factor,although there is no reason why one could not be assigned and combined with established performancemetrics, e.g. relative performance, quality, or cost, provided these other attributes can also be expressed inan ordinal fashion (or interpreted outside of the environmental assessment altogether).

Environmental Concern

Life-cycle stage Materials choice Energy use Solid residues Liquid residues Gaseous residues

Pre-manufacture (1,1) (1,2) (1,3) (1,4) (1 ,5 )

Produc t manufacture (2,1) (2,2) (2,3) (2,4) (2 ,5 )

Produc t packaging andtransport

(3,1) (3,2) (3,3) (3,4) (3 ,5 )

Produc t use (4,1) (4,2) (4,3) (4,4) (4 ,5 )

Refurbishment/rec ycling/disposal

(5,1) (5,2) (5,3) (5,4) (5 ,5 )

FFFFFigurigurigurigurigure 3-e 3-e 3-e 3-e 3-11111 AT&T’s Environmentally responsible product assessment matrix (Reprinted with permissionfrom Graedel et al. 1995. Copyright 1995 American Chemical Society)



28

ReferencesCurran MA, editor. 1996. Environmental life-cycle assessment. New York: McGraw-Hill.Fava J. 1999. Life-cycle assessment: what is it and how does it fit into a broader environmental framework? SETAC News

19(1):24.Fava J, Consoli F, Denison R, Dickson K, Mohin T, Vigon B, editors. 1993. A conceptual framework for life-cycle impact

assessment. Pensacola FL: Society of Environmental Toxicology and Chemistry (SETAC).Fava J, Denison R, Jones B, Curran MA, Vigon B, Selke S, Barnum J, editors. 1991. A technical framework for life-cycle

assessment. Pensacola FL: Society of Environmental Toxicology and Chemistry (SETAC).Graedel TE. 1998. Streamlined life-cycle assessment. Upper Saddle River NJ: Prentice-Hall.Graedel TE, Allenby BR, Comrie PR. 1995. Matrix approaches to abridged life-cycle assessment. Environmental Science and

Technology 29(3):134–139.Huang E, Hunkeler D. 1995. Life-cycle concepts for minimizing environmental impacts: a corporate survey. Nashville TN:

Vanderbilt University.[USEPA] U.S. Environmental Protection Agency. 1997. Streamlining life cycle assessment: concepts, evaluation of methods, and

recommendations. Draft report. Office of Research and Development. Contact Mary Ann Curran (513) 569-7782.[USEPA] U.S. Environmental Protection Agency. 1995. Life-cycle impact assessment: a conceptual framework, key issues, and

summary of existing methods. Research Triangle Park NC: Office of Air Quality Planning and Standards. EPA/530/R-95/011.

[USEPA] U.S. Environmental Protection Agency. 1994. Development of a pollution prevention factors methodology based onlife-cycle assessment: lithographic printing case study. Washington DC: Office of Research and Development. EPA/600/R-94/157.

[USEPA] U.S. Environmental Protection Agency. 1993. Life-cycle assessment: inventory guidelines and principles. WashingtonDC: Office of Research and Development. EPA/600/R-92/245.

Weitz KA, Todd JA, Curran MA, Malkin MJ. 1996. Streamlining life cycle assessment: consideration and a report on the state ofpractice. The International Journal of Life Cycle Assessment 1(2):79–84.



CHAPTER 4

Conclusions

The primary message of this report is that streamlining is an inherent part of the goal-and-scope definition processof LCA. Life-Cycle Assessment designers do not decide whether to streamline as much as where and how to stream-line. Streamlining is, therefore, a disciplined process of designing an LCA study to gather sufficient information tomake a sound decision or to meet the requirements of other applications.

Practitioners encounter a number of challenges when applying the LCA process to a real-life problem. Thesechallenges might include, among others, making decisions about omitting pieces of data, dealing with data gaps,deciding which of several emissions or outputs to include in LCIs, how to request and incorporate confidentialinformation from private companies, and how to set up spreadsheet-based LCI models for in-house studies. In theplanning phase of LCA, there are challenges associated with developing study plans and realistic objectives,including associated costs and schedules, while being unsure of where to obtain data, data completeness, accuracy,and of time required for collection. Supporting information to address some of these challenges is available inscattered sources, but has not been collated in a user-friendly manner. Therefore, practitioners need informationand tools to support the LCA planning and scoping process so that uncertainty in minimized.

Some recent LCA initiatives are focusing on developing information resources to support LCAs1. These initiatives,many of which are in early stages, will give practitioners easier access to data and information. However, research isneeded to assist practitioners in dealing with practical problems experienced and to provide direction for planningand scoping to minimize arbitrary and inconsistent decision-making on the part of LCA practitioners.

In earlier chapters, we provided some general guidelines for approaching streamlining and presented the limita-tions introduced by the application of different streamlining approaches. This information will help LCA practitio-ners by presenting a better understanding of the potential implications and effects of applying various scoping andstreamlining decisions that they may not have considered previously.

Clearly, it is impossible to devise a universal, “one-size-fits-all” set of streamlining guidelines. However, studies thatinclude explicit decisions to streamline LCA methods should possess the following characteristics if they are to haveutility and validity from a user’s perspective:

• Relative differences between elements of a product or process should be shown, along with an indication ofhow certain or appropriate the information is.

• The metrics or criteria should be tailored to fit the application as well as the organizational policies andgoals.

• The characteristics included should span the entire life cycle, but not necessitate interpretation or applica-tion on an aggregated basis.

• The characteristics available may include both conventional inventory items and more interpreted metricsreflecting materials management practices, competitive influences, or environmental consequence charac-teristics.

• The criteria or metrics should be compatible with both a weighting or valuation process and other productor process design criteria such as cost, customer needs, and legal/regulatory requirements.

Uncertainty is also an important factor when considering streamlining. It is very difficult to accurately quantify allpossible sources of uncertainty in any LCA; streamlined or not.

Communication of streamlining decisions is crucial to enable users of the study to place the results in context andto understand the limitations or caveats on the conclusions. Exhibit 4-1 presents a format that could be included ineach study to communicate with potential users. The inclusion of such a format would assist in preventingaccidental misuse of the results.

1 Such as the Society for the Promotion of Life-Cycle Development (SPOLD), CHAINET ([email protected]), the DOE-sponsored Database (LCAD), the EcoSite web site (http://www.ecosite.co.uk/), the ISO Technical Report on Data Format (http://www.iso.ch/), and SETAC Europe’s workgroup on Data Availability and Quality ([email protected]).



30

EEEEExhibit 4-xhibit 4-xhibit 4-xhibit 4-xhibit 4-11111 Study profile

This profile summarizes characteristics of the study methodology that are relevant to the study’s use. The first group of features indicatesthe extent to which the study “streamlined” the LCA methodology. The second group of features provides information on the data thataffect the analyses that can be supported by the study.

Place a mark on each line to indicate the relative position of the study.

Study feature More streamlined Less streamlined

EXAMPLE VERY STREAMLINED T FULL- SCALE LCA

Completeness of life-cycle stages One stage only All stages

Breadth of impacts/pollutants Single impacts/pollutants All impacts/pollutants

Quantification of data Qualitative data Quantitative data

Specificity of data Generic/averages Product specific/actual

Data quality Estimates/high uncertainty Measured/low uncertainty

Other features

Transparency Final totals only Fully transparent

Temporal specificity No specificity Some specificity

Spatial specificity No specificity Some specificity

Scale Local Global

Availability of disaggregated data Only aggregate available All available unaggregated



Glossary

EnvirEnvirEnvirEnvirEnvironmental Life-Conmental Life-Conmental Life-Conmental Life-Conmental Life-Cyyyyycle Assessment : cle Assessment : cle Assessment : cle Assessment : cle Assessment : see Life-Cycle Assessment

FFFFFunctional Uunctional Uunctional Uunctional Uunctional Unit : nit : nit : nit : nit : The quantity of product that is used to base calculations of material and energy flows across asystem.

Life CLife CLife CLife CLife Cyyyyycleclecleclecle : Consecutive and interlinked stages of a product system, from raw material acquisition, throughmanufacturing, use and final disposal.

Life-CLife-CLife-CLife-CLife-Cyyyyycle Assessment (Lcle Assessment (Lcle Assessment (Lcle Assessment (Lcle Assessment (LCCCCCA) :A) :A) :A) :A) : Compilation and evaluation of the inputs and outputs and the potential environ-mental impacts of a product or process system throughout its life cycle.

Life-CLife-CLife-CLife-CLife-Cyyyyycle Impact Assessment (Lcle Impact Assessment (Lcle Impact Assessment (Lcle Impact Assessment (Lcle Impact Assessment (LCIA) : CIA) : CIA) : CIA) : CIA) : A phase of LCA aimed at understanding and evaluating the magnitudeand significance of the potential environmental impacts of the product or process system.

Life-CLife-CLife-CLife-CLife-Cyyyyycle Inventorcle Inventorcle Inventorcle Inventorcle Inventory (Ly (Ly (Ly (Ly (LCI) : CI) : CI) : CI) : CI) : A phase of LCA involving the accounting of inputs and outputs across a givenproduct or process life cycle.

Life-CLife-CLife-CLife-CLife-Cyyyyycle Scle Scle Scle Scle System : ystem : ystem : ystem : ystem : The boundaries of the interconnected activities associated with a product or process includingall mass and energy inputs and outputs. A system is defined by the function of a product, process, or activity beingevaluated.

Life-CLife-CLife-CLife-CLife-Cyyyyycle Thinking : cle Thinking : cle Thinking : cle Thinking : cle Thinking : Using the life-cycle concept to evaluate environmental issues in a holistic system-wideperspective.

ScrScrScrScrScreening Leening Leening Leening Leening LCCCCCA : A : A : A : A : An application of LCA used primarily to determine whether additional study is needed and wherethat study should focus.

StrStrStrStrStreamlined Leamlined Leamlined Leamlined Leamlined LCCCCCAAAAA : Identification of elements of an LCA that can be omitted or where surrogate or generic data canbe used without significantly affecting the accuracy of the results.

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