217 Chapter 9 Life Cycle Environmental Strategies and Considerations for Product Design To implement a process of integrated design that takes into consideration all the phases of the life cycle, from the defi nition of product specifi cations to its disposal, harmonizing a wide range of factors and including environ- mental aspects, it is necessary to use opportune strategies allowing environ- outlined a general view of how an intervention oriented toward environ- mental protection can be integrated in the design and development process through suitable design strategies for the environmental performance of a product’s life cycle. In this chapter, these same environmental strategies are considered in greater detail, highlighting any aspects of particular interest to the designer and describing the tools and techniques aiding their application. For each of the strategies, particular emphasis will be placed on the defi nition of the determinant factors conditioning their applicability and effectiveness, and on the connection between these strategies and certain product properties (reliability, durability)—the traditional subjects of engineering design. 9.1 Strategies for Improving Resources Exploitation and Determinant Factors A general overview of what may be considered the most effective environ- mental strategies in the life cycle approach was presented in Chapter 8. Underscoring the need to assimilate such strategies in the product design and development process, it is opportune to focus on those which can be directly linked to design choices, and thus become true and proper design strategies (Section 8.2.1). As highlighted before, the material dimension of the product–entity is directly connected to choices made in the specifi cally designed-related phases of the development process—conceptual, embodiment, and detail design. The important parameters of such choices are referable to precisely this 2722_C009_r02.indd 2172722_C009_r02.indd 217 11/30/2005 1:50:08 PM11/30/2005 1:50:08 PM © 2006 by Taylor & Francis Group, LLC mental requirements to be incorporated in design practice. Chapter 8 218 Product Design for the Environment physical dimension of the product (system architecture, materials, component shapes and dimensions, interconnections, and junctions) and it was suggested how an improvement in the environmental performance of its life cycle could be achieved. Figure 9.1 highlights two main strategy typologies that, as well as expedients for reducing the resources used in product manufacture, could achieve this improvement: • Useful Life Extension Strategies—Maintenance, repair, upgrading, and adaptation of the product • End-of-Life Strategies—Reuse and remanufacturing of systems and components, recycling of materials in the primary production cycle or in external cycles Both of these types of intervention strategies have great potential in relation to the environmental optimization of resource fl ows throughout the prod- uct’s life cycle. Extending the useful life allows greater exploitation of the resources used in production, avoiding the consumption of additional resources in the manufacture of replacement products. Intervening to recover the product, or parts of it, at the end-of-life allows its constituent components or materials to be reused in the production of new products, thus reducing FIGURE 9.1 Environmental strategies for improving exploitation of resources. 2722_C009_r02.indd 2182722_C009_r02.indd 218 11/30/2005 1:50:09 PM11/30/2005 1:50:09 PM © 2006 by Taylor & Francis Group, LLC Life Cycle Environmental Strategies and Considerations 219 the consumption of virgin material resources, conserving all or part of the energy resources used, and reducing the volumes of waste. In the fi nal analy- sis, these strategies favor an increase in the intensity with which the resources employed in manufacturing the product are used, thereby improving their exploitation. This aspect constitutes a substantial difference with respect to those strategies directed at reducing the resources used in production An effective integration between these two types of strategies for improving exploitation of resources is both desirable and necessary, given that the actions of interventions for extending the useful life can strongly condition the opportunities for recovery, since these depend on the level of use to which a product, its components, and constituent materials have been subjected during the phases preceding recovery. Products that have been used for long periods of time usually show a signifi cant deterioration in their functional performance, and consequently allow a lower level of recovery than products that are little used. The latter often still exhibit highly effi cient performance and are, therefore, suitable for reuse. 9.1.1 Infl uence of External Factors and Product Durability Applying strategies for the extension of the useful life and recovery at end-of-life is, in general, conditioned by a wide range of factors determin- ing its effectiveness (Rose et al., 1998; van Nes et al., 1999). The evaluation of these factors is, therefore, essential for a correct implementation of these strategies in product development. In this respect, external factors condi- tioning the life expectation of a product are of particular importance (Woodward, 1997): • Functional Life—The period of time for which need for the product is predicted to last • Technological Life—The period of time that ends when the product is so technologically obsolete that it must be replaced by another based on superior technology • Economic Life—The period of time that ends when the product’s economic obsolescence is such it must be replaced by another char- acterized by analogous performance but costing less • Social and Legal Life—The period of time that ends when changes in the desires of the consumer or in normative standards require the product to be replaced All these factors, which can be considered external to the context of design choices linked to the product’s physical dimension, must be considered along 2722_C009_r02.indd 2192722_C009_r02.indd 219 11/30/2005 1:50:09 PM11/30/2005 1:50:09 PM © 2006 by Taylor & Francis Group, LLC (Chapter 8, Section 8.2). 220 Product Design for the Environment with a fi nal, internal factor, which can be identifi ed as the “physical life.” This is the period of time for which the product is expected to physically last, maintaining its functional performance. This is, therefore, the factor directly linking the main design choices (architecture, materials, shapes, and geome- tries) with the predicted lifespan of the product. In the design phase, the possibility of providing for the extension of the product’s useful life and the reuse of parts depends precisely on the length of a product’s physical life, which in turn is strictly bound to the durability of its components (Giudice et al., 2003), understood in general terms as the capacity to maintain the functional performance required of them. However, this property should not be maximized indiscriminately since, for example, in product sectors with a high level of technological innovation (and there- fore with rapid obsolescence), excessive duration has a negative environ- mental value, guaranteeing a useless extension of product and component life that uses more resources in the production phase. 9.1.2 Identifi cation of Optimal Strategies The defi nition of both strategies for improving resource exploitation must, therefore, be subordinate to an evaluation of the external factors noted above, linked to the market reality and to regulatory standards, company policies, technological innovation, and aesthetic–cultural conditioning—all factors that vary widely according to the product typology. Having quantifi ed the main external factors, it is possible to identify the strategies most appropriate to the product for varying its durability and that of its components. A series of signifi cant evaluations can be made by comparing the physi- cal life with the “replacement life,” defi ned as the period of time for which the product is effectively usable. This is comparable to the period of time the prod- uct is present on the market up to its defi nitive replacement, thus incorporat- ing all the external conditioning considered above. Physical life represents the predicted duration of a product’s full effi ciency (its potential lifespan), while replacement life represents its effective lifespan, conditioned by factors such as technological and economic obsolescence and other external factors. On the basis of this comparison, a distinction can be made between two types of useful life extension strategies: • Maintenance, repair, and (more generally) service operations constitute strategies intervening on the physical life (Physical life extension strategies). • Upgrading and adaptation of the product constitute strategies intervening on the replacement life (Replacement life extension strategies). 2722_C009_r02.indd 2202722_C009_r02.indd 220 11/30/2005 1:50:09 PM11/30/2005 1:50:09 PM © 2006 by Taylor & Francis Group, LLC Life Cycle Environmental Strategies and Considerations 221 Figure 9.2 shows how, depending on the product typology, it is possible to identify the favorable conditions for extending the useful life by using the two different types of strategies. For physical life extension strategies, these conditions correspond to a long replacement life (indicating that the product may be used for a long time), and a short physical life (revealing the brief duration of some components, and therefore the limited capacity of the entire system to guarantee the required performance). Conversely, for replacement life extension strategies, these conditions correspond to a short replacement life and a long physical life. These conditions not only indicate the inappro- priateness of planning maintenance and service interventions (pointlessly prolonging the product’s life), but also reveal a poor design, unsuited to the predicted short span of effective use. Examples of the latter are over- dimensioning or using unnecessarily high-performance materials. This highly ineffective situation can be remedied through the upgrading or adaptation of the product. The other areas of the graph indicate conditions of equilibrium between the two factors, representing the result of good design wherein the design choices were such that the physical duration of the system was calibrated on its expected effective useful life. This particular condition is generally referred to as a condition of environmental effi ciency, where the resources used in manufacturing the product are gauged on the basis of the effective exigencies, avoiding over-dimensioning and consequent pointless wastage. FIGURE 9.2 Identifi cation of optimal strategies: Extension of product useful life. 2722_C009_r02.indd 2212722_C009_r02.indd 221 11/30/2005 1:50:09 PM11/30/2005 1:50:09 PM © 2006 by Taylor & Francis Group, LLC 222 Product Design for the Environment In an analogous way, Figure 9.3 shows the conditions favoring different recovery strategies, from low-level recovery (recycling of materials) to a higher level (reuse of the entire product) where: • Area 1 represents the condition where the product, whose effective useful life and presence on the market is expected to be short, is composed of rapidly deteriorating components. This represents a condition of gauged duration and is therefore, in principle, eco- effi cient. At the end-of-life, any integral components are potentially reusable in other products, but the most probable recovery strategy is that of recycling the materials where possible. • Area 2 represents the condition where the product, whose effective useful life and presence on the market is again expected to be short, is composed of long-lasting and functionally effi cient components. At the end-of-life, the product may still be fully effi cient but, as a result of external factors, cannot easily be reused because it is obso- lete. Many of the components can potentially be reused as spare parts or in other products. The most probable recovery strategy is again the recycling of materials where possible. • Area 3 represents the condition where the product, whose effective useful life and market presence is expected to be long, is composed of rapidly deteriorating components, so that its performance is not long- lasting enough. At the end-of-life, components that are still effi cient FIGURE 9.3 Identifi cation of optimal strategies: Recovery at product end-of- life. 2722_C009_r02.indd 2222722_C009_r02.indd 222 11/30/2005 1:50:10 PM11/30/2005 1:50:10 PM © 2006 by Taylor & Francis Group, LLC Life Cycle Environmental Strategies and Considerations 223 can be reused in the manufacture of a product of the same type. For the remaining components, only the recycling of materials is possible. • Area 4 represents the condition where the product, whose effective useful life and market presence is again expected to be long, is composed of long-lasting and functionally effi cient components. Like Area 1, this represents, in principle, an eco-effi cient condition of gauged duration. If at the end-of-life the entire product is fully effi - cient and if the length of the replacement life will allow it, in this case it is possible to directly reuse the entire product. This would, in theory, represent the most effi cient strategy for environmental protec- tion unless the use of the product involved a signifi cant environmen- tal impact that could be avoided by using a new, more effi cient product in its stead. As an alternative to direct reuse, it is possible to reuse some of the components. Finally, it is always possible to resort to recycling the materials if feasible. 9.1.3 Use Process Modeling The factors conditioning the strategies for improving exploitation of resources, described above, are strictly dependent on how the product is used and on the context in which this use takes place. To best defi ne the most effective design strategies, it is therefore necessary to have a clear vision of the way in which the product’s use process (understood as the phase of the life cycle where the product performs its intended function) may develop. This depends on how the product behavior (i.e., the way in which it executes its function) interacts with the behavior of the user, and on how this interaction is confi gured in the context of the environment where it takes place. Ultimately, the use process is to be understood as an evolutionary process of the product–user–environment system and must be anticipated at the design stage. This requires a modeling of the use process, allowing the designer to simulate the way this process develops so that it is possible to make well- founded projections regarding the various factors that may condition the design strategies, ensuring a sound and truly effective product development. provide meaningful examples of how this problem can be approached— limiting it to particular aspects and then using models to simulate the func- tional behavior of products and variations in the level of quality (Hata et al., 2000) or user behavior (Sakai et al., 2003). The complex dynamics of the product–user–environment system deter- mine the various factors, internal and external to the product, infl uencing both its replacement life and its physical life. Therefore, these dynamics should be analyzed for a meaningful estimation of the two important param- eters. However, while the estimation of the physical life can be based on 2722_C009_r02.indd 2232722_C009_r02.indd 223 11/30/2005 1:50:10 PM11/30/2005 1:50:10 PM © 2006 by Taylor & Francis Group, LLC Studies of life cycle simulations, already discussed in Chapter 3, Section 3.2.4, 224 Product Design for the Environment well-established modeling methods (such as fi nite element modeling that is able to forecast the behavior of a product’s performance in relation to the conditions of use with reliability), the estimation of the environmental condi- tions and the interaction with the user, manifested in the various factors conditioning the replacement life (functional, technological, economic, social) is still a subject of research today (van der Vegte and Horvath, 2002). 9.2 Strategies for Extension of Useful Life and Design Considerations During their use, products can be subjected to servicing operations such as maintenance and repair of worn or damaged components. The opportune- ness of these operations can be assessed after an accurate estimation of the environmental implications; if the maintenance and/or repair results in a signifi cant environmental impact, it may be more appropriate to retire the product unless its substitution requires the manufacture of a product with an even greater environmental cost. The requisites of durability (the capacity to maintain initial performance levels over time) and maintainability (suitability for maintenance interven- tions aimed at restoring performance levels to their initial values) are of particular importance in the context of design. In reality, from a complete perspective of environmental effi ciency these requisites must not be maxi- mized indiscriminately. As noted in the case of durability, strengthening these properties is positive only up to a certain point, beyond which they begin to generate an impact greater than that caused by the replacement of the product (due, for example, to a higher consumption of resources in the use phase than that of a new, more effi cient product). Maintenance (i.e., the set of activities regarding periodic prevention and minor replacement interventions) is extremely important in limiting the environmental and economic costs of repair, as well as the impacts of dump- ing in waste disposal sites and of manufacturing a replacement product. To facilitate maintenance it is necessary to perform cleaning operations during use, ensure the accessibility of parts, arrange for the use of adequate equip- ment, and provide for systems to monitor the condition of parts and compo- nents. Other aspects that can extend the useful life of products are upgradability (in relation to various phenomena of technological evolution and modifi cation) and adaptability (for products rapidly becoming obsolete and composed of more reconfi gurable components). The strategies aimed at extending a product’s useful life were noted in • Maintenance—Cleaning components; monitoring and diagnosis; substitution of parts subject to wear 2722_C009_r02.indd 2242722_C009_r02.indd 224 11/30/2005 1:50:10 PM11/30/2005 1:50:10 PM © 2006 by Taylor & Francis Group, LLC Chapter 8, Section 8.2.2, and can be summarized as: Life Cycle Environmental Strategies and Considerations 225 • Repair—Regeneration or replacement of damaged and worn parts • Upgrading and adaptation—Substitution of obsolete parts; recon- fi guration of components, adapting them to user requirements or changes in the operating environment It is appropriate to specify that in this book “adaptation” is meant as “recon- fi guration” (i.e., an operation to change behaviors or states of the product resulting in a new function) (Tomiyama, 1999). This meaning differs from other more general defi nitions used in the literature, where “adaptation” is described as a process aiming at transferring products or components in additional usage phases, including maintenance, repair, remanufacturing, upgrading, or rearrangement (Seliger et al., 1998). With regard to the factors that render a product predisposed to the applica- tion of one or more of these useful life extension strategies, it is appropriate to make the following distinction: • The determinant factors making product upgradability and adaptability appropriate can only be analyzed on the basis of purely qualitative assessments. • The determinant factors making the provision and planning of maintenance and repair interventions appropriate or necessary are quantifi able on the basis of well-established engineering techniques, as is the level of product maintainability and reparability. This distinction, which is clearly a direct consequence of the different effects these strategies have on the replacement life and physical life (Section 9.1.2), has direct implications for the design tools and techniques, which are adequately developed only in relation to the strategies of servicing and main- tenance (i.e., those that can intervene on the product’s physical life). In fact, strategies, the most appropriate DFX components are those aimed at main- taining performance during the phase of use—Design for Serviceability (DFS) (Makino et al., 1989; Gershenson and Ishii, 1993; Subramani and Dewhurst, 1993) and Design for Maintainability (Klement, 1993; Kusiak and Lee, 1997). These approaches to the problem of extending the prod- uct’s useful life are closely interconnected and substantially complemen- tary. It is necessary, however, to defi ne the relationships between them more fully. The term “service” includes interventions of diagnosis, maintenance, repair, and whatever else may be necessary to guarantee that the system functions correctly (Gershenson and Ishii, 1993). Design for Serviceability therefore includes, in general terms, Design for Maintainability. In this context, Design for Reliability (Rao, 1992; Birolini, 1993; Wallace and Stephenson, 1996) also plays a leading role. The reliability of the system is 2722_C009_r02.indd 2252722_C009_r02.indd 225 11/30/2005 1:50:10 PM11/30/2005 1:50:10 PM © 2006 by Taylor & Francis Group, LLC as was noted in Chapter 8 (particularly in Section 8.3.2) with regard to these 226 Product Design for the Environment generally defi ned as the measure of its capacity to maintain functionality over a certain period of time, and is expressed by the probability that the system will maintain this functionality (Blanchard et al., 1995). It can also be quantifi ed by the percentage of the time during which the system operates correctly, or by the frequency of malfunctions (Gershenson and Ishii, 1993). Reliability is thus a product requisite that determines the necessity for interventions of maintenance or repair, predicted and favored by DFS. Ultimately, the latter is the design approach that best combines the most appropriate characteristics for achieving strategies for extending the prod- uct’s physical life. It must be conducted in strict correlation with the design of the system’s reliability, as confi rmed by studies on the development and use of design rules formulated to take into account both reliability and main- tainability (Kusiak and Lee, 1997). 9.2.1 Design for Serviceability Using the term “service” for the set of diagnosis, maintenance, and repair interventions, together with any other intervention aimed at maintaining the functionality of a system, the term “serviceability” is understood as the facil- ity with which a system can be subjected to these interventions, expressed by evaluation of: • How easy it is to perform these interventions • How much time they require and how much they cost Design for Serviceability thus has the objective of aiding the designer in making choices promoting the development of products prearranged for service interventions (diagnosis, maintenance, repair) (Makino et al., 1989). 9.2.1.1 Main Aspects of Serviceability On the basis of the defi nition of service given above, the main aspects of serviceability can be summarized as follows (Gershenson and Ishii, 1993; Klement, 1993): • Diagnosability—A property of the constructional system making it possible to identify the causes of malfunction and defi ne the conse- quent service interventions necessary. Arranging the components in groups according to function can favor diagnosability. • Maintainability—A property of the constructional system making it possible to operate planned or required maintenance interventions. It renders the components requiring maintenance accessible to the 2722_C009_r02.indd 2262722_C009_r02.indd 226 11/30/2005 1:50:11 PM11/30/2005 1:50:11 PM © 2006 by Taylor & Francis Group, LLC [...]... intervention • Increase the value of the profit at the peak 9. 3.3 Approaches and Tools for Design As was noted in Chapter 8, Section 8.3.2, various DFX tools are oriented toward the planning of processes at the end-of -life They belong to the general area of Design for Product Retirement/Recovery (Ishii et al., 199 4; NavinChandra, 199 4; Kriwet et al., 199 5; Zhang et al., 199 7; Gungor and Gupta, 199 9) Using more... frequently made to Design for Remanufacturing (Shu and Flowers, 199 3; Bras and McIntosh, 199 9) and Design for Recycling (Burke et al., 199 2; Beitz, 199 3) Another DFX technique, known as Design for Disassembly, is oriented toward design and planning for the disassembly of systems (Boothroyd and Alting, 199 2; Jovane et al., 199 3; Scheuring et al., 199 4; Harjula et al., 199 6) As noted previously, although Design. .. greater their market value) As an alternative to disassembly, it is possible to consider a fragmentation process, followed by the separation and cleaning of the pieces Apart from the economic aspect, not all materials are equally recyclable It is possible that the performance characteristics of the recycled material are substantially different than those of the initial virgin material, or that a material... materials 9. 3.4 Quantitative Evaluation of the Potential for Recovery In order to evaluate the effect that design choices can have in terms of disassemblability and recyclability, certain indices can be used that quantify various characteristics of the constructional system that are ascribable to these properties (Navin-Chandra, 199 1; Simon and Dowie, 199 3; Takata et al., 2003) The more important indices... environmental advantage is twofold: first, the impact due to the disposal of waste materials is avoided and, second, nonvirgin resources are made available, thus avoiding the impacts due to the production of a corresponding quantity of energy obtained from natural resources Therefore, the criteria for the choice of materials direct the designer toward materials allowing their original performance characteristics... damage; design standardized parts and components • Upgrading and adaptation Design modular and reconfigurable architecture for adaptation to different environments; design multifunctional products for adaptation to the evolutions of the user 9. 2.5 Design Variables From an analysis of the specific factors determinant for the strategies and of the design expedients directed at achieving the requisites for. .. constructional system can be associated with each level of design action, as shown in Table 9. 2 These can be summarized on the basis of certain constructional standards (GE Plastics, 199 2; ICER, 199 3; VDI 2243, 2002) and contributions found in the literature (Beitz, 199 3; Jovane et al., 199 3; Chen et al., 199 4; Dowie and Simon, 199 4) For more details regarding the disassembly of products, refer to Chapters... Ishii, K., Eubanks, C.F., and Di Marco, P., Design for product retirement and material life cycle, Materials and Design, 15(4), 225–233, 199 4 Jovane, F et al., A key issue in product life cycle: Disassembly, Annals of the CIRP, 42(2), 651–658, 199 3 Kamrani, A. K and Salhieh, S.M., Product Design for Modularity, Kluwer Academic Publishers, Boston, 2000 Kimura, F et al., Product modularization for parts reuse... complex products using the modularity concept It can aid the designer in implementing an integrated product design and development approach (Chapter 8, Section 8.1.1), matching the criteria set by design for functionality and manufacturing, and those related to the environmental requirements Some implications of modularity on product design for the life cycle are treated in Chapter 11 For further details,... therefore, a product requisite determining the necessity for the maintenance or repair interventions foreseen and favored by Design for Serviceability For further details regarding reliability parameters (failure rate, reliability of a component or system, reliable life, and reliability frequency), refer to the specialist literature (Bazovsky, 196 1 and 2004; Rao, 199 2; Ireson et al., 199 5) 9. 2.2 Quantitative . end-of -life. They belong to the general area of Design for Product Retirement/Recovery (Ishii et al., 199 4; Navin- Chandra, 199 4; Kriwet et al., 199 5; Zhang et al., 199 7; Gungor and Gupta, 199 9) Serviceability (DFS) (Makino et al., 198 9; Gershenson and Ishii, 199 3; Subramani and Dewhurst, 199 3) and Design for Maintainability (Klement, 199 3; Kusiak and Lee, 199 7). These approaches to the. general terms, Design for Maintainability. In this context, Design for Reliability (Rao, 199 2; Birolini, 199 3; Wallace and Stephenson, 199 6) also plays a leading role. The reliability of the