Designing For Sustainability


Dicksen Tanzil and Earl R Beaver

BRIDGES to Sustainability

Design is a critical element in the implementation of sustainable development. Meeting the needs of the growing global community while minimizing negative impacts to the environment and to societal well-being requires that we develop alternative patterns of resource utilization, production, and consumption. Obviously, innovations in multiple fields, including policy, business management, infrastructure planning, and social sciences, are necessary for such transformation. Re-designing the products, services, and manufacturing processes that serve people's needs, however, is arguably one of the best places to start.

To companies that have embraced the goal of sustainable development, incorporating sustainability considerations into design also makes practical sense. As often pointed out in standard design textbooks, impacts of a product or a process are largely "locked in" during early design stages as decisions regarding product specifications, materials, technology, and so on, are made. While corrective or remedial actions may be taken after the product or manufacturing process is commercialized, options available at these later stages tend to be limited, less effective, and more costly. Thus, with greater emphasis on reputation and risk management experienced in industry today, designing for sustainability is becoming increasingly important.

This section provides an introductory overview of some of the concepts and ideas that underlie the development of sustainable design approaches. This overview is followed by a discussion of "cradle-to-cradle" design, a lifecycle-based approach to material assessment and product design, and a brief discourse on the emerging principles of sustainable engineering. These correspond to some of the emerging

Transforming Sustainability Strategy into Action: The Chemical Industry, Edited by B. Beloff, M. Lines, and D. Tanzil

Copyright © 2005 John Wiley & Sons, Inc.

thoughts and approaches that may serve to guide more sustainable design in the chemical industry.

5.1.1 Designing for Sustainability: What It Means

Designing for sustainability represents the broadening of the design objectives to include aspects not customarily considered by the chemists, material scientists, and engineers involved in the design process. Traditionally, design objectives are largely limited to economic ones. Products are designed primarily to provide the greatest market value, while processes are designed to minimize costs. Environmental considerations are conventionally applied as design constraints and accounted for only at the end of the design process. For manufacturing processes, this typically results in end-of-pipe treatment - an important element of environmental costs that can be reduced through more efficient use of material and energy resources. Furthermore, uncertainties related to long-term availability of nonrenewable resources, shipping of hazardous materials, and health and safety effects of chemicals in the environment, to name a few, are driving the incorporation of sustainability considerations into the design of chemical products and processes.

Incorporating sustainability into design requires a more systemic view (see Section 5.3.2 for detailed descriptions on systems thinking) beyond the boundaries of a chemical facility. This often includes the consideration of a product's lifecycle as well as the needs of a broader set of stakeholders, such as:

• consumers' need for products and services that improve their quality of life;

• shareholders' need for economic gains to be generated from the products and services; and

• society's need for products and services to be sourced, manufactured, delivered, used, and disposed of with no negative effects on their health, safety, and environment.

The linkage between consumers' and shareholders' needs is obvious to any company that remains in business. Economic gains can be realized only when the products are marketable and match people's needs (including the needs of the industrial customers). However, societal issues, including the societal impacts of a company's environmental, health, and safety (EHS) performance, are becoming increasingly important due to the demonstrable impacts of EHS liabilities, public relation, and corporate reputation to the bottom line. Even when considering customers' needs, viewing the market through the lens of sustainable development may result in the identification of new opportunities, such as applying the company's expertise and products to satisfy the needs of people in the less-developed economies. In short, a designer may view designing for sustainability as design with the multiple objectives of maximizing benefits and minimizing risks to all stakeholders.

Related to the inherent ambiguity in the concept of sustainable development, "designing for sustainability" may be understood differently by different people.

In this chapter, "designing for sustainability" is used as a broad term that refers to the integration of all of the sustainability considerations into the design of industrial products and processes. As such, the term encompasses a broad range of environmentally conscious chemical process design approaches that have been developed in the literature as well as emerging approaches that push the boundaries of design considerations in the chemical industry. They include approaches that originated in the field of industrial ecology, such as lifecycle design and design-for-environment, which are based on a systems view and tend to focus on design to improve environmental performance of a product system along the product's lifecycle (see Table 5.1 for descriptions of terminologies). Other approaches that focus specifically on aspects of chemical product and process design, including green chemistry, green engineering, and inherently safer chemical processes, are also considered here as

TABLE 5.1. Several Terminologies Related to Designing for Sustainability




Industrial ecology

Design for Environment (DfE)

Lifecycle design

Green chemistry Green engineering

Inherently safer chemical processes

A systems-oriented subject that seeks to optimize resources, energy, and capital through the study of industrial and economic systems and their interactions with the natural ecosystems. A product design approach originated in industrial ecology and a concurrent design approach called "Design for X" (DfX, where X is any desirable product characteristics such as safety, manufacturability, recyclability, etc.); typically focuses on reduction of environmental impacts and resource consumption throughout the product lifecycle. Similar to DfE, emphasizing the integration of lifecycle and environmental impact consideration at each stage of product development cycle. Design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.a Design, commercialization, and use of processes and products that are feasible and economical while minimizing generation of pollution at the source and risk to human health and the environment.b Eliminating or significantly reducing process hazards through material substitution, alternative reaction routes, process intensification/simplification, etc.

Graedel and Allenby, 2003

Graedel and Allenby, 1996; Fiksel, 1996

Keoleian and Menerey, 1993

Anastas and Warner, 1998

Allen and Shonnard, 2002

Hendershot, 2004

a, accessed October 23, 2004 b, accessed October 23, 2004

part of designing for sustainability. Viewed more broadly, designing for sustainabil-ity reflects a crucial paradigm shift for the 21st century: the transition from environmental management to systems design - coming up with solutions that integrate environmental, social, and economic factors and radically reduce resource use, while increasing health, equity, and quality of life for all stakeholders.

The different elements of designing for sustainability are currently practiced in industry to varying degrees. In order to gain relevance to the industry, the design approaches must be effective in reducing costs and risk exposure and result in reasonable short-term as well as long-term financial benefits. Thus, green chemistry and engineering and inherently safer chemistry appear to have gained greater acceptance as they directly address environmental, health, and safety issues specific to the chemical industry. However, industrial ecology and lifecycle design approaches are only gradually becoming more relevant as the industry begins to discover opportunities for new products and services found through working with the value chain, that is, with suppliers and industrial customers, in reducing impacts of their processes and products. Development of high-performance, light-weight polymers for transportation represents an oft-cited example. Obviously, numerous policy and societal aspects are also critical in driving these changes.

5.1.2 Design and Lifecycle Assessment

Systems thinking and, in particular, lifecycle concepts (Box 5.1: How Sustainability Uses Lifecycle Concepts) underlie many of the different approaches for more sustainable designs. These approaches are becoming increasingly relevant to the industry as companies strive to work with their suppliers and customers in reducing impacts. Arguably the most widely recognized tool for incorporating systems thinking into design is lifecycle assessment (LCA). The ISO 14040 series of standards from the International Organization for Standardization defines LCA as "the consideration of inputs, outputs, and potential environmental impacts of a product system throughout its life-cycle." While skewed mainly towards the environmental aspects of sustainability, LCA forms a basis of a broader analysis of sustainability impacts.

Lifecycle assessment was born out of the realization that there are significant environmental impacts throughout the lifecycle of an industrial product. Making decisions without considering the entire lifecycle often lead to suboptimization; that is, one may simply shift the adverse environmental impacts outside the boundaries of one's process or facility. Outsourcing toxic production to the suppliers, for instance, is as poor a decision as improving process safety while making the product less safe. In both cases, adverse impacts are reduced within the facility boundaries. However, as one takes a systemwide view over the entire lifecycle, it becomes clear that the total impacts are not reduced.

In its formal configuration, LCA is almost always used for a comparative study -evaluating multiple designs or decision alternatives. The comparison is performed on the basis of a "functional unit," which may be a physical unit (e.g., a pound of a chemical product or a piece of gadget) or a service unit. The latter is usually more representative of the value delivered by the product system. For example, in performing LCA for textile dye alternatives, BASF (Saling et al., 2002) uses a unit "m2 of jeans dyed" (a service unit) as the basis of the comparison, instead of a unit kg of dye. in this case, the lifecycle performance of a technology or a product is judged by the service that it provides, instead of product weight.

Typically, all stages in the lifecycle of a product system are included in LCA. As illustrated in Figure 5.1, this consists of extraction (including processing of the raw materials), production, use, and end-of-life. Transportation, which occurs between the stages and within each stage, is also generally considered. Such assessment is often termed "cradle-to-grave," that is, encompassing the entire product lifecycle from raw material extraction (cradle) to end-of-life (grave). Options related to end-of-life, such as reuse and recycling, are inherently part of the assessment.

For products that go to a vast number of outlet uses, including most commodity chemicals such as acids, bases, and engineering polymer resins, a "cradle-to-grave" analysis is often impractical. Lifecycle assessment remains relevant, however, especially in the form of "cradle-to-gate" analysis. instead of including all the typical lifecycle stages, the analysis may stop at the manufacturer's exit gate, or to the point that the product is shipped to customers. Such analysis is particularly important in evaluating alternative processes that uses different starting materials, or the same set of materials but at significantly different amounts or compositions. in addition, lifecycle thinking may be employed qualitatively to identify various uses and end-of-life issues that the manufacturers may face in the future.

Methodology for performing lifecycle assessment has been discussed in many books dedicated to the subject (e.g., Goedkoop, 1994; Curran, 1996) and will not be elaborated in great depth here. In essence, LCA begins with the definition of goal and scope, and is followed by the development of "lifecycle inventory" (LCI), where information on the inflows and outflows of materials and energy for





Air Emissions Wastewater Solid wastes

Figure 5.1. Schematic of the lifecycle of a product.

Air Emissions Wastewater Solid wastes

Figure 5.1. Schematic of the lifecycle of a product.

each relevant lifecycle stage are collected and tabulated. Energy is considered in terms of the consumption of primary energy.1 Thus, secondary forms of energy, such as electricity and steam, are considered not in terms of their inherent energy content. Instead, it is accounted in terms of the energy contained in fuels and other primary sources consumed in generating the secondary energy sources.

The lifecycle inventory is then analyzed for impacts to the environment through a methodology called "lifecycle impact assessment" (LCIA). Each flow in the inventory is analyzed for its contribution to multiple impact categories, such as human and ecosystem toxicity, global warming potential, air acidification, water eutrophication, resource depletion, and so on. When desired, one may use a set of weighting factors to aggregate the various impact categories into a single environmental performance index (sometime called the "environmental footprint"). The various metrics and indicators used in LCIA will be discussed in greater details in Chapter 6 (Section 6.1).

Finally, as the last step in LCA methodology, the findings obtained from LCIA are analyzed for their significance, statistical uncertainty, and so on. Primary concerns may be identified and recommendations made based on the analysis.

Lifecycle assessment provides a formal, systematic methodology for assessing and quantifying impacts along the lifecycle of a product system. The process, however, can easily become time-consuming and costly. Consequently, the full LCA is generally performed only for cases where there are significant differences in the life-cycle (e.g., differences in the primary raw materials or in how the products are used and disposed). Furthermore, the full LCA is usually completed only during the later stages of design when much of the information required is more readily available and there is greater chance of commercialization to justify the costs.

Nevertheless, the lifecycle thinking formalized in LCA lies behind many design strategies and guidelines as well as screening methodologies used in the early stages of product and process design. These LCA-inspired screening methodologies are sometime called "streamlined LCA" (Graedel, 1998) and typically rely on the use of a two-dimensional matrix, with lifecycle stages on one dimension and impacts on the other. The streamlined LCA also tends to be more qualitative, with a relative score assigned for each cell in the impact versus lifecycle stage matrix. The use of a more qualitative matrix system also allows considerations that are not commonly included in the formal LCA, such as noise and other nuisance factors, public perception, market position, and so on.

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