Designing Sustainable Medical Devices

Stakeholders in the medical device manufacturing industry are becoming more concerned about the environmental impact of their products and processes.^1,2 These effects range from the potential negative effects of substances such as phthalate plasticizers leached from plastic products to emissions resulting from the incineration of disposed products.^3–5 In addition, consumers are also becoming more aware of the negative impact that manufacturers can have on the environment. To combat such effects, they are subsequently demanding sustainable products.

Government initiatives continue to increase environmental awareness through the development of new policy and legislation, encouraging industry to become more accountable for the environmental impact of their products and operations. For example, the Waste Electrical & Electronic Equipment (WEEE) Directive and the Producer Responsibility Obligations (Packaging Waste) regulations of 2008 have set precedents that will likely drive regulatory bodies to make changes in policy regarding end-of-life disposal of products for other manufacturing sectors.⁶ Such regulations could make it more difficult for companies to develop successful new products, at least in the short term.

In such competitive environments, new product development cannot rely solely on traditional criteria such as cost, quality, and delivery. Effective environmentally sensitive product design enables manufacturers to gain a prominent competitive advantage in the development of green products. As a result, more and more businesses are adopting environmental management systems to organize and assess environmental effects, and meet the growing demand from consumers and legislation for green products.

The ISO 14001 standard, “Environmental Management Systems—Requirements with Guidance for Use,” sets guidelines to enable businesses to recognize the environmental effects of their products and processes.⁷ For ISO 14001 accreditation, a company must identify its environmental aspects and determine significant effects, while demonstrating continual improvement.

Life Cycle Assessment

Life cycle assessment (LCA) is a useful technique to evaluate the environmental impact of products, identify problem areas, and make improvements at the most effective stages of a product's life cycle. Various studies have shown the benefits of performing LCA at the product design stage to effectively lower the overall negative environmental effect.^8–11

One tool, called SimaPro, is an LCA software package that uses Eco-indicator LCA methodology to aid in material selection for products.^12–15 The Eco-indicator method provides impact assessment and ecodesign scoring. Some noticeable observations from these studies are that a detailed LCA is an extremely useful method for environmental impact evaluation, but it can be costly and time-consuming, and the results can be difficult to communicate with nonexperts.

From a designer's point of view, the ideal process would include a single indicator that evaluates the environmental effects of a product or design, so that it can be incorporated directly into the decision-making process, along with the other design considerations.^12,13

In-House Web-Based Tool

Although there are various LCA software tools available, they can be difficult to use on large product ranges. The user must have prior knowledge of LCA inventory databases and internal product details before starting an LCA. These need to be entered manually into the program for each product, which is time-consuming and usually carried out by an experienced LCA practitioner. In some cases, materials used may not be present in the LCA inventory, and the user must choose the closest substitute, which can introduce error. Many companies already hold a huge amount of information relating to their products in computer databases.

One manufacturer of single-use respiratory-care devices has developed an in-house tool that performs a streamlined LCA on products using existing company data to obtain an immediate environmental impact score for any product it manufactures. Internally, although the tool was developed to aid in the design process, it also has value in other departments, because the system essentially provides a baseline score that enables product comparisons.

Departments can use the tool to set targets to lower the environmental impact and identify areas of high environmental concern when designing, purchasing, and marketing products. Such a tool would aid manufacturers in the decision-making process. The following example is a real-life scenario of how manufacturers can develop a similar tool to aid designers in developing more sustainable products.

Electronic Database

One company stored information relating to its products in standard structure query language databases managed by Efacs, an electronic database and software program. The Efacs system was used to organize the company's data and contained features such as the bill of material (BOM) for each product. Each product BOM had detailed information on the product and was organized in a hierarchical structure. Information included all components, subcomponents, and packaging such as weights and materials. Also stored in a database was information on the manufacturing processes.

Gathering Environmental Data

The company used LCA software to collect the environmental data for the scoring tool. The Eco-Indicator 99 methodology was chosen because it satisfied the criteria set out by the second Society of Environmental Toxicology and Chemistry Europe LCA working group. It also produced a single score that was considered the most appropriate to the company.¹⁶⁻¹⁹ The process involved creating a project within the scoring tool that calculated an environmental impact score for all materials and processes and incorporated the required disposal scenarios of landfill or incineration. These figures were stored in a separate material scores table.

The first step involved collecting a list of all the materials and finding them (or the most appropriate materials) within the scoring tool databases. The next step involved calculating the environmental impact using Eco-Indicator 99 methodology. Table I shows Eco-Indicator 99 scores using the collected data for polypropylene in various scenarios. The scores for all materials were collected in the same way.

Scoring Tool Specification

Because the scoring tool is Web based, users have easy access to the data. The user can type any component part or product code that the company manufactures into the tool. Once a part code is entered, the scoring tool must read data from the BOM. Hierarchy is built using the BOM for each manufacturing site, and the tool assumes that materials are the last leaves in the BOM hierarchy. The results of the BOM should be displayed in the table showing part number, description of part, material number, description of material, generic material type, and weight of material. Then the system calculates the total quantity of each material used for each part (if more than one is used). If material quantity is not in kilograms when read from the BOM, the tool converts it to kilogram quantity. If weight information is missing, the tool displays an empty textbox so that it can be entered manually. The tool displays a dropdown menu for each material so that materials can be changed, and the button to calculate the score is activated only when the fields are satisfied.

When calculating the score, the tool gets information from the populated material scores table by multiplying quantity with score values. The results are summed for each selected product and displayed in a report for landfill and incineration disposal scenarios (see Figure 1). Figure 2 shows a simplified flow diagram of the described system.

Environmental Product Scoring System in Practice

The simple-to-use Web-based tool enables the streamlined LCA of a product to be carried out in two steps. This is important, because in order to design a more sustainable product, the designer needs to benchmark the existing product. New product designs are usually based on products already in production. The first use of the tool is to score the existing product to provide the benchmark so that targets can be set and any improvements recognized. Because the products are made of components and subcomponents, the tool can change the materials and weights based on these. Any changes are reflected in the scores that can be compared side-by-side with the benchmark.

With the possibility that no benchmark exists (i.e., a completely new product), a number of competing designs with different components, materials, and weights can be entered into the tool. Again, all scores calculated for each design are compared side-by-side.

The tool also has dynamic features that are summarized in Table II so that designers can change and compare products in five steps.

The designer has the ability to view any product BOM (as in the example shown in Figure 3), add or remove any existing or new component, change any material and weight, and compare the environmental impact of numerous designs side-by-side (see Figure 4). All the design ideas and results can be saved to a file for future reference.

This dynamic ability is important for design because it allows new product configurations to be easily scored. A new product can be made and scored from any combination of existing and new components.

Conclusion

The environmental scoring tool achieved the objective of quick and accurate environmental impact scores for existing products, setting the benchmark to design more-sustainable products. Error was greatly reduced when comparing products because environmental impact scores for selected materials have already been decided. Having those data precludes the need for the user to have prior knowledge of the environmental effects of materials and products. These features mean the tool could be used by nonexperts of environmental/LCA and provide accurate results, unlike traditional LCA software. The scoring tool also runs from a live database that eliminates error associated with incorrect data input by users and reduces the time involved to complete the analysis. Products can be scored in seconds rather than hours, making it easier to evaluate existing design procedures.

For medical devices, there are factors that are not taken into account in generating an environmental impact score at this early assessment stage. For example, the additional environmental impact associated with the leaching of phthalate plasticizers from plastics should be added at a later stage. There are also effects of product sterilization (of which a variety of techniques are used) before and after use, which have not yet been included.

Another important limitation is the lack of available environmental data for thermoplastic elastomers and biopolymer materials, which could be used in future products. Estimates, however, can be made by manually performing an LCA using existing data on raw materials and processes. Research in these areas will be used to develop the environmental scoring tool to aid in the design of future sustainable medical devices.

Acknowledgments

This project was jointly funded by the Engineering and Physical Sciences Research Council's engineering doctorate program and Intersurgical Ltd.

Jonathan-Lee Marshall is sustainability manager and advisor for Babcock Infrastructure Services (Reading, Berkshire, UK); Mike Hinton is technical director for Intersurgical Ltd. (Wokingham, Berkshire); Luiz Wrobel, PhD, is a professor and deputy of head at Brunel University (Uxbridge, Middlesex, UK); and Gera Troisi, PhD, is a lecturer at Brunel University.

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