Methodology of Product Sustainable Redesign. Case Study: Furniture of a Clothing Retail Store

Design for sustainability (DfS) has been mainly focused on the integration of environmental aspects into product design (usually referred to as Eco-design). However, sustainability does not only consist of the environmental impact. Three dimensions: environment (planet), economy (profit) and social well-being (people) should be taken into account according to a worldwide approach [1, 2] and should be simultaneously analyzed to effectively achieve sustainability assessment. Consistent with this perspective, the Life Cycle Sustainability Assessment (LCSA) methodology [3‐5] was developed based on the same structure already established in Life Cycle Assessment (LCA) method [6, 7].

On the other hand, eco-design studies [8] are generally aimed at comparing different stages of the entire life cycle of a product, comparing impacts of different alternatives and evaluating impacts in order to propose improved alternatives. Studies which include a new sustainable product redesign, its sustainability assessment and a comparison with the initial design, are usually not carried out.

In this work, a practical scheme to project more sustainable products considering environmental, economic and social aspects is proposed and applied in the case of the furniture used in a clothing retail store. A redesign phase, in which sustainability strategies consistent with the initial product specifications like operation or appearance, is addressed. In addition, indicators of each sustainability dimension are compared to detect improvements. The methodology applied and results obtained are shown in the following sections.

A methodology composed of three main phases is proposed to achieve more sustainable design [9] (Fig. 1):

In this work, furniture used in a clothing retail store is the system analyzed and the product creation stage is the object of study. To value social issues, UNEP's guidelines [11] were used. The environmental dimension is evaluated by the Global Warming Potential (GWP₁₀₀) indicator, which represents total emissions of the greenhouse gases calculating the radiative forcing over a time horizon of 100 years. For the economic dimension, the budget of material execution (BME) that expresses the total cost to develop each piece of furniture is the indicator proposed. Finally, workers are selected to analyze the social dimension of sustainability and the indicator used is the time required by the workers in the production process (T_w).

The environmental module of Cype software, Probas database [12] and emission factors of electric commercial companies were used to calculate sustainability indicators.

The methodology was applied to design more sustainable furniture, which is used in a clothing retail store located in the centre of a big city. As is shown in Fig. 2, a set of furniture pieces is needed to obtain a good arrangement and exhibition of the selling items: three glass and two chipboard shelves on the store sidelines and other in the storefront to hang and expose clothes, a set of bars to show accessories, a central table to put down the tried clothes by the customers and where the shop assistants blend it and finally, two exhibitor furniture to expose costume jewelry, charge and packaging the sold items.

The production process of the furniture pieces is analyzed in detail to obtain energy consumptions, economic costs and working times. Materials used are laminated chipboard, walnut wood, templated glass and corten steel ASTM A588, which is acquired in boards, sheets and profiles of different sizes.

The following inventory data, in reference to one unit of the furniture piece, are shown in Table 1: quantity, mass and material type used by each piece, energy consumption, working time needed in processing and production total costs. If the furniture piece of 3. Chipboard shelf is reviewed, we can observe that 2 units are used at the clothing store, which has a mass of 68,7 kg each one, the materials used to fabricate them are laminated chipboard and corten steel ASTM A388, an energy consumption of 0,37 MJ is required in processing, the working time is 125,6 s and the production costs are 182,7 €. Sustainability indicators of the initial design were calculated. Greenhouse emissions of 494,4 KgCO₂eq, a total execution cost of 2153,4 € and an average working time of 2,1 h were obtained. These indicators will be compared with those obtained after the redesign process in Fig. 3.

The next phase consists of the furniture redesign process having into account the specifications of the initial design, keeping the store esthetics unchanged and to guaranty the storing and display of the clothes. Concerning the production stage, the strategies of materials quantity reduction, replacement or elimination of elements and selection of low-impact materials are considered suitable to achieve a sustainability improvement.

Table 2 shows the initial design and the redesign of the furniture pieces 3, 5, 7 and 8. Different sustainability strategies are applied in each case preserving initial design specifications. The production process of the redesigned furniture pieces is analyzed taking into account these strategies and energy consumptions, economic costs and working times are obtained for the new design projected. As is shown in Table 2, significant improvements of the mass of the raw material and thus, in GWP₁₀₀ indicator, are obtained. At the same time, emissions, working times and costs can be reduced in the production process. In all cases, the percentage reduction of indicators according to the sustainability strategies applied, are indicated.

Finally, the third phase of redesign methodology is carried out. A comparison between the environmental, economic and social indicators of the furniture initial pieces and its redesign are shown in Fig. 3. An improvement of the sustainability indicators is achieved. A reduction of 40% and 20% is reached in the environmental and economic indicators respectively. The working time is decreased in 1,15 h.

This work presents a redesign methodology to achieve more sustainable products. Three phases are carried out: sustainability assessment, redesign process and comparing designs. A set of suitable indicators was selected to simultaneously assess the three sustainability dimensions and to compare initial and final designs.

The redesign of furniture used in a clothing retail store was performed. A production inventory was obtained by means of a detailed study of each furniture piece. Data of materials, energy consumptions, production costs and working times were calculated in both initial design and projected redesign of furniture. The early specifications of each furniture piece like operation and appearance were taken into account in the redesign process.

A substantial improvement of the furniture sustainability indicators at the production stage was managed by the application of different sustainability strategies. Particularly, the use of pine wood and the pieces’ elimination were the most effective strategies.

A significant enhancement of greenhouse emissions and processing costs and a slight improvement in the working times was achieved.