Introduction

Growing business recognise sustainability as an important concept for survival in the competitive world. Those organisations have been forced to adopt practices that are designed in a manner to maintain environmental safety (Yagi and Halada 2001) and minimize resource utilisation (Ljungberg 2007). Sustainable organizations must be capable of reducing cost and preventing environmental problems for ensuring clean and green atmosphere. Green system integrates product and process design issues with production planning and control in such a manner to identify, quantify, assess and manage the flow of environmental wastes with the objective of reducing environmental impact (Kaebernick et al. 2003). Such system should be focussed on maximising resource efficiency for the manufacture of sustained products. Sustainability is the critical intersection between factors like manufacturing and product design practices and environmental issues and concerns. Sustainable system focuses on triple bottom line like profitability, people, and planet. In this context, the quantification of sustainability gains importance as it is an indicator of environmental friendly aspects. The uniqueness of the study is that it is an attempt to apply multi-grade fuzzy approach for the assessment of sustainability which overcomes the drawbacks associated with conventional crisp approaches. The multi-grade fuzzy assessment of sustainability evaluation is a new contribution to the theory. The research objectives formulated includes:

  • How to formulate the new theory for sustainability evaluation?

  • How to overcome the drawbacks associated with conventional crisp approaches?

  • How to apply fuzzy method for sustainability evaluation?

In order to fulfil the above-mentioned research objectives, the research study has been conducted. This article reports a project that has been focussed on the assessment of sustainability of an electronic switches manufacturing organization. Besides assessing sustainability, the gaps as well as the improvement areas for sustainability improvement have been derived.

Literature review

The literature has been reviewed from the perspective of sustainability assessment.

Choi et al. (1997) have developed an assessment methodology on the basis of the ‘material balance’ of a process and the relationship amongst different processes. As a result, the amount of solid waste generated, the energy consumed, the waste-water incurred as well as the level of noise are obtained. Afgan et al. (1999) have presented the sustainability assessment of desalination plants for water production based on resources, environmental and economical indicators. Ravetz (2000) has presented an integrated assessment approach for sustainability appraisal in city regions. The author has presented the integrated city assessment method for total environmental metabolic of city region. Robert (2000) has presented that most concepts and tools for sustainable development function as metrics. Some of those metrics are LCA, ecological footprinting (EF), and Factor X. An environmental management system (EMS), like ISO 14001 is an administrative vehicle that should systematically align a firm’s specific outcomes and activities with a general framework for sustainability. Calderon (2000) has presented a method for the assessment of sustainability of urban pilot process. Noble (2002) has suggested the approach of strategic environmental assessment (SEA) practice to contribute to the design of more sustainable policies and strategies and have explored the current status of SEA in Canada. Pope et al. (2004) have proposed integrated assessment process focussed on minimizing unsustainability to achieve triple bottom line. Brunner and Starkl (2004) have presented the role of decision aid system for evaluating sustainability. Wiek and Binder (2005) have presented an approach for constructing sustainability solution spaces for decision making. This approach enables the decision maker for enabling sustainability assessment for city regions. Munda (2005) has presented a multi-criterion framework for measuring sustainability. Ugwua and Haupt (2007) have presented key performance indicators for infrastructure delivery and computational methods required to achieve sustainability objectives. Ticehurst et al. (2007) have presented a bayesian network approach for assessing the sustainability of coastal lakes in New Southwales of Australia. Lee and Huang (2007) have presented the concept of sustainability index for Taipei. Their analysis results demonstrated that social and environmental indicators are moving towards sustainability developments where economical and institutional dimensions are relatively poor. Pulselli et al. (2007) have presented the engineering analysis of building, manufacturing, maintenance used for the evaluation of housing sustainability. Lozano (2008) has presented an innovative method to represent sustainability in three dimensions namely venn diagram, three concentric circles and the planning hexagon which show the complex and dynamic equilibria among economic, environmental and social aspects, and the short, long and longer term perspectives. Chen et al. (2009) have presented a method for energy and resource constraints based on certain measures such as emergy yield ratio, emergy load ratio, emergy sustainability index, net economic benefit index, renewable to evaluate local sustainability of constructed wetland in Beijing. Tseng (2009) has presented the evaluation procedure of firms’ sustainable indicators in an uncertain environment. Amekudzi et al. (2009) have presented the concept of sustainability of foot print and a model that could be used in analysing the sustainability of other infrastructure system for regional sustainable development. Benedetto and Klemes (2009) have presented an ‘Environmental Performance Strategy Map’ to analyse environmental and economic impacts on a wide perspective with reference to a production system. This graphical map allows combining the main environmental indicators with the ‘Sustainable Environmental Performance Indicator’ as a single measure for sustainability of a given option so that comparison of different options for strategic decision-making purposes can be facilitated.

Based on the literature review, it has been inferred that no concrete research has been reported from the perspective of multi-grade fuzzy assessment of sustainability. In this context, this research study has been initiated.

Conceptual model for sustainability assessment

The conceptual model for sustainability assessment is presented in Table 1. The concept model for sustainability assessment has been formulated from three perspectives of sustainability namely environmental, economic and social perspectives.

Table 1 Conceptual model for sustainability assessment
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This model consists of three levels. First level represents three sustainability enablers; second level consists of 12 sustainability criteria; third level consists of 37 sustainability attributes. The economic sustainability enablers consist of criteria such as Financial health, Economic performance, Potential financial benefits and Trading opportunities. The environmental sustainability enabler consist of criteria namely Air resources, Water resources, Land resources and Mineral & energy resources. The criteria pertaining to Social sustainability consist of Internal human resources, External population, Stake holder participation and Macro social performance. This model is a comprehensive model for sustainability assessment as it focuses on the triple bottom line namely profitability, planet and people.

Methodology

The methodology followed during this study is as shown in Fig. 1.

Fig. 1
figure 1

Methodology

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As shown, the project begins with the literature review on sustainability assessment. Then a conceptual model for sustainability assessment has been developed. This is followed by the identification of a sustainable manufacturing organisation for the conduct of case study. The manufacturing processes involved in organization have been studied. Then the sustainability assessment has been carried out. This is followed by the gap analysis and the identification of improvement areas for sustainability improvement.

Case study

About case company

The case study has been carried out in an Indian electronics switches manufacturing organization located in Coimbatore, India (hereafter referred to as ABC). ABC manufactures cam operated rotary switches, relays, starters and modular switches. ABC has implemented ISO 9001:2000 Quality Management System, ISO 14001 Environmental Management System. ABC is an organization aspiring to attain world class status.

Assessment of sustainability using multi-grade fuzzy method

The sustainability index of an organization is represented by I. It is the product of overall assessment factor R and overall weight W. The equation for sustainability index is given by

$$ I = W \times R $$

The assessment has been divided into five grades since every sustainability factor involves fuzzy determination. I = {10, 8, 6, 4, 2}. 8–10 represents ‘extremely sustainable’, 6–8 represents ‘sustainable’, 4–6 represents ‘generally sustainable’, 2–4 represents ‘not sustainable’ and less than 2 represents ‘extremely in sustainable’. Five experts participated in discussion section for sustainable assessment Table 2 shows the single factor assessment and weights provided by experts.

Table 2 Single factor assessment vector and weights provided by experts
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Primary assessment calculation

The calculation pertaining to ‘Financial health’ criterion is as shown as follows:

Weights pertaining to ‘Financial health’ criterion W 11 = (0.4, 0.3, 0.3)

Assessment vector pertaining to ‘Financial health’ criterion is given by

$$ R_{11} = \left[ {\begin{array}{*{20}c} 9 & 8 & 9 & 8 & {10} \\ 8 & 7 & 6 & 6 & 7 \\ 5 & 8 & 7 & 6 & 5 \\ \end{array} } \right] $$

Index pertaining to financial health criterion is given by

$$ I_{11} = W_{11} \times R_{11} $$
$$ I_{11} = \left( {7.5,7.7,7.5,6.8,7.6} \right) $$

Using the same principle, the index pertaining to various sustainability criteria have been derived

$$ \begin{aligned} I_{12} &= \left( {9.6,8.6,8.4,7.8,7.9} \right) \\ I_{13} &= \left( {9.5,8.5,7.5,7.5,7.5} \right) \\ I_{14} &= \left( {8.4,8.4,8.6,8.4,9} \right) \\ I_{21} &= \left( {7.1,8,7,6.6,6.5} \right) \\ I_{22} &= \left( {3.5,6,8,7,7} \right) \\ I_{23} &= \left( {6,7,6.5,7,6.5} \right) \\ I_{24} &= \left( {7.5,8.5,7,8,7} \right) \\ I_{31} &= \left( {9.1,8.9,8.7,8.7,8.1} \right) \\ I_{32} &= \left( {9.2,9.6,8,8.2,7.8} \right) \\ I_{33} &= \left( {9.5,8.3,7.5,7.1,5.7} \right) \\ I_{34} &= \left( {7.8,8.2,8.4,7.9,7.4} \right) \\ \end{aligned} $$

Secondary assessment calculation

The calculation pertaining to ‘Economic sustainability’ enabler is given by

Weight pertaining to ‘Economic sustainability’ enabler is given by

$$ W_{1} = \left( {0.3,0.4,0.2,0.1} \right) $$

Assessment vector pertaining to ‘Economic sustainability’ enabler is given by

$$ R_{1} = \left[ {\begin{array}{*{20}c} {7.5} & {7.7} & {7.5} & {6.8} & {7.6} \\ {9.6} & {8.6} & {8.4} & {7.8} & {7.9} \\ {9.5} & {8.5} & {7.5} & {7.5} & {7.5} \\ {8.4} & {8.4} & {8.6} & {8.4} & 9 \\ \end{array} } \right] $$

Index pertaining to economic sustainability enabler is given by

$$ I_{1} = W_{1} \times R_{1} $$
$$ I_{1} = \left( {8.805,8.29,7.97,7.5,7.84} \right) $$

Using the same principle, the following indices have been derived for remaining sustainability enablers.

$$ \begin{gathered} I_{2} = \left( {5.77,7.22,7.15,7.12,6.75} \right) \hfill \\ I_{3} = \left( {8.95,8.55,8.19,8.07,7.39} \right) \hfill \\ \end{gathered} $$

Tertiary assessment calculation

The value of sustainability index of ABC has been computed as follows:

$$ {\text{Overall}}\;{\text{weight}}\;W = \left( {0.3, 0.4, 0.3} \right) $$
$$ {\text{Overall}}\;{\text{assessment}}\;{\text{vector}}\;R = \left[ {\begin{array}{*{20}c} {8.805} & {8.29} & {7.97} & {7.5} & {7.84} \\ {5.77} & {7.2} & {7.15} & {7.12} & {6.75} \\ {8.95} & {8.55} & {8.19} & {8.07} & {7.39} \\ \end{array} } \right] $$

Sustainability index I = W × R

$$ \begin{aligned} I &= \left( {7.6345,7.932,7.708,7.494,7.269} \right) \\ \bar{I} &= \frac{1}{s}\left( {7.6345,7.932,7.708,7.494,7.269} \right) \\ &= 7.6075 \in \left( {6,8} \right) \\ \end{aligned} $$

Results and discussions

The sustainability index computed using multi-grade fuzzy approach is found to be 7.6. This belongs to the range (6–8) which indicates that ABC is a sustainable organization. This result very much coincided with environment prevailing at ABC. But still scope exists for improving the sustainability of ABC. The target areas identified for sustainability improvement at ABC include the following:

  • Financial health

  • Stratospheric ozone depletion

  • Water usage

  • Land usage and transformation

  • Regulatory and public services

  • Monitoring

Validation

In order to validate the study, a feedback session has been conducted to gather the responses of the executives. The responses of the executives have been presented using a Likert’s scale of range 0–10. The mean responses of the values indicated by the executives are shown in Table 3

Table 3 Mean Responses of the executives
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As shown, the least mean response is 8.0 and the maximum one is 9.4. The mean value of the responses indicates the practical compatibility of the implementation of sustainability assessment using multi-grade fuzzy method.

Statistical validation

In order to conduct a detailed statistical analysis of the feedback of the executives, their responses were entered in Software Package for Social Sciences (SPSS). This package was also used to conduct t test in order to examine the acceptance of ‘Assessment of sustainability using multi-grade fuzzy method’. In the first case, the test value assigned was 10 which affirm that “100% of the executives’ opinions favoured the successful assessment of sustainability assessment in practice at 95% confidence interval”. As the significant (two-tailed) values for some cases are less than 0.05, this null hypothesis was rejected.

In the second case, the null hypothesis was set as “90% of the executives’ opinions favoured the successful quantification of sustainability assessment in practice at 95% confidence interval”. In this case, the significant (two-tailed) values are greater than 0.05. Hence, this null hypothesis was accepted. On the whole, this validation study indicates the feasibility of assessment of sustainability using multi-grade fuzzy approach in practice with a success rate of 90%.

Industrial implications

The implications as a result of sustainability assessment have been explained from three perspectives.

Economic perspective

Efforts have been taken to assess the internal financial stability by means of measuring the financial health of the organisation. Further, the feasibility of national/international subsidies based on technological improvements has been explored.

Environmental perspective

Efforts have been taken to infuse sustainability characteristics in early product design phases through the implementation of advanced techniques. Product designs have been evaluated for their sustainability impacts and efforts are being taken to minimise the environmental impacts.

Social perspective

The top management has institutionalised the corporate social responsibility concept. ‘Inclusive growth’ has been added in the vision of the organisation. Inculcation of moral and ethical values among the workforce has been included as an important task. Various ways to utilise the idle time of workforce have been explored.

Conclusion

The increasing competition has been forcing the manufacturing organization to recognise the importance of sustainability phenomena. Sustainability focuses on triple bottom line (Pope et al. 2004). Manufacturing organizations today recognise environmental waste as eighth deadly waste. The contemporary organizations are forced to evolve sustainable products which are environmental conscious. Modern organizations have been implementing ISO 14001 Environmental Management System. But mere implementation of ISO 14001 Environmental Management System does not ensure sustainability. In this context, the assessment of sustainability gains vital importance. The sustainability assessment of ABC implies that ABC is a sustainable organization. But still there exists scope for sustainability improvement of ABC. In this regard, the target areas for sustainability improvement of ABC have been identified. This kind of sustainability assessment exercise would enable the contemporary organization to survive in the competitive market scenario for achieving world class status.

Limitations and future research direction

The concept model for sustainability assessment has been test implemented in a single manufacturing organisation; multi-grade fuzzy method has been used for sustainability evaluation. In future, more number of studies could be conducted for several organisations; advanced fuzzy logic method could also be used.