Environmental sustainability requirement specification levels for comprehensive requirements engineering

The consideration of sustainability early in product development presents significant challenges for the field of mechanical engineering. Linking broad corporate strategies to specific product attributes such as dimensions and functions requires repeated, case-by-case evaluations. This article introduces a novel approach for systematically integrating sustainability into requirements engineering by establishing specification levels for environmental sustainability requirements. These levels offer a structured method to address sustainability at different stages of product design and development, regardless of data availability. By defining aspects such as sustainability assessment methods, data quality, reference products, and verification processes, these levels extend traditional requirements engineering practices to tackle the unique challenges of sustainable design. The scientific novelty of this paper lies in its structured approach to formulating sustainability requirements. It presents a framework for classifying sustainability requirements with varying levels of data quality while simultaneously identifying potential areas for improvement. These include enhancing data quality and establishing evaluation and validation processes for sustainability metrics. By providing a systematic method for defining and refining sustainability requirements, the paper supports more precise and actionable sustainability assessments, ultimately facilitating more robust decision-making in sustainable product development and manufacturing. The specification levels enable the verification and traceability of sustainable development. The effectiveness of the specification levels is illustrated in this article by performing the requirements development in a case study, developing an iteration of a mechanical engineering product with a focus on sustainability.