Supply of parts to the workstations of assembly lines is a critical design and operational issue. Even if automation and collaborative robots are increasingly employed in industry, human operators are frequently employed in manual parts picking and assembly. These are time consuming activities asking to be efficiently performed at a high rate and for prolonged periods. Therefore, ergonomic analysis is necessary to reduce the risk of work-related musculoskeletal injuries due to biomechanical loads. Proper layout of shelves storing parts containers along the production line, and the location of containers on the shelves, may improve picking efficiency and reduce biomechanical risk. Several manufacturing companies use computer-aided ergonomic tools to improve the study of manual production lines, racking, shelving, and workstations. The paper describes the development of a support tool to configure industrial light shelves for feeding the assembly lines. The approach includes the development of a knowledge base to support the geometrical configuration of the shelving and the ergonomics analysis based on the RULA method, considering the shelf’s positions and the operator’s postures. As a test case, the model has been used to evaluate the ergonomic score of the configured shelving based on a prescribed picking sequence. Results show that the proposed approach can help in comparing the goodness of a candidate shelving layouts to improve the design of parts storage systems in order to reduce operators' workload and ergonomic risk.