Improving factory layout under a mixed floor and overhead material handling condition

Purpose In spite of having a number of general‐purpose algorithms for solving plant layout problems, facility planners may still face a challenging task to adjust these algorithms to handle special, but not uncommon, layout problems. The purpose of this study is to propose a new method for addressing the impact of overhead space utilization on a plant layout solution. Design/methodology/approach A new method for adjusting material flow under a mixed floor and overhead material handling condition is incorporated in an existing plant layout procedure. A case study involving the layout improvement in a lawn mower engine assembly facility is presented to illustrate the effectiveness of the proposed method. Findings The analysis of solutions for the case study shows that the layout generated by the proposed modified material flow approach is a more economical solution. The case also shows, when it is important to optimize the use of space, the overhead space should be considered as part of any methodology for designing a good layout. Research limitations/implications The proposed modified material flow approach can be applied to any facility where the use of overhead space for material handling is justifiable by limited floor space and/or by high cost of land. The proposed method can be applied to small to medium size problems with minimal computational effort. However, as the size of facility grows, the manual calculation becomes more time consuming and potentially erratic. Originality/value This paper should be useful to both researchers and practitioners who deal with overhead space utilization in designing facility layouts.