Developing design guidelines for a case-picking warehouse

Warehouses can be characterized in many ways, including the number of items stored, the average number of cases per pallet, throughput and inventory requirements, and demand profile, to name a few. Thus, there is no one-size-fits-all design for case-picking warehouses, and hundreds of designs are possible. Moreover, the decision variables in warehouse design are interrelated and this further complicates the design process. The purpose of this paper is to provide a set of guidelines for arriving at a “good” design configuration for a manual, case-picking warehouse. Our goal in developing a set of guidelines is that it would provide a design that is close to the optimal solution, which could then be further analyzed and improved. We limit the decision variables considered in our analysis to include the size and layout of the forward area, dock door configuration, pallet area shape, and pallet rack height. To develop our design guidelines we employ a statistical-based methodology, whereby we use one set of data to develop the guidelines and an independent set of data to evaluate the performance of the guidelines. Our response variable is the number of labor hours. We use analytical models to evaluate labor hours for each design in the solution space. The most impactful parameter that influences our guidelines is using a forward area. Other parameters include: the ratio of SKUs to bottom-level pallet locations, ABC curve skewness, and number of lines per batch. Our results indicate that our guidelines provide a good design that minimizes labor hours.