Development of Spare Part Classification Methodology Considering Maintainability, Criticality, and Inventory Management Aspects in The Oil Processing Industry

Management of spare parts in maintenance activities is indispensable for several companies, especially the manufacturing industry. The insufficiency of spare part inventories, results in the potential of equipment breakdown which has an impact on costs for equipment downtime due to damage. Otherwise, inventory excess may result in high storage costs and dead stock of materials that have been unused up to a certain period. In addition, the company should be able to manage the inventory level of the spare parts so that their quality is maintained and to prevent a decline in quality; therefore, it is ready to use whenever the spare part is needed. Spare part management involves both the maintenance aspect and the inventory aspect because they are interrelated. In this research, we determine how to classify spare parts considering these two aspects. This classification will be divided into two parts; the first is the classification of spare parts based on the function of spare parts to the equipment and impact in terms of production, health, safety, and environment. The second part is multi-criteria classification using the Analytical Hierarchy Process (AHP) with the criteria of lead time, unit price, the probability of failure, and availability of equipment. The two parts are combined in a decision diagram to determine the final criticality of the spare part from all these aspects. The methodology was developed in one of the oil processing industries in Indonesia and can be implemented as a step in establishing inventory management policies. From the research results, it is known that the development of the methodology can obtain the criticality level of spare parts so that the priority of spare part supply in the warehouse can be determined.