Value adding and non-value adding activities in turnaround maintenance process : classification, validation, and benefits

The increasing popularity of lean thinking has made the analysis of value-adding (VA) and non-value adding (NVA) a popular activity to eliminate waste and improve productivity. Despite the great success of the Taiichi Ohno's waste taxonomy and its adaptation and diffusion into the maintenance sector, a systematic classification of VA and NVA remains as a significant challenge for lean practitioners. The aim of this research is to develop a system to classify VA and NVA activities for lean applications in turnaround maintenance (TAM) projects. First, a comprehensive literature review was conducted on existing methods of defining and classifying value and waste. As a result of this review, an initial system to classify VA and NVA in TAM was proposed, which was then refined in three focus group studies conducted with a group of TAM participants. The improved classification system was evaluated by applying value stream mapping (VSM) in terms of the ontology effectiveness and efficiency using a sample case. The classification system contributes to an accurate classification of value, and waste and the relevant root causes in the TAM processes. The classification system provides an insight on a consolidated understanding and classification of VA and NVA in TAM projects.