The wastes of production in construction: A TFV based taxonomy

A paper by the authors presented at IGLC 21 in 2013 concluded that the classical list of seven wastes presented by Ohno is context specific (related to mass production) and that there is a need for the creation of a list specific for construction. The present paper presents a draft of such a list. The draft list is constructed in compliance with the Transformation - Flow - Value theory of production. Three main categories of waste are established: Material waste, time loss and value loss. The first is related to the transformation perspective, the second to the flow perspective and the third to the value perspective. Making do, buffering and task diminishment are not included as such in the proposed taxonomy. The paper therefore discusses how these phenomena relate to the categories of waste in the proposed taxonomy. A taxonomy of waste must be based on an explicit definition of the term waste. The two terms value and waste are tightly interconnected. Although value and waste are among the most central and used terms in the "lean" literature, no commonly accepted definitions of the two terms exist. The following definitions are proposed: :Value is a wanted output : Waste is the use of more than needed, or an unwanted output Value is related to wanted things (coming out of production), whereas waste can be related both to activities (inside production) and to unwanted things (coming out of production).