How to Reduce Batch-Size

Anni Schmidt Nielsen1 & Mikkel Andreas Thomassen2

1Civil Engineer, MSc. MT H0jgaard a/s, Knud H0jgaards Vej 9, DK-2860 S0borg Phone +45 3954 4000, nil@mthojgaard.dk
2Project Manager. MT H0jgaard a/s, Knud H0jgaards Vej 9, DK-2860 S0borg Phone +45 3954 4000, mlt@mthojgaard.dk

Abstract

One of the key elements of lean is the elimination of internal inventories along the production line. However, even though the benefits from reducing inventories theoretically are well described (increased learning, visible bottlenecks and reduced capital costs and production time etc.), the concept is not easily introduced at the construction site. Thus, this mainly empirical paper aims at investigating the question: "How can significant reduction in batchsizes be achieved at the construction site". More precisely it is investigated if reduced building time is a way of forcing a reduction in batch-size at the construction site. In order to answer this question, two projects carried out by MT H0jgaard are used as case studies. Both projects have been subject to considerable reduction in the building period, although for different reasons. The paper at one hand illustrates, partly due to reduced batch-size, that it is possible to make significant reductions in construction durations and at the same time maintain and perhaps improve quality, cost and work environment on site. At the same time the case studies show that it is dangerous to reduce building time if the right contingencies are not in place. In particular, the way project management handles time pressure is of essence in this respect. The involvement of the construction crews working on site in the decision making and ongoing planning seem to be far a more efficient way of handling time pressure than by centralizing decisions at the project management level and as part of this increase the amount and richness of time schedules. Hence, this study supports the idea that The Last Planner System has an important role to play in reducing batch-size in construction. The possibility of designing activities in ways where fewer hand-overs are needed is an important way of gaining time. Experience from previous projects is also of vital importance as it allows subcontractors to be honest about their real time consumption. In this way, the case studies suggest that there is a positive interaction between reductions in building time and batch-size on one side and The Last Planner System together with the concepts of partnering and supply chain management on the other.

Keywords

Buffer management, work structuring, implementation, lean construction, fast track projects, last planner system

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Reference

Nielsen, A.S. & Thomassen, M.A. 2004, 'How to Reduce Batch-Size' In:, Bertelsen, S. & Formoso, C.T., 12th Annual Conference of the International Group for Lean Construction. Helsingør, Denmark, 3-5 Aug 2004.

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