Using the line of balance for production system design

Abstract

The line of balance (LOB) is a tool for project planning and control that provides great visibility for the flows of work in a construction site. The LOB depicts information related to when, where and what activities are done at any time as well as activity batch size, pace, and buffers between different crews. Besides making work flows more transparent to those managing a project, this tool can serve as a means to simulate and discuss different alternatives and strategies to sequence activities in the long run. This paper presents a study carried out in a construction company in Fortaleza, Brazil in which the authors used the LOB in the initial planning phase of a high-rise residential project. Based on the information provided by different LOBs, representing different scenarios, the authors discussed with projects managers, superintendents, and crews the advantages and disadvantages of each scenario regarding the project’s lead time, activities cycle time, gang sizes, batch sizes, buffers, sequencing, interferences between crews, learning effect and productivity. The paper presents the project’s personnel views about the different scenarios and respective indicators, and discusses the implications of the group’s chosen scenario for the project as whole. The LOB was developed in spreadsheet software (Microsoft® Excel) and had a high rate of success as the project’s participants could easily understand the concepts used to develop each scenario, simulate, and evaluate the impacts they had on the project’s performance. Based on other papers’ conclusions about the topic, this paper aims at contributing to the discussion about production system design based on solid production indicators depicted through low-cost and low-level of abstraction tools such as the Line of Balance.