Standardized work (SW) is a type of action-oriented procedure that sets a basis for continuous improvement in the Toyota Production System. However, the usefulness and applicability of this practice to construction is still unclear. Furthermore, while some studies have addressed the key elements of SW, the role played by the concept of slack as a fundamental element of operations design is rarely discussed in an explicit way. This is a drawback since slack resources allow for the system to cope with variability from different sources.Considering the context of the construction industry, the aim of this study is to carry out an exploratory investigation of the role played by slack in SW. This analysis is mostly based on a matrix that checks strategies for the deployment of slack resources against sources of variability in construction. Results indicate that SW, in construction, should account for a broader range of slack resources in comparison to what is accounted for in manufacturing. In addition, we propose that slack resources and the corresponding variability sources be explicitly anticipated when designing SW for construction operations.

Resumo Nos últimos anos, tem se observado um aumento na utilização de sistemas construtivos industrializados, entre os quais estruturas metálicas, que podem contribuir para eliminar perdas e reduzir duração dos empreendimentos. O presente trabalho tem como objetivo propor um conjunto de diretrizes para o planejamento e controle do processo de montagem de estruturas metálicas prefabricadas, utilizando conceitos e ferramentas relacionados à Produção Enxuta. A abordagem metodológica utilizada foi design science research, sendo o trabalho desenvolvido em parceria com uma empresa que projeta, fábrica e monta sistemas construtivos em aço. Foram implementadas diversas melhorias no planejamneto e controle da produção (PCP) da empresa, em duas etapas: a primeira com a participação de um pesquisador como facilitador do processo; e a segunda com a implementação conduzida por gerentes da própria empresa. Os resultados obtidos evidenciaram a necessidade de adaptação dos modelos de PSP e do PCP existentes na literatura ao contexto de sistemas de estruturas metálicas. A principal contribuição do trabalho foi a proposição de um conjunto de diretrizes para conceber o processo de PCP em empresas que fornecem sistemas construtivos de aço.

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Construction projects are known to be complex, due to being subject to uncertainty and variability. The use of buffers to protect them from the detrimental impact of variability has been well-researched. A key managerial choice is not whether or not to buffer variability, but rather how to define the necessary combination of buffers. Slack is a concept related to buffers but has been used in the literature to describe a broader range of strategies for coping with complexity. It allows an organisation to adapt to internal pressures for adjustment or to external pressures for change in policy. This paper aims to further develop the concept of slack and to unveil its relationships with other concepts and ideas that are partly overlapping such as buffers, resilience, robustness, flexibility, and redundancy. A concept map was devised in order to articulate the nature of the slack concept. This paper explores in detail this concept map and proposes a conceptual role for slack in the realm of Lean.

The Line of Balance (LOB) is a planning technique that has been used for more than 30 years in construction. However, what is rarely discussed is how the LOB should be applied in projects already in progress. This research was developed in the Design Science Research (DSR) format and sought to analyze how LOB can bring about significant changes in the management of collaboration, planning and production. This paper puts forward a collaborative method of training on LOB in projects that are already in progress for which it draws on a two case studies on multifamily residential building. The benefits of LOB for those involved in the workshop were collected by gathering multiple pieces of evidence and analyzing the correlations. In the participants' perception, there are three main benefits concerning to adopting LOB: (i) understanding the sequencing of activities and how to achieve the uninterrupted flow of teams; (ii) assessing the risk of mobilization and remobilization; (iii) assessing milestone dates and constraints. Moreover, participants´ perception, the training had a excellent evaluation, and it contributed to increasing their collaboration and engagement in relation to the planning of the project.

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Construction projects are exposed to a wide diversity of variabilities, which suggests the existence of a correspondent wide diversity of variability coping mechanisms, whether they are designed or not. This wide diversity is not properly accounted for by the concept of buffer, as it neglects the social and informal dimensions of coping with variability. The use of the concept of slack is proposed as an alternative. A companion IGLC 29 paper defines slack and discusses its relationships with proxy concepts such as flexibility and resilience. This paper presents nine practical examples of slack in managerial processes and topics that are of interest for the lean construction community. These examples suggest that, while slack has been concealed by the lack of theorization and consistent terminology, it is ubiquitous in lean construction. Opportunities for future studies are outlined.