Slack Categories for Managing Risks in the Delivery and Assembly of Engineer-to-Order Prefabricated Building Systems

Industrialization brings several advantages to the construction industry, which are strongly related to moving production activities to a controlled environment. By contrast, there are additional challenges in managing the overall construction process due to the combined effect of interdependence between off-site and on-site processes and uncertainty caused by internal and external factors. In the context of engineer-to-order (ETO) industrialized building systems, products are customer-specific and require continuous negotiations between the provider and the customer, making the system even more complex and requiring reliable information. The use of slack may be interpreted as a dimension of project risk management, offering opportunities to make production systems more responsive to the impacts of project complexity. However, in the context of ETO industrialized building systems, research on using slack is still scarce. The research work aims to devise a framework of slack categories to support planning and control systems for the delivery and assembly of ETO industrialized building systems. Regarding theoretical contributions, some connections were established between different categories of slack and some core concepts and principles of the lean production philosophy, such as production flow and pull production. This investigation also explores the use of some digital technologies, such as four-dimensional building information modeling.