Lean Construction is a production management-based approach to project delivery — a new way to design and build capital facilities. Lean Construction embodies a philosophy of production management that is often contrasted to mass production and craft production. While the construction industry has adopted elaborate techniques for project and contract management, by comparison, the management of production has been neglected. It can be argued that construction remains essentially a craft form of production. Our industry develops one-of-a-kind custom prototypes. The AEC industry has never been a mass producer. Nevertheless, the achievements of manufacturing have triggered development of production management thinking and techniques in the design and construction of capital facilities. The development of an AEC production theory is needed to help manage and better integrate the Facility Delivery Process providing better value to the customer and reduce waste.
Lean Construction planning and control techniques reduce waste by improving workflow reliability. The starting point is improving the reliability of assignments at the crew level. This is in contrast to current management approaches that rely on project level plans to manage contracts instead of managing work, and contract commodity-based control systems that do not measure planning systems performance. Lacking a predictable workflow, design squads, field crews, or similar production units must adopt a strategy of flexibility to keep busy. Unfortunately, flexibility applied at one workstation demands flexibility downstream. This current practice injects uncertainty in the flow of work, rendering it impossible to plan!
Lean Construction starts by stabilizing the workflow through reliable planning which shields the crew from that uncertainty management cannot control. Injecting certainty into the flow of work by shielding improves performance of the immediate production unit up to 30% or more while stabilizing flow downstream. Predictable flow at any point in the supply and assembly chain then makes it possible to reduce inflow variation upstream and redesign operations downstream. These techniques have been proven in both design and construction, on small and larger design-build or competitively bid as well as very large fast-track projects, and by independent specialty contractors.