Origins of Lean Principles
The lean principle, in simple terms, is all about reducing non-value-adding activities and materials (Waste) in a process. The origins of the lean concept can be traced back to the Japanese automobile industry called Toyota. It was an evolved mass production process in which an extreme emphasis was placed on finding and rectifying defects and potential defects in the production line.
Prior to this approach, the production continued regardless of the defects in a part in the production line. More resources were added to these defected pieces only to be rejected in the final QC stage as non-value-adding elements or waste.
To address this problem, a new production system called the Toyota Production System was created. In this system, once a defect was identified it was stopped from moving further in the production line. This process gave birth to a new manufacturing approach with almost zero non-value-adding materials.
In 1992, Koskela introduced the 11 principles of lean which helped industries worldwide to apply these principles to their production processes to get them leaner and much more efficient. This list was meant to give a more comprehensive view of lean studied and applied over time.
In 2013, the 11 Koskela principles were summarized to a list of 5 major principles which captured the fundamentals of the lean approach.
5 Fundamental Principles of Lean
- Setting Value: This is defining what exactly the client’s requirements are. The delivery of these objectives is what is defined as the delivery of value to the client.
- Value stream: This is where the process is stripped for information to its lowest level and it is classified into essential or non-value-adding categories. Once this is done, all non-value-adding tasks are removed from the process.
- Flow: This specifies the allocation and movement of resources. The easiest and the most efficient flow of resources is decided to ensure the availability of these essential resources for all departments at the time of need. This establishes the availability of personnel and resources at optimum times and the working of the supply logistics.
- Pull:The lean process eliminates the need of a buffer in inventory. The materials are only made available at the right time of need with the right amount and specification. This process focuses more on the efficient delivery of these materials on demand. The need for a resource is communicated with the supplier in advance to ensure its timely delivery.
- Perfection: This is an essential step in every process management. The existing process flow and methods are tweaked to best cater the needs of efficient delivery.
Lean Principles in Construction
The construction industry, initially shied away from the application of lean principles into their process. The reason quoted was the difference of delivery in construction when compared to the manufacturing process. Every project is considered unique and independent. In-depth studies pointed out the similarities between the construction and manufacturing industries to further explore the application of lean principles in the AEC industry. Unlike manufacturing, construction involves projects that are carried out on site based on a contract.
This is however undergoing a few changes in the current era. New-age practices of prefabrication and off site production illustrate the gradual change in gap between the delivery process in construction and manufacturing.
How BIM meets Lean principles
The BIM practice in itself covers the basic principles of lean construction. Establishing the priorities and values are also among the initial steps of a BIM project. The design is adjusted and arranged to provide the best output from a given amount of invested resources and material. The schedules single-handedly solve the material flow issues by giving us a real-time requirement of materials at every stage of the design.
The BIM process facilitates 3D visualizations or representations of possible design approaches. These representations help us to easily define the key ‘values’ of the project and communicate these values with the various actors from all domains contributing to the workflow.
Designing various alternatives is one of the major boons of BIM. This easily covers the value stream part of the lean methodology. All non essential and non-value-adding elements are minimized or eliminated by exploring every possible design alternative.
It cuts down the ambiguity with regard to the amount of resources needed for the project to be completed. Every change in the design reflects its change into all other information such as cost estimation, material count and scheduling. The design can also be analyzed for its power consumption with green practices, further reducing the energy needed for the building to sustain making it much leaner for the long run.
BIM is extremely effective in perfecting the design. Every aspect of design from aesthetics to cost estimation can be calculated and established to the finest detail, leaving no or very less room for unexpected wastage and reworks. The design is continuously altered to be more efficient, cost effective, easier to manufacture and to be constructed. Lean principles in construction may seem alien to those who haven’t explored its applications. But fortunately enough, the modern AEC industry and its focus on BIM implicitly includes the lean principles into the construction process. So it would be safe to say, BIM is lean!
How BIM meets Lean Construction practices
|Lean Construction||Intersection with BIM|
|Estimation of wastage (time, materials and effort)||Structural clash tests|
|Design alternatives to select most suitable design|
|Performance simulations for the most efficient energy solution|
|Customer value (achieve requirements)||Visualization of solutions that ensure clear understanding of the model|
|Analysis for the best result|
|understanding between client and supplier by use of 3D models and walkthroughs|
|Reduced cycle Times||Automated generation of changes and material schedules and quantities|
|Provide accurate information to prefabrication|
|Visualizing of work flow to check for process conflicts (teams and tasks)|
|Work Flow||Through making detail schedules of tasks and materials delivery times|
|Collaboration||Ability to work concurrently on same design solutions by different teams|