LEAN CONSTRUCTION – A SERIES OF ARTICLES
EPISODE 03 – KEY LEAN THEORIES & CONCEPTS THAT ARE PARACTICED IN LEAN CONSTRUCTION
BY ENG. KOKILA ARANDARA
The last two episodes discussed the definitions, background, rationale, leading practitioners and facilitators related to the Lean Construction topic. The top Lean Construction practicing companies that were explained are summarized here. Those are Vinci (France), Bechtel (USA), CRCC (China), Lindner Group (Germany), Marina Technology and Construction Pte. Ltd (Singapore), Southland Industries (New Zealand), CPB Contractors (Australia), Central Japan International Airport Company (CJIAC) (Japan). Similarly, the following organizations are summarized as the facilitating, and training organizations that the author introduced in the previous articles. Those organizations are HIRAYAMA Co., Ltd (Japan), Lean Construction Australia and New Zealand (LCANZ), Building & Construction Authority of Singapore (BCAS). Xi’ An Jiaotong Liverpool University (China), Lean Construction Institute (the USA), and International Group for Lean Construction (IGLC). This episode discusses some key lean theories and concepts that are practiced in the Lean Construction sector.
Lean Management is a Philosophy and there are Rules and Principles to be followed. Firstly, the Four Rules of Lean are stated and explained. There are four rules of lean and they are stated below.
The 4 Rules of Lean:
- Structure every activity
- Clearly connect each customer and suppler
- Specify and simplify every flow
- Improve through experiments at the lowest level possible towards the ideal state.
The practitioners and followers of lean in the construction sector shall follow these four rules. One of dictionary definitions for the term rule is “one of a set of explicit or understood regulations or principles or principle governing conduct or procedures within a particular area of activity”. In that sense, these rules are a clear set of guidelines and procedure that are to be focused on by the lean community. From the construction sector’s point of view, these rules are still valid and applicable. The companies that were mentioned above are on the lean journey (lean construction) and following these lean rules. The first rule aligns any construction project and activity towards a structured and organized phase. It guides to consider every activity in every stage, section, and division. For example, in the construction sector, every activity at the planning and designing stage, at the execution stage (construction), at the administration and control stage, and at last but not least at construction quality control and assurance divisions could be structured. The particular structure could be further reviewed for improvements within sites, projects, construction segments (maybe buildings, roads, and other infrastructures), organizations. In conventionally, the construction sector may run with a set of unstructured activities and it may count for drastic deviations of behaviours and handling of activities. The way of Lean Construction could change the mode to gain more results even by using the same set of resources only. The second rule explains the connectivity between customer and supplier. It is a very sensitive rule that connects two kinds of humans who are having different behaviours at a glance at two ends. In the construction sector also, both internal & external customers (clients) and suppliers could be identified. Throughout the construction sector (construction value stream), these customers and suppliers are stationed. The most last customer of this stream (or chain) is the final customer (can be called consumer) who consumes the final product/s produced/constructed by the respective contractor/s or project teams. The most first supplier of the same stream is the suppliers who supply materials/products/concepts to the immediate next receiver (i.e., internal customer). These materials/products/concepts etc; are flowing step by step to the next stages throughout the construction project. We have noticed that customer and supplier linkage at any point of the construction value stream is strong when the lean construction approach is evident because such construction projects follow the second rule of lean. The third rule guides lean community and lean organizations to keep the focus on every flow. Accordingly, lean organizations would not just maintain their flows (activities/steps of the process) as it is and but they would specify and simplify such flows. There are specified tools to use to specify and simplify flows and ECRS (Eliminate, Combine, Re-arrange and Simplify) is the one of examples that would be explained in the latter part of this article also. Further, for example, the materials unloading process could be specified and simplified by considering the flow under the 3rd rule. If a particular organization does not follow lean construction concepts and/or lean rules (particularly 3rd rule), room for improvements in each flow would be limited. The 4th rule facilitates to organizations to proceed with improvements confidently and without disturbing the existing operations and business returns. Behaviours and approaches of employees and employers of lean organizations would not make panic situation/s in case of improvements and smooth role out would be guaranteed.
In addition to the four rules of lean, there are five principles coming under lean philosophy. The next paragraph explains those five principles of lean. The 5 principles are mentioned below.
- Specify the Value
- Map the Value Stream
- Create the Flow
- Establish Pull
- Pursuit perfection
These principles are described by Dan Jones, Daniel Roos, and James Womack in two successful Lean books titled: ‘The machine that changed the World’ (Jones, Roos, & Womack , 1990) and ‘Lean thinking’ (Womack & Jones, 1996). The first principle describes the starting point. If an organization goes on a lean journey, the value-focused to deliver to their ultimate customer (client) to be clearly specified. In conventional organizations and companies may not define specific values to be delivered. Lean organizations align with the first principle of lean and then all stakeholders would be aware of what the value for the customer/s is demarcated and focused on by their company/organization. It may include aspects of quality, delivery, time of the product/service produced by the organization/company. When it comes to Lean Construction, the value to specified while keeping the focus on end consumers or their representatives (client/s). The second principle talks about the visibility and visualization of the value creation throughout the process. In the Lean approach, the chain of processes that build up the product or services starting from supplier/s towards the customer/s is called the “Value Stream”. Accordingly, the 2nd principle guides organizations to act to map the value stream. For this mapping, there are standardized tools and procedures that could be applied. Basically, a value stream map addresses information flow, material flow, and time lines of the stream at the bird-eye view but not at the process level. The value stream mapping can be applied in the construction sector (organization-wise or project-wise) and it would visualize value creation across the sector/project. The 3rd rule aligns the organizations to focus on the value stream by using the mapped version for easiness to avoid the barriers of the stream in order to create a flow. It is clear that by avoiding such obstacles, the stream would be able to flow smoothly. It implies that 3rd principle creates the environment for the business/organization/construction sector to perform effectively and efficiently. Such obstacles are described as “Waste” in lean vocabulary and lean practitioners shall improve and calibre their eyes to see and identify such waste in the value stream that is mapped and visualized. Those wastes are defined and explained in the next paragraph of this article. The fourth principle makes further smoothens the flow. In general, a stream that flows could move products/services toward the customer due to a push or pull applied to the value stream. However, it is safer and further practical if the stream flow is maintained with a pull system rather than a push system. In that sense, this 4th principle is valid to practice in the construction sector also in order to keep a continuous flow in the value stream. The fifth principle is the most important one here as it keeps the momentum to make sure the efforts put in the four principles are continued. The 5th principles enable to move the business/organization gradually towards the ideal state. This ideal state is again to be defined by considering the first principle. Accordingly, it becomes a cycle too and then 5 principles could be understood as a cyclic process as shown in Figure 01.
Figure 01: The Five Lean Principles (Jones, Roos, & Womack , 1990)
In addition to Lean Rules and Lean Principles, this article explains two key Lean Terms (Value-Added and Wastes) as those two terms are appeared in here. “Value-Added” means that any activity that increases the shape or form or function of a product or service and that the customer (client) is willing to pay for it. On the other hand, “Waste” is described as any activity that is not adding value. Those are again called “Non-Value-Added” activities. However, there are two categories of waste and those are “Necessary Non-Value-added” and “Pure waste”. In general, the term “waste” found in lean vocabulary mentions that pure-waste. For example, in construction, making a wall by using brick and mortar is a value-added activity while bending and taking movements of a mason (or both helper and mason) are considered as waste. It is because “the making a wall” activity increases the formation of the product (may be a building or a wall) and “bending and taking actions of a person” would not increase the shape or form or function of the product. By identifying and eliminating such wastes (non-value-added activities) the productivity of a particular process/project/sector could be improved. Lean construction means making such approaches collectively in the sector to enhance the productivity of the construction sector.
To identify and eliminate the aforementioned wastes, there are tools and concepts used by lean practitioners and the community. At last, but not least, Lean Tools are also defined and a few tools are stated below before conclude the series of episodes here. 5S (Five S) is a powerful and well-known lean tool (concept) that is applied in most sectors. Basically, 5S is considered as the foundation for productivity improvements. 5S is defined as five activities namely Sort, Set in Order, Shine, Standardize, and Sustain. The Japanese term of 5S is the collection of words namely Seiri, Seiton, Seiso, Seiketsu, and Shisuke. In lean construction, the 5S concept could be applied at any stage and it leads to identifying and eliminating process waste. For example, 5S could be practiced in sites, site offices, design processes, design offices, warehouses, and everywhere. Here, it should be stated that 5S is not a just tool to use for housekeeping but to practice aggressively to enhance productivity. Standardized Work-Sheet (STW) is another fruitful lean tool that is used in lean organizations. From the construction point of view, the same STW tool could be applied and each activity (for example fixing a door, installation of doors, fixing of floor tiles) could be standardized. Standardized work would avoid and eliminate those variations could happen person to person and quality and deliveries could be assured. “Last Planner System (LPS)” is given here as a lean tool specifically applied in lean construction. LPS is a production system and it could be used to produce a predictable workflow. It is basically a role of a person or group of persons accountable for a production unit at the operational level. Also, the LPS is a socio-technical production planning & control system and it could be further available to produce reliable workflow and rapid learning in the planning, design, construction, and commissioning of projects (Erazo-Rondinel, Vila-Comun, & Alva, 2020). If there is a delay in completing one work segment, it could directly affect the process and the progress of the downstream’s (of the value stream) work segments and therefore, flow variability is a vibrant limitation in the construction sector. To overcome such limitations, LPS is used to provide improved project control in lean construction.
With these, the series of episodes on “Lean Construction” is concluded. Three consecutive articles including this as the 3rd and the last one, explained what is lean construction, what are the leading global lean construction organizations that are practicing and facilitating lean construction and finally the lean theories and concepts. For more details, the given list of references could be referred to.
The author would thank the original authors/researchers/publishers of the references that are referred in this series of articles. Also, the editor and panel of editors of SLEN are highly appreciated for their kind corporation to make this a successful publication. All the professionals in the construction sector of Sri Lanka are invited to make a positive approach in their capacity to Lean Construction for the betterment of the sector and the country.
References:
Erazo-Rondinel, A. A., Vila-Comun, A., & Alva, A. (2020). Application of the Last Planner® System in a Sports Infrastructure Project in Peru. 28th Annual Conference of the International Group for Lean Construction (IGLC28) (pp. 529-540). Berkeley, California, USA, : doi.org/10.24928/2020/0091, online at iglc.net. .
Jones, D., Roos, D., & Womack , J. (1990). The Machine that Changed the World. Washington: Free Press.
Womack , J. P., & Jones, D. T. (1996). Lean Thinking. New York: Free Press.
Eng. Kokila Arandara
Lead-Lean Construction Practitioner in Sri Lanka,
Founding Director,
Lean & Green Solutions (Pvt) Ltd.
