Lean construction (production) principles and significance of theory
Khaleel Ahmed, Lecturer, Dudley College of Technology
THE key motives behind integrating lean thinking into construction processes are clients’ needs and requirements. Lean has been defined as a way of doing more with less effort, less equipment, and less time, while meeting customers’ expectations1.
According to Womack and Jones, value is a starting point for lean thinking, and it is meaningful only when a product has been delivered at a specific time and price which is considered as one of key motives by construction companies/businesses.
This is also the first principle of the Toyota Way, which is associated with Liker’s 4P model2 (philosophy, process, people and partners and problem-solving). Liker3 suggests this as being the starting point and how the company should thrive to achieve this.
Lean is considered as one of the most powerful manufacturing models of current times. Another popular view considers lean as a set of practices, which can be grouped into four categories of justin-time, total quality management, productive maintenance and human resources management. This popular view is considered to be compatible with the Toyota Production Syste4.
Lean theories and principles
One of the key principles of lean as defined by Knights and Willmott is the use of information technology for just-in-time services and stock inventories, which discourages companies to keep excessive staff or items. This resonates with principle seven of Toyota Production System and Liker has talked about automation and equipment in this principle.
As different sectors are likely to have different issues within their production environments, tools or methods, all manifestations of leans are considered contextual. Tzortzopoulos, Kagioglou and Koskela wonder if the concept of lean production is meant for lean within car manufacturing or other similar examples. It is argued that construction sector has its own unusual features, which differ from ones within a production environment.
As different sectors are likely to have different issues within their production environments, tools or methods, all manifestations of leans are considered contextual. This makes the Toyota Production System a contextual application of general principles.
According to Bollard, construction sector has seen chronic problems for many decades, hence looking at the issues being faced by the construction sector would provide to be an ideal case of lean construction. As theories are fundamental in establishing our understanding and explanation of various processes, this article highlights some relevant lean theories and principles.
Koskela’s Transformation-Flow-Value (TFV) theory is regarded as a new production philosophy to construction. These theories may prove beneficial in the implementation of integrative managerial approaches as well as lean project and production management. Some of these theories are available, whilst some are in development.
A few of these theories which provide consistent foundation for design and production include the TFV model, the theory of constraints, queuing theory, the V model and the method of analysis and synthesis.
A few of these theories which provide consistent foundation for design and production include the TFV model1, the theory of constraints, queuing theory, the V model and the method of analysis and synthesis.
A sound understanding and implementation of these three perspectives (TFV) would help address many of issues faced by the construction sector e.g., waste produced on site can be reduced by understanding design as flow of information. This can be achieved by reducing non-value-generating tasks which will in turn result in improved efficiency.
An example of such issues is where large piles of material are purchased on a discounted price resulting in waste, which is later transported from site. Seven wastes have been identified by Ohno and Koskela argues that time is wasted by non-transformation activities on site and lesser the activities are the better it is.
Liker has also attributed to this as principle three, recommending using a pull system to avoid overproduction, although an inventory buffer can be an option too if zero inventory by the company is not achievable.
Flow
Similarly, the concept of flow is quite relevant when there is insufficient communication and collaboration on site between different team members/stakeholders.
Fatigue and tiredness are example of other issues faced on construction sites and staff would often have to do some level of training to manage these issues. It may be common for certain construction sites where personnel may be suffering from fatigue due to long working hours.
This will most likely result in slower reaction times on the site, having problem in making informed decisions and/or assessing hazards/ risks and most importantly being unable to provide accurate details and attention to tasks happening.
To introduce changes to current processes and overcome challenges, three theories of management (planning, execution and control) are also relevant. Principle 10 by Liker puts emphasis on the provision of safe working environment and has linked this to a human resource model. These issues have a knock-on effect on the end client, who expects effective flow of details/updates from the site. Also, the theory of production appears quite relevant, which requires effective flow of information to the client.
Tzortzopoulos, Kagioglou and Koskela have compared this with monozukuri, which is regarded as the theoretical interpretation of Toyota Production System.
Another example where the concept of value can be related to is when the weekly activities happening on a site result in small proportion of weekly tasks being achieved. This has a direct consequence on client’s requirements.
Principle nine encourages having a good team leader, who can assess the tasks at sufficient level and be a role model. Similarly, principle 10 focusses on the effective use of tools by employees to solve problems.
According to Koskela, production management equates to transfer clients’ needs into products which conform to the specification. The concept of value will help mitigate such issues by adding value through improved processes.
Master plan
Most companies usually run construction processes based on a master plan and in some instances this master plan may have been static and non-lean for a particular business. In these scenarios, the concept of transformation will be helpful in development of a target process. The key strength of this theory is decomposition, which allows division of the total task into smaller tasks, which are mutually independent.
A process model must display content of activities, the priority order of these activities, main inputs, and outputs and how the information flows along the process and finally the roles and responsibilities of various stakeholders.
This concept will help optimise smaller tasks (sub-process ) and hence yielding optimal implementation of master plan. This requires affective use of emerging technology, which can help implement these changes in the master plan. Liker has attributed the use of technology to the success of processes in principle eight.
To introduce changes to current processes and overcome challenges, three theories of management (planning, execution and control) are also relevant. For example, issues due to poor communications or fatigue may require implementing plans by the top management. Koskela and Howell6 have noted that management-as-organising is not exclusive, and plans are accepted on purposeful actions.
Similarly, the execution of these plans and determination of performance including any deviations are governed by the theory-of-execution and theory-of-control. The process of controlling has been divided into two subprocesses which are reporting of performance and controlling of change.
Non-lean processes could be a general representation of various project stages and in some instances could be linked to RIBA’s plan of work. The master plan may have been translated to a Gantt chart with different key processes and procedures.
Although a company may have a systematic planning and management process in place, the master plan might not be being revised to suit individual project needs.
As a result, the master plan fails to reflect processes for site-specific tasks e.g., information on type and format of deliverables, quality, and verification processes for the existing data. A process model must display content of activities, the priority order of these activities, main inputs, and outputs and how the information flows along the process and finally the roles and responsibilities of various stakeholders.
The master plan should also provide information on protocols for communication and collaboration purposes, which is a key aspect of lean principles. According to Kagioglou et al7, a collaborative environment and communication at the right time to help make informed decision is one of the six key principles in the development of a process protocol.
Khaleel Ahmed, Lecturer, Dudley College of Technology
References
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1 Womack, JP, & Jones, DT (2003) Lean thinking: Banish waste and create wealth in your corporation. London: Simon & Schuster, Limited.
2 Liker, J and Meier, D (2006) Toyota Way field book: a practical guide for implementing Toyota’s 4Ps. U.S: McGraw-Hill.
3 Liker, J (2020) The Toyota Way, Second Edition: 14 Management Principles from the World’s Greatest Manufacturer. 2nd Edition. New York: McGraw-Hill.
4 Tzortzopoulos, P, Kagioglou, M, & Koskela, L (Eds.). (2020) Lean construction: Core concepts and new frontiers. Oxon: CRC Press LLC.
5 Koskela, LJ (2000) An exploration towards a production theory and its application to construction. Available at: https:// www.vttresearch.com/sites/default/files/pdf/publications/2000/P408.pdf (Accessed: 15 February 2023).
6 Koskela, LJ and Howell, G (2002) The underlying theory of project management is obsolete. Available at: https:// usir.salford.ac.uk/id/eprint/9400/1/2002_The_ underlying_theory_of_project_management_is_obsolete. pdf (Accessed: 15 February 2023).
7 Kagioglou, M, Cooper, R, Aouad, G, and Sexton, M (2000) Rethinking construction: The generic design and construction process protocol. Engineering, Construction and Architectural Management, 7(2), pp.141-153.