Prior research has investigated the sources of waste in order to gain better understanding of waste in production systems and to promote the use of lean methods [1]. The study considered two types of waste, operational waste and organizational waste. In comparison with the manufacturing industry, the three peculiarities of construction, specific customer, site production, and temporary organization are acknowledged[2]. This article will give you a summary on the different sources of waste between construction and manufacturing.

Source of Operational Waste

A product of the construction industry, such as a building or a house, is produced on a construction worksite. Once materials are delivered to the site, they don’t leave the site and only wait to be consumed. After completing the project, a contractor needs to hand over the finished product to the client in the same location as where the construction worksite is. Therefore, it is necessary not only to ensure the product’s quality, but also at the same time to develop the living environment for users of the product during the construction process. These conditions lead to differences in supply chain management and managerial control, compared with operations within the factory environment, which provides finished products to the market that is accessed by end users.

The size of the managed resources, including materials and machines/equipment/facilities, on a construction site is usually much larger than in the case of the manufacturing industry. Depending on the nature of tasks, construction professionals may track the progress of a project by calculating the amount of materials/components constructed or installed. However, similar control is carried out using the number of finished products in the case of a factory. The same production lead time approach as in the manufacturing industry can be used in the construction industry by dividing larger tasks (i.e. building or floor) into smaller work chunks or even into smaller areas (location-based planning and control). Such a difference in the physical and temporal scales of management resources brings the result that in construction, a reliable picture of the whole of production, and progress against plan, cannot be confirmed at a glance.

In addition, there is the general principle that the more there is repetition, the easier it is to reduce variability. In factories, many repeated operations are included in the mass production system, catering to mass consumption. In the construction industry, this principle is confirmed in operations when constructing a building which consists of multiple rooms with exactly the same structure. Table 1 summarizes the mentioned differences in the attributes of a production system between the two industries.

Table 1. Differences of the production system attributes between manufacturing and construction, with reference to construction peculiarities

Source of Organizational Waste

Construction projects that have different specifications are executed at the same time in different locations. Although many different specialists join one project, they cannot also witness the completion of the project together. The former causes a geographical boundary and the latter draws out a temporal boundary for communication among specialists in a project. In addition, this two-boundary structure has other structures nesting inside it. Each structure involves each worksite of each current project. A construction site with this structure, which hinders communication among project members, is shown in Figure 1.

The two-boundary structure contains the following four sub-boundaries that are prone to lead to losses in communication:

a. Boundary between today’s you and tomorrow’s you (imagine ‘you’ as one member on worksite at present)
b. Boundary between the head office and a worksite
c. Boundary among members of different teams
d. Boundary among projects in different locations

The first, second, and fourth boundary can also be found in the manufacturing industry. However, the third boundary does not usually exist as the same people operate together every day in the same factory. Regarding the first boundary, information sharing among employees occurs in their workplace every day to reduce the variation in the management of resources, such as machines operated and materials used. For the second boundary, in the overall competitive environment, the geographical distribution of a factory network causes that the information of operational status of each one has to be gathered and analysed by the head office, to give quick support. The fourth boundary relates to the advanced information sharing including technology transfer and knowledge management. Even if all factories of a company manufacture different products, the exchange of valuable experiences with each other ought to be recognized as a worthwhile opportunity to innovate for improved production system performance.

The third boundary is a special hindrance factor of the construction industry when compared to the manufacturing industry, where the same people work every day together. A construction project is realized by many different specialists such as architects, quantity surveyors, plasterers, carpenters, and plumbers. They join together in one project, however they don’t work continuously together from the start to the finish of the project. The situation hinders the accurate delivery of information on plan progress to the next participants. The main countermeasure for the problem rests in their understanding based on both their experiences from past projects and the continuous maintenance of process transparency through information sharing. It is very important to overcome this boundary on construction worksites.

Figure 1. Nested structure model of communication in the construction industry

Future Works

Construction and manufacturing industries have the common goal of providing customers fulfillment of their requirements through production. However, the production systems in these two industries are different. By understanding the differences, these industries can exchange experiences and knowledge about lean methods developed in each. This is expected to support the reduction of production-related waste, which is a precondition for the survival of humankind.

References

[1] Murata K., Tezel A., Koskela L., & Tzortzopoulos P. (2018). “Sources of Waste on Construction Worksite: A Comparison to the Manufacturing Industry.” Proceedings of 26th Annual Conference of the International. Group for Lean Construction, Chennai, India, 973–981.

[2] Koskela, L., Bølviken, T. & Rooke, J. (2013). “Which Are the Wastes of Construction?”, Proceedings of 21th Annual Conference of the International Group for Lean Construction, 3-12., Fortaleza, Brazil.