Researchers have suggested “a broader definition of waste to include not only material waste, but also waste generated in a construction project such as waiting times, transportation times…” (Hosseini, Nikakhtar, Wong, & Zavichi, 2012, p. 415).
The definition of waste as well as its classification has been approached by various researchers. In general, researchers have commonly included defects and excess processing as some of the more common factors considered as waste (Senaratne & Wijesiri, 2008). Additionally, other factors have been mentioned in specific industries to broaden this classification. The lean approach for the elimination of waste, as described by Ohno (1988), is as follows: “All we are doing is looking at the time line, from the moment the customer gives us an order to the point when we collect cash. And we are reducing that time line by removing the non-value-added wastes” (p. 9). The lean approach towards construction adopts both physical and non-physical waste production. On the basis of the existing literature, waste in the context of construction can be classified into eight types, namely defects, overproduction, waiting, not-utilizing talent, transportation, inventory excess, motion waste, and excess processing.
Production process that is not efficiently designed can lead to waste (Hosseini et al., 2012). The goal of lean production is to reduce processes that neither add value nor are necessary (Jimmerson, Weber, & Sobek, 2005). Excess processing refers to the act of providing more value in a product than is required by the customer (Ohno, 1988). By providing more value than necessary, excess processing can cost organizations financial burden with respect to the materials used and the staff time required (El-Namrouty, 2013). Such financial costs can build up over time and can be significantly high. Additionally, excessive processing also decreases employee efficiency as the time spent in excess processing cannot be used on production of products that are required by the customers (Gupta & Jain, 2013).
Researchers have suggested various causes that may lead to excess processing. The major reason identified is the lack of clear specifications and standards (Bhamu & Sangwan, 2014). Such a deficiency may cause employees to work without adequate guidance to the best of their ability without knowing the activities that add the most value to the product for the customer (Senaratne & Wijesiri, 2008). Thus, employees, lacking clear guidance, may often spend time working on components and processes that are not necessary. Additionally, the presence of practices that are not standardized can also lead to excess processing (Forsberg & Saukkoriipi, 2007). Organizations that do not have standard operating procedures may experience employees working through different methods from one individual to another on similar production processes (Jasti & Kodali, 2014). Excessive processing can also result from problems associated with design. The specification of machine operation, as provided by designers, can often be stricter than necessary. A looser specification guidance can lead to cheaper and more efficient methods for machine operation.
Researchers have suggested various ways in which excess processing waste can be reduced or eliminated. Most importantly, researchers recommend organizations to develop and implement standard operating procedures, which can be provided to employees in the form of written guidance (Jimmerson, Weber, & Sobek, 2005). This step can be of significant importance due to the simplicity of implementation of process and the potential benefits that may result from it. Standard operating procedures can ensure there is a standardization of the methods for production across different employees (Gupta & Jain, 2013). In addition to standard operating procedures, organizations can also ensure efficient training for all employees with the goal of ensuring the education of the most effective methods for quality controls. Researchers also suggest that wastes that are directly related to excess processing, such as overproduction, can be reduced to influence excess processing waste (Hosseini et al., 2012; Ohno, 1988). Organizations can also benefit from the use of standard operating procedures and training via clarity among all employees regarding common standards and specifications regarding expectations.
Researchers also suggest conducting a review of designs in the production process with the goal of recognizing looser machine operating guidance without compromising quality (Forsberg & Saukkoriipi, 2007). The adoption of cheaper and simpler processes can result in the reduction of excess processing. Further, organizations can also consider the review of component design, with the goal of changing the component design to reduce excess processing (El-Namrouty, 2013). Redesigning process plans is another action that can simplify production process and eliminate excessive processing during the manufacturing process. Process mapping can also be used to determine activities that do not add value, which cause excess processing (Hicks, 2007). This tool includes the process of indicating every process step in symbols and establishing relationships between different steps. Process mapping may reveal processes, sequences, and stages that may not be necessary for the ultimate creation of value for the customer.
Author: Henri Suissa
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