Value and Waste in Lean Construction

Fidelis Emuze, Tarcisio Saurin, Fidelis A. Emuze, Tarcisio A. Saurin, Fidelis Emuze, Tarcisio Saurin, Fidelis A. Emuze, Tarcisio A. Saurin

• Publisher: Routledge
• Year: 2015
• Print ISBN: 9780367355654
• eBook ISBN: 9781317447627
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Construction & Architectural Engineering
• Index: Technology & Engineering

Non-value adding activities are otherwise known as 'waste' in the lean construction lexicon. The aim of this collection is to build a common understanding of the role and contribution of value-adding activities in achieving stipulated objectives and continuous improvement in construction projects, and to contrast this with waste. Although the lean approach to construction projects has been widely covered, this is the first book that explicitly provides the link between value and waste in the Architecture, Engineering and Construction (AEC) sector.

This internationally researched collection seeks to create a paradigm shift, which will shape work processes and future directions for how value is conceptualized and operationalized in both the project management and business aspects of construction. The readers will gain an understanding of:

• The value-adding paradigm in construction
• How to make value-supporting decisions
• Waste identification and control in practice

With contributions from South Africa, Brazil, Norway, and the USA, the implications of this book are globally relevant. This is essential reading for all higher level students of construction management and economics, and all professionals interested in value management.

Part I
Theory of waste in construction

1
Wastes in construction

Concepts and types

Fidelis A. Emuze and Tarcisio A. Saurin

This chapter offers insights into wastes in construction. The attributes of wastes are discussed in order to illustrate its impact on value. By means of examples, the chapter explains the concept of waste and how it can have a negative impact on project success. The chapter reviews current literature on waste to argue that activities have to be examined in order to identify, analyse and remove waste, which tends to proliferate if unchecked in the construction process. In other words, project actors should be conversant with the different wastes in construction that occur in the design and production phases of a project, so that strategies can be put in place for the removal of such wastes.

1.1 Background

The construction management literature has alluded to the fact that, in general, performance of projects has remained poor. Time and again, owners and sponsors have asked architects, engineers and contractors to deliver projects within agreed performance parameters of cost, quality, time, health and safety (H&S) and the environment. However, failure to finish projects within these parameters is frequent, and it is usually associated with waste. Just as in the manufacturing industry, waste in construction has negative effects, such as cost overrun, time overrun, low productivity, lack of H&S and lack of competitive advantage (Alwi et al., 2002a, 2002b; Han, 2008; Hwang et al., 2009; Koskenvesa et al., 2010). As a result, waste elimination is a leading principle in lean construction, and a number of lean practices have been used to eliminate waste and enhance value in production environments (Gupta and Jain, 2013). The objective of this introductory chapter is to give an overview of waste in construction, with a discussion of relevant concepts, types of wastes and examples. The discussion thus highlights the need to create awareness of the prevalence of wastes in construction, and the associated impact on project performance.

1.2 Concepts of waste and value

The main goal of lean construction is to eliminate waste from the system by trimming production to make it as value-adding as practically possible. Waste reduction increases production capacity, since the total capacity of a production system is the sum of work and waste in the system (Ohno, 1988). Shingo (1981) defines waste as activities that consume time and resources but fail to add value to the final product. Waste may also be an unwanted physical functionality of the product, as well as the use of more resources than is needed, or an unwanted output. In fact, the concept of waste is inseparable from the concept of value, which means that what is waste for one particular client may not be waste for another client – it all depends on what counts as value for the client. Value is related to outputs that derive from a production system, while waste is related to activities inside a production system, and to unwanted outputs that emerge from the system (Bolviken et al., 2014).

The terms ‘value’ and ‘waste’ usually have economic connotations. For instance, value is the price a client pays for a required product or service, and waste is unneeded costs that the client may decline payment for (Han et al., 2007). The costs of waste can take the form of ‘direct cost’, where production resources are wasted, and ‘indirect costs’, such as low return on investment, as a result of excessive inventory and low output (Bolviken et al., 2014). It is also worth noting that work that does not add value but is necessary under an operating condition constitutes hidden waste. By contrast, a clear instance of waste is work that does not add value and is not necessary, and where clients’ willingness to pay for such work is uncertain. This explanation therefore suggests that value-adding activities should be enhanced; hidden wastes should be made visible and diminished as far as possible; and clear instances of waste should be eliminated in the construction process (Han et al., 2007; Emuze et al., 2014).

1.3 Types of wastes in construction

In a lean production environment, the three broad types of waste are muri, mura and muda.

• Mura is unevenness/non-uniformity, which is variation in work output concerning volume and quality within a production system. Although mura itself is not waste, it leads to muri and muda.
• Muri is overburden, which is described as unreasonable demands on employees or processes, in the form of high workload or non-familiarity with the work to be done.
• Muda is a waste of resources in the form of non-value-adding activity and/or work that creates waste. Such activity contributes to variation in output, and can be controlled through process investigation and removal of root causes (Ohno, 1988).

In construction, Alarcon (1997) used the earlier work of Shingo (1981), which proposes the seven classic wastes, as a starting point. These wastes have informed subsequent classification of wastes in construction (see Table 1.1). It is, however, notable that Sutherland and Bennett (2007) observe that overproduction could be the worst waste among the classic wastes, because it means resources were spent to manufacture unnecessary products, and therefore contributing to the other six classic wastes. In contrast, Koskela et al. (2013: 7) contend that ‘overproduction is not a dominant waste in construction’. In fact, the classic wastes are context-specific to the manufacturing environment, and, as such, it is crucial to develop a list of wastes that are appropriate in construction (Koskela et al., 2013). This is necessary, as well-known wastes in construction, such as those arising from rework, design errors and omissions and work accidents, are not explicit in the classification of Shingo (1981). Making do, as a waste, has also been proposed in construction. Koskela (2004a) explains that making do occurs when a task has been started before all the preconditions for such an activity have been met. Making do occurs to keep capacity busy, although it usually has detrimental side-effects, such as an increase in work in process, a need for rework and creation of H&S hazards.

Table 1.1 Classification of waste in the production environment

Waste in manufacturing	Waste due to overproduction Waste due to stocktaking (taking inventory) Waste due to transportation Waste due to the system/processing itself Waste due to defective products Waste due to wait periods Waste due to movement
Waste in construction	Work not done Rework Unnecessary work Errors Stoppages Waste of materials Deterioration of materials Loss of labour Unnecessary movement of materials Excessive vigilance Extra supervision Additional space Delays in activities Extra processing Clarifications Abnormal wear and tear of equipment Making do

Sources: Alarcon (1997); Koskela (1992; 2004a)

The classification of wastes based on the transformation–flow–value (TFV) theory of production control is another contribution (Bolviken et al., 2014). Transformation-related waste results mainly in material loss; flow-related waste leads to time loss; and value-related waste leads to value loss (Bolviken et al., 2014) (see Table 1.2).

1.4 Identification of wastes in construction projects

Table 1.2 A taxonomy of the wastes in the construction production environment

Transformation-related waste	Flow-related waste	Value-related waste
Material waste	Unnecessary movement of people in the work flow	Lack of quality in the main product
Non-optimal use of materials	Unnecessary work in the work flow	Lack of intended use in the main product, which hinders value for the community as a client
Non-optimal use of machinery, energy or labour	Inefficient work in the work flow	Harmful emissions as a by-product
	Waiting in the work flow	Injuries and work-related sickness as a by-product, which hinders value for workers who constitute internal clients in a project
	Unused working space in the product flow
	Unprocessed materials in the product flow
	Unnecessary transportation of materials in the product flow

Source: adapted from Bolviken et al. (2014: 820).

Besides a context-specific list of wastes, a project-specific list of wastes can also be produced in order to address the context of a project. Alarcon (1997) proposes a cause–effect matrix that supervisors can use to address wastes on project sites. This matrix can be used by supervisors to capture the views of a project team concerning prevailing wastes, and their causes, on a site. A simple way of doing the work of the matrix is to use a form, such as that depicted in Table 1.3. The form has fields for ‘Task/activity’, ‘Location’, ‘Project’, and ‘Date of task’, so that background information can be obtained, which may be needed for a better understanding of a particular situation. The form also has a field for ‘Observed proceedings’, where proceedings can be recorded in the form of genchi genbutsu, which is one of the five principles of the ‘Toyota Way’, which enables the problem to be seen firsthand (Marksberry, 2011). In this case, going to the source to find the facts by ‘seeing for yourself’ is crucial for corrective decisions that are based on consensus in order to achieve predetermined goals. In other words, the observed proceedings should be based on firsthand knowledge of what has transpired on-site, since an attempt to understand another person’s account of the event is always vulnerable to either bias or incorrect interpretation. Observing proceedings assists the site manager or the supervisor to capture the immediate and the remote effects of events. An accurate assessment of actual waste can then be made based on the observed proceedings, and the associated deliberations among project actors. The cause of the waste can also then be discerned from the observations and the brainstorming session among the project actors concerned. The recorded causes of the waste, which must now be removed, should also assist the project team to reach consensus in terms of an intervention strategy.

The hypothetical example provided in Table 1.3 is with reference to the removal of formwork from already-cast columns, as the task that triggered the waste analysis procedure. In Table 1.3, the ‘Observed proceedings’ field indicates that the columns have voids, which are honeycombs that occur when the mortar has failed to effectively fill the spaces among coarse aggregate particles. While the main problem is concrete casting, the effect of the observed process will cost the contractor more money to fix, because voids are always structural defects that require repairs. Often this cost will end up being passed on to the client. Given that the columns may have to be demolished and recast, the waste that has occurred constitutes rework. One of the causes of the problem could be unworkability of the concrete, and segregation. Excessive bleeding due to loose joints in the formwork can also be a major contributing factor. In correcting the defect, the supervisors in the project would have to undertake the interventions proposed in Table 1.3.

The link between cost and waste in a construction production environment shows the importance of identifying wastes. A case study which used time study and work sampling to observe activities in a precast concrete factory in the USA shows that approximately 47 per cent of the activities conducted in a continuous two-hour period constituted non-value-adding activities (waste) (Nahmens and Mullens, 2011). The activities that made up the 47 per cent included getting tools and materials (25 per cent), rework (15 per cent) and several kinds of waiting periods (7 per cent). The researchers observed that once the activity had started, several issues necessitated flow interruptions. The issues pertained to poor access to materials and tools, rework, poorly defined process flows (sequencing) and supervision matters. Another study, which was conducted in Canada, indicates that many types of wastes can be found on a construction site (Song and Liang, 2011). For instance, Song and Liang (2011) report that a unique sloped-floor design necessitated chipping off of excessive height for about 30 per cent of the columns at the beginning of the project. The chipping-off exercise necessitated rework. Rework is a classic example of waste, in which both direct and indirect cost is significant (Love and Li, 2000; Love and Sohal, 2003). Even the indirect cost of rew...

Table of contents

• Cover
• Title
• Copyright
• Contents
• List of figures
• List of tables
• List of exhibits
• Notes on contributors
• Acknowledgements
• Introduction: goal of lean construction
• PART I Theory of waste in construction
• PART II Value in construction
• PART III Control of waste in construction
• Conclusions: concepts and new learning frontiers
• Glossary
• Index