the application of lean construction to reduce waste in construction flow process

The Application of Lean Construction to Reduce

Wastes in Construction Process Flow

by

TAN WEE LENG

Thesis submitted in fulfilment of

the requirements for the award of

the Degree of Master of Science (Project Management)

School of Housing, Building & Planning,

Universiti Sains Malaysia

2004

i

ACKNOWLEDGEMENT

I would like to express my greatest gratitude to my research supervisor Dr. Mohd Wira

Mohd Shafiei for his mentor and encouragement during the whole process of preparing

this thesis. I would like to thank my family and friends who were always there for me

whenever in needed the most. Special thank to my employer, Mr. Chew Hock Jin who

supported and tolerated me throughout my whole Master program in USM, to my sister

Lee Kheng who helped my in my SPSS analysis, and last but not least, to all the

respondents who took part in completing and returned the questionnaires for this

research.

Without all of you, this thesis would not be existed in the first place. Thanks a lot.

Regards,

Tan Wee Leng

April 2004

ii

ABSTRCT

There are a lot of non-value adding activities or wastes in construction practices and

many among those were left unnoticed or unattended. Previous studies have shown that

there were significant amounts of values loss due to construction process flow wastes

and tremendous productivity improvements can be achieved by simply targeting at

reducing or eliminating those wastes and/ or improve the process flow.

This thesis was conducted on the basis to study the waste concepts and the level of

“leanness” in local construction practices based on philosophies and principles drawn

by Lean Construction. A quantitative survey was carried out through structured

questionnaires over a randomly selected group of managerial personnel in construction

activities.

The results from the study show that the respondents have a relatively low recognition

over contributory time wastes group compared to direct conversion wastes group and

non-contributory time wastes group as categorised in the study. The correlation analyses

also show almost no significant inter-relationships between wastes recognition and

wastes controlled, wastes recognition and wastes occurrence frequencies, and wastes

controlled and wastes occurrence frequencies for those 3 waste categories (except 1

negative significant case are recorded on waste recognition vs. waste controlled for

contributory time wastes). This has suggested that a very high level of subjectivity

possessed by the respondents on recognising, controlling and witnessing the actual

occurrence of construction wastes where majority cases are recorded with non-

consistent pairs relationships. In this study, a cluster of waste cause variables have also

been examined against their likelihood to impact on the construction processes as well

as relating those variables directly to specific construction wastes. This will serve as a

good exercise to expose the root sources to particular construction wastes.

In conclusion, the outcomes of the research suggested that there still have rooms for

construction process improvements with the application of lean construction and proper

waste concepts instilled to all level of construction personnel and processes.

iii

CONTENT PAGE

pp.

Acknowledgement

i

Abstract

ii

Abstrak

ii (a)

Content Page

iii

List of Tables

vi

List of Figures

viii

List of Appendixes

x

1) Chapter 1: Introduction

1.1) Research background

1.2) Problem statement

1.3) Research aim

1.4) Research objectives

1.5) Research scopes

1.6) Research limitations

1.7) Research methodology

1.8) Research significance

1.9) Thesis structure

1.10) Summary

1

3

4

5

6

7

8

11

12

14

2) Chapter 2: The Problems in Construction and The Trends in

Improvement Strategies

2.1) Introduction

2.2) Problems in construction

2.3) Manufacturing as source of references and innovations

2.4) Emergency of new production philosophy in manufacturing

2.5) The concept of new production philosophy

2.6) The impacts of new production philosophy in construction

2.7) The impact of new production philosophy in Malaysia construction

industry

15

17

18

20

24

25

28

iv

pp.

3) Chapter 3: The Concepts of Production and The Principles Behind New

Production Philosophy

3.1) Introduction

3.2) The concept of production

3.2.1) Transformation concept

3.2.1.1) Core principle of transformation concept

3.2.1.2) Critiques on transformation concept

3.2.2) Flow concept

3.2.2.1) Core principle of flow concept

3.2.3) Value generation concept

3.3) Main ideas and techniques of new production philosophy

3.3.1) Just In Time (JIT)

3.3.2) Total Quality Control (TQC)

3.3.3) Other related concepts

3.4) Principles of new production philosophy

3.5) Flows in construction production

3.6) Challenges of implementing Lean Construction

31

31

32

32

34

35

36

37

40

40

41

42

45

57

59

4) Chapter 4: The Concepts of Waste and Modeling Construction Wastes

and Performances

4.1) Introduction

4.2) Construction waste in general

4.3) Waste and value loss in construction activities

4.3.1) Waste and value loss due to quality of works

4.3.2) Waste and value loss due to constructability

4.3.3) Waste and value loss due to material management

4.3.4) Waste and value loss due to non-productive time

4.3.5) Waste and value loss due to safety issues

4.4) New concept of waste in Production Activities

4.5) Underlying the waste concepts in construction

4.6) Waste classification

4.7) Key construction waste causes

4.8) Modeling waste and performance in construction

59

59

64

64

65

66

66

67

67

71

75

81

85

5) Chapter 5: Research Methodology

5.1) Introduction

5.2) Method of research

5.3) Profile of respondents

5.4) Structures of questionnaire

5.5) Score assignment

5.6) Analysis methods

90

90

95

96

97

98

v

pp.

6) Chapter 6: Data Analysis and Interpretation

6.1) Introduction

6.2) Descriptive analysis results

6.2.1) Respondents and their organisation’s background

6.2.1.1) Position of respondents

6.2.1.2) Nature of work of respondents

6.2.1.3) Main core construction projects involved by the

respondent’s organisation

6.2.1.4) CIDB registration grade of the respondent’s companies

6.2.1.5) Main project clients

6.2.2) Respondent’s waste perceptions and control actions

6.2.2.1) Analysis on direct conversion wastes

6.2.2.2) Analysis on non-contributory time wastes

6.2.2.3) Analysis on contributory time wastes

6.3) Inferential analysis results

6.3.1) Correlation among direct conversion wastes concepts and

perceptions, waste event control and frequencies of waste event

occurrences

6.3.2) Correlation among non-contributory time wastes concepts and


occurrences

6.3.3) Correlation among contributory time wastes concepts and


occurrences

6.3.4) Ranking on frequencies of occurrences for wastes exist in

construction processes

6.3.5) Ranking on likeliness for sources/ causes for the construction

wastes

6.4) Causes and Effects Matrix

103

103

105

106

107

107

108

109

110

110

117

124

131

131

133

135

137

139

141

7) Chapter 7: Conclusions and recommendations

7.1) Introduction

7.2) Discussion of the findings of the research

7.2.1) Relating the research findings to research objectives

7.2.2) Rewritten hypotheses and interpret the results

7.3) Limitations of the research

7.4) Challenges in implementing Lean Construction

145

145

145

149

153

154

Reference

xi

Appendices

xiv

vi

LIST OF TABLES

pp.

Table 1.1:

Breakdown of scopes covered in each phase of the

research

9

Table 1.2:

Contents summary for the chapters covered in this thesis 12

Table 2.1:

Waste in construction: Compilation of existing data 16

Table 2.2:

Context of manufacturing and construction production 19

Table 5.1:

Waste elements in 3 separate waste group 93

Table 5.2:

Waste causes factors group 94

Table 6.1:

Construction waste recognition under direct conversion

waste category

111

Table 6.2:

Construction waste control practices under direct

conversion waste category

113

Table 6.3:

Matrix table between waste concepts and control

practices for direct conversion wastes

115

Table 6.4:

Construction waste recognition under non-contributory

time waste category

118

Table 6.5:

Construction waste control practices under non-

contributory time waste category

120

Table 6.6: Matrix table between waste concepts and control

practices for non-contributory time wastes

122

Table 6.7: Construction waste recognition under contributory time

waste category

125

Table 6.8:

Construction waste control practices under contributory

time waste category

127

Table 6.9: Matrix table between waste concepts and control

practices for contributory time wastes

129

vii

pp.

Table 6.10:

Correlation Pearson-r results summaries for hypothesis 1,

2 and 3

132

Table 6.11:

Correlation Pearson-r results summaries for hypothesis 4,

5 and 6

134

Table 6.12: Correlation Pearson-r results summaries for hypothesis 7,

8 and 9

136

Table 6.13: Construction waste variables ranking

137

Table 6.14: Sources/ causes of construction waste ranking

139

viii

LIST OF FIGURES

pp.

Figure 1.1:

Research methodology flow chart

8

Figure 3.1:

Hierarchical decomposition of production process with

transformation concept

33

Figure 3.2:

Production as a flow process 37

Figure 3.3:

The conceptual scheme of a supplier-customer pair 38

Figure 3.4:

Simplified diagrams categorizing the principles of lean

production for production improvement

56

Figure 3.5:

The preconditions for a construction task 58

Figure 4.1:

Performance improvement in conventional, quality and

new production philosophy approaches.

69

Figure 4.2:

Koskela’s flow process model. 72

Figure 4.3:

Serpell’s Modeling of the construction process 72

Figure 4.4:

Categories of wastes of productive time 80

Figure 6.1:

Composition of respondent’s position 105

Figure 6.2:

Percentage of categorisation of respondent’s nature of

work

106

Figure 6.3: Composition of the main core construction projects by

the respondent’s company

107

Figure 6.4:

CIDB registration of the respondent’s company 108

Figure 6.5: Percentages of main project clients of the respondent’s

company

109

Figure 6.6: Breakdown of direct conversion waste recognition cases

112

Figure 6.7:

Breakdown of direct conversion waste event control

cases

114

ix

pp.

Figure 6.8:

Breakdown of non-contributory time waste recognition

cases

119

Figure 6.9: Breakdown of non-contributory time waste control

practice cases

121

Figure 6.10: Breakdown of contributory time waste recognition cases

126

Figure 6.11: Breakdown of contributory time waste control practice

cases

128

Figure 6.12: Percentage breakdown of the wastes recognition by

nature of work of the respondents

130

Figure 6.13: Causes and Effects relationship for the cases of major causes

(Categorised)

142

Figure 6.14: Causes and Effects relationship for the cases of others causes

(Categorised)

143

x

LIST OF APPENDICES

pp.

Appendix 1:

Correlation Pearson r results from SPSS 10.0

xiv

Appendix 2:

One way t-test results from SPSS 10.0 xv

Appendix 3:

SPSS data inputs sheets xvi

Appendix 4:

Causes and Effects matrix tables xxii

Appendix 5:

Sample of questionnaires xxiv

1

CHAPTER 1

INTRODUCTION

1.1 Research background

Construction is a key sector of the national economy for countries all around the world,

as traditionally it took up a big portion in nation’s total employment and its significant

contribution to a nation’s revenue as a whole. However, until today, construction

industries are still facing numbers of contingent problems that were bounded to be

resolved since the past time. The chronic problems of construction are well known such

as Low productivity, poor safety, inferior working conditions, and insufficient quality.

(Koskela, 1993) and the phenomenon of the poor performance and conditions in

construction had long been witnessed and recorded by academics and practitioners

throughout the world regardless in developed countries e.g. England (Eaton, 1994) or

in developing countries e.g. Chile. (Serpell et al., 1995)

Nowadays, increasing foreign competition, the scarcity of skilled labour and the need to

improve construction quality are the key challenges faced by the construction industry.

Responding to those challenges imposes an urgent demand to raise productivity, quality

and to incorporate new technologies to the industry. A lack of responsiveness can hold

back growth, and to development of the needed infrastructure for the construction

industry and other key activities in the country. (Alarcón, 1994)

2

Pertaining to the challenges faced by the construction industry, numerous researches

and studies had been carried out for the past decades to identify the causes to the

construction problems and some of them had went on to suggest and recommend

solutions to rectify those identified problems. The early phase of these studies mainly

focused on the “end” side of the construction process with the introduction of new

technologies and equipment to speed up the construction process and improve overall

productivity. It was only until late 1980s where a new construction improvement

movement was being initiated by looking into the “mean” side of the construction

process-related problems in a more holistic and structured way based on the philosophy

and ideology of lean production. With the lean construction paradigm, construction

industry had started to be reviewed and evaluated in the possibilities of implementing

these new lean perspectives of production concepts in the construction processes to

optimise the overall construction performance on construction stage as well as design

stage. However, in construction, there has been rather little interest in this new

production philosophy. (Alarcón, 1994) This matter laid on whether or not the new

production philosophy has implications for construction and will give any significant

impacts on the productivity improvement.

According to the scholars and researchers in Lean Construction, the new construction

production philosophy is laid on the concepts of conversion and flow process.

Therefore, performance improvement opportunities in construction can then be

addressed by adopting waste identification/ reduction strategies in the flow processes in

3

parallel with value adding strategies with the introduction of new management tools and

with proper trainings and education programs. Unfortunately, these new lean

construction concepts especially those on wastes and values most of the times are not

well understood by construction personnel. Particularly, waste is generally associated

with waste of materials in the construction processes while non-value adding activities

such as inspection, delays, transportation of materials and others are not recognised as

waste. (Alarcón, 1995) As the result of that, the productivity of construction industry

cannot be fully optimised due to the narrow interpretation on the concept of waste

current adopted. In this case, substantial education programs need to be arranged for all

related parties involved in order to implement the new process improvement strategies

successfully throughout the construction process cycle.

1.2 Problem statement

It is presumably that construction industries in Malaysia are facing the same generic

(process-related) problems/ wastes on construction activities which was also faced by

their counterparts regardless those in developed countries or developing countries.

However, the main problem in Malaysia (might be the same for most of other countries)

is the lack of clear indicators on quantitative parameters to assess the extent of those

problems/ wastes to have been impacted on the overall performance and productivity of

local construction industries. To date, there have not been many well-documented

quantitative studies and records on to process-related problems/ wastes which arisen on

construction site in Malaysia. As a result of that, the introduction of the concepts and

4

framework of new lean construction ideology are seen as an opportunity to address the

existing problems in local construction industry and utilising concepts and framework

of new lean construction ideology can then go further to formulate the extent of impacts

of those problems/ wastes on a more structured and quantitative basis.

Prior to assess the severity of the process-related problems/ wastes which existed in the

construction processes for the local construction industries, the differentiate of

traditional and new production/ construction concepts will have to be drawn prior to

further investigation and evaluation on any project performances. New measurement

parameters such as waste, value, cycle time or variability that was not covered under

traditional concepts are to be introduced into this study as accordance to the lean

construction ideologies and the subjects in this case; the local construction personnel

will be subsequently examined with those new parameters to review the level of

understanding and practicability in local construction industry compare to the

requirements and the concepts set forth by lean construction philosophy.

1.3 Research aim

This research is intended to verify and reevaluated the status of existing productivity

and performances on construction activities and processes for local construction

industries. This is meant to have a clearer picture on how “lean” is local construction

industry performed currently under the compilation of new measurement parameters on

5

particularly on waste and cycle time pertaining to the concepts and principles of Lean

Construction.

In line with this, this research will intend to reveal the perception of the local

contractors by seeing waste recognition and reduction as strategies in improving

construction productivity. This will be an important factor to be evaluated as the key

factors of the success for the practice of lean construction improvement strategies

mostly based on the mind set and readiness of the practitioners mainly personnel with

the leading role in the cycle of the construction projects to drive the whole program.

1.4 Research objectives

The research seeks to confirm four (4) objectives, which are:

1. Examine the general perceptions of the local construction industry with the lean

construction principles of practices.

2. Determine the degree of problems arisen from wastes identified in existing

scenario and practices in local construction industry.

3. Identify the source of wastes (classified under lean construction) and related

them to the waste identified in local construction industry.

4. Study the potential project productivity improvements by reducing and

eliminating the wastes as classified under lean construction.

6

1.5 Research scopes

The scopes of the research are as follows:

1. The area of this study is confined to the Peninsular of Malaysia excluding East

Malaysia.

2. The primary data will be collected through questionnaires mainly through postal

and electronic mailing to selective group of respondents (mainly site personnel

who has a leading role in the construction management e.g. project managers,

general managers, resident engineers, site managers, site engineers and

supervisors, etc) for the construction and consultant firms in the confined area of

study.

3. The conducted sample surveys are not to be considered as a specific case in

depth but to capture the main characteristics of the population using a fixed

sample. Thus, there will be no limitation imposed to the qualification level and

working experience of the respondents.

4. The primary data collection is conducted from XX th November 2003 until

XXth February 2003. The returned completed questionnaires that received

during the designated period will be analysed and the responses beyond this time

frame will be ignored.

7

1.6 Research limitations

There are certain limitations to this research as the writer wish to highlight as follow:

1. Research Validity

The study approach for this research is based on structured surveys to be carried

out based on postal and electronic mailing questionnaires. Therefore, the feedback

from the respondents will provide as a sole dependable source of result in

supporting the research finding. Field data collections for all the local construction

projects will very much help in verifying the feedback from the structured surveys

but due to time constraints and the insignificant of field data collections to support

the research finding, field data collections is discarded from the research design

and it is recommended that in the future, further studies on the field to be carried

out as a collective efforts to justify the finding of this research.

2. Research Reliability

As mentioned early, the concepts of lean construction are relatively new in

Malaysia, thus there might be little attention given by the local construction

industry to the area of parameters or variables need to be measured and evaluated.

This might affects the consistency of the results in the data measurement where

the subjectivity of answering from the respondents is required.

8

1.7 RESEARCH METHODOLOGY

FORMULATE PROBLEM

STATEMENT

RESEARCH

SCOPES

RESEARCH

OBJECTIVES

RESEARCH DESIGN

DATA COLLECTION &

PROCESSING

SECONDARY

DATA

PRIMARY

DATA

DATA ANALYSIS

CONCLUSION &

EVALUATION

First Stage

Second Stage

Third Stage

Fourth Stage

Fifth Stage

RESEARCH REPORT Sixth Stage

Figure 1.1

Research methodology flow chart

9

First Phase

q Formulation

Problem Statement

q In formulation of the problem statement for this

study, extensive preliminary literature studies are

required as the areas of study are relatively new in

Malaysia.

q The concepts of “Lean Construction” need to be

further explored and examined before forming the

research aims, objectives and scopes

q Sources of references will include journals,

technical reports, proceedings, publishing on the

Internet and books.

q The research aims, objectives and scopes will then

be established together with the discussion with

the supervisor in order to formulate the direction of

the research.

Second Phase

q Research Design

q A quantitative research approach will be adopted

for this study requiring the development and

dissemination of a questionnaire survey.

q A sample survey will be conducted through a

randomly selected subject group throughout

Peninsular Malaysia.

q Questionnaires are to be properly designed and

10

structured. The factors and variables to be outlined

and put into questions in a way that enable the

quantitative data collected later will then be able to

be tested according to pre-determined research

objectives.

Third Phase

q Data Collection &

Processing

q The methods of data collection to be adopted

includes:

a. Postal questionnaires

b. Email questionnaires

q The data collected will then be properly organised

prior to data analysis process

Fourth Phase

q Data Analysis

q Statistical analysis will be carried out on the data

collected via descriptive statistic and inference

statistic.

q The significant of the outlined factors and

variables to be analysis against the research

problem statement

q SPSS (Statistical tool) will be utilised to analysis

particular data to reach particular conclusion

11

Fifth Phase

q Conclusion &

Evaluation

q This phase will evaluate and conclude the results

from the data analysis and conclude by answering

the research objectives with the findings from the

data collected and analysed

q Attach with constructive recommendations for

further researches

Sixth Phase

q Research Report

q This will involved substantial submission of write

up, orgainising the data format and outline

q Constant discussion with the supervisor throughout

the write up processes, until the approval of draft,

Amendment draft and finally Final manuscript

Table 1.1

Breakdown of scopes covered in each phase of the research

1.8 Research significance

To the benefits of local construction practices, this research is set to be one of the

pioneer efforts of instill the lean construction philosophy and principles into the

practical application on local construction industry. Production weaknesses and

problems of the industry will be redefined and reassessed in order to reformat a new

strategy and plan for productivity improvement in the local construction practices.

12

Whereas academically, the compilation of this research was also intended to set up

some frameworks for quantitative measurement on the productivity performances and

wastes measurement for local construction industry and perhaps set ground for future

researches to refine or reengineer the construction processes and practices of the local

construction industry.

1.9 Thesis structure

CHAPTER BRIEF CONTENTS

CHAPTER 1

INTRODUCTION

This chapter covers the overall perspective for the research,

such as research background, problem statement, research

aims, objective, scope, methodology and limitation

The extensive literature review will be divided into three main chapter (chapter 2-4) as

follows:

CHAPTER 2

THE PROBLEMS IN

CONSTRUCTION AND

THE TRENDS IN

IMPROVEMENT

STRATEGIES

This chapter will focus on the following subjects:

q Examine the background of the problems existed in

current construction processes

q Study the trends of improvement strategies in

construction

q Study the emergency of new production philosophy

CHAPTER 3

THE CONCEPTS OF

PRODUCTION AND

THE PRINCIPLES

BEHIND NEW

PRODUCTION

PHILOSOPHY


q Theory of production and comparison of various types of

production philosophy

q Review the core of the lean ideology and the significant

benefit of lean production practices

q Review the challenges of implementing lean production

philosophy into construction industry

13

CHAPTER 4

THE CONCEPTS OF

WASTE AND NEW

TOOLS OF MODELING

CONSTRUCTION

WASTES AND

PERFORMANCES


q Study the definition, concept and classification of waste

based on lean construction

q Outline the wastes in construction practices

q Review some of the principles of construction process

improvement and models of waste as suggested by the

lean construction paradigm

CHAPTER 5

RESEARCH

METHODOLOGY

This chapter will focus on the questionnaire design e.g. the

formulation of the hypotheses and the ways those hypotheses

are to be tested with the factors and variables identified in

the questionnaire. A general overview on the statistical

concepts will be studied to ensure the data are analysed

accordingly and to generate the data outputs relevant to the

hypotheses formulated.

CHAPTER 6

DATA ANALYSIS AND

INTERPRETATION

This chapter processes, analyses and then interprets the result

collected from the field survey and to stand out the aims and

objectives for this research

CHAPTER 7

CONCLUSIONS AND

RECOMMENDATIONS

This chapter concludes the whole study based on the

findings. The tested hypotheses will be related to the

research objectives and further interpreted and conclusion on

the achievement of the research objectives will be drawn.

Some recommendations will also be drawn from the findings

and the limitation during the research period will also be

highlighted

Table 1.2

Contents summary for the chapters covered in this thesis

14

1.10 Summary

This research is conducted based on the criterions discussed above to reevaluated the

status of existing productivity & performances and the perception of waste concepts for

Malaysia construction industries based on lean construction concept and principles. The

further explanation of each of the subsequent chapters as summarised in Table 1.2 is

presented in the following chapters.

15

CHAPTER 2

THE PROBLEMS IN CONSTRUCTION AND THE TRENDS IN

IMPROVEMENT STRATEGIES

2.1 Introduction

Construction industries worldwide have become notorious for under-performance in

many aspects such as quality, safety, productivity and product delivery to planned

budgets, programmes and client satisfaction. According to Adrain (1987), the

construction industry in US has been rated among the worst industries in term of

productivity improvement for the period between 1970 to 1986. The rate of productivity

for US construction industry always performed lower than the annual total US

productivity between the period of 1970 to 1986 as reported by U.S. Department of

Commerce. Koskela (1993) also conducted a study to indicate the order of magnitude

of non value-adding activities (waste) on various partial studies carried out in Sweden

and US. From Koskela’s data compilation, it has shown that construction processes are

characterised by high content of non value-adding activities leading to low productivity

as shown in Table 2.1 below.

16

Waste Cost Country

Quality costs (non-conformance) 12% of total of project cost US

External quality cost (during facility use) 4% of total project costs Sweden

Lack of constructability 6-10% of total of project cost US

Poor materials management 10% &12% of total of project cost US

Excess consumption of materials on site 10% on average Sweden

Working time used for non-value adding

activities on site

Approx. 2/3 of total time US

Lack of safety 6% of total project cost. US

Table 2.1:

Waste in construction: Compilation of existing data (Koskela, 1992)

Previous studies in the UK, Scandinavian countries, and US also reflecting the same

scenario where the studies indicated up to 30% of construction is rework, only 40-60%

of potential labour efficiency, accidents can account for 3-6% of total costs, and at least

10% of materials are wasted (DETR, 1998). The cost of rework in Australian

construction projects has been reported as being up to 35% of total project costs and

contributes as much as 50% of a project's total overrun costs. In fact, rework is one of

the primary factors contributing to the Australian construction industry's poor

performance and productivity. (Love et al, 2003)

In general, a very high level of wastes/ non added value activities are assumed to exist

in construction and it is difficult to measure all waste in construction. Several partial

studies from various countries have confirmed that wastes in construction industry

represent a relatively large percentage of production cost. (Formosa, Carlos T et al,

2002). The existences of significant numbers of wastes in the construction have

depleted overall performance and productivity of the industry and certain serious

measures have to be taken to rectify the current situation.

17

2.2 Problems in construction

The chronic problems of construction are well known: low productivity, poor safety,

inferior working conditions, and insufficient quality. (Koskela, 1993) However, most of

the time, those critical problems of construction were left unattended because people of

the industry refrained to believe or accept that there is a solution to those problems.

According to Koskela (1992), the incapability to improve the productivity level of

construction projects is mainly perceived by people in the industry as due to its

peculiarities and special features: one-of-a-kind nature of projects, site production, and

temporary multi-organisation. Most people concluded that its fragmented nature, lack of

co-ordination and communication between parties, adversarial contractual relationships,

and lack of customer focus inhibit the industry's performance.

Unlike manufacturing activities where the production activities are fundamentally

governed and controlled under a rather routine process, construction activities are

subjected to relatively wide range of variables and wastes factors throughout its

information management and resource flow process as compared to manufacturing

activities. These variables and wastes generated in construction activities are mainly due

to its large fieldwork component, the provisional nature of some of its organisations,

and its intensive use of labour and non-stationary equipment and indeed, those

construction peculiarities and variables will restraint the efficiency of the construction

processes compared to those stationary & well-controlled manufacturing processes, but

all of those peculiarities and variables can be overcome with the application of new

18

flow design and improvements as well as new technologies adoption. (Alarcon, 1994)

Therefore, the organisation, planning, allocation and control of these resources,

processes and technologies are what finally determine the productivity that can be

achieved.

2.3 Manufacturing as source of references and innovations

Throughout the years, manufacturing has always been a reference point and a source of

innovations to construction. Several efforts had been made to transfer the successful

techniques and solutions from manufacturing process into construction in order to

relieve the problems in construction industry. Most of the early efforts involved new

technology and process adoption from manufacturing practices i.e. industrialisation,

prefabrication and modularisation (new process adoption) and computer integrated

construction and automated construction (new technology adoption). However, there

have been no signs of major improvements to construction has resulting from both

trends of process dissemination and solutions as quoted by Koskela (2000). The main

reasons behind the failure of achieving any major improvements from both trends are

mainly due to certain key features between manufacturing and construction.

A comparison with manufacturing shows the key features, which distinguishes

construction from manufacturing, is the extent of uncertainty evident throughout the

production phase as shown in Table 2.2

19

Start of manufacturing production Start of construction in the field What Highly defined Evolving as means refines ends

How Highly defined. Operations plan is in great

detail based on many trails.

Primary sequence of many tasks is

inflexible and the interdependencies are

documented and analyzed. Positions in

process determine required skills

Partly defined but details un-examined.

Extensive planning remains by hard logic

but may change. Interdependencies due to

conflicting measurements, shared

resources, and intermediate products only

partly understood. General craft skills to

be applied in a variety of positions

Assembly Objectives Produces one of a finite set of objects

where details of what and how are known

at the beginning of assembly

Make the only one. The details of what

and how are not completely known at the

beginning of assembly

Improvement Strategy Rapid learning during the first units

preparing for production line

Rapid learning during both planning and

early sub-assembly cycles

Table 2.2

Context of manufacturing and construction production

However, there was a new development trend based on a new production philosophy

derived from manufacturing was slowly caught the attentions of the academics and

practitioners in construction industry in late 1980’s. In the last three decades have seen

great improvements in performance in manufacturing. Lean industries now use less of

everything: Less on the manufacturing space, less on the human effort in factories, less

on the investment in tools and less on the product development time. In general,

significant improvements in all performance indicators have been observed

simultaneously in manufacturing industry. All these improvements have not been the

product of a radical or sharp change of technology but the result of the application of a

new production philosophy leading to “Lean Production”.

These new development trend stresses on the importance of basic theories and

principles related to production management and now, the same practices have been

progressively promoted as an ideal solution as improvement strategies for construction

industry especially in waste reduction and elimination strategies. Among the earliest

20

academics promoting the new production philosophy in construction industry included

Lauri Koskela and Luis F Alarcón. Koskela (1992) identified the overwhelming

dominance of conversion thinking in construction and argues for replacing conversion

model with a flow/ conversion model in order to reduce waste. Alarcon (1995) also

pointed out that performance improvement opportunities could be addressed by

adopting waste identification/ reduction strategies in parallel to value adding strategies.

In other words, identifying and measuring waste will served as an effective way to

assess the performance of any production systems because it will usually point out areas

of potential improvement and the main causes of inefficiency. Waste measures are more

effective to support process management, since they enable some operational costs to be

properly modeled and generate information that is usually meaningful for the

employees, creating conditions to implement decentralised control.

2.4 Emergency of new production philosophy in manufacturing

Traditional manufacturing production philosophy and practices from the earlier days of

industrialisation era never went beyond the concept of the overall production process to

be treated as a mean of transformation process only, and by ignoring the flow process

has limited the full potential of process improvement. In 1950’s, those traditional

manufacturing production system were set for a paradigm shift when Taiichi Ohno

(1912-1990), a former Toyota (a Japanese major car manufacturer) executive had set

out to develop a new production system called Toyota Production System. Ohno's

original ideas were based on the adoption of production strategies identified according

21

to the demand of the downstream production chain, part of a production plan that

ensured the planned pace was maintained throughout the production process.

The basic idea in the Toyota production system is the elimination of inventories and

other waste through small lot production, reduced set-up times, semiautonomous

machines, co-operation with suppliers, and other techniques and in other words, the idea

was to achieve a continuous production flow by adopting monitoring measures for each

process phase, aiming to reduce inventories. (Conte & Gransberg, 2001) The

production philosophy behind Toyota production system is called Just-In-Time

production (JIT) and throughout the years, it has remained among the core practices of

the new production philosophy. Big productivity gains from Just-In-Time production

(JIT) and later as lean production, had been reported from manufacturing since the end

of 1970’s (Koskela, 2000)

Simultaneously, quality issues were attended to by Japanese industry under the

guidance of American consultants like Deming, Juran and Feigenbaum. Quality

philosophy evolved from a statistical method of quality assurance to a wider approach,

including quality circles and other tools for company-wide development. These ideas

were developed and refined by industrial engineers in a long process of trial and error;

establishment of theoretical background and wider presentation of the approach was not

seen as necessary.

22

However, the ideas on new production philosophy was not widely spread around the

industry at the beginning stage, it only diffused to Europe and America starting in about

mid 1970, especially in the automobile industry. Since the end of 1970’s, a lot of new

approaches to production management have been introduced into manufacturing

industry i.e. JIT (Just-In-Time), TQM (Total Quality Management), Time Based

Competition, Value Based Management, and Concurrent Engineering. It turns out that

for all the production management mentioned above were having the same common

idea but only they were viewing it from more or less different angles.

In years, the general conception of the new production philosophy evolved through

three levels: it was viewed as a tool (e.g. kanban and quality circles), as a manufacturing

methodology (e.g. JIT and TQM) and as a general management philosophy (e.g. lean

production) (Koskela, 1993). This common idea shared by a conceptualisation of

production or operations in general; the different in view angle is determined by the

design and control principles emphasized by any particular approach. (Koskela, 1993)

For instance JIT stresses the elimination of wait times whereas TQM aims at the

elimination of errors and related rework but both apply under the same

conceptualisation of production and operation e.g. a flow of work, material or

information.

In the beginning of the 1990’s, the new production philosophy, which is known by

several different names (world class manufacturing, lean production, new production

system) is the emerging mainstream approach. It is practiced, at least partially, by major

23

manufacturing companies in America and Europe. The new approach has also diffused

to new fields, like customised production, services, administration, and product

development. In recent years, this new production philosophy has been disseminated

and diffused in other industries, and this includes the construction industry (Koskela

2000), in the meantime, the new production philosophy has been undergoing further

development, primarily in Japan.

The latest development on new production philosophy now is closely integrated with

the ideology of lean thinking aiming for a leaner production chain throughout every

stage of the processes. The term “lean” was first used by John Krafcik, who was a

master’s student at MIT in the mid-1980s and it refers to a general way of thinking and

specific practices that emphasize less of everything – fewer people, less time, lower cost

(Cusumano & Nobeoka, 1998). Womack and Jones, (1996) suggested that Lean

Thinking provides production processes a way of specify value, line up value-creating

actions in the best sequence, conduct these activities without interruption whenever

someone requests them, and perform them more and more effectively. Freeman (1999)

concurred that Lean Thinking is not just about cutting down wastes (wasted time,

wasted effort and wasted materials) but it is also about putting on value and it involves

focusing on the whole process; from the earliest design to final handover.

24

2.5 The concept of new production philosophy

The core of the new production philosophy is based on the conclusive understanding

that all production systems are constituted of 2 main activities: Conversions and Flows

(waiting, moving, and inspecting). In the new production paradigm, only conversion

activities add value to the final product whereas flow activities do not; value is

determined under the value stream of the customers with the satisfaction of their

requirements and cost paid on the final product. Therefore, the primary objectives for

process/ performance/ productivity improvement under the flagship of new production

philosophy should be targeted separately. That can be done through the improvement of

flow activities (through which the conversion activities are bound together) by primarily

focusing on reducing or eliminating them and on the other hand, conversion activities

should be focused on making them more efficient.

This has important implications for the design, control, and improvement of production

processes, because according to Koskela (1992), traditional production management

paradigm sees the whole process simply as a conversion of an input into an output that

can be divided into sub-processes, which are also conversion processes. All activities

have been treated as though they were value-adding conversions without separating

from the flow processes. This has led to complex, uncertain and confused flow

processes, expansion of non value-adding activities, and reduction of output value.

25

Based on the understanding of the production process can be consists of both

conversion and flow activities, a generic process improvement plan based on new

production philosophy can be derived from the study of Enton (1994) on lean

productivity of construction professions. The first step to implement process

improvement plan is by analysis and separation of conversions and flows activities. For

conversions activities identified, those activities should be channeled into the quality

cycles (Quality control, Quality assurance and Total Quality Management) to increase

efficiency of value added conversions. Whereas, for flow activities, the approach should

be consists of way of flows simplification (through Elimination, simplification and

automation) in order to reduce or eliminate non-value added flow activities.

2.6 The impacts of new production philosophy in construction

In recent years, application of new production philosophy in construction are getting

more and more popular especially in the developing countries i.e. US and Europe.

Koskela (1992) identifies the overwhelming dominance of conversion thinking in

construction and argues for replacing the conversion model with flow/conversion model

in order to reduce waste. This has inspired Gregory Howell, a civil engineer, and

Research Director Glen Ballard from Lean Construction Institute of Idaho began to

investigate the performance of project planning systems. They later espoused the

concept of "Lean Construction" by seeing a potential for applying the general principles

set by Lauri Koskela (a researcher with VT Building Technology in Espoo) into

construction. (Wright, 2000)

26

According to Lean Construction Institute, Lean Construction is a production

management-based approach to project delivery; a new way to design and build capital

facilities and it extends from the objectives of a lean production system; maximise value

and minimise waste and to specific techniques and applies them in a new project

delivery process. The application of lean production philosophy to construction – or

Lean Construction, as it has been called by a group of collaborating researchers since

1993 (Koskela, 2000). Since then, the enthusiasms over lean construction paradigm are

intensified and widely accepted practitioners and academics around the world under the

belief that the implementation of Lean Construction will dramatically improve

construction performance and labour productivity.

Nowadays in UK and US, Lean Construction philosophy and principles are gradually

being introduced into universities’ mostly at post-graduate level. A lot of researches and

case studies have already been carried out using lean construction theories and

principles to formulate models and frameworks by the mean to evaluate the

performance and productivity in various aspects of the construction industry. Flow

improvement concepts and waste reduction/ elimination still remained major focus

among those researches in which they are viewed as value enhancement to the whole

construction production processes.

The development in UK’s construction industry eventually went onto an even higher

level of implementation with the establishment a nationwide movement of “Rethinking

27

Construction”. The origins of Rethinking Construction lie in a landmark report

published in 1998 led by Sir John Egan. As a report, it set clear targets for

improvements in the construction industry in UK, supported the principles of Best

Value and built upon the work of the 1994 Latham report. It has now matured and is

becoming a positive force that will bring major change within the construction industry

in UK.

The essences of Egan Report are nominally based on Lean Construction principles with

the setting a number of year-on-year targets on the basis of promoting a continuous

improvement in productive processes through a reduction of “waste” (time, cost, rework

and accidents) and an increase in “value” (quality, improvements, finish products, etc)

as shown below:

1. Reduce costs – capital by 10%

2. Reduce time – construction by 10%

3. Improve predictability – time and cost by 20%

4. Reduce defects – at handover by 20%

5. Increase productivity – by 10%

6. Increase profit and turnover – by 10%

7. Reduce accidents – by 20%

28

One of the example that Egan report impacts on construction industry in UK was a

major shift to long-term partnering deals between architects and housing associations in

UK following Department of the Environment, Transport & the Regions edict that

social housing must be 100% Egan-compliant within four years periods. In the Housing

Corporation's guide to allocation, a timetable sets out that the proportion of

Corporation-funded building procured on Egan principles must be 10% in 2000/2001,

rising to 30% in 2001/2002, 60% in 2002/2003, and reaching 100% in 2003/2004. That

policy had forced the UK’s developing associations to a fast-track conversion of their

procurement policies.

This radical shift in social housing procurement would have fundamentally altered the

relationship between housing associations and architects in UK. Developing

associations now have the Egan targets: 10% annual reduction in the cost and time of

construction, a 20% increase in predictability, 20% reduction in defects and other

standards for improvement. In this way, many UK’s housing associations will have to

look for consultants who understand the design/build/project management process to

achieve it for them.

2.7 The impact of new production philosophy in Malaysia construction industry

There have not been any significant signs of positive impacts of the new production

philosophy in Malaysia construction industry either in national level or domestic level.

The problems in Malaysia construction industry are still at a very serious level. For

29

example in construction safety, Abdul Rashid Abdul Aziz and Abdul Aziz Hussin

(2003) has quoted on a recent construction safety study carried out in 2001. In their

paper quoted that “the awareness of safety procedures and laws to be low among site

operatives; both site operatives and main contractors exhibit apathy for safety; and

safety enforcement is weak”. These phenomena of construction safety in Malaysia are

also backed by the statistics on construction accidents rate published by from DOSH,

which is also referred in their paper. This is only one dimension of problems in

Malaysia construction industry and besides that, there was always news about delay on

construction projects and low quality of project execution and delivery regardless

private or public projects.

Academically, lean construction are not being considered as a main source of research

direction in Malaysia, which is very much unlike countries like United Kingdom and

United States where they have post-graduate studies specially focus on the research of

lean construction. Literally, there were too few literature studies available under this

research topic locally although some partial studies on material wastes only but not

looking into the aspects of the construction process as a whole.

Institutionally, we have yet to witness any radical movements being planned towards

achieving leaner and more efficient construction industries as a whole as such as what

had been drafted in United Kingdom. This idea requires a throughout commitment and

understanding over the entire construction industries in order to achieve those goals and

the improvement over performance will be very significant.

30

Overall, the impacts of new production philosophy to local construction industries are

still considered minimal and so in reverse the potential of improvement in this field is

vast. Therefore, local construction industries need to be more aware of the new

concepts, principles, tools and instruments behind this new lean construction

philosophy. This is important efficient in order to make the local construction practices

leaner, more effective and able to sustain their competitiveness edges over other

compatriots in the industries inside or outside Malaysia.

31

CHAPTER 3

THE CONCEPTS OF PRODUCTION AND THE PRINCIPLES BEHIND NEW

PRODUCTION PHILOSOPHY

3.1 Introduction

When we start to discuss about new production philosophy, lean production or even

lean construction and their impacts on the production system, apparently, this would

signify that the existing conventional production philosophy or concepts inherited

numbers of deficiencies or problems which need to be rectified or overcome.

In this chapter, new production philosophy or lean production is to be examined in

detail on various perspectives starting on the conceptual of production into the

derivation of main and related ideas and techniques in new production philosophy,

compressing the principles behind the new production philosophy and finally the

practical implementation of new production philosophy in actual construction practices.

3.2 The concept of production

A historical analysis carried out by Koskela (2000) has revealed that there are three

concepts of production where the conceptualisation of production can be grouped based

32

on the generation of transformation-flow-value model of production theory or simply as

TFV model.

3.2.1. Transformation concept

Since the beginning of the 20th

century, transformation concept has been the

dominant theory of production, both in practice and research where production

is conceptualised as a process of transformation or “a transformation of inputs

to outputs”. Production management equates to decomposing the total

transformation into elementary transformations and tasks, acquiring the inputs to

these tasks with minimal cost and carrying out the tasks as efficiently as

possible.

3.2.1.1 Core principle of transformation concept

The first core principle which has been used in conjunction with transformation

concept stated that: The transformation process can be decomposed into sub-

processes, which also are transformation process as reflected in Figure 3.1, of

breaking up the total transformation (production process) into much smaller and

more manageable transformations and eventually can be further breakdown into

individual continual tasks.

33

Figure 3.1

Hierarchical decomposition of production process with transformation concept

The second core principle of the transformation model is a general acceptance of

independency principle that the cost of the total process can be minimised

through minimising the cost of each sub-process. The key issue pertaining to

this principle leads to the assumption that every sub-processes of a total process

are independent from each other and therefore cost minimisation can be applied

through focus on cost management in each operation, sub-process or

department.

The third core principle formulated currently recommended that It is

advantageous to insulate the production process from the external environment

through physical or organisational buffering. This principle is related to the

independence assumption from the second core principle as discussed above and

Production

Process

Subprocess

A

Subprocess

B

Material,

Labours Products

Source: Koskela, Lauri (2000). An Exploration towards a production theory and its application to construction

34

it reflects that the transformation process that is most important, and it is thus a

requisite to shield it from the erratic conditions in the environment.

3.2.1.2 Critiques on transformation concept

Transformation concept is conventionally wide-accepted in term of production

theory and practical was mainly due to its sufficient power to model reality, and

excellent power of various tools derived from it to analysis and control production

in an easy and simple way. However, its oversimplification in theory formulation by

considering all processes are transformation activities tends to undermine the full

optimum of efficiency and productivity for the production process. Below are some

of the critiques as cited by Koskela (2000):

1. By focusing on conversions, the model abstracts away physical flows between

conversions. These flows consist of moving, waiting and inspecting activities. In

a way, this is a correct idealisation; from the customer point of view these

activities are not needed since they do not add value to the end product.

However, in practice, the model has been interpreted so that

a) These non value-adding activities can be left out of consideration or

b) All activities are conversion activities, and are therefore treated as value-

adding.

35

2. The output of each conversion is usually variable, to such an extent that a share

of the output does not fulfill the implicit or explicit specification for that

conversion and has to be scrapped or reworked

3. The specification for each conversion is imperfect; it only partially reflects the

true requirements of the subsequent conversions and the final customer.

3.2.2. Flow Concept

The flow view of production, firstly proposed by the Gilbreths (1922) in

scientific terms, has provided the basis for JIT and lean production. This view

was firstly translated into practice by Ford (1926); however, the template

provided by Ford was in this regard misunderstood, and only from 1940’s

onwards the flow view of production was properly developed in Japan, first as

part of war production and then at Toyota. As a result, the flow view is

embodied in JIT and lean production and the triumph of the JIT and lean

production has practically proven the power of this conception.

The new production concept of flow was emerged apparently from the

erroneous view of decomposition in the transformation model of production that

is the intervals between transformations, which happen to be non-

transformations activities. In flow concept, production is viewed as a flow,

where, in addition to transformation, there are waiting, inspection and moving

stages. Production management equates to minimising the share of non-

36

transformation stages of the production flow, especially by reducing variability.

In this context, flow model is looking beyond transformation model by taking

non-transformations activities into consideration as to improve overall flow

efficiency.

3.2.2.1 Core principle of flow concept

The first core principle of this flow concept is the introduction of time as an

input (or resource) in production and therefore the main focus is in the amount

of time consumed by the total transformation and its parts by aiming for the

production improvement at shortening of the total time of production. With the

introduction of time also implies that production has to be conceived as a

physical process and not only as an economic abstraction in cost terms.

The second core principle of the flow concept is that time is consumed by two

types of activities in the overall production flow which are transformation

activities and non-transformation activities. Gilbert (1922) categorised the non-

transformation activities as transfer, delay and inspection as showed in Figure

3.2 and it is obvious that these non-transformation activities are unnecessary and

the less of them is better and best if there are none of them.

37

Figure 3.2

Production as a flow process

There are 3 main principles in production system design, control and

improvement utilising flow concepts as shown below and they are seen to be

centering over a common basic goal, which is eliminate waste from flow

process.

1. The first principle is to reduce the share of non-value-adding activities

(waste),

2. The second principle is to reduce lead time and variability

3. The third principle provides practical ways in implementation such as

simplify by minimising the number of steps, parts and linkages, increase

flexibility and increase transparency.

3.2.3 Value Generation Concept

The value generation view was initiated by Shewhart (1931) and further refined

in the framework of the quality movement but also in other circles. The value

Moving Waiting Processing A Inspection Moving Waiting Processing B Inspection

Scrap Scrap


38

generation concept are formulated not a same as transformation and flow

concept by incorporating customer as the ultimate value determinate to the

production and argued that the goal of production is to satisfy customer needs.

In this case, value generation concept covers external needs and to ensure the

internal physical process can generate appropriate values to the customer/ end-

user. Figure 3.3 will illustrate the conceptual scheme of a supplier-customer

pair and introduces the customer and product with its features. It is clear from

the framework that it is not the transformation itself that is valuable, but the fact

that the output corresponds to the requirements, wishes, etc of the customer

which is valuable instead.

Figure 3.3 The conceptual scheme of a supplier-customer pair

This third concept of value generation concept views production as a means for

the fulfillment of customer needs. Production management equates to translating

these needs accurately into a design solution, and then producing products that

conform to the specified design. It focus on control of the transformation and

flow, namely control for the sake of the customer and it is important to highlight

Supplier Customer

Requirements,

expectations

Value through

products and

services


39

that the value generation concept does not focus on any particular aspect of

physical production like transformation and flow model do but rather on its

control in securing value generated for the customer.

In this circumstances, conventional production philosophy would referred to production

system is merely based on transformation concepts while new production philosophy

would engulf both flow concepts and value generation concepts in the development of

production system. The most significant differences between conventional and the new

production philosophy can be discussed in two areas: conceptualisation of production

and focus of improvement. For conventional production philosophy, production is

perceived as consists of conversions only with all the activities in the processes are

regarded as value adding, and the focus of process improvement only will happen by

implementing new technology into the activities.

Whereas for new production philosophy, production is perceived as consists of

conversions and flows where activities in the processes can be divided into value adding

and non-value adding activities, therefore the focus of process improvement can be

broken down into 2 separated areas which are the elimination or reduction for non-value

adding activities and the increase of process efficiency for value adding activities

through continuous improvement and new technology.

40

3.3 Main ideas and techniques of new production philosophy

Several factors make it difficult to present a coherent overview of the ideas and

techniques of the new production philosophy. This is because this field is still relative

young and in constant evolution where new concepts emerge and the content of old

concepts change. The same concept is used to refer to a phenomenon on several levels

of abstraction. It is not clear where to place the boundaries between related concepts.

However, the overview over two historically important “root” terms, Just In Time (JIT)

and Total Quality Control (TQC) can help to enhance the understanding of the basic

concepts for new production philosophy, while other related newer concepts, which are

primarily outgrowths of JIT and TQC. These outgrowths show that the field of

application of the original ideas has extended far beyond the production sphere.

3.3.1 Just In Time (JIT)

The starting point of the new production philosophy was in industrial engineering

oriented developments initiated by Ohno and Shingo at Toyota car factories in the

1950’s. The driving idea in the approach was reduction or elimination of inventories

(work in progress). This, in turn, led to other techniques that were forced responses to

coping with fewer inventories: lot size reduction, layout reconfiguration, supplier co-

operation, and set-up time reduction. The pull type production control method, where

production is initiated by actual demand rather than by plans based on forecasts, was

introduced.

41

The concept of waste is one cornerstone of JIT. The following 7 wastes were recognised

by Shingo as (1) Overproduction, (2) Waiting, (3) Transporting, (4) Too much

machining (overprocessing), (5) Inventories, (6) Moving, (7) Making defective parts

and products. Elimination of waste through continuous improvement of operations,

equipment and processes is another cornerstone of JIT.

3.3.2 Total Quality Control (TQC)

The starting point of the quality movement was the inspection of raw materials and

products using statistical methods. The quality movement in Japan has evolved from

mere inspection of products to total quality control. The term total refers to three

extensions:

1. Expanding quality control from production to all departments,

2. Expanding quality control from workers to management, and

3. Expanding the notion of quality to cover all operations in the company.

The quality methodologies have developed in correspondence with the evolution of the

concept of quality. The focus has changed from an inspection orientation (sampling

theory), through process control (statistical process control and the old seven tools -

Fishbone Diagram, Control Chart, Pareto Chart, Run Graphs, Histogram, Flow charts or Check sheets &

Correlation Diagram), to continuous process improvement (the new seven tools - Affinity

Diagram, Interrelationship Diagraph, Tree Diagram, Matrix Diagram, Prioritisation Grid, Process

42

Decision Programme Chart & Activity Network Diagram), and presently to designing quality into

the product and process (Quality Function Deployment).

3.3.3 Other related concepts

Many new concepts have surfaced from JIT and TQC efforts. These have been rapidly

elaborated and extended, starting a life of their own. Several of these concepts are

described below.

1. Total Productive Maintenance (TPM)

Total Productive Maintenance is a comprehensive program to maximise

equipment availability in which production operators are trained to perform

routine maintenance tasks on a regular basis, while technicians and engineers

handle more specialised tasks. The scope of TPM programs includes

maintenance prevention (through design or selection of easy-to-service

equipment), equipment improvements, preventive maintenance, and predictive

maintenance (determining when to replace components before they fail).

TPM tackles the "six big losses" and is closely tied to the practices of 5S, the six

big losses are:

1. Breakdown losses

2. Setup & Adjustment losses

3. Idling & minor stoppages

43

4. Reduced speed losses

5. Start up losses

6. Quality defects

2. Concurrent engineering

Concurrent engineering is a cross-functional, team-based approach in which the

product and the production process are designed and configured within the same

time frame, rather than sequentially. Ease and cost of constructability, as well as

customer needs, quality issues, and product life cycle costs are taken into

account earlier in the development cycle.

The main ideas about concurrent engineering is to achieve an improved design

process characterized by rigorous up-front requirements analysis, incorporating

the constraints of subsequent phases into the conceptual phase, and tightening of

change control towards the end of the design process.

3. Continuous improvement

Continuous improvement is a never-ending effort to expose and eliminate root

causes of problems; small-step improvement as opposed to big-step or radical

improvement. A Continuous Improvement strategy involves everyone from the

44

very bottom to the very top, the basic premise being that small regular

improvements leads to a significant positive improvement over time.

The main goal of the continuous improvements is to affect the mindset as well

as achieve the improvements of the techniques. In this case, everyone pitches in

and receives training in the appropriate skills; responsible for their own efforts,

areas and progress of their teams and the employees will continuously suggest

improvements to meet quality, cost and delivery target improvements. The key

idea of continuous improvement is to maintain and improve the working

standards through small, gradual improvements.

4. Visual management

Visual management is an orientation towards visual control in production,

quality and workplace organisation. The core principal of visual management is

the ability to understand that, with a quick look at the shop floor what orders are

being done, if production is ahead, on par or behind and what needs to be done

next. No orders are missed or lost and every one knows if they are behind or

ahead on the day’s production. Shop floor staff will take on more self-managing

responsibility with this method as day-to-day decisions are handled on the shop

floor.

45

Generally this method is implemented on large boards next to particular areas on

the shop floor, and as much information is shared as is feasible, ranging from

maintenance to production targets and production output to injuries.

5. Re-engineering

Re-engineering is the radical reconfiguration of processes and tasks, especially

with respect to implementation of information technology. The key issue in re-

engineering is in recognising and breaking away from outdated rules and

fundamental assumptions in order to establish a radical change to the processes

and tasks for improvement.

6. Value based strategy (or management)

Value based strategy (or management) is a customer-oriented, in contrast to

competitor-oriented approach toward overall production process. It is a

continuous improvement to increase customer by conceptualizing and

articulating value as the basis for competing.

3.4 Principles of new production philosophy

In various subfields of the new production philosophy, a number of heuristic principles

for flow process design, control and improvement have evolved. According to Koskela

46

(1993), there was ample evidence that through these principles, the efficiency of flow

processes in production activities can be considerably and rapidly improved.

Many of those principles are closely related, but not on the same abstraction level.

Some are more fundamental, while others more application oriented. It is also important

to note that the understanding of these principles is of very recent origin. It is presumed

that knowledge of these principles will rapidly grow and be systematised. The

principles of new production were further breakdown as follows (Koskela, 1992)

1. Reduce the share of non value-adding activities

Reducing the share of non value-adding activities is regarded as the most fundamental

principle of new production philosophy or lean production where it is the center of idea

for new production philosophy, which differentiates it from conventional production

thinking.

There are 3 main sources of non value-adding activities:

1. Non value-adding activities exist by design in hierarchical organisations. Every

time a task is divided into two subtasks executed by different specialists, non

value-adding activities increase: inspecting, moving and waiting. In this way,

traditional organisational design contributes to an expansion of non value-

adding activities.

47

2. Ignorance is another source of non value-adding activities. Especially in the

administrative sphere of production, many processes have not been designed in

an orderly fashion, but instead just evolved in an ad hoc fashion to their present

form. The volume of non value-adding activities is not measured, so there is no

drive to curb them.

3. Non value-adding activities exist also due to the nature of the production: work-

in-process has to be moved from one conversion to the next, defects emerge,

accidents happen.

With respect to all three causes for non value-adding activities, it is possible to

eliminate or reduce the amount of these activities. However, this principle cannot be

used simplistically. This is because some of the non value-adding activities produce

value for internal customers, like planning, accounting and accident prevention. Such

activities should not be suppressed without considering whether more non value-adding

activities would result in other parts of the process. However, accidents and defects, for

example, have no value to anybody and should be eliminated without any hesitation.

Most of the principles presented below address suppression of non value-adding

activities. However, it is possible to directly attack the most visible waste just by

flowcharting the process, then pinpointing and measuring non value-adding activities.

2. Increase output value through systematic consideration of customer

requirements

48

This is another fundamental principle. Value is generated through fulfilling customer

requirements, not as an inherent merit of conversion. The organisational and control

principles of the conventional production philosophy have tended to diminish the role of

customer requirements. In many processes, customers have never been identified nor

their requirements clarified. The dominant control principle has been to minimise costs

in each stage; this has not allowed for optimisation of cross-functional flows in the

organisation.

The practical approach to this principle is to carry out a systematic flow design, where

customers are defined for each stage, and their requirements analysed. Other principles,

especially enhanced transparency and continuous improvement, also contribute to this

principle.

3. Reduce variability

Production processes are variable. There are differences in any two items, even though

they are the same product, and the resources needed to produce them (time, raw

material, labor) vary from time to time. From the customer point of view a uniform

product is better. Thus, reduction of variability should go beyond mere conformance to

given specifications and reduction of variability within processes must be considered an

intrinsic goal.

49

The practical approach to decreasing variability is made up of the well-known

procedures of statistical control theory. Essentially, they deal with measuring

variability, then finding and eliminating its root causes. Standardisation of activities by

implementing standard procedures is often the means to reduce variability in both

conversion and flow processes. Another method is to install fool-proofing devices

(“poka-yoke”) into the process as been introduced by Shingo in Toyota Production

System.

4. Reduce the cycle time

Time is a natural metric for flow processes and it can be used to drive improvements in

both cost and quality. A production flow can be characterised by the cycle time, which

refers to the time required for a particular piece of material to traverse the flow.

The basic improvement rationale in the new production philosophy is to compress the

cycle time, which forces the reduction of inspection, move and wait time. In addition to

the forced elimination of wastes, compression of the total cycle time also provides faster

delivery to the customer, reduced need to make forecasts about future demand, decrease

of disruption of the production process due to change orders and establish easier

management because there are fewer customer orders to keep track of.

Practical approaches to cycle time reduction include the following:

50

1. Eliminating work-in-progress (this original JIT goal reduces the waiting time

and thus the cycle time)

2. Reducing batch sizes

3. Changing plant layout so that moving distances are minimised

4. Keeping things moving; smoothing and synchronising the flows

5. Reducing variability

6. Changing activities from sequential order to parallel order

7. Isolating the main value-adding sequence from support work

8. Decrease organisational layers and empowering the persons working directly

within the flow

In general, solving the control problems and constraints preventing a speedy flow.

5. Simplify by minimising the number of steps and parts

One fundamental problem of complexity is extra cost incurred. If other things are being

equal, the very complexity of a product or process increases the costs beyond the sum of

the costs of individual parts or steps. Another fundamental problem of complexity is

reliability: complex systems are inherently less reliable than simple systems.

Furthermore, the human ability to deal with complexity is bounded and easily exceeded.

Simplification can be understood as

1. Reducing of the number of components in a product

51

2. Reducing of the number of steps in a material or information flow

Simplification can be realised, on the one hand, by eliminating non value-adding

activities from the production process, and on the other hand by reconfiguring value-

adding parts or steps. Organisational changes can also bring about simplification.

Vertical and horizontal division of labor always brings about non value-adding

activities, which can be eliminated through self-contained units (multi-skilled,

autonomous teams).

Practical approaches to simplification include:

1. Shortening the flows by consolidating activities

2. Reducing the part count of products through design changes or prefabricated

parts

3. Standardising parts, materials, tools, etc.

4. Decoupling linkages

5. Minimising the amount of control information needed.

6. Increase output flexibility

At first glance, increase of output flexibility seems to be contradictory to simplification.

However, according to some studies, many companies have succeeded in realising both

goals simultaneously. Some of the key elements are modularised product design in

connection with an aggressive use of the other principles, especially cycle time

compression and transparency.

52

Practical approaches to increased flexibility include:

1. Minimising lot sizes to closely match demand

2. Reducing the difficulty of setups and changeovers

3. Customising as late in the process as possible

4. Training a multi-skilled workforce.

7. Increase process transparency

Lack of process transparency increases the propensity to err, reduces the visibility of

errors, and diminishes motivation for improvement. Thus, it is an objective to make the

production process transparent and observable for facilitation of control and

improvement. The goal to achieve process transparency is to substitute self-control for

formal control and related information gathering and this can be achieved by making

the process directly observable through organisational or physical means,

measurements, and public display of information.

Practical approaches for enhanced transparency include the following:

1. Establishing basic housekeeping to eliminate clutter: the method of 5-S (Sort, Set,

Shine, Standardise, Sustain)

2. Making the process directly observable through appropriate layout and signage

3. Rendering invisible attributes of the process visible through measurements

53

4. Embodying process information in work areas, tools, containers, materials and

information systems

5. Utilising visual controls to enable any person to immediately recognise

standards and deviations from them

6. Reducing the interdependence of production units (focused factories).

8. Focus control on the complete process

There are two causes of segmented flow control: the flow traverses different units in a

hierarchical organisation or crosses through an organisational border. In both cases,

there is a risk of suboptimisation.

There are at least two prerequisites for focusing control on complete processes. First,

the complete process has to be measured and secondly, there must a controlling

authority for the complete process. Several alternatives are currently used. In

hierarchical organisations, process owners for cross-functional processes are appointed,

with responsibility for the efficiency and effectiveness of that process. A more radical

solution is to let self-directed teams control their processes. For inter-organizational

flows, long-term co-operation with suppliers and team building have been introduced

with the goal of deriving mutual benefits from an optimised total flow.

54

9. Build continuous improvement into the process

The effort to reduce waste and to increase value is an internal, incremental, and iterative

activity that can and must be carried out continuously. There are several necessary

methods for institutionalising continuous improvement:

1. Measuring and monitoring improvement.

2. Setting stretch targets (e.g. for inventory elimination or cycle time reduction), by

means of which problems are unearthed and their solutions are stimulated

3. Giving responsibility for improvement to all employees; a steady improvement

from every organisational unit should be required and rewarded.

4. Using standard procedures as hypotheses of best practice, to be constantly

challenged by better ways.

5. Linking improvement to control: improvement should be aimed at the current

control constraints and problems of the process. The goal is to eliminate the root

of problems rather than to cope with their effects.

10. Balance flow improvement with conversion improvement

In a situation where flows have been neglected for decades, the potential for flow

improvement is usually higher than conversion improvement. On the other hand, flow

improvement can be started with smaller investments, but usually requires a longer time

than a conversion improvement.

55

The crucial issue is that flow improvement and conversion improvement are intimately

interconnected as better flows require less conversion capacity and thus less equipment

investment and vice verse more controlled flows make implementation of new

conversion technology easier. However, it is often worthwhile to aggressively pursue

flow process improvement before major investments in new conversion technology.

Later, technology investments may be aimed at flow improvement or redesign.

11. Benchmark

Unlike technology for conversions, the best flow processes are not marketed to us; we

have to find the world class processes ourselves. Often benchmarking is a useful

stimulus to achieve breakthrough improvement through radical reconfiguration of

processes and by means of it, fundamental logical flaws in the processes may be

unearthed.

The basic steps of benchmarking include the following:

1. Knowing the process; assessing the strengths and weaknesses of subprocesses

2. Knowing the industry leaders or competitors; finding, understanding and

comparing the best practices

3. Incorporating the best; copying, modifying or incorporating the best practices in

your own subprocesses

4. Gaining superiority by combining existing strengths and the best external

practices.

56

In summary, we can see that these principles of new production philosophy or more

precisely lean philosophy are mainly revolving around improvement over flows of the

processes. There is not much concern about the transformation or conversion concepts

while the concepts of value are rather integrated into enhancing value to flows activities

and not so much on the value of the products itself. The dimensions of the principles

can be further grouped into three ideas for flows improvement that are flow

compression, flow dynamic and flexibility and flow stability and control. Figure 3.4

simplified the principles of lean production for production improvement

Figure 3.4

Simplified diagrams categorizing the principles of lean production for production improvement

Flow Compression

q Reduce share of non

value-adding

activities

q Reduce variability q Reduce the cycle

time

q Simplify by

minimising the

number of steps and

parts

Flow Dynamic & Flexibility

q Increase output

value

q Increase output

flexibility

q Increase process

transparency

q Benchmarking

Flow Stability & Control

q Focus control on the

complete process

q Build continuous

improvement into

the process

q Balance flow

improvement with

conversion

improvement

Principles of lean production for production improvement

57

3.5 Flows in construction production

The production in construction is of assembly-type, where different material flows are

connected to the end product. In construction, there are 3 types of flows as suggested by

Koskela (2000): material flow (the transportation of components to the site for

particular installation), location flow (e.g. one particular trade goes through the different

part of the building or construction site to get their work done) and assembly flow (e.g.

the sequential of works of assembly and installation).

There are at least seven resource flows (or preconditions) that unite to generate the

construction task as illustrated In Figure 3.5 below. Many of these resource flows are of

relatively high variability, and thus the probability of a missing input is considerable.

For example, it is not uncommon that detailed drawings are still lacking at the intended

start of the work. Latent errors in drawings will emerge as problems during construction

on site. External conditions also form one specific source of variability. The

productivity of manual labour is inherently variable, and the availability of space and

connecting works is dependent on the progress of tasks of previous trades, thus bound

to be variable. Thus, in comparison to the typical manufacturing. Construction

productions are subjected to more sources of variability and the insight gained is that

construction consists of assembly tasks involving a high number of input flows.

Planning and controlling production becomes very important and tasks and flows have

to be considered in parallel in production management because: “realization of tasks

58

heavily depends on flows, and progress of flows in turn is dependent on realization of

task” (Koskela, 2000)

Figure 3.5 The preconditions for a construction task (Koskela, 2000)

In construction actually it is the installation team that moves from location to location.

This leads to another important feature of construction. In factory production, one part

can physically be only at one workstation at any one time. However, in construction,

several work units or trades can work on one part (e.g. a room) simultaneously at the

same time with lessened productivity due to interference and congestion of space of

operation. Thus, this phenomenon of congestion has a more dramatic influence on

construction productivity especially at workstation congestion and not so much of part

congestion, which is common in manufacturing.

Construction design

Components and materials

Workers

Equipment

Task

External conditions

Space

Connecting works

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CHAPTER 4

THE CONCEPTS OF WASTE AND MODELING CONSTRUCTION WASTES

AND PERFORMANCES

4.1 Introduction

In general, in lean production and lean construction paradigm sees that all those

activities that produce cost, direct or indirect, but do not add value or progress to the

product can be called waste. Waste is measured in terms of costs, including opportunity

costs. Other types of waste are related to the efficiency of the processes, equipment or

personnel and are more difficult to measure because the optimal efficiency is not always

known.

In this chapter, we will look into the definition, concept and classification of waste

based on new production philosophy and lean construction and outline the different

researches on wastes in construction practices and review some of the principles of

construction process improvement and some models of wastes and performance in

construction as suggested by the lean construction paradigm.

4.2 Construction waste in general

Waste in the construction industry has been the subject of several research projects

around the world in recent years. However, Most studies tend to focus on the waste of

materials, which is only one of the resources involved in the construction process. This

60

seems to be related to the fact that most studies are based on the conversion model, in

which material losses are considered to be synonymous of waste. Formosa, et al (2002)

stated that many people in the industry have considered waste are directly associated

with the debris removed from the site and disposed of in landfills and they suggested

that the main reason for this relatively narrow view of waste is perhaps the fact that it is

relatively easy to see and measure. The main focus for those conventional material

waste studies in construction are seen to be restricted to physical waste or material

waste in construction and/ or the specific impacts due to the physical waste itself.

Formoso, et al. (1999) in their earlier research paper entitled “Method for Waste

Control in Building Industry” had significantly grouped some researches and studies

done by other researchers around the world on the wastes in construction into 2 main

aspects based on the impacts of the construction waste:

1. Researches and studies mostly focused on the impacts on environmental

damage that result from the generation of material waste. For example:

a) The research on construction waste conducted by The Hong Kong

Polytechnic and the Hong Kong Construction Association Ltd. In year 1993

aimed to reduce the generation of waste at source, and to proposed

alternative methods for treatment of construction waste in order to reduce

the demand for final disposal areas.

b) The research project conducted by Brossik and Brouwers in The Netherlands

year 1996, concerned with the measurement and prevention of construction

61

waste, regarding sustainability requirements stated by Dutch environmental

policies.

2. Researches and studies mostly concerned with the economic impacts of waste in

the construction industry. For example:

a) The most extensive studies on this theme was carried out by Skoyles in UK

year 1976 whereby he actually monitored material wastes in 114 building

sites, and concluded that there was a considerable amount of waste that can

be avoided by adopting relatively simple prevention procedures. Some other

findings from Skoyles’s researches also pointed out that storage and

handling was a major cause of waste while most of the problems concerning

waste on building sites are related to flaws in the management system, and

have very little to do with the lack of qualification of workers.

Besides that, Formosa and his co-authors have also documented some extensive studies

and surveys done in Brazil, which the concentration of those studies were more towards

identifying the types of material wastes in construction. For example,

1. Pinto developed a study in 1989 based on one site only; pointing out for the fact

that indirect waste (materials unnecessarily incorporated in the building) can be

higher than direct waste (rubbish that should be disposed in other areas).

2. The first research project on construction waste developed at the Federal

University of Rio Grande do Sul (UFRGS) started in April 1992. The main

62

objective of that study was to analyse the main causes of material waste in the

building industry in order to propose guidelines for controlling it in small sized

firms. Seven building materials were monitored in five different sites during a

period ranging from five to six months.

3. The Brazilian Institute for Technology and Quality in Construction (ITQC) more

recently coordinated a much more ambitious research project on material waste

measurement, which was developed for the Brazilian construction industry,

involving 15 universities (including UFRGS) and more than one hundred

building sites. For over 2 years, eighteen materials had their waste monitored by

using a data collection method similar to the projects carried out at the Federal

University of Rio Grande do Sul (UFRGS) in 1992.

Some conclusions that were drawn from those conventional construction waste studies

above such as:

1. The waste of building materials is occasionally far higher than the nominal

figures assumed by the companies in their cost estimates.

2. There is a very high variability of waste indices from site to site. Furthermore,

similar sites might present different levels of wastes for the same material. This

indicates that a considerable portion of this wastage can be avoided.

3. Some companies do not seem to be concerned about material waste, since they

do not apply relatively simple procedures to avoid waste on site. None of them

63

had a well-defined material management policy, neither a systematic control of

material usage.

4. The lack of knowledge was an important cause of waste. Most building firms

did not know the amount of waste they had.

5. Most causes of waste are related to flaws in the management system, and have

very little to do with the lack of qualification and motivation of workers. Also,

waste is usually the result of a combination of factors, rather than originated by

an isolated incident.

6. A significant portion of waste is caused by problems, which occur in stages that

precede production, such as inadequate design, lack of planning, flaws in the

material supply system, etc.

From here, if we take a look at a different perspective, all the above construction waste

researches carried out would suggest that the flow aspects in construction have been

historically neglected while previous researches were mainly concentrated on the

conversion aspects in construction. If this assumption were true, it logically follows that

current construction would demonstrate a significant amount of waste, loss of value,

and non value-adding activities apart from the waste and value loss to the value-adding

activities.

64

4.3 Waste and value loss in construction

In search for the waste, loss of value and non value-adding activities in current

construction practices, Koskela (1992) has managed to present a few evidences from

various partial studies done by other researchers around the world apart from the

material waste from conversion activities. Although in his research paper entitled “The

Application of The New Production Philosophy to Construction” stated that there has

never been any systematic attempt to observe all wastes in a construction process but

nevertheless, partial studies can be used from various countries to indicate the order of

magnitude of non value-adding activities in construction. Basically, In Koksela’s

research paper, he has been looking for the evidences of waste and value loss due to

quality of works, material management, non-productive time, safety and

constructability.

4.3.1. Waste and value loss due to quality of works

The first element of waste and value loss was compiled in term of quality costs the

subsequent findings from 3 different projects are stated as follow:

1. In numerous studies from different countries done in 1991, the cost of poor

quality (no- conformance) as measured on site has turned out to be 10 - 20% of

total project costs. In a Belgian study, it has also recorded the causes of these

65

quality problems are 46% design-related, 22% construction-related and 15% are

related to material supply

2. In a very detailed Swedish study on a design-construct project carried out in

1991, the costs of quality failures for a construction company were found to be

6%. In Sweden and Germany, it was found out that external quality costs or the

loss of value (understood as exceptional maintenance) to owners during facility

use are estimated to be 3% of the value of annual construction production. In the

case of Sweden. 51% of these costs are associated with design problems, 36%

with construction problems and 9% with use problems.

3. In an American study of several industrial projects, deviation costs averaged

12.4% of the total installed project cost. The researchers of the study also

recorded the causes of these quality problems are 78% design-related, 17%

construction-related and 20% are related to material supply

4.3.2. Waste and value loss due to constructability

The second factor that contributed to waste and value loss as compiled by Koskela is

the factor of constructability. Constructability is the capability of a design to be

constructed, or in a more elaborated word, constructability of a design depends on the

consideration of construction constraints and possibilities. It was found from a

constructability report in 1986 stated that projects where constructability has been

specifically addressed have reported 6 - 10% savings of construction costs.

66

4.3.3. Waste and value loss due to material management

Materials management in construction site was generally being neglected. Some

researchers such as Bell & Stukhart have estimated that 10 - 12% savings in labour

costs could be produced by materials-management systems. Furthermore, a reduction of

the bulk material surplus from 5 - 10% to 1 - 3% would result from a better material

management practice. Besides that, some researchers also reported that savings of 10%

in materials costs can be achieved from vendor cooperation in streamlining the material

flow.

4.3.4. Waste and value loss due to non-productive time

As for work flow processes, It has been found that construction work flow consists of a

lot of non value-adding activities where they consume a high percentage of overall

working time. All the estimation given from the researches compiled by Koskela, the

average distribution of working time used in value-adding activities ranging around

30% to 40%. Oglesby and his co-author estimated around 36% in 1989 while Levy in

1991 claimed that the average share of working time is 31.9 % in the United States.

There are similar figures from other countries but some other researches did show a

greater variance in percentage. For example, the average distribution of working time of

the 17 observed building projects survey in Chile conducted by Serpell, et al. (1995)

67

during 1990 and 1994 shows that the minimum value of productive work was 35% and

the maximum was 55%.

4.3.5. Waste and value loss due to safety issues

Another waste factor is lack of safety. In the United States, safety-related costs are

estimated to be 6 percent of total project costs as reported by Levitt & Samelson in

1988.

Thus, there is strong empirical evidence showing that a considerable amount of waste

and loss of value exists in construction apart from the conventional understanding of

physical waste or material waste. A large part of these wastes has been hidden, and it

has not been perceived as actionable.

4.4 New concept of waste in production activities

In new production philosophy, “waste” has been given a broader concept and definition

as compared to its usual narrow meaning. According to the new production philosophy,

waste should be understood as any inefficiency that results in the use of equipment,

materials, labour, or capital in larger quantities than those considered as necessary in the

production of a building. Waste includes both the incidence of material losses and the

execution of unnecessary work, which generate additional costs but do not add value to

the product (Koskela 1992). Therefore, waste should be defined as any losses produced

68

by activities that generate direct or indirect costs but do not add any value to the product

from the point of view of the client.

Two other definitions below as quoted by Alarcon (1995) expressed the broaden

dimension of wastes as seen by new production paradigm.

Toyota defines waste as:

“Anything that is different from the minimum quantity of equipment,

material, parts and labour time that is absolutely essential for

production.”

A western definition for waste would be following:

“Anything different from the absolute minimum amount of resources of

materials, equipment, and manpower necessary to add value to the

product.”

In this lean production paradigm, the concept of waste is directly associated with the

use of resources that do not add value to the final product. This is very much different

from the conventional conversion view of production processes where not significant

attempts to separate the activities into value-adding or non value-adding activities. The

conventional view sees all activities combined as a whole and therefore waste is being

69

monitored and evaluated as a whole conglomerated additional costs to the production

and mainly it only captured costs for the material wastes. The new production

philosophy intend to look into and detail out the dimension of waste by identifying non

value-adding activities and introduce new measures to wastes such as additional costs or

opportunity costs especially due to time waste and value loss which very much invisible

in conversion model.

Figure 4.1 will show a clearer picture on the different in concept of waste for

conventional conversion model compared to new production philosophy.

Figure 4.1

Performance improvement in conventional, quality and new production philosophy approaches.

(Simplified from the figure of Koskela (1992))

Conventional View

New Production Philosophy

Total Cost of A

Process

Cost of non value-adding activities

Cost of value-adding activities

Performance

improvement

rationale:

Increase

process

efficiency

Reduce or eliminate non value-

adding activities and increase

process efficiency of value-

adding activities

70

This means that there are 2 approaches to improving processes for new production

philosophy compared to conventional conversion view. One is to improve the efficiency

of both value-adding and non value-adding work, and the other is to eliminate waste by

removing non value-adding activities. Therefore, waste should be defined as any losses

produced by activities that generate direct or indirect costs but do not add any value to

the product from the point of view of the client.

The ideal outcomes that can be pictured by adopting new production philosophy or lean

production will be production will be managed in the way that actions are aligned to

produce unique value for the client. Project duration and cost are considered in “project-

as-production system” terms making concern for project total cost and duration more

important than the cost or duration of any activity. Coordination is accomplished in

general by the central schedule while the details of work flow are managed throughout

the organisation by people who are aware of and support project goals performance.

The primary objectives for this new movement will be looking at value to the client and

throughput, the movement of information or materials to completion. Improvement

results from reducing waste that is the difference between the current situation and

perfection, i.e., meeting customer unique requirements in zero time with nothing in

store.

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4.5 Underlying the waste concepts in construction

In construction, the application of the lean production model mainly stems from a

discussion of Koskela's work, which emphasised the importance of the production

process flow, as well as aspects related to converting inputs into finished products as an

important element to reduce wasted value. Production should be seen as a flow that

generates value through conversion processes, characterised by cost, time frame, and

the degree of added value. In other word, the new production theory seeks cycle time

reduction, total waste elimination, zero defects and flexible output and in doing that, it

requires the evaluation of new measurements, such as waste, value, cycle time or

variability that was not covered under traditional concepts.

It is worthwhile to understand the construction production process before underlying the

waste concepts in construction. Koskela (1992) has proposed a flow process model, in

which production is conceived as a flow of materials and information through four

types of stages: transport (moving), waiting (delay), processing (conversion), and

inspection as shown in Figure 2. This model differentiates between value-adding

activities and non value-adding activities and also concentrates on the process flow

rather than the exchange among the processes. As a rule in this model, only processing

activities are value-adding activities. Reducing the share of the non value-adding

activities is the target for continuous improvement. (Koskela, 1992)

72

Figure 4.2

Koskela’s flow process model (Koskela 1992)

Serpell et al. (1995) have proposed a much more open and dynamic construction

process model as described in Figure 4.3. The model presents the construction

production process on which work has been based on a system that correlated with the

environment around it. Part of the environment is controllable but other factors are

outside of its control.

Figure 4.3

Serpell’s Modeling of the construction process (Serpell et al. 1995)

MOVING WAITING PROCESSING

A

INSPECTION

MOVING WAITING PROCESSING

B

INSPECTION

REWORK

REWORK

REJECT

REJECT

73

The main and most critical components of the construction process as portrayed in

Figure 4.3, are:

1. Flows and conversion management: Responsible of making the decision that

define the performance of the system

2. Flows: Are the inputs to the system and they contemplate all activities up until

the completion of the end product. Those inputs can be separated in two types,

resources (labour, materials and construction equipment), and information.

There are two types of flows as portrayed in the model: external flows and

internal flows. External flows are usually uncontrollable such as Suppliers’

provision of resources and design information. Internal flows are usually

controllable such as flows of materials from a warehouse.

3. Conversion activities: The processes that transform the flows into finished and

semi-finished products. The method used in this activities decided by the flows

and conversion management.

4. Products: The results of conversion activities.

There are three areas or elements of interest where waste can occur and improvements

can be carried out according to Serpell’s model:

74

1. Flows, both internal and external, which are the inputs to the conversion

activities and can be classified into two groups: construction resources

(materials, labour and equipment) and construction information.

2. Conversion processes and resultant products, which are the processes that

transform the flows into completed and partially completed products.

3. Flows and process management which corresponds to the management actions

and decisions that determine the way things are done and the application of

construction resources. This management is responsible for the performance of

the construction process and is characterised by different styles or approaches

according to companies and managers.

Waste elimination/ reduction (alongside value enhancement to construction), still

remained prominent focus in the current lean construction practices for process

improvement. This is because from experience shows those non value-adding activities,

which involved human in the flow of work, predominate in the majority of processes.

Taylor (1913) pointed out that the economic loss caused by material waste is smaller

than the ones related to the inefficiency of human work. Ford (1927) also suggested

that human work should be the focus of waste prevention, since the value of materials

depends, to a great extent, on the work that has been spent on them. Studies had shown

that usually around 3% to 20% of the steps add value, and their share in total cycle time

is only around 0.5% to 5% (Alarcon, 1994).

75

4.6 Waste classification

Industry researchers and practitioners have acknowledged that there are many non-value

adding activities during the design and construction process and majority of those

wasteful activities consuming time and effort without adding value for the client. Since

the beginning of a construction project, Construction Managers have to deal with many

factors that may negatively affect the construction process, producing different types of

waste (Serpell et al, 1995). Waste includes both the incidence of material losses and the

execution of unnecessary work that generates additional costs but does not add value to

the product (Koskela, 1992). Moreover, some researchers, Alarcon (1993), Koskela

(1992) and Serpell et al. (1995) stated that waste in construction and manufacturing

include delay times, quality costs, lack of safety, rework, unnecessary transportation

trips, long distances, improper choice of management, methods or equipment and

poor constructability.

Regarding the possibility to control the incidence of waste, Formoso, et al. (1999)

commented that there is an acceptable level of waste, which can only be reduced

through a significant change in the level of technological development. Based on the

ratio of prevention investment cost over the cost of waste itself, they have classified

wastes into two general groups:

1. Unavoidable waste (or natural waste), in which the investment necessary to its

reduction is higher than the economy produced, The percentage of unavoidable

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waste in each process depends on the company and on the particular site, since it

is related to the level of technological development.

2. Avoidable waste, when the cost of waste is significantly higher than the cost to

prevent it.

Waste can also be classified according to its origin, i.e. the stage that the main root

cause is related to. Although waste is usually identified during the production stage, it

can be originated by processes that precede production, such as materials

manufacturing, training of human resources, design, materials supply, and planning.

However, the most classical waste classification according to lean production paradigm

is perhaps the classification done by Shigeo Shingo in his book “Study of Toyota

Manufacturing System” in 1981 as it has been quoted by various other lean construction

researches in relation of the study of wastes in construction example Alarcon (1994),

Womack and Jones, (1996), Formoso, et al. (1999), Koskela (2000) and many

others.

Shingo proposed the following waste classification whereby waste was classified by it

nature, which based on the Ohno’s framework of Toyota Production System:

1. Waste due to overproduction;

2. Waste due to wait periods;

3. Waste due to transport;

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4. Waste due to system itself;

5. Waste due to stock;

6. Waste due to operation;

7. Waste due to defects;

Based on Shingo’s seven wastes, Formoso, et al. (1999) went on to propose their main

classification of waste based on the analysis of some Brazilian building sites they had

carried out as shown below. It was thought that the further classification will help

managers to understand the different forms of waste, why they occur and how to act in

order to avoid them.

1. Overproduction: related to the production of a quantity greater than required or

earlier than necessary. This may cause waste of materials, man-hours or

equipment usage. It usually produces inventories of unfinished products or even

their total loss, in the case of materials that can deteriorate. An example of this

kind of waste is the overproduction of mortar that cannot be used on time.

2. Substitution: is monetary waste caused by the substitution of a material by a

more expensive one (with an unnecessary better performance); the execution of

simple tasks by an over-qualified worker; or the use of highly sophisticated

equipment where a much simpler one would be enough.

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3. Waiting time: related to the idle time caused by lack of synchronisation and

levelling of material flows, and pace of work by different groups or equipments.

One example is the idle time caused by the lack of material or by lack of work

place available for a gang.

4. Transportation: concerned with the internal movement of materials on site.

Excessive handling, the use of inadequate equipment or bad conditions of

pathways can cause this kind of waste. It is usually related to poor layout, and

the lack of planning of material flows. Its main consequneces are: waste of man

hours, waste of energy, waste of space on site, and the possibility of material

waste during transportation.

5. Processing: related to the nature of the processing (conversion) activity, which

could only be avoided by changing the construction technology. For instance, a

percentage of mortar is usually wasted when a ceiling is being plastered.

6. Inventories: related to excessive or unnecessary inventories which lead to

material waste (by deterioration, losses due to inadequate stock conditions on

site, robbery, vandalism), and monetary losses due to the capital that is tied up.

It might be a result of lack of resource planning or uncertainty on the estimation

of quantities.

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7. Movement: concerned with unnecessary or inefficient movements made by

workers during their job. This might be caused by inadequate equipment,

ineffective work methods, or poor arrangement of the working place.

8. Production of defective products: it occurs when the final or intermediate

product does not fit the quality specifications. This may lead to rework or to the

incorporation of unnecessary materials to the building (indirect waste), such as

the excessive thickness of plastering. It can be caused by a wide range of

reasons: poor design and specification, lack of planning and control, poor

qualification of the team work, lack of integration between design and

production, etc.

9. Others: waste of any nature different from the previous ones, such as burglary,

vandalism, inclement weather, accidents, etc.

Some researchers have proposed some qualitative model by postulating the loss of

productivity in construction using categories of non-productive time. Researchers such

as Borcherding in 1986 explained the loss of productivity in large and complex

constructions using five categories of non-productivities time as listed below:

1. Waste due to waiting or idle;

2. Waste due to travelling;

3. Waste due to slow work;

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4. Waste due to ineffective work;

5. Waste due to rework

Borcherding’s five waste categories of non-productive time are found very much

similar to the categories of wastes of productive time proposed by Serpell et. al (1995)

derived from their case studies as shown Figure 4.4 below:

Figure 4.4

Categories of wastes of productive time (Serpell et al. 1995)

However, they highlighted some limitations to the waste classification of non-

productive time for example the waste of time related to slow work is related to the

efficiency of processes, construction equipment and personnel. But it is difficult to

measure it because it is first necessary to know the optimal efficiency that can be

achieved, which is not always possible.

Waste of time

(man-hours &

equipment time)

Work

inactivity

Ineffective

work

Waiting time

Idle time

Travelling

Resting

Physiological needs

Reworking

Working slowly

Inventing work

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Instead of classifying the waste of productive time, Serpell et. al (1995) went a step

further to breakdown those wastes factors in relation of work categories. There are 3

types of work categories as proposed:

1. Productive work (value-adding activities)

2. Contributory work (non value-adding activities but essential for conversion

process): Those contributory work which are classified as waste include

transporting, instruction, measuring, cleaning and others

3. Non-contributory work (non value-adding activities): Those non contributory

work which are classified as waste include waiting, idle time, travelling, resting,

physiological needs, and rework

There are also other categories of waste that have been mentioned in the literature, such

as accidents, working under sub-optimal conditions (Koskela 2000), design and

products that do not meet users’ needs. (Womack and Jones 1996) The main role of

existing classification of waste is to call the attention of people to most likely problems,

since not all waste is obvious: it “often appears in the guise of useful work.” (Shingo

1988)

4.7 Key construction waste causes

After understanding the classification of waste, it is important to examine the type of

possible causes that lead to the occurrence of waste in construction process. This is

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deem important because just by knowing the waste itself just would help to monitor

them but not reduce or eliminate them from the process loops. To work out a

continuous improvement strategy in reducing and eliminating those wastes in

construction processes, the origin of the waste itself has to be identified.

A typical waste identification survey underlined a few examples of waste sources

according to different area of functions such as administration, use of resources and

information systems. Several potential sources of waste can be grouped under the

particular area of functions and it can be created to suit the need of particular projects

such as the diagnostic survey developed by students Francisco Lowener, Francisco Lira

and Marcelo Beratto as documented by Alarcon (1994) listed down the following

potential sources of waste in their project:

A. Administration

1. Unnecessary requirements

2. Excessive control

3. Lack of control

4. Poor planning

5. Bureaucracy

B. Use of resources

1. Surplus

2. Shortage

3. Misuse

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4. Poor distribution

5. Poor quality

6. Availability

C. Information systems

1. Unnecessary

2. Defective

3. Late

4. Unclear

Serpell et. al (1995) on the other hand identified several controllable causes of waste.

Although his study was mainly concentrated on wasted time but the classification of the

causes to waste is found rather structured and detailed compared to the previous listed

in waste identification survey. They divided the controllable wastes as identified from

their research projects into three different activities, which associate to flows,

conversions, and management activities.

1. Controllable causes associated to flows

The principal flow causes were as follow:

a) Resources

q Materials: Lack of materials at the work place; materials are not well

distributed; inadequate transportation means

q Equipment: Non availability; inefficient utilisation; inadequate

equipment for work needs

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q Labour: personal attitudes of workers; stoppage of work

b) Information

q Lack of information;

q Poor information quality

q Timing of delivery is inadequate

2. Controllable causes associated to conversions

The following causes were identified:

a) Method

q Deficient design of work crews

q Inadequate procedures

q Inadequate support to work activities

b) Planning

q Lack of work space

q Too much people working in reduced space

q Poor work conditions

c) Quality

q Poor execution of work

q Damages to work already finished

3. Controllable causes associated to management activities

The following causes were identified:

a) Decision making

q Poor allocation of work to labour

q Poor distribution of personnel

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b) Ineffective supervision/ control

q Poor or lack of supervision

4.8 Modeling waste and performance in construction

Modelling and evaluation of wastes and performance in construction projects has been a

challenge for the construction industry for decades. Several models and procedures have

been proposed for the evaluation of project performance at site and project level. Some

of these models focus on prediction of project performance while others focus on

measuring. Traditional models offer only a limited set of measures as most of them

limit their analysis to a number of measures such as cost, schedule, or productivity

(usually labour productivity).

The introduction of new production philosophies in construction requires new measures

of performance (Koskela, 1992), such as waste, value, cycle time or variability. The

shortcomings of the traditional control systems, and models are unable or not

appropriate to measure those new performance elements but Alarcon (1993) suggested

that some of the concepts developed in previous research can be utilised in modelling

new performance elements for construction required for continuos improvement.

It is worthwhile to point out some of opinions of different researchers and authors

related to the extent of performance elements in the aspects of construction process.

Among all, one of the most classical opinions was from Sink (1985, as documented by

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Alarcon 1993). Sink has characterised performance in a broad definition, as 7 criteria

or elements on which management should focus its efforts on: Those 7 criteria or

elements are as explained below:

1. Effectiveness: A measure of accomplishment of the ‘right’ things:

a) On time (timeliness),

b) Right (quality),

c) All the ‘right’ things (quantity), where ‘things’ are goals, objectives,

activities and so forth,

2. Efficiency: A measure of utilization of resources. It can be represented as a ratio

of resource expected to be consumed divided by the resources actually

consumed

3. Quality: A measure of conformance to specifications. In construction projects,

quality has 2 dimensions:

a) The first and overall one is that of the completed project functioning as the

owner intended

b) The second concerns the many details involved in producing the results

4. Productivity: Theoretically this is defined as a ratio between output and input

and it is primary measured in terms of cost. In the context of the construction

industry, the output is the structure or facility that is built or some components

of it. The major input into the construction process includes work force,

materials, equipment, management, energy and capital.

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5. Quality of work life: A measure of employees’ affective response to working

and living in organizational systems. Often, the management focus is on

insuring that employees are ‘satisfied’, safe and secure and so forth

6. Innovation: This is the creative process of adaptation of product, service,

process or structure in response to internal as well as external pressures,

demands and changes, needs and so forth

7. Profitability: A measure or a set of measures of the relationships between

financial resources and uses for those financial resources. For example,

revenues/ costs, return on assets and return on investments.

Embarking with the new production philosophies, Koskela (1992) has proposed some

new measures as required for construction, to stimulate continuous improvement such

as:

1. Waste: Number of defects, rework, number of design errors and omissions,

number of change orders, safety costs, excess consumption of materials, etc;

2. Value: Value of the output to the internal customer;

3. Cycle time: Cycle time of main processes and sub processes;

4. Variability: Deviations from the target, such as schedule performance.

The problem of performance evaluation is a multi-attribute or multi-criteria one.

Generally, the evaluations of performance in construction are concentrated on few

aspects only mainly on profitability and productivity. Furthermore, different managers

probably will use different performance elements and some will have different weight

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for each individual measures. Therefore, a model for evaluation or prediction must have

the flexibility to include the individual organisational objectives in the evaluation

process. It also must have the ability to examine the effect of changes in those

objectives in the evaluation process.

There are a few categories of performance and evaluation models, which can be

grouped by the functions of each model as discussed in Luis F. Alarcon (1993) in his

paper entitled “ Modeling waste and performance in construction”.

1. Measurement and Performance Evaluation Models

Function: Establish a framework for measurement and evaluation that may allow

improved quality of the information available for decision-making and research.

Examples:

a) Delay models use stopwatch techniques to record productive time and delay

occurring during the day

b) Work study-based models which are extensively used to indirectly measure

labour productivity

c) Activity models use work sampling techniques to catagorise activities

observed into productive, supportive or idle times.

2. Prediction Models

Function: Provide systematic procedures to account for the different factors that

affect productivity

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3. The Productivity Theory Factors Model

Function: Provides both standard procedures for collecting information and a

more rigorous way of accounting for productivity factors.

4. The Conceptual Construction Process Model

Function: Shows a different perspective on the problem that explains more

thoroughly the functional relationships and influences that affect productivity

5. Casual Models

Function: Provide a qualitative model structure to explore actions that can affect

productivity and to understand the mechanisms which product the results.

It is important to build a bridge between traditional and new philosophies in

construction performance improvement. As suggested by Alarcon (1993) that

traditional models and concepts in measuring and evaluating performance elements can

be improvised in order to incorporated new performance elements proposed by new

production philosophies.

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CHAPTER 5

RESEARCH METHODOLOGY

5.1 Introduction

This chapter will explain the methodology in carrying out this academic research.

Aspects involved included method of research, research subjects, tools for analysis,

points or marks assignment, sequences of research, and analysis of the research data.

5.2 Method of research

The purposes of this research are to see whether the lean construction principles of

waste concepts have been well comprehended, accepted and adopted by the local

construction personnel especially in waste recognition, reduction and elimination for the

continuous improvement in construction processes. A quantitative research approach

was adopted for this research requiring the development and dissemination of a

questionnaire survey. Due to the population of this research are virtually too difficult to

be quantified as the main targeted respondents would include all personnel who has

direct managerial experiences in construction field, the non-probability sampling

methods will be adopted in this research instead of probability sampling. Purposive

sampling for specific groups or types of respondents will be conducted by using expert

sampling technique which involves the assembling of a sample of managerial personnel

with known or demonstrable experience and expertise in managing construction field

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processes. The expert sampling has been seen as the best way to elicit the views of

those who have specific expertise and experiences dealing with the local construction

practices. It is also very useful for situations where a targeted sample needs to be reach

quickly and where sampling for proportionality is not the primary concern in this

research.

The research is conducted through structured questionnaires where those questionnaires

were sent to the particular “qualified” respondents. The respondents were approached

through their companies and firms, which registered in the CIDB annual directory

yearbook. A pilot survey was conducted during November year 2003 where 20 sets of

questionnaires were sent out to a random group of pilot respondents in postal mail (with

returned envelop and stamp attached) around peninsular Malaysia for a period of 1

month but the respond rate to the questionnaires were are low with only 2 sets of

surveys were returned during the trial period.

Due to the circumstances of low respond rate in the pilot survey, a new approach of

distributing the questionnaires has been taken. The targeted research locations have

been focus more into northern region of peninsular Malaysia where direct contacts with

the potential qualified respondents were more easily accessible. Besides 20 new sets of

questionnaires were posted out together with 20 sets post out through e-mail throughout

peninsular Malaysia, there were also 30 sets of questionnaires were hand-delivered

(mainly in northern Peninsular Malaysia) to the respondents from December 2003 until

February 2004. Until the due date, 27 of questionnaires were returned (including 2 from

pilot survey) which represented an average response rate of 30%. Compared to the 40%

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average response rate for the 5 years quantitative research carried out by Alwi et al

(2002) on construction wastes in Indonesia with 300 questionnaires sent, this research

carried out are considerably low in average response rate but if compared to the

timeframe and resources available for data collection in this research, the 30% response

rate are reasonably acceptable for numbers of questionnaires sent.

This research was postulated around determining the general perceptions and actions of

the construction personnel against wastes in construction and the concept of non-

productive time or wasted time as suggested by Serpell et al. (1995) were then

integrated into the research process as the key element of lean construction philosophy

regarding flow concept. In this case, Waste in construction process is classified into

three main categories, which are direct conversion waste, non-contributory time waste

and contributory time waste. 19 waste elements are outlined consists of 9 direct

conversion wastes, 7 non-contributory time wastes and 3 contributory time wastes as

shown in Table 5.1 and all those waste elements were derived from different previous

studies carried out by Serpell et al (1995), Alarcon (1994 & 1995), Formosa, et al

(1999 & 2002) and Alwi et al (2002).

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Direct Conversion Wastes Non-Contributory Wastes Contributory Wastes

1 Over-allocation/ unnecessary

equipment on site

Waiting for others to complete

their works before the

proceeding works can be

carried out (idle time)

Time in supervising and

inspecting the construction

works


materials on site

Waiting for equipment to be

delivered on site

Time for instructions and

communication among

different tiers and trades of

workers


workers on site

Waiting for materials to be

delivered on site

Time for transporting workers,

equipment and materials

4 Unnecessary procedures and

working protocols

Waiting for the skilled workers

to be on site

5 Material loss/ stolen from site

during construction periods

Waiting for the clarification

and confirmation by client and

consultants

6 Material deterioration/

damaged during construction

periods

Time for rework/ repair works/

defective works

(Rework)

7 Mishandling or error in

construction applications/

installation

Time for workers’ resting

during construction

(Physiological needs &

Resting)

8 Materials for rework/ repair

works/ defective works

9 Accidents on site

Table 5.1

Waste elements in 3 separate waste groups

In response to the examine the frequencies causes of wastes and their inter-relation with

waste elements, several waste causes factors were also substrated from previous

literature studies by Serpell et al (1995), Alarcon (1994 & 1995) and Alwi et al (2002)

and categorised into 5 main groups of cause factors which are Management &

Administration Factors (4 factors), People Factors (6 factors), Execution Factors (6

factors), Material Factors (6 factors) and Information and Communication Factors (3

factors). The entire breakdown of the waste cause factors is shown in Table 5.2.

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Management & Administration Factors

1 Poor coordination among project participants

2 Poor planning and scheduling

3 Lack of control

4 Bureaucracy

People Factors

1 Lack of trades skills

2 Inexperience inspectors

3 Too few supervisors/ foreman

4 Uncontrolled sub-contracting practices

5 Supervision too late

6 Poor labour distribution

Execution Factors

1 Inappropriate construction methods

2 Outdated equipment

3 Equipment shortage

4 Poor equipment choice or ineffective equipment

5 Poor site layout and setting out

6 Poor site documentation

Material Factors

1 Delay of material delivery

2 Poorly scheduled delivery of material to site

3 Poor quality of material

4 Inappropriate/ misuse of material

5 Poor storage of material

6 Poor material handling on site

Information and Communication Factors

1 Defective or Wrong information

2 Late information and decision making

3 Unclear information

Table 5.2

Waste Causes Factor Group

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5.3 Profile of respondents

A randomly selected group of targeted respondents consists of those personnel who

have a commanding role in the construction process and resource management and

extensive site experiences were targeted as respondents for the sample survey. There

has been a wide spectrum of personnel with different position and job title, which had

been responded to the survey and for the purpose of analysis and comparison, the whole

sample of respondents have been regrouped into 2 main categories which are

1. Project management orientated group

2. Site operative management orientated group

Project management orientated group will feature those who have relatively more

responsibilities in overall project execution and resource management and not so much

on site operative management by its nature of job scope. Therefore, this group will

involve personnel more on planning, inter-coordinating and directing role in

construction process and as for the sample respondents for this research will include

project managers, general managers, project schedulers/ planners, quantity surveyors.

While Site operative management orientated group will feature those who have

relatively more responsibilities on the site operative management by its nature of job

scope. The group will mainly involve personnel in solving construction problems on

site, more on intra-coordinating with internal groups and trades, and as for the sample

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respondents for this research will include site managers, site engineers, resident

architect/ engineer and senior quality manager.

5.4 Structure of questionnaires

The structure of questionnaires is divided into 5 main sections. (Refer sample of

questionnaire in Appendix 5) The first 2 sections of questionnaires are intended to

examine the general perception and acceptance of Lean Construction philosophy of

local construction industries based on the respondents’ waste concepts. In this case, the

respondents were asked to recognise 19 wastes elements and their personnel

experiences in controlling those waste elements during construction processes. There

are 2-options available for the respondents and there were required to answer whether

the wastes elements as listed is a waste or non-waste and whether they are controlled or

not controlled during the construction processes.

The third and fourth sections are intended to review the extent of waste problems in

existing local industry by ranking them in term of frequencies of occurrences and rate

the likelihood of particular waste sources/ causes in their construction practices where

they work. For section 3, Respondents were able to identify how frequently the waste

occurred using 5 categories: (1) Never; (2) Very Rare; (3) Seldom; (4) Frequent; and (5)

Very Frequent and the respondents were provided with five different scales from 1 (no

significant effect variable) to 5 as (high detrimental effect variable); Foe section 4,

Respondents were asked to determine the likelihood of particular waste sources/ causes

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using 4 categories: (1) Most unlikely; (2) Unlikely; (3) Likely; (4) Most Likely and the

respondents were provided with five different scales from 1 (no significant likelihood)

to 5 as (high detrimental likelihood)

The fifth section is to examine the relevant sources of wastes as outlined in the fourth

section to have caused the particular construction wastes. The respondents were asked

to identify the most possible causes and other possible causes to the wastes elements in

order to create a matrix table between construction wastes and their sources of wastes.

5.5 Score Assignment

Score assignment is a process of assigning values for each of the item and this is an

important process of conducting inferential analysis especially for correlation test using

Pearson-r where aggregation of points are required for this research. Score assignment

for section 1 and 2, each positive answer is assigned with 2 points and each negative

answer is assigned with 1 point. Based on the waste categories in Table 5.1, the

maximum points for direct conversion wastes that can be aggregated for each case is (2

X 9) equal to 18 points and the minimum of (1 X 9) equal to 9 points; Maximum points

for non-contributory time waste is (2 X 7) or 14 points and minimum of (1 X 7) or 7

points whereas for maximum points for contributory time wastes is (2 X 3) or 6 points

and minimum of (1 X 3) or 3 points

Score assignment for section 3 and 4 is based on the multiple-scale format. For section

3, points are ranged from 1 to 5 and maximum points that can be aggregated for direct

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conversion wastes is (5 X 9) or 45 points, minimum of (1 X 9) or 9 points; for non-

contributory time wastes, maximum that can be achieved is (5 X 7) or 35 points and

minimum of (1 X 7) or 7 points while maximum for contributory time wastes is (5 X 3)

or 15 points and minimum of (1 X 3) or 3 points. For section 4, points are ranged from

1 to 4 but since correlation are not going to be tested in this section but rather each item

is going to be tested separately with One-way t-test for ranking purposes, therefore not

aggregation of points are required.

5.6 Analysis Methods

After all the primary data have been collected and processed, those data will then be

analysed according to the appropriate analysis methods. Analysis methods in this

research are mainly divided into 2 parts: (1) Descriptive analysis and (2) Inferential

statistical analysis. Descriptive statistical analysis is used to present the background

profiles about the respondents and provide further information for the inferential

statistical analysis, besides that, the analysis on the descriptive data about the waste

recognition and waste control events in section 1 & 2 will also be conducted under the

same category. Inferential statistical analysis will be used to test certain research

hypothesis, type of analysis tools to be used include Coefficient Pearson r for

correlation testing and one-way t-test for frequencies ranking.

In most analyses carried out in 3 separate categories namely direct conversion wastes,

contributory process time wastes and non-contributory process time wastes in order to

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see the different between each categories especially dealing with contributory process

wastes and non contributory process waste which is rarely considered in conventional

waste concepts for construction processes.

Although it is logically understood that when we recognised certain wastes, we will try

our best to avoid it or control it, however, in this research, the inter-relationship

between understanding of wastes and actual control practices of wastes in construction

processes will be examined in order to found out any contradictions to the logic of

relationship between recognising the waste and the actions in controlling them. 4

different scenarios are anticipated which are extreme scenarios where type of waste

elements are recognised as waste and have been given a proper attention in controlling

them or vice versa not recognising them and therefore not given any control actions into

it. Of course, another 2 scenarios the cases would be the potential cases of recognising

the waste elements but do not act on them or vice verse acting on certain waste elements

which they are not recognised as waste.

On the other hand, Inferential statistic analysis will use correlation Pearson-r to conduct

testing on 9 hypotheses to see whether any significant inter-relationship existed between

understanding of wastes and actual control practices of wastes in construction processes

based on 3 cases of waste categories. The 9 hypotheses are:

Hypothesis 1: There is inter-relationship between construction’s direct conversion

wastes are been perceived with the tendency to control those wastes

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wastes are been perceived with the frequencies of occurrences of such

wastes during the processes

Hypothesis 3: There is inter-relationship between the tendency to control those

construction’s direct conversion wastes with the frequencies of

occurrences of such wastes during the processes

Hypothesis 4: There is inter-relationship between construction’s non-contributory time


Hypothesis 5: There is inter-relationship between construction’s non-contributory time




construction’s non-contributory time wastes with the frequencies of


Hypothesis 7: There is inter-relationship between construction’s contributory time






construction’s contributory time wastes with the frequencies of


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In every case above, the correlation Pearson-r will tell us the magnitude and direction of

the association between two variables. SPSS creates a correlation matrix of the two

variables. All the information we need is in the cell that represents the intersection of

the two variables.

In SPSS, the outcomes of the Pearson-r analysis will provide us three pieces of

information: (1) the correlation coefficient, (2) the significance and (3) the number of

cases (N)

The correlation coefficient is a number between +1 and -1. This number tells us about

the magnitude and direction of the association between two variables. The magnitude is

the strength of the correlation. The closer the correlation is to either +1 or -1, the

stronger the correlation. If the correlation is 0 or very close to zero, there is no

association between the two variables. The direction of the correlation tells us how the

two variables are related. If the correlation is positive, the two variables have a positive

relationship (as one increases, the other also increases). If the correlation is negative, the

two variables have a negative relationship (as one increases, the other decreases).

One-Way t-test will be carried out basically to get the ranking on the frequencies of

occurrence of the wastes elements in section 3 and the likelihood of recognition certain

wastes causes factors as in section 4. In SPSS, the outcomes of the One-Way t-test

analysis will provide us four pieces of information: (1) the number of cases (N), (2) the

mean value, (3) the standard deviation and (4) the standard error means. The ranking

will be done separately in a descending order from the greatest magnitude of the mean

102

value to the lowest mean value to differentiate the degree of frequencies and likelihood

from the less significant to the most significant as rated by the respondent of the

research.

The last part of the analysis will be involving the development of the Causes and

Effects Matrix table by combining all the inputs by the respondents in section 5 into the

whole list of construction wastes and waste causes table. From there, descriptive

statistic analysis will take place in sorting out the wastes causes factors and put them

into 6 wastes factors as discussed previously and represent the Matrix Table in Bar

charts format for easy interpretation of the results.

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CHAPTER 6

DATA ANALYSIS AND INTERPRETATION

6.1 Introduction

This chapter will present all the results obtained from the data analysis waste concepts

and waste causes factors in construction processes. Descriptive statistic analysis and

inferential statistic analysis will be utilised to present the results. The presentation of

analysis of descriptive statistic analysis will be conducted in the form of bar charts, pie

charts and matrix tables to show the distribution and frequencies of the particular

variables. The presentation of analysis of inferential statistic analysis will be done by

using result outputs generated directly from SPSS 10.0

6.2 Descriptive analysis results

This section will discuss about the analysis results from descriptive analysis. The

segments, which are in the discussion, include information about the respondents and

their organisation’s background and the respondent’s waste perceptions and control

actions grouped under the waste categories as outlined in Chapter 5.

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6.2.1 Respondents and their organisation’s background

There are 5 segments analysed under this category include the position of the

respondents in their organisation, nature of their work grouped as outlined in Chapter 5,

main core construction projects handled by their organisation, CIDB registration grade

of their firm, and their main project clients. This descriptive analysis will eventually

show the actual profile of the respondents who have eventually taken this waste

construction study.

105

6.2.1.1 Position of respondents

The respondents for this research consists of 27 project and site management personnel

with a wide spectrum of positions ranging from project manager, project planner,

general manager, quantity surveyor, resident engineer/ architect, site engineer, site

manager and senior quality manager. Results from the data analysis has seen that 2

position of respondents figured almost 63% of all the other position held by the

respondents in the organisation, those two positions are project manager (9 Nos) and

site engineer (8 Nos). The composition of the respondent’s position are shown in the

Figure 6.1 below:

Figure 6.1

Composition of respondent’s position

0

1

2

3

4

5

6

7

8

9

Nos.

1

Position

Project Manager

Project Planner

General Manager

Quantity Surveyor

Site Manager

Site Engineer

Resident Architect/ Engineer

Sr. Quality Manager

106

6.2.1.2 Nature of work of respondents

Based on the data of the respondent’s position in their organisation, the further

categorisation of their positions has to be conducted for the purposes of statistic analysis

later in the chapter. The categorisation is based on the nature of work as outlined in

chapter 5. 27 respondents are to be categorised into 2 main groups, which are project

management orientated group and site operative management group. The results from

the categorisation found that there is rather balance in term of percentage between both

designated groups where each holds approximate 50% from the poll. Figure 6.2 will

present the percentage of those different groups

Figure 6.2

Percentage of categorisation of respondent’s nature of work

52%

48%

Project Management

Site Management

107

6.2.1.3 Main core construction projects involved by the respondent’s organisation

Respondents were asked to select the most appropriate type of construction project,

which represent the main core construction projects involved by their company. The

results from the data analysis show almost 78% of the records for core construction

projects are made up of public & community buildings (8 Nos), residential &

commercial scheme (7 Nos) and Industrial projects (6 Nos). High-rise building and civil

& road construction each only recorded 3 Nos. each by the respondents as main core

construction projects by their firm. Figure 6.3 shows the composition of the projects

distribution:

Figure 6.3

Composition of the main core construction projects by the respondent’s company

0

1

2

3

4

5

6

7

8

Nos.

1

Main core construction projects

Highrise Building

Residential & Commercial

BuildingIndustrial Building

Public & Community Building

Civil & Road Construction

108

6.2.1.4 CIDB registration grade of the respondent’s companies

The respondents were also asked to indicate the CIDB registration grade into 2

categories that are Below Grade 3 and Grade 3 and above. The analysis results from this

sample of respondents show that big portions of respondent’s companies obtain CIDB

registration Grade 3 and above which are almost 83% of the total sample or (22 Nos).

Only 3 companies are with CIDB registration below grade 3 only or about 11% of the

overall sample while there are 2 Nos. missing input in this field. (Refer Figure 6.4)

Figure 6.4

CIDB registration of the respondent’s company

11%

82%

7%

below Grade 3

Grade3 & Above

Missing

109

6.2.1.5 Main project clients

There are 2 types of main project clients classified related to the projects that their

company was engaged with and the respondents are to select between private clients

and public clients as their main project clients. The analysis results recorded a fair share

of main project client based among this sample of respondents where 15 of the

respondents reported that their main clients are from the private sectors (or about 55%)

and 12 of the respondents reported their main clients are from public sectors (or about

45%). (Refer Figure 6.5)

Figure 6.5 Percentages of main project clients of the respondent’s company

56%

44%

Private

Public

110

6.2.2 Respondent’s waste perceptions and control actions

The descriptive analysis on the respondent’s waste perceptions and control actions will

mainly focusing on identifying the numbers of counts on wastes recognised and waste

events controlled as reckon by the respondents for 3 waste categories as defined in

Chapter 5 namely, direct conversion wastes, non contributory wastes and contributory

wastes.

Since the lean construction philosophy considered all those waste elements as tabulated

in the questionnaires as construction wastes which need to be reduced, eliminated or

somehow controlled, the degree of perceptions on wastes for the local construction

industries eventually can be verified by determining the numbers of positive counts on

each of those wastes elements. Besides that, an analysis over a matrix tables by cross-

tabbing both the waste concepts and waste control actions will be carried out to study

the frequencies of 4 different potential scenarios which are anticipated to be occurred.

6.2.2.1 Analysis on direct conversion wastes

Under this category, there are 9 wastes elements, which were asked to be identified by

the respondents based on their own experience and opinion. Those items are indexed as

F, G, H, I, J, K, L, N, S in the section A, B and C of the questionnaires. For the total of

27 respondents by calculation as (9 X 27), it sums up a total of 243 overall counts of

inputs.

111

For construction waste recognition, all the inputs are tabulated in Table 6.1 below and a

total of 204 positive counts are recorded or approximately 84% and it is shown a high

recognition on the waste concepts for the elements tested in this category.

# F G H I J K L N S

1 2 2 2 2 2 2 2 2 2 1 NON WASTE

2 2 2 2 2 2 2 2 2 1 2 WASTE

3 2 2 2 1 2 2 2 2 2

4 2 2 2 2 2 2 2 2 2

5 1 1 1 1 2 2 2 2 2

6 2 2 2 2 2 2 2 2 2

7 2 2 2 2 2 2 1 2 2

8 1 1 1 2 1 1 2 1 2

9 1 1 1 2 2 2 2 2 2

10 1 1 1 2 1 1 1 2 2

11 2 2 2 2 2 2 2 2 2

12 2 2 2 1 2 2 2 2 2

13 2 2 2 2 1 2 2 2 1

14 2 2 2 2 2 2 2 2 2

15 2 2 2 1 2 1 2 2 2

16 2 2 2 2 2 2 2 2 2

17 2 2 2 2 2 2 2 2 2

18 2 2 2 2 2 2 2 2 2

19 1 2 1 2 2 2 2 2 2

20 2 2 2 2 2 2 2 2 2

21 2 2 2 2 1 2 2 2 1

22 2 2 1 1 2 2 2 2 2

23 2 2 2 2 2 2 2 2 2

24 1 2 2 2 2 2 2 2 2

25 2 2 2 2 2 2 2 2 1

26 1 1 1 2 2 2 2 2 2

27 1 2 2 2 2 2 2 2 2

Table 6. 1

Construction waste recognition under direct conversion waste category

Legend:

F: Over-allocation/ Unnecessary equipment on site

G: Over-allocation/ unnecessary materials on site

H: Over-allocation/ unnecessary workers on site

I: Unnecessary procedures and working protocols

J: Material loss/ stolen from site during construction

periods

K: Material deterioration/ damaged during

construction periods

L: Mishandling or error in construction applications/

installation

N: Materials for rework/ repair works/ defective works

S: Accidents on site

Note: The values given in the table do not have

any significant meaning in this descriptive

statistic analysis, as they are values inputs for

inferential statistic analysis later in the chapter

112

This analysis concluded that a high recognition rate on direct conversion wastes by the

respondents. The breakdown of numbers of the waste elements recognised as wastes

under this direct conversion category are shown in Figure 6.6 below. The result shows

that Item N: (Materials for rework/ repair works/ defective work) is the most recognised

construction wastes with 26 positive counts while Item F: (Over-allocation/

Unnecessary equipment) is the least recognised construction wastes with only 19

positive counts under the direct conversion waste category.

Figure 6.6

Breakdown of direct conversion waste recognition cases

For construction waste events control, due to a respondent miss out on the whole range

of input for this section, the total counts will calculated as (9 X 26) equal to 234Nos. of

inputs as tabulated in Table 6.2 below. A total of 168 positive counts are recorded or

19

8

22

5

20

7

22

5

23

4

24

3

25

2

26

1

23

4

0

5

10

15

20

25

30

F G H I J K L N S

Non Waste

Waste

113

approximately 72% and it shows a slight drop in percentage on the waste control

practices for the elements tested compared to the construction waste recognised

previously by the same set of respondents. In other words, the respondents recognise the

direct conversion wastes more than eventually control them.

# F G H I J K L N S

1 2 2 2 2 1 1 2 2 1 1 NOT CONTROL

2 2 2 2 2 1 1 2 2 1 2 CONTROL

3 2 2 2 2 1 2 2 2 1 - MISSING

4 2 2 2 2 1 2 2 2 1

5 1 1 1 2 2 2 2 2 2

6 - - - - - - - - -

7 2 2 2 1 1 2 1 2 1

8 2 2 2 2 2 2 2 2 2

9 2 2 2 2 2 2 2 2 2

10 2 2 2 1 1 1 2 1 1

11 1 1 1 2 2 2 1 2 1

12 2 2 2 1 2 2 2 1 2

13 2 2 2 1 2 2 1 2 2

14 2 1 1 1 1 1 1 1 1

15 2 2 2 2 2 2 2 1 1

16 2 2 2 2 2 1 2 2 2

17 2 2 2 2 2 2 2 2 2

18 1 1 1 2 2 2 2 2 2

19 2 2 2 2 2 2 2 2 1

20 2 2 2 2 1 2 2 2 1

21 2 2 2 1 2 2 2 2 2

22 2 2 2 2 2 2 2 2 2

23 1 1 1 2 2 2 1 1 1

24 2 1 1 1 2 2 2 1 1

25 2 2 2 1 1 1 2 2 2

26 2 2 2 2 1 1 2 2 1

27 2 2 2 2 2 2 2 2 2

Table 6.2 Construction waste control practices under direct conversion waste category

However, the analysis result still shows that there are high control exercises on direct

conversion wastes as reported by the respondents. The breakdown of numbers of the

Legend:






periods




installation







114

waste elements recognised as wastes under this direct conversion waste category are

shown in Figure 6.7. From chart in Figure 7 however shows that Item F: (Over-

allocation/ Unnecessary equipment on site) have the highest positive counts (22 Nos)

on event controlled while Item S: (Accidents on site) is recorded as the least event

controlled with 12 Nos. of positive counts.

Figure 6.7 Breakdown of direct conversion waste event control cases

By cross tabbing of both Table 6.1 & 6.2 will result in a matrix table as show in Table

6.3 below. This matrix table can be used to explain the inter-relationship between the

direct conversion waste concepts of the respondents with their actual control practices

on construction processes. As anticipated, there are 4 potential scenarios as observed,

which are Case 1: Waste recognised and controlled; Case 2: Waste not recognised and

22

4

1

20

6

1

20

6

1

18

8

1

16

10

1

19

7

1

20

6

1

20

6

1

12

14

1

0

5

10

15

20

25

30

F G H I J K L N S

Missing

Non Control

Control

115

not controlled; Case 3: Waste recognised but not controlled and Case 4: Waste not

recognised but controlled.

# F G H I J K L N S

1 137 Case 1: Waste & Control

2 8 Case 2: Non Waste & Not Control

3 58 Case 3: Waste & Not Control

4 31 Case 4: Non Waste & Control

5 - Matrix not available due to missing input

6 - - - - - - - - -

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Table 6.3

Matrix table between waste concepts and control practices for direct conversion wastes

From the analysis, it is found that Case 1 is the most occurrence scenario with 137 cases

(58.5%) followed by Case 3: 58 cases (24.8%), Case 4: 38 cases (13.2%) and finally

Case 2: 8 cases (3.5%). However, These results show that over half of the direct

conversion construction wastes have fully been recognised and controlled

simultaneously but this analysis result is not very convincing as there are still very high

Legend:






periods




installation



116

percentage of cases where wastes were partially recognised and controlled and not

recognised and controlled at all.

117

6.2.2.2 Analysis on non-contributory time wastes

Under this category, there are only 7 wastes elements, which were asked to be identified

by the respondents based on their own experience and opinion. Those items are indexed

as A, B, C, D, E, M and O in the section A, B and C of the questionnaires. For the total

of 27 respondents by calculation as (7 X 27), it sums up a total of 189 overall counts of

inputs.


total of 129 positive counts are recorded or approximately 68% and it is still a high

recognition on the waste concepts for the elements tested in this category but it is

relatively lower in percentage compared to analysis carried out previously on direct

conversion waste.

118

# A B C D E M O

1 1 2 2 2 1 2 1 1 NON WASTE

2 2 2 2 2 2 2 1 2 WASTE

3 2 1 1 1 1 2 1

4 2 1 1 2 2 2 1

5 2 2 2 2 2 2 1

6 2 2 2 2 1 2 2

7 2 2 1 2 2 2 1

8 2 2 2 2 2 1 1

9 2 2 2 2 2 2 1

10 1 1 1 1 2 1 2

11 2 2 2 2 2 2 1

12 2 2 2 2 1 2 2

13 1 1 2 2 1 2 1

14 2 2 2 2 2 2 1

15 1 2 2 2 2 2 1

16 2 2 2 2 2 2 2

17 1 1 1 1 2 2 1

18 2 2 2 2 1 2 1

19 2 2 2 2 2 2 1

20 2 1 1 2 2 2 1

21 1 1 1 2 2 2 1

22 2 2 2 2 1 2 2

23 2 1 1 1 1 2 1

24 2 2 2 2 2 2 1

25 2 2 2 2 2 2 1

26 2 2 2 2 1 2 1

27 2 1 2 2 2 2 1

Table 6.4

Construction waste recognition under non-contributory time waste category

The breakdown of numbers of the waste elements recognised as wastes under this non-

contributory time waste category are shown in Figure 6.8. It is worthwhile to point out

that most of the respondents do not recognised Item O: (Time for workers’ resting

during construction) as construction as only 5 out of 27 respondents recognised it as

construction waste. On the opposite side, the most recognised construction waste under

this non-contributory time waste category is Item M: (Time for rework/ repair work/

defective works) which recorded a 25 positive counts out of the maximum 27.

Legend:

A: Waiting for others to complete their works before

the proceeding works can be carried out

B: Waiting for equipment to be delivered on site

C: Waiting for materials to be delivered on site

D: Waiting for the skilled workers to be on site

E: Waiting for the clarification and confirmation by

client and consultants

M: Time for rework/ repair works/ defective works

O: Time for workers’ resting during construction





119

Figure 6.8 Breakdown of non-contributory time waste recognition cases

The same reason as in direct conversion waste category analysis, the total counts for the

analysis of construction waste event control will calculated with less 1 missing inputs

range so it would be (7 X 26) equal to 182 total counts. All the inputs are tabulated in

Table 6.5 below and a total of 148 positive counts are recorded or approximately 81%

and it shows an increase in percentage on the waste event control for the elements tested

compared to the construction waste recognised under this category. In other words, the

respondents control non-contributory time waste more than eventually recognising

them.

21

6

18

9

19

8

23

4

18

9

25

2

5

22

0

5

10

15

20

25

30

A B C D E M O

Non Waste

Waste

120

# A B C D E M O

1 2 2 2 2 1 2 2 1 NOT CONTROL

2 2 2 2 2 2 2 2 2 CONTROL

3 2 2 2 2 2 2 2 - MISSING

4 2 2 2 2 1 2 2

5 2 2 2 2 2 2 2

6 - - - - - - -

7 2 2 2 2 1 2 2

8 2 2 2 2 2 2 2

9 2 2 2 2 2 2 2

10 2 2 2 2 1 2 1

11 2 2 2 1 2 2 1

12 2 2 2 2 1 1 1

13 2 2 1 1 1 2 2

14 1 2 1 1 1 1 1

15 2 2 2 2 1 1 2

16 2 2 2 2 2 2 2

17 2 2 2 2 2 2 2

18 2 2 2 2 2 2 1

19 2 2 2 2 1 2 2

20 2 2 2 2 2 2 2

21 2 2 1 1 1 2 2

22 2 2 2 2 1 2 2

23 2 2 2 2 2 1 1

24 2 2 2 1 1 2 2

25 2 2 2 2 1 2 1

26 2 2 2 2 2 2 2

27 2 2 2 2 1 2 2

Table 6.5 Construction waste control practices under non-contributory time waste category


contributory time waste category are shown in Figure 6.9. It shows that Item E:

(Waiting for the clarification and confirmation by client and consultants) is the least

controlled waste event where more than half of the respondents reported as waste event

not being controlled. Item B: (Waiting for equipment to be delivered on site) on the

other hand recorded a perfect waste control event

Legend:














121

Figure 6.9 Breakdown of non-contributory time waste control practice cases

Same as direct conversion waste analysis, the cross tabbing of both Table 6.4 & 6.5 for

non-contributory waste will result in a matrix table as show in Table 6.6 below. This

matrix table can be used to explain the inter-relationship between the non-contributory

waste concepts of the respondents with their actual control practices on construction

processes. Again, 4 potential scenarios cases are to be investigated for non-contributory

time waste category.

25

11

26

01

23

3

1

21

5

1

12

14

1

22

4

1

19

7

1

0

5

10

15

20

25

30

A B C D E M O

Missing

Non Control

Control

122

# A B C D E M O






6 - - - - - - -

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Table 6.6 Matrix table between waste concepts and control practices for non-contributory time wastes


(56.7%) followed by Case 4: 48 cases (24.8%), Case 3: 24 cases (13.2%) and finally

Case 2: 10 cases (5.3%). The result shows that about half of the non-contributory

construction time wastes are recognised and controlled simultaneously and again, this

results are not considered very convincing which resembles the result obtained from the

matrix table for direct conversion waste as a very high percentage of cases where wastes

were partially recognised and controlled and not recognised and controlled at all still

existed. The obvious different between direct conversion waste analysis with non-

Legend:










123

contributory waste analysis is the percentage of occurrences for Case 3 & 4. Non-

contributory time waste analysis has a higher percentage of occurrences for Case 4 and

a relatively low percentage of occurrences for Case 3 whereby direct conversion waste

analysis has a higher percentage for Case 3 and lower for Case 4. Both Case 1 and Case

2 of the 2 analysis relative constant where Case 1 stays around 57% – 58% and Case 2

at a low 3.5% - 5%

124

6.2.2.3 Analysis on contributory time wastes

Under this category, there are only 3 wastes elements, which were asked to be identified

by the respondents based on their own experience and opinion. Those items are indexed

as P, Q & R in the section A, B and C of the questionnaires. For the total of 27

respondents by calculation as (3 X 27), it sums up a total of 81 overall counts of inputs.


total of 10 positive counts are recorded or approximately 12% and this a very low

recognition on the waste concepts for the elements tested under this category compared

to analysis carried out previously on direct conversion waste and non-contributory time

waste where both categories are above 70 % - 80% of recognition.

125

Table 6. 7

Construction waste recognition under contributory time waste category

The breakdown of numbers of the waste elements recognised as wastes under this

contributory time waste category are shown in Figure 6.10. It is not surprising to see

that all the 3 items registered under contributory time wastes are recording significant

negative counts, which represent non waste recognition for the contributory time

wastes. Very much different with the first 2 waste recognition analysis, all 3 items are

recording high negative counts that above 20 counts where Item P: (Time in supervising

and inspecting the construction works) with the greatest numbers of negative counts (26

Nos.) followed by Item R: (Time for transporting workers, equipment and materials) –

P Q R

1 1 2 2 1 NON WASTE

2 1 1 1 2 WASTE

3 1 1 1

4 1 1 1

5 1 1 1

6 1 1 1

7 1 1 1

8 1 1 1

9 1 1 1

10 2 1 1

11 1 1 2

12 1 1 1

13 1 1 1

14 1 1 1

15 1 1 1

16 1 1 2

17 1 2 1

18 1 1 1

19 1 1 1

20 1 1 1

21 1 1 1

22 1 2 1

23 1 2 2

24 1 1 1

25 1 2 1

26 1 1 1

27 1 1 1

Legend:

P: Time in supervising and inspecting the

construction works

Q: Time for instructions and communication among

different tiers and trades of workers

R: Time for transporting workers, equipment and

materials





126

23 Nos. and Item Q: (Time for instructions and communication among different tiers

and trades of workers) – 22 Nos.

Figure 6.10

Breakdown of contributory time waste recognition cases

The total counts for the analysis of construction waste event control will calculated with

less 1 missing inputs range so it would be (3 X 26) equal to 78 total counts. All the

inputs are tabulated in Table 6.8 below and a total of 69 positive counts are recorded or

approximately 88% and it shows an tremendous increase in percentage on the waste

event control for the elements tested compared to the construction waste recognised

under this category. This vast contrast of percentages between wastes recognition and

waste event control under this category suggested that the respondents do not see

1

26

5

22

4

23

0

5

10

15

20

25

30

P Q R

Non Waste

Waste

127

contributory time wastes as a waste but in actual practices, they obvious notices the

important of controlling those events.

2P 2Q 2R

1 1 1 2 1 NOT CONTROL

2 2 2 2 2 CONTROL 3 2 2 2

4 2 2 2

5 2 2 2

6 - - -

7 2 2 2

8 2 2 2

9 2 2 2

10 1 1 1

11 2 2 2

12 2 2 2

13 2 2 2

14 2 2 2

15 2 2 2

16 2 2 2

17 2 2 2

18 2 1 2

19 2 2 2

20 2 2 2

21 2 2 2

22 1 2 2

23 2 1 2

24 2 2 2

25 2 2 2

26 1 2 2

27 2 2 2

Table 6.8

Construction waste control practices under contributory time waste category


contributory time waste category are shown in Figure 6.11. It shows that all the 3 items

are having high positive counts for waste event control where all 3 items of contributory

time waste are recording above 20 Nos. of positive counts lead by Item P: (Time in

supervising and inspecting the construction works) with 25 Nos.

Legend:


construction works




materials





128

Figure 6.11 Breakdown of contributory time waste control practice cases

Again, by cross tabbing of both Table 6.7 & 6.8 for contributory waste will result in a

matrix table as show in Table 6.9 below. Therefore, the inter-relationship between the

contributory waste concepts of the respondents with their actual control practices on

construction processes can be explained using this matrix table. 4 potential scenarios

cases are to be investigated for contributory time waste category.

25

11

21

5

1

22

4

1

0

5

10

15

20

25

30

P Q R

Missing

Non Control

Control

129

P Q R






6 - - -

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

Table 6.9

Matrix table between waste concepts and control practices for contributory time wastes


(79.5%) followed by Case 1: 7 cases (9.0%), Case 2: 6 cases (7.7%) and finally Case 3:

3 cases (3.8%). The result shows that contributory time wastes has not been regarded as

construction wastes by most of the respondents. Nevertheless, in actual practices, they

seek to control those particular waste elements under contributory time wastes category,

which explained that they subconsciously acknowledged the important of controlling

those elements in their construction processes.

Legend:


construction works




materials

130

If we study the overall waste recognition, it is found that the percentage of project

management orientated personnel will have a slightly higher percentage of construction

waste recognition (72.6%) over site operative management orientated personnel

(61.7%) (Refer Figure 6.12 below)

Figure 6.12

Percentage breakdown of the wastes recognition by nature of work of the respondents

However, in certain wastes elements, site operative management personnel were

recorded higher recognition percentage compared to project management personnel for

example Item 1S: (Accidents on site), site operative management personnel were

recorded (13 out of 13) 100% recognition compared to project management personnel

only recorded (10 out of 14) 71.4% of recognition for that particular items.

193

73

150

97

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Project Management Orientated Position Site Management Orientated Position

non waste

waste

(72.6%) (61.7%)

(27.4%) (39.3%)

131

6.3 Inferential analysis results

This section will discuss about the analysis results from inferential analysis. Statistic

tools such as correlation Pearson-r and One-Way t-test will be utilised to test some

hypotheses of the study and determine the frequency ranking of each particular event or

case as rated by the respondents.

6.3.1 Correlation among direct conversion wastes concepts and perceptions, waste

event control and frequencies of waste event occurrences

There are 3 hypotheses to be tested under this direct conversion wastes category:


wastes are been perceived (D_WASTE1) with the tendency to

control those wastes (D_WASTE2)


wastes are been perceived (D_WASTE1) with the frequencies of

occurrences of such wastes during the processes (D_WASTE3)


construction’s direct conversion wastes (D_WASTE2) with the

frequencies of occurrences of such wastes during the processes

(D_WASTE3)

132

The purpose of these 3 hypotheses is to study whether any significant correlation

existed among waste conception, waste event control and the frequencies of wastes

events occurrences. These 3 hypotheses are to be tested together using correlation

Pearson r, and the results show that there are not significant correlations among each

other (refer Table 6.10) as the two-tail sig. value (K) is more than 0.05 for 3 cases

tested. Hence Hypothesis 1, 2 and 3 is rejected.

Hypothesis 1 Test

Variables

D_WASTE1

D_WASTE2

-.193

K = .364 >.05

Hypothesis 2 Test

Variables

D_WASTE1

D_WASTE3

-.040

K = .842 >.05

Hypothesis 3 Test

Variables

D_WASTE2

D_WASTE3

-.080

K = .698 >.05

Table 6.10 Correlation Pearson-r results summaries for hypothesis 1, 2 and 3 (Refer Appendix 1 for

Correlation Pearson-r result outputs from SPSS 10.0)

133

6.3.2 Correlation among non-contributory time wastes concepts and perceptions,

waste event control and frequencies of waste event occurrences

Same as direct conversion wastes, there are 3 hypotheses to be tested under this non-

contributory wastes category:

Hypothesis 4: There is inter-relationship between construction’s non-contributory

time wastes are been perceived (NON_CON1) with the tendency

to control those wastes (NON_CON2)

Hypothesis 5: There is inter-relationship between construction’s non-contributory

time wastes are been perceived (NON_CON1) with the


(NON_CON3)


construction’s non-contributory time wastes (NON_CON2) with

the frequencies of occurrences of such wastes during the

processes (NON_CON3)




Pearson r, and the results show that there are not significant correlations among each

134

other (refer Table 6.11) as the two-tail sig. value (K) is more than 0.05 for 3 cases

tested. Hence Hypothesis 4, 5 and 6 is rejected.

Hypothesis 4 Test

Variables

NON_CON1

NON_CON2

-.003

K = .989 >.05

Hypothesis 5 Test

Variables

NON_CON1

NON_CON3

-.291

K = .141 >.05

Hypothesis 6 Test

Variables

NON_CON2

NON_CON3

.297

K = .141 >.05

Table 6.11 Correlation Pearson-r results summaries for hypothesis 4, 5 and 6 (Refer Appendix 1 for


135

6.3.3 Correlation among contributory time wastes concepts and perceptions, waste

event control and frequencies of waste event occurrences

Same as previous 2 wastes categories, there are 3 hypotheses to be tested under this

contributory wastes category:


wastes are been perceived (CON1) with the tendency to control

those wastes (CON2)


wastes are been perceived (CON1) with the frequencies of

occurrences of such wastes during the processes (CON3)


construction’s contributory time wastes (CON2) with the


(CON3)




Pearson r, and the results show that there are significant correlations between the way

contributory time wastes have been perceived (CON1) with the tendency to control

those wastes (CON2) as the 2-tail sig. value (K) signify the correlation is significant at

0.01 level or value K < 0.01 with a negative correlation (r = -.551) whereas the other 2

136

cases are tested non-significant with the 2-tail sig. value (K) is more than 0.05. (Refer

Table 6.12) Hence Hypothesis 7 is accepted and hypothesis 8 and 9 is rejected. The

case of Hypothesis 7 is true if we look back at the matrix table for contributory time

waste (Table 6.9) which also indicated that the most cases recorded among the cross

tabbing exercises proved that Case 4: Wastes not recognised but controlled is among the

most registered cases whereby in term of count inputs, it should be results in a negative

counts for wastes recognition and positive counts for wastes event control for a overall

negative correlation.

Hypothesis 7 Test

Variables

CON1

CON2

-.551**

K = .004 >.01**

Hypothesis 8 Test

Variables

CON1

CON3

-.223

K = .263 >.05

Hypothesis 9 Test

Variables

CON2

CON3

.268

K = .185 >.05

Table 6.12

Correlation Pearson-r results summaries for hypothesis 7, 8 and 9 (Refer Appendix 1 for


137

6.3.4 Ranking on frequencies of occurrences for wastes exist in construction

processes

The purpose of this analysis is to determine the frequency of occurrences of

construction wastes as experienced by the respondents, the frequencies of occurrences

for construction wastes are analysed by using one-way t-test to determine the mean

values, standard of deviation and standard error mean and the mean of scores were

listed in descending order as shown in Table 6.13

# Construction Waste Variables N Mean Std.

Deviation

Std. Error

Mean

Waste Categories

P3 Time in supervising and inspecting the

construction works 27 4.00 .83 .16 Contributory Time

E3 Waiting for the clarification and confirmation by

client and consultants 27 3.81 .79 .15 Non-Contributory Time

Q3 Time for instructions and communication among

different tiers and trades of workers 27 3.78 .75 .14 Contributory Time

A3 Waiting for others to complete their works before

the proceeding works can be carried out 27 3.67 .73 .14 Non-Contributory Time

M3 Time for rework/ repair works/ defective works 27 3.37 .69 .13 Non-Contributory Time

N3 Materials for rework/ repair works/ defective

works 27 3.33 .73 .14 Direct Conversion

C3 Waiting for materials to be delivered on site 27 3.30 .95 .18 Non-Contributory Time

R3 Time for transporting workers, equipment and

materials 27 3.26 .94 .18 Contributory Time

B3 Waiting for equipment to be delivered on site 27 3.15 .86 .17 Non-Contributory Time

K3 Material deterioration/ damaged during

construction periods 27 3.11 .89 .17 Direct Conversion

J3 Material loss/ stolen from site during

construction periods 27 3.07 .83 .16 Direct Conversion

L3 Mishandling or error in construction applications/

installation 27 3.04 .90 .17 Direct Conversion

I3 Unnecessary procedures and working protocols 27 3.00 .96 .18 Direct Conversion

O3 Time for workers’ resting during construction 27 2.96 .85 .16 Non-Contributory Time

G3 Over-allocation/ unnecessary materials on site 27 2.93 .83 .16 Direct Conversion

D3 Waiting for the skilled workers to be on site 27 2.67 .92 .18 Non-Contributory Time

S3 Accidents on site 27 2.52 .70 .13 Direct Conversion

F3 Over-allocation/ unnecessary equipment on site 27 2.44 .85 .16 Direct Conversion

H3 Over-allocation/ unnecessary workers on site 27 2.41 .84 .16 Direct Conversion

Table 6.13 Construction waste variables ranking (Refer Appendix 2 for t-test results output from SPSS

10.0)

138

From the mean ranking results, it shows that time wastes categories regardless of

contributory time or non-contributory time wastes occurred at the top of the list

compared to direct conversion wastes. Therefore, it is recommended that for

construction processes improvements, it is eventually those contributory and non-

contributory times waste variables that have to be given more attentions and in real fact,

most of them are related to process flows and sequences and this can lead to lean

construction’s tools and methods which are developed mostly to tackle those wastes

resulted from process flow inefficiencies.

139

6.3.5 Ranking on likeliness for sources/ causes for the construction wastes

The purpose of this analysis is to determine the respondent’s recognition of particular

sources/ causes factors that cause construction wastes. Same as ranking for the

frequencies of wastes occurrences, the rating on these likelihood of waste sources/

causes factors as rated by the respondents are analysed by using one-way t-test and the

mean of scores were listed in descending order as shown in Table 6.14

# Sources/ Causes for Construction Wastes N Mean Std.

Deviation

Std. Error

Mean

Sources/ Causes Factors

Categories

E2 Late information and decision making 27 3.63 .56 .11 Information and

Communication Factors

D2 Poorly scheduled delivery of material to site 27 3.37 .63 .12 Material Factors

A1 Poor coordination among project participants 27 3.37 .63 .12 Management &

Administration Factors

E3 Unclear information 27 3.26 .53 .10 Information and


A2 Poor planning and scheduling 27 3.26 .59 .11 Management &


D3 Poor quality of material 27 3.26 .71 .14 Material Factors

A3 Lack of control 26 3.23 .59 .12 Management &


D1 Delay of material delivery 27 3.22 .70 .13 Material Factors

E1 Defective or Wrong information 27 3.15 .53 .10 Information and


B2 Inexperience inspectors 27 3.11 .51 9.75E-02 People Factors

D4 Poor equipment choice or ineffective equipment 27 3.11 .80 .15 Material Factors

D6 Poor site documentation 27 3.07 .68 .13 Material Factors

B3 Too few supervisors/ foreman 27 3.04 .59 .11 People Factors

B5 Supervision too late 27 2.96 .71 .14 People Factors

B4 Uncontrolled sub-contracting practices 27 2.93 .62 .12 People Factors

B1 Lack of trades skills 27 2.93 .62 .12 People Factors

C3 Equipment shortage 27 2.93 .62 .12 Execution Factors

D5 Poor storage of material 27 2.93 .73 .14 Material Factors

C6 Poor site documentation 27 2.89 .58 .11 Execution Factors

C5 Poor site layout and setting out 27 2.85 .66 .13 Execution Factors

C4 Poor equipment choice or ineffective equipment 27 2.81 .56 .11 Execution Factors

A4 Bureaucracy 27 2.78 .58 .11 Management &


B6 Poor labour distribution 27 2.70 .67 .13 People Factors

C1 Inappropriate construction methods 27 2.67 .73 .14 Execution Factors

C2 Outdated equipment 27 2.52 .80 .15 Execution Factors

Table 6.14

Sources/ causes of construction waste ranking (Refer Appendix 2 for t-tests results

output from SPSS 10.0)

140

As from the mean ranking result shows that Item E2: (Late information and decision

making) is highly regarded as the main contributory sources or causes to the

construction wastes with the highest mean value (3.63) and with a 0.26 from the second

rank item D2: (Poorly scheduled delivery of material to site)

Among the clusters of cause factors observed from Table 6.14, there are 3 categories of

waste sources/ causes factors are widely acknowledged as the key contributory factors

to construction wastes. Those categories included Information and Communication

Factors, Management and Administration Factors and Material Factors as most of the

Cause factors captured under these 3 categories are rated with the mean value over 3.

Overall, the likelihood of recognising the items above as the sources/ causes of wastes

that will impact on the productivity of the projects, are still reasonably high as most of

the mean value for the items tested were clustering around the scale “3” value

representing “likely as a sources/ causes of wastes”. However, there are also some

exceptions such as Item C1: (Inappropriate construction methods) and Item C2:

(Outdated equipment) both recorded a slightly low mean values of 2.67 and 2.52

respectively.

141

6.4 Causes and Effects Matrix

The purpose of this analysis to relate the particular sources or causes to the construction

wastes and this is to give us a better picture of what leads to the waste in construction

processes as suggested by the respondents feedback on this research. Figure 6.13 is the

overall analysis on Causes and Effects Matrix of the “Major cause” to the construction

wastes based on 5 main causes factors while Figure 6.14 is the Causes and Effects

Matrix of the “Other causes” to the construction wastes. (Refer overall Causes and

Effects Matrix tables in Appendix 4 for a detailed understanding on actual one to one

relationship between wastes causes to wastes itself as per the data gather from the

respondents of this research)

142

Figure 6.13

Causes and Effects relationship for the cases of major causes (Categorised)

0 5 10 15 20 25

Nos. of major cause related

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

Ty

pe

of

Co

ns

tru

cti

on

Wa

ste

sManagement & Administration

Factors

People Factors

Execution Factors

Materials Factors

Information & Communication

Factors

Not relevant

Legend:







client/ consultants

F: Over-allocation/ unnecessary equipment on site





periods




installation

M: Rework/ repair works/ defective works

N: Workers’ resting during construction

O: Supervising and inspecting the construction works

P: Instructions and communication among different

tiers and trades of workers

Q: Transporting workers, equipment and materials

R: Accidents on site

143

Figure 6.14

Causes and Effects relationship for the cases of others causes (Categorised)

The matrix table provides a clearer insight into the types of causes factors that directly

related construction wastes, as we shall see that in Figure 6.13, Management and

Administration Factors has a relatively high counts numbers in causing the construction

wastes items ranging from Item A to Item I and Item Q, Materials Factors dominants

over Item J & K and People Factors score higher in Item M, N and O. By conducting

0 5 10 15 20 25 30 35

Nos. of other causes related

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

Typ

es o

f co

nstr

ucti

on

waste

s

Management & Administration

Factors

People Factors

Execution Factors

Materials Factors

Information & Communication

Factors

Not relevant

Legend:







client/ consultants

F: Over-allocation/ unnecessary equipment on site





periods




installation

M: Rework/ repair works/ defective works

N: Workers’ resting during construction

O: Supervising and inspecting the construction works

P: Instructions and communication among different

tiers and trades of workers

Q: Transporting workers, equipment and materials

R: Accidents on site

144

this causes and effects matrix exercise, we can know that each types of construction

wastes has a different roots causes to the problems and it is important to identify those

particular causes to the problems in order to a proper corrective or preventive actions

can be carried to ensure continuous improvement in performance of construction

activities.

145

CHAPTER 7

CONCLUSIONS AND RECOMMENDATIONS

7.1 Introduction

This chapter concludes the whole study based on the findings. The tested

hypotheses will be related to the research objectives and further interpreted and

conclusion on the achievement of the research objectives will be drawn. Some

recommendations will also be drawn from the findings and the limitations during

the research period will also be highlighted

7.2 Discussions of the findings of the research

The discussion on the findings of the research will be carried in 2 separate ways:

1. Relating the research findings to research objectives

2. Rewritten hypotheses and interpret the results

7.2.1 Relating the research findings to research objectives

1. Research objective 1: General perceptions on construction wastes based on

lean construction principles

146

From the research results, it is found that the general perceptions and lean

concepts of local construction personnel particularly on construction

wastes and their tendency to control these wastes are at an acceptable

level. The local construction site personnel can identified most wastes as

outlined and the tendency of controlling those wastes is even higher than

recognising the wastes themselves. However, from the results, it also

shows that the recognition over flow related construction wastes is rather

low compared to direct conversion wastes or physical wastes especially

those related to contributory time wastes. This signify that the local

construction personnel are still not fully comprehend the concepts of flows

and non value-adding activities and tends to included these contributory

work as part and parcel of conversion process.

In fact, lean construction philosophy sees these contributory works as not

adding any values to the client even though they are sometimes necessary

for the progress of the overall construction processes. On the bright side,

the research results also show a very high percentage on those contributory

works as being controlled during the construction processes signaling that

those contributory time wastes are actually well aware off those activities

even though they being not recognised as construction wastes.

Besides that, it is also found that there are different levels of waste

recognition between project management orientated personnel and the site

147

operative management orientated personnel. Project managerial personnel

recorded higher overall waste recognition compared to site operative

managerial personnel suggesting that they are more sensitive to overall

construction wastes issues and those related to process flows, whereas site

operative managerial personnel are found more concentrated for

conversion wastes where the percentage of recognising some conversion

wastes are higher than the project managerial personnel.

2. Research Objective 2: Degree of problems arisen of the wastes identified

Based on the ranking of the event occurrences frequencies for waste events

existed in construction processes shows that the most frequent waste

events occurred in construction activities are actually flow related with

both contributory time wastes and non-contributory time wastes were at

the top of the ranking list. On the other hand, many direct conversion

wastes are recorded rather low scores mostly in the range of “Seldom” and

“Very Rare” occurrence events.

Eventually by breaking down the waste categories, it is made clear that the

flow time wastes are the prominent events that occurred in construction

processes. Therefore, based on that information, a better performance

improvement strategies can be arranged to target at those flow related

wastes events, as those events are usually invisible or ignored by

148

conventional construction management. The construction processes can be

further streamlined by reducing or eliminating those flow waste elements

by implementing the lean construction principles and practices such as

employee involvements, kanzan, JIT concepts etc at all level of

construction processes.

3. Research Objective 3 & 4: Waste cause and effect relationship and

potential improvement strategies

In this research, major sources of wastes are also been identified directly

related to the respective construction wastes from the wastes causes and

effects matrix as shown in Appendix 4. From the aggregated results shows

that management and administrative factors are recognised as the dominant

sources of wastes for most of the cases while material factors and people

factors are more dominant for a few wastes types. If compared to the

ranking of the likelihood for waste factors to impact the construction

productivity in general, information and communications factors which are

hardly seen as a dominant factor of any construction wastes types at the

top of the ranking list follow tightly by management and administrative

factors. On the low side, the executive factors and people factors scored

relatively low in the ranking.

149

This is a very good exercise to point out the causes and effects relationship

between the sources of waste and waste itself for processes control,

reengineering or redesign by targeting directly at the respective sources of

wastes for processes improvement. In most leaner construction

organisition, they usually practise this exercise in a survey called waste

identification survey (WIS) through work sampling practices in order to

monitor and improve their flow performance from time to time during their

construction activities.

7.2.2 Rewritten hypotheses and interpret the results

From inferential statistical analyses in chapter 6, 9 hypotheses testing were

conducted with Pearson-r correlation. The results from the analyses had concluded

following hypotheses as:

For direct conversion wastes inter-relationship testing

1. There is no significant inter-relationship between construction’s direct

conversion wastes perceived with the tendency to control those wastes.

2. There is no significant inter-relationship between construction’s direct

conversion wastes perceived with the frequencies of occurrences of such

wastes during construction.

150

3. There is no significant inter-relationship between the tendency to control

direct conversion wastes with the frequencies of occurrences of such


For non-contributory time wastes inter-relationship testing

4. There is no significant inter-relationship between construction’s non-

contributory time wastes perceived with the tendency to control those

wastes.

5. There is no significant inter-relationship between construction’s non-

contributory time wastes perceived with the frequencies of occurrences of

such wastes during construction.

6. There is no significant inter-relationship between the tendency to control

non-contributory time wastes with the frequencies of occurrences of such


For contributory time wastes inter-relationship testing

7. There is no significant inter-relationship between construction’s

contributory time wastes perceived with the tendency to control those

wastes.

8. There is no significant inter-relationship between construction’s

contributory time wastes perceived with the frequencies of occurrences of

such wastes during construction.

151

9. There is significant inter-relationship between the tendency to control

contributory time wastes with the frequencies of occurrences of such


The non-significant over almost all the hypotheses tested (except contributory

time wastes recognition and control recorded a negative significant score or -.551)

in correlation testing shows that there were not uniformity in the way the

construction waste are recognised and controlled even with the high recognition

and control rates. Recognising particular construction wastes or frequencies of

occurrence of construction wastes on site by the construction personnel do not

prompt them to control them and vice versa, recognizing construction wastes are

not prompt by the frequencies of occurrence of those wastes during construction

site. The construction wastes are treated very subjectively from cases to cases and

suggested that no proper doctrine or philosophy in supporting for particular waste

recognition and control mechanism.

In the importance of continuous process and productivity improvement, having the

correct concepts and understanding and having the right attitudes to mitigate and

control the flow and flow related wastes are very essence. In this case, the worst

scenario would be someone actually not knowing what is the waste and therefore

not put in any efforts to control it and letting the wastes to repeat from time to

time. There might be some other reasons for not recognising wastes and not

controlling them. Some would not treat it as a waste as those wastes are

152

recoverable due to defaults by others and some misunderstanding that wastes are

necessary to avoid others bigger wastes from happening. For example, as cited

from the only 1 qualitative inputs from all 27 questionnaires received stated that

waiting for clarification and confirmation by client and consultants is not a waste

because he/ she believed that it is important to wait for clarification and

confirmation “because lack of this will be more wastage (redo the task)”. From

the results of cross-tab matrix tables shows a relatively low percentage of that

particular scenario (less than 7%) and that should be a good sign for the local

construction industries.

However, for the scenarios of knowing the wastes but not controlling them hit a

rather high numbers of cases and percentage especially in direct conversion

wastes. This is particularly not a good sign where those wastes are left behind the

construction processes and hinder the full potential of process improvement. The

results to this might be abundant. One of the reason would be the costs to control

or improve the wastes might be higher that the cost of the wastes itself. Besides

that, the reasons of not control the wastes even the wastes are identified and

recognised perhaps is due to not sufficient tools and knowledge to control them

and some might due to misunderstanding during execution and not well trained

personnel.

153

7.3 Limitations of the research

One of the limitations to this research is the design of the research by trying to

discuss lean construction philosophy in a general perceptive of construction

processes, which restricted to site construction processes only. In the real essences

of lean construction, lean construction principles are universal and can be applied

in all aspects of construction processes flow improvement from the very start of

the projects until the very end of project execution and delivery. In that context,

the overall process flow improvement can include design management, supply

chain management, sub-contracting management etc and not just restricted to

wastes of the area of this study.

In that bigger extent of interpretation on lean construction, the potential

productivity improvement is even greater but it required a higher degree of

commitment and leadership while this research is only focusing one main concept

of flow as suggested by lean construction and studies the related perceptions and

actual control practices on flow related wastes as well as the potential

improvement available based on the findings of the research.

The other limitations to this study is the lack of qualitative data on this research,

those qualitative data can be useful in answering certain reasons behind of

particular understanding, attitudes and actions by the respondents. In this research,

only one qualitative data are provided among all respondents although in the

154

questionnaire has prepared column for the respondents to express their views and

opinions.

7.4 Challenges in Implementing Lean Construction

There have been many general principles of lean construction highlighted in the

previous chapters. The principles cited relate to three broad areas: improving the

activity or task (workstation) operation, optimising the overall process, and

learning from external facilities and organisations (benchmarking). Different

principles apply at each level, and the concepts upon which these principles are

based may also differ. For example, at the total process level, construction can be

viewed as a series of sequential operations whereas at the activity and subtask

levels, the work is largely composed of concurrent operations. Also, at the total

process level, analyses of the work tend to be process oriented. At the activity

level, analyses are more product-oriented.

Due to the diffusing concepts and principles of lean construction, Implementing it

into the existing processes will somehow turn out to be more difficult especially

this implementation is something which has to deal with mindset and culture

changes. Therefore, it is outlined with a few key challenges that need to be

seriously looked into in order to successfully adopt and implement the new

philosophy of lean construction into the conventional practices.

155

1. Management commitment

Leadership is needed to realise a fundamental shift of philosophy, with the

goal of improving every activity in the organisation. Without an active

initiative from the management, change will stop at all natural barriers.

Management must understand and internalise the new philosophy. The change

will be realised only through people; it cannot be delegated to staff specialists,

like in the case of investment into new technology. Management must create

an environment, which is conducive to change.

2. Focus on measurable and actionable improvement

The focus should be on actionable and measurable improvement, rather than

just on developing capabilities. Of course, defining various flow processes and

focusing on their bottlenecks to speed up and smooth out material and

information flows means just that. Short-term successes then reinforce

motivation for further improvement.

Originally in JIT, the overarching goal was to reduce or eliminate inventories.

However, reduction of inventories uncovered other problems, which had to be

solved as a forced response. Cycle time, space and variability have also been

used as drivers, because they too are increased by underlying problems.

Especially cycle time provides an excellent, easy to understand driver, which

can be improved continually.

156

3. Involvement

Employee involvement happens naturally, when organisational hierarchies are

dismantled, and the new organisation is formed with self-directed teams,

responsible for control and improvement of their process. But also even if the

hierarchy remains intact, involvement can be stimulated through problem

solving teams. Employee involvement is thus necessary, but not sufficient for

realising the full potential of continuous improvement.

4. Learning

Implementation requires a substantial amount of learning. First, learning

should be directed at principles, tools and techniques of process improvement.

In the next phase, the focus turns to empirical

xi

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xiv

APPENDIX 1:

CORRELATION PEARSON R RESULTS FROM SPSS 10.0

Correlations

D_WASTE1 D_WASTE2 D_WASTE3

D_WASTE1 Pearson Correlation 1.000 -.193 -.040

Sig. (2-tailed) . .346 .842

N 27 26 27

D_WASTE2 Pearson Correlation -.193 1.000 -.080

Sig. (2-tailed) .346 . .698

N 26 26 26

D_WASTE3 Pearson Correlation -.040 -.080 1.000

Sig. (2-tailed) .842 .698 .

N 27 26 27

Correlations

NON_CON1 NON_CON2 NON_CON3

NON_CON1 Pearson Correlation 1.000 -.003 -.291

Sig. (2-tailed) . .989 .141

N 27 26 27

NON_CON2 Pearson Correlation -.003 1.000 .297

Sig. (2-tailed) .989 . .141

N 26 26 26

NON_CON3 Pearson Correlation -.291 .297 1.000

Sig. (2-tailed) .141 .141 .

N 27 26 27

Correlations

CON1 CON2 CON3

CON1 Pearson Correlation 1.000 -.551** -.223

Sig. (2-tailed) . .004 .263

N 27 26 27

CON2 Pearson Correlation -.551** 1.000 .268

Sig. (2-tailed) .004 . .185

N 26 26 26

CON3 Pearson Correlation -.223 .268 1.000

Sig. (2-tailed) .263 .185 .

N 27 26 27

** Correlation is significant at the 0.01 level (2-tailed).

xv

APPENDIX 2

ONE-WAY T-TEST RESULTS FROM SPSS 10.0

One-Sample Statistics

N Mean Std. Deviation Std. Error

Mean

A3 27 3.67 .73 .14

B3 27 3.15 .86 .17

C3 27 3.30 .95 .18

D3 27 2.67 .92 .18

E3 27 3.81 .79 .15

F3 27 2.44 .85 .16

G3 27 2.93 .83 .16

H3 27 2.41 .84 .16

I3 27 3.00 .96 .18

J3 27 3.07 .83 .16

K3 27 3.11 .89 .17

L3 27 3.04 .90 .17

M3 27 3.37 .69 .13

N3 27 3.33 .73 .14

O3 27 2.96 .85 .16

P3 27 4.00 .83 .16

Q3 27 3.78 .75 .14

R3 27 3.26 .94 .18

S3 27 2.52 .70 .13

One-Sample Statistics

N Mean Std. Deviation Std. Error

Mean

A4_1 27 3.37 .63 .12

A4_2 27 3.26 .59 .11

A4_3 26 3.23 .59 .12

A4_4 27 2.78 .58 .11

B4_1 27 2.93 .62 .12

B4_2 27 3.11 .51 9.75E-02

B4_3 27 3.04 .59 .11

B4_4 27 2.93 .62 .12

B4_5 27 2.96 .71 .14

B4_6 27 2.70 .67 .13

C4_1 27 2.67 .73 .14

C4_2 27 2.52 .80 .15

C4_3 27 2.93 .62 .12

C4_4 27 2.81 .56 .11

C4_5 27 2.85 .66 .13

C4_6 27 2.89 .58 .11

D4_1 27 3.22 .70 .13

D4_2 27 3.37 .63 .12

D4_3 27 3.26 .71 .14

D4_4 27 3.11 .80 .15

D4_5 27 2.93 .73 .14

D4_6 27 3.07 .68 .13

E4_1 27 3.15 .53 .10

E4_2 27 3.63 .56 .11

E4_3 27 3.26 .53 .10

xvi

APPENDIX 3

SPSS DATA INPUT SHEETS

(RESPONDENT’S INFO)

POSITION P_TYPE CIDB CLIENT

1 4 2 2

1 4 2 2

2 3 2 1

1 1 2 1

2 5 2 2

1 2 2 1

1 4 1 2

2 4 2 2

2 2 - 1

2 3 2 1

1 2 1 1

2 4 - 2

1 3 2 1

1 5 2 2

1 2 2 1

1 3 2 1

2 2 2 1

1 2 2 2

2 1 2 1

2 3 2 1

1 3 2 1

2 4 2 2

2 2 1 1

1 5 2 2

1 4 2 2

2 4 2 2

2 1 2 1

xvii

APPENDIX 3

SPSS DATA INPUT SHEETS (CONT’D)

(WASTE CONCEPTS)

A1 B1 C1 D1 E1 F1 G1 H1 I1 J1 K1 L1 M1 N1 O1 P1 Q1 R1 S1

1 2 2 2 1 2 2 2 2 2 2 2 2 2 1 1 2 2 2

2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1

2 1 1 1 1 2 2 2 1 2 2 2 2 2 1 1 1 1 2

2 1 1 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 2

2 2 2 2 2 1 1 1 1 2 2 2 2 2 1 1 1 1 2

2 2 2 2 1 2 2 2 2 2 2 2 2 2 2 1 1 1 2

2 2 1 2 2 2 2 2 2 2 2 1 2 2 1 1 1 1 2

2 2 2 2 2 1 1 1 2 1 1 2 1 1 1 1 1 1 2

2 2 2 2 2 1 1 1 2 2 2 2 2 2 1 1 1 1 2

1 1 1 1 2 1 1 1 2 1 1 1 1 2 2 2 1 1 2

2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 2 2

2 2 2 2 1 2 2 2 1 2 2 2 2 2 2 1 1 1 2

1 1 2 2 1 2 2 2 2 1 2 2 2 2 1 1 1 1 1

2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 2

1 2 2 2 2 2 2 2 1 2 1 2 2 2 1 1 1 1 2

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 2 2

1 1 1 1 2 2 2 2 2 2 2 2 2 2 1 1 2 1 2

2 2 2 2 1 2 2 2 2 2 2 2 2 2 1 1 1 1 2

2 2 2 2 2 1 2 1 2 2 2 2 2 2 1 1 1 1 2

2 1 1 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 2

1 1 1 2 2 2 2 2 2 1 2 2 2 2 1 1 1 1 1

2 2 2 2 1 2 2 1 1 2 2 2 2 2 2 1 2 1 2

2 1 1 1 1 2 2 2 2 2 2 2 2 2 1 1 2 2 2

2 2 2 2 2 1 2 2 2 2 2 2 2 2 1 1 1 1 2

2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 2 1 1

2 2 2 2 1 1 1 1 2 2 2 2 2 2 1 1 1 1 2

2 1 2 2 2 1 2 2 2 2 2 2 2 2 1 1 1 1 2

xviii

APPENDIX 3


(WASTE CONTROL EVENTS)


2 2 2 2 1 2 2 2 2 1 1 2 2 2 2 1 1 2 1

2 2 2 2 2 2 2 2 2 1 1 2 2 2 2 2 2 2 1

2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 1

2 2 2 2 1 2 2 2 2 1 2 2 2 2 2 2 2 2 1

2 2 2 2 2 1 1 1 2 2 2 2 2 2 2 2 2 2 2

- - - - - - - - - - - - - - - - - - -

2 2 2 2 1 2 2 2 1 1 2 1 2 2 2 2 2 2 1

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

2 2 2 2 1 2 2 2 1 1 1 2 2 1 1 1 1 1 1

2 2 2 1 2 1 1 1 2 2 2 1 2 2 1 2 2 2 1

2 2 2 2 1 2 2 2 1 2 2 2 1 1 1 2 2 2 2

2 2 1 1 1 2 2 2 1 2 2 1 2 2 2 2 2 2 2

1 2 1 1 1 2 1 1 1 1 1 1 1 1 1 2 2 2 1

2 2 2 2 1 2 2 2 2 2 2 2 1 1 2 2 2 2 1

2 2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2

2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

2 2 2 2 2 1 1 1 2 2 2 2 2 2 1 2 1 2 2

2 2 2 2 1 2 2 2 2 2 2 2 2 2 2 2 2 2 1

2 2 2 2 2 2 2 2 2 1 2 2 2 2 2 2 2 2 1

2 2 1 1 1 2 2 2 1 2 2 2 2 2 2 2 2 2 2

2 2 2 2 1 2 2 2 2 2 2 2 2 2 2 1 2 2 2

2 2 2 2 2 1 1 1 2 2 2 1 1 1 1 2 1 2 1

2 2 2 1 1 2 1 1 1 2 2 2 2 1 2 2 2 2 1

2 2 2 2 1 2 2 2 1 1 1 2 2 2 1 2 2 2 2

2 2 2 2 2 2 2 2 2 1 1 2 2 2 2 1 2 2 1

2 2 2 2 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2

xix

APPENDIX 3


(FREQUENCIES OF OCCURRENCES)


3 3 3 2 5 4 4 4 4 3 4 4 3 3 3 3 3 2 4

3 3 2 2 4 3 3 2 4 2 2 3 4 4 3 5 4 3 2

3 3 4 3 4 3 3 3 3 3 3 3 3 3 3 4 4 4 2

4 3 3 3 4 3 4 4 4 4 4 3 4 4 3 5 4 3 3

4 3 4 3 3 3 3 3 3 2 2 2 3 3 2 3 3 4 2

4 4 4 3 3 3 4 3 3 4 4 4 4 4 5 5 5 3 3

3 1 2 1 4 1 2 2 2 4 4 5 4 3 2 5 5 2 3

2 2 2 1 2 3 3 2 1 1 2 2 2 2 2 4 4 2 1

4 3 3 3 3 2 2 2 2 3 3 2 3 3 3 4 3 3 2

3 4 2 3 4 3 4 3 2 4 3 3 3 4 2 4 3 3 3

5 4 5 3 3 3 3 2 4 3 4 3 4 2 2 3 4 3 3

5 3 3 4 4 3 3 1 3 2 2 2 3 3 3 5 5 4 2

3 3 4 4 4 3 3 2 3 3 3 2 3 2 3 3 3 3 3

4 2 3 2 5 2 4 2 4 3 5 5 5 5 3 2 2 4 3

4 4 4 3 5 3 3 3 3 4 3 4 4 4 5 5 4 5 3

4 5 5 4 4 1 2 2 3 3 3 2 3 3 4 5 5 5 2

3 3 2 2 3 1 1 1 1 2 2 2 4 4 3 4 4 1 2

4 4 4 2 4 1 2 1 3 3 3 3 3 3 2 4 3 4 3

4 3 3 3 3 3 3 4 3 4 4 3 4 4 3 4 4 3 3

3 4 4 4 5 2 2 3 5 3 3 3 4 4 3 5 4 3 3

4 4 4 4 4 3 4 2 4 3 3 3 3 4 2 4 3 4 3

4 3 2 1 3 1 3 2 2 3 3 3 2 3 3 4 4 4 1

3 4 5 3 4 3 2 2 2 4 3 4 4 3 4 3 4 4 2

4 2 3 2 3 2 3 2 3 2 1 2 3 3 4 4 3 3 3

4 2 3 2 5 3 2 2 4 3 3 3 3 3 2 3 4 3 2

3 3 3 2 4 2 3 3 3 4 4 4 3 3 3 4 4 2 2

5 3 3 3 4 2 4 3 3 4 4 3 3 4 3 4 4 4 3

xx

APPENDIX 3


(SCORE AGGREGRATION)

D_WASTE1 D_WASTE2 D_WASTE3 NON_CON1 NON_CON2 NON_CON3 CON1 CON2 CON3

18.00 15.00 26.00 11.00 13.00 23.00 5.00 4.00 8.00

17.00 15.00 33.00 13.00 14.00 24.00 3.00 6.00 12.00

17.00 16.00 29.00 9.00 14.00 21.00 3.00 6.00 12.00

18.00 16.00 24.00 11.00 13.00 24.00 3.00 6.00 12.00

14.00 15.00 16.00 13.00 14.00 20.00 3.00 6.00 10.00

18.00 - 28.00 13.00 - 27.00 3.00 - 13.00

17.00 14.00 29.00 12.00 13.00 25.00 3.00 6.00 12.00

12.00 18.00 25.00 12.00 14.00 27.00 3.00 6.00 10.00

15.00 18.00 30.00 13.00 14.00 24.00 3.00 6.00 10.00

12.00 13.00 34.00 9.00 12.00 22.00 4.00 3.00 10.00

18.00 13.00 25.00 13.00 12.00 21.00 4.00 6.00 10.00

17.00 16.00 23.00 13.00 11.00 22.00 3.00 6.00 14.00

16.00 16.00 32.00 10.00 11.00 27.00 3.00 6.00 9.00

18.00 10.00 26.00 13.00 8.00 17.00 3.00 6.00 8.00

16.00 16.00 17.00 12.00 12.00 13.00 3.00 6.00 14.00

18.00 17.00 21.00 14.00 14.00 22.00 4.00 6.00 15.00

18.00 18.00 27.00 9.00 14.00 26.00 4.00 6.00 9.00

18.00 15.00 21.00 12.00 13.00 25.00 3.00 5.00 11.00

16.00 17.00 33.00 13.00 13.00 24.00 3.00 6.00 11.00

18.00 16.00 30.00 11.00 14.00 29.00 3.00 6.00 12.00

16.00 17.00 21.00 10.00 11.00 29.00 3.00 6.00 11.00

16.00 18.00 22.00 13.00 13.00 23.00 4.00 5.00 12.00

18.00 12.00 31.00 9.00 12.00 23.00 5.00 5.00 11.00

17.00 13.00 21.00 13.00 12.00 18.00 3.00 6.00 10.00

17.00 15.00 21.00 13.00 12.00 21.00 4.00 6.00 10.00

15.00 15.00 25.00 12.00 14.00 21.00 3.00 5.00 10.00

17.00 18.00 28.00 12.00 13.00 21.00 3.00 6.00 12.00

xxi

APPENDIX 3


(WASTE SOURCES/ CAUSES)

A4_1 A4_2 A4_3 A4_4 B4_1 B4_2 B4_3 B4_4 B4_5 B4_6 C4_1 C4_2 C4_3 C4_4 C4_5 C4_6 D4_1 D4_2 D4_3 D4_4 D4_5 D4_6 E4_1 E4_2 E4_3

4 4 4 3 3 3 4 3 3 3 3 3 3 3 3 4 3 3 4 4 4 3 3 2 3

3 4 4 2 2 3 2 2 2 3 3 2 2 3 3 3 3 3 2 2 2 3 2 4 3

3 3 3 3 2 2 2 2 2 2 3 2 3 3 2 2 4 3 2 2 2 2 3 3 3

4 3 3 2 3 4 3 2 2 2 2 3 3 3 2 3 2 2 3 2 3 2 3 4 3

3 3 2 2 3 3 3 3 4 2 2 4 3 3 3 3 4 4 4 2 1 2 2 4 4

2 2 2 2 3 3 2 3 3 2 2 3 2 2 2 3 3 3 3 2 3 3 3 3 3

3 4 3 2 2 3 3 2 3 3 2 2 3 3 2 2 3 3 2 4 2 2 3 3 3

4 3 3 3 3 3 3 3 4 4 1 1 3 2 4 3 4 4 3 4 4 4 3 4 4

3 3 3 3 3 3 4 3 3 2 2 2 3 3 3 3 2 3 3 3 3 3 3 4 3

3 3 3 3 4 3 3 3 3 3 3 3 4 3 3 3 3 3 3 3 3 3 3 3 3

4 4 - 4 4 4 3 4 2 3 3 2 2 2 2 2 4 4 4 4 4 4 4 4 4

4 4 4 3 4 3 3 4 4 3 4 4 4 4 4 3 4 4 3 3 3 3 4 4 3

3 3 3 4 3 4 4 3 3 2 3 2 3 2 3 3 3 4 4 3 3 3 4 4 4

4 4 4 3 3 4 4 3 4 4 4 4 4 4 4 3 4 4 4 4 3 4 4 4 4

4 3 3 3 3 3 4 3 3 3 3 2 3 3 3 3 3 4 4 4 3 3 3 4 3

4 4 4 3 3 3 3 4 4 3 2 2 3 3 3 3 4 4 4 4 4 4 4 4 3

2 2 4 2 2 3 3 3 3 2 3 2 2 2 2 2 2 2 3 3 3 3 3 3 2

4 3 3 3 3 2 2 3 2 3 2 3 3 3 3 4 3 4 4 3 3 4 3 4 4

4 3 3 3 3 3 3 3 3 3 3 3 2 3 4 3 3 4 4 3 3 4 3 4 3

3 3 4 2 3 3 3 2 3 3 3 3 3 3 3 3 4 3 3 4 4 4 4 4 3

4 4 4 3 4 4 3 3 4 3 4 3 3 3 3 4 3 4 4 4 3 3 3 4 4

3 3 3 3 3 3 3 4 3 3 3 3 3 3 3 3 3 3 4 2 2 3 3 4 3

3 4 3 3 3 3 3 3 2 3 2 2 4 3 3 2 3 4 3 3 3 3 3 3 4

3 3 3 2 2 3 3 3 2 3 2 2 2 3 3 2 4 3 3 4 2 2 3 4 3

3 3 3 3 3 3 3 2 3 1 3 3 3 2 2 3 3 3 3 3 3 3 3 3 3

4 3 3 3 2 3 3 3 3 3 2 1 3 2 2 3 4 3 3 3 3 3 3 4 3

3 3 3 3 3 3 3 3 3 2 3 2 3 3 3 3 2 3 2 2 3 3 3 3 3

xxii

APPENDIX 4

CAUSES AND EFFECTS MATRIX TABLES

MAJOR CAUSE

A1 A2 A3 A4 B1 B2 B3 B4 B5 B6 C1 C2 C3 C4 C5 C6 D1 D2 D3 D4 D5 D6 E1 E2 E3 F

A 8 7 5 2

B 12 3 1 3 1 2

C 8 3 1 4 5 1

D 1 5 5 5 1 1 1 2 1

E 8 3 2 1 7 1

F 5 5 3 2 2 1

G 10 4 2 3 1 1

H 9 5 7

I 4 6 4 4 2

J 1 1 1 1 1 1 11 3 1

K 1 2 1 1 1 2 1 9 3

L 2 2 2 3 2 2 2 1 4

M 1 1 5 3 3 2 2 1 2

N 1 1 4 2 1 7 5

O 1 9 6 1 4

P 4 2 3 1 5 1 1 1 3

Q 3 7 1 1 4 1 1 3

R 3 1 5 1 2 2 1 1 1 1 1 2

xxiii

APPENDIX 4

CAUSES AND EFFECTS MATRIX TABLES (CONT’D)

OTHER CAUSES

A1 A2 A3 A4 B1 B2 B3 B4 B5 B6 C1 C2 C3 C4 C5 C6 D1 D2 D3 D4 D5 D6 E1 E2 E3 F

A 3 5 5 1 1 1 1 1 1 1 1 1 2 1 2 3 1

B 4 1 2 1 1 3 1 3 3 1 1 1 1

C 5 2 2 1 1 2 5 2 1 4 1 1

D 5 3 3 1 1 2 4 1

E 1 1 1 3 1 1 1 1 1 2 5 6

F 2 2 1 1 1 1 1 1 1 1 1

G 2 1 1 2 4 1 2 1 1 1

H 3 1 1 1 1 5 1 1

I 1 1 1 2 2 1 1

J 1 2 1 1 3 3

K 1 2 3 1 2 2 1 3 3

L 1 2 2 1 1 2 1 1 1 3 1 2

M 1 3 3 1 3 1 1 1 3 4 1 1

N 1 1 1 1 1 1 1 2 1 1

O 1 2 1 2 3 1 1 1

P 1 2 1 1 1 2 1

Q 1 2 1 1 1 1 1 1 1

R 3 1 2 1 2 3 2 1 1 1 1

xxiv

APPENDIX 5

SAMPLE OF QUESTIONNAIRE

Construction Wastes Study Based on Lean Construction

This study is focused on the study of wastes concepts based on Lean Construction Philosophy in

local construction industry. The questionnaire will consist of 4 sections, which intend to study:

1) The general perception and acceptance of Lean Construction philosophy and the

waste concepts by local construction industry

2) The extent of waste problems in existing local industry

3) The relevant sources of wastes to have significant impacts on project

4) And finally to create correlation matrix between wastes and the sources of wastes

Background Information

A. Please indicate your position in the project organisation

Position

q Project Manager

q Resident Engineer

q Site Engineer

q Site Supervisor

q Project Scheduler/ Planner

q Foreman

q Other (Please specify):

______________________

B. Please select the most appropriate type of construction project to describe the area of projects

most frequently involved by your company:

q High rise building

q Residential & commercial scheme

q Industrial projects

q Public & community buildings

q Civil & road construction

q Others ( Please specify):

_____________________

C. Please indicate the CIDB registration grade:

q Below Grade 3

q Grade 3 and above

D. Please select the most project clients related to the projects carried out:

q Private

q Public

xv

Section A: General Perception

1. To your experience and opinion, which are the following items or activities can be

best represented or described as “Waste” or “Non Value Added” to Construction site:

(Please indicate X in the Waste column for waste activities and Non-Waste column for

non-waste activities)

Waste Non-Waste

A. Waiting for others to complete their works before


B. Waiting for equipment to be delivered on site

C. Waiting for materials to be delivered on site

D. Waiting for the skilled workers to be on site

E. Waiting for the clarification and confirmation by


F. Over-allocation/ unnecessary equipment on site

G. Over-allocation/ unnecessary materials on site

H. Over-allocation/ unnecessary workers on site

I. Unnecessary procedures and working protocols

J. Material loss/ stolen from site during construction

periods

K. Material deterioration/ damaged during construction

periods

L. Mishandling or error in construction applications/

installation

M. Time for rework/ repair works/ defective works

N. Materials for rework/ repair works/ defective works

O. Time for workers’ resting during construction

P. Time in supervising and inspecting the construction

works

Q. Time for instructions and communication among


R. Time for transporting workers, equipment and

materials

S. Accidents on site

xvi

Section B: Existing Scenario and Practice in The Local Industry

2. To your experience in your work field, is any of the following events are properly

controlling and mitigated in the construction site.

(Please indicate X in the Yes column for controlled events and No column for

uncontrolled events)

Yes No

A. Waiting for others to complete their works before





E. Waiting for the clarification and confirmation by






J. Material loss/ stolen from site during construction

periods

K. Material deterioration/ damaged during construction

periods

L. Mishandling or error in construction applications/

installation




P. Time in supervising and inspecting the construction

works

Q. Time for instructions and communication among


R. Time for transporting workers, equipment and

materials


xvii

3. To your experience in your work field, what is the frequency of occurrence of the

mentioned activities on construction site

Please indicate the frequency of occurrence of the mentioned activities by using the scale

of 1 to 5. (1 = Never, 5 = Very Frequent).

1 2 3 4 5

Never Very Rare Seldom Frequent Very Frequent

A. Waiting for others to complete their works before the proceeding works

can be carried out




E. Waiting for the clarification and confirmation by client and consultants





J. Material loss/ stolen from site during construction periods

K. Material deterioration/ damaged during construction periods

L. Mishandling or error in construction applications/ installation




P. Time in supervising and inspecting the construction works

Q. Time for instructions and communication among different tiers and

trades of workers

R. Time for transporting workers, equipment and materials


xviii

Section C: Sources/ Causes of Wastes

4. To your opinion, please identify the most likely sources/ causes of wastes to impact

on the productivity of the projects

Please indicate the frequency of occurrence of the mentioned activities by using the scale

of 1 to 5. (1 = Most Unlikely, 4 = Most Likely).

1 2 3 4

Most Unlikely Unlikely Likely Most Likely

Management & Administration Factors

A1 Poor coordination among project participants

A2 Poor planning and scheduling

A3 Lack of control

A4 Bureaucracy

People Factors

B1 Lack of trades skills

B2 Inexperience inspectors

B3 Too few supervisors/ foreman

B4 Uncontrolled sub-contracting practices

B5 Supervision too late

B6 Poor labour distribution

Execution Factors

C1 Inappropriate construction methods

C2 Outdated equipment

C3 Equipment shortage

C4 Poor equipment choice or ineffective equipment

C5 Poor site layout and setting out

C6 Poor site documentation

xix

Material Factors

D1 Delay of material delivery

D2 Poorly scheduled delivery of material to site

D3 Poor quality of material

D4 Inappropriate/ misuse of material

D5 Poor storage of material

D6 Poor material handling on site

Information and Communication Factors

E1 Defective or Wrong information

E2 Late information and decision making

E3 Unclear information

xx

Section D: Cause and Effects Relationship

5. To your experience in your work field, please relate the waste variations to the

contributory sources of wastes.

(Please fill in other secondary causes [if any] in the Other Causes Column, the causes

can be either from the list below or whichever causes differ from the list [Please specify])

A1 Poor coordination among project

participants

A2 Poor planning and scheduling

A3 Lack of control

A4 Bureaucracy

B1 Lack of trades skills

B2 Inexperience inspectors

B3 Too few supervisors/ foreman

B4 Uncontrolled sub-contracting practices

B5 Supervision too late

B6 Poor labour distribution

Example:

For A: Waiting for others to complete their

works before proceeding works can be carried

out

Major cause column can be filled with one major

cause to the problem for example A2: poor

planning & scheduling

Other cause can be filled with more than 1 cause

for example A3, A4 & B5 and so on.

C1 Inappropriate construction methods

C2 Outdated equipment

C3 Equipment shortage

C4 Poor equipment choice or ineffective

equipment

C5 Poor site layout and setting out

C6 Poor site documentation

D1 Delay of material delivery

D2 Poorly scheduled delivery of material to

site

D3 Poor quality of material

D4 Inappropriate/ misuse of material

D5 Poor storage of material

D6 Poor material handling on site

E1 Defective or wrong information

E2 Late information and decision making

E3 Unclear information

F Not relevant

xxi

Events Major

Cause Other Causes

A Waiting for others to complete their works before the proceeding

works can be carried out

B Waiting for equipment to be delivered on site

C Waiting for materials to be delivered on site

D Waiting for the skilled workers to be on site

E Waiting for the clarification and confirmation by client/ consultants

F Over-allocation/ unnecessary equipment on site

G Over-allocation/ unnecessary materials on site

H Over-allocation/ unnecessary workers on site

I Unnecessary procedures and working protocols

J Material loss/ stolen from site during construction periods

K Material deterioration/ damaged during construction periods

L Mishandling or error in construction applications/ installation

M Rework/ repair works/ defective works

N Workers’ resting during construction

O Supervising and inspecting the construction works

P Instructions and communication among different tiers and trades of

workers

Q Transporting workers, equipment and materials

R Accidents on site

the application of lean construction to reduce waste in construction flow process

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