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Applying Lean Construction
Techniques to Identifying and
Reducing Waste in Grinaker-LTA
Building Inland (GLTA)
STANLEY TAVERO GEORGE
Dissertation submitted to Milpark Business School in partial fulfilment
of the requirements of
Master in Business Administration
Johannesburg, March 2010
Supervisor: Sarel Visagie
Declaration
I, Stanley Tavero George, declare that this research report is my own, unaided
work, except as indicated in the acknowledgements, the texts and references. It
is being submitted in partial fulfilment of the requirements of the degree of Master
of Business Administration at Milpark Business School, Johannesburg. It has not
been submitted before, in whole or part for any degree or examination at any
other institution.
Stanley Tavero George
Signed on………………….Day of…………………………………2010
ABSTRACT
This study evaluated the current understanding and attitude towards waste recognition and the tendency to waste reduction within the Grinaker-LTA Building Inland business unit. The principles of Lean Construction were used as a basis for benchmarking the current state and as a tool to take the organization forward in this ever increasingly competitive building construction market.
Two construction sites within Gauteng were used in this study. Employees were asked to respond to questionnaires that were structured to solicit certain information out of them. The collected data was analysed using tables and graphs.
The study showed that there was no conclusive evidence that Grinaker-LTA was either traditionalistic or lean in the way that employees regarded waste on construction sites. However, an important imperative came out that the ability to recognize waste on site does not necessarily prompt action to reduce or eliminate it. Furthermore all five possible sources of waste on site were identified as being likely to be causing waste on sites. This situations reveals that GLTA needs to move towards a more lean position.
This study recommended that Grinaker-LTA should start to scientifically evaluate its waste management programmes if it must stay ahead of the pack because operational efficiency is the answer to today’s profitable organizations. To achieve this goal, there is need for top management commitment, inclusivity, benchmarking and creation of a learning organization.
Finally, it is also recommended that further research be undertaken to understand the organizational behaviour and design the service profit chain.
DEDICATION
To my siblings and friends
ACKNOWLEDGEMENTS
I am extremely grateful to all the people who helped in the successful
production of this dissertation. Firstly, I am deeply appreciative of the
assistance, advice and support given to me by my supervisor, Mr S
Visagie. I also want to thank all the people who took their valuable
time to complete my questionnaire, may God bless you.
Last but not least I would like to thank my partner and friends for
enduring long hours without their loved one as I worked on this project.
List of Abbreviations
CIDB Construction Industry Development Board
GLTA Grinaker LTA Building Inland
JIT Just In Time
TFV Transformation Flow and Value Model
TPS Total Production System
TQA Total Quality Assurance
TQC Total Quality Control
TQM Total Quality Management
TPM Total Productive Maintenance
Table of Contents
1.0 Dissertation Title…………………………………………………………………1
1.1 Introduction……………………………………………………………..1
1.2 Problem Statement……………………………………………………..3
1.3 Purpose and importance of study…………………………………….5
1.3.1 Purpose…………………………………………………...5
1.3.2 Importance……………………………………………..…5
1.3.3 Review of existing literature…………………………….6
1.4 Research objectives……………………………………………………7
1.5 Research methodology………………………………………………...7
1.5.1 Definition and scope of the research study…………...8
1.5.2 Definition……………………………………………….…8
1.5.3 Scope…………………………………………………..…9
1.5.4 Limitations of the research study………………………9
1.5.4.1 Research validity………………………………9
1.5.4.2 Research reliability…………………………….9
1.6 Structure of the dissertation………………………………………….10
1.7 Timelines…………………………………………………………….…11
1.8 Conclusions………………………………………………………….…11
2.0 Related literature review………………………………………………….…….13
2.1 Introduction………………………………………………………..……13
2.2 Comparison to manufacturing……………………………………..…14
2.3 Lean production in manufacturing…………………………………...16
2.4 The new production system…………………………………………..17
2.5 Impact of new production system on construction…………………18
2.6 Impact of new production system in South Africa……………….…19
2.7 The concept of production………………………………………….…19
2.7.1 Transformation…………………………………………...20
2.7.2 Flow concept……………………………………………..21
2.7.3 Value generation concept……………………………….22
2.7.4 Just in time………………………………………………..22
2.7.5 Total quality control………………………………………23
2.7.6 Total productive maintenance…………………………..23
2.7.7 Concurrent engineering…………………………………24
2.7.8 Continuous improvement………………………………..24
2.7.9 Visual management………………………………………25
2.7.10 Value based strategy management…………………….25
2.8 Flows in construction………………………………………………..26
2.9 Construction waste…………………………………………………..28
2.9.1 Introduction……………………………………………..28
2.9.2 Waste and value loss in construction………………..29
2.9.3 Waste and value loss due to quality of works…….…29
2.9.4 Waste and value loss due to constructability………..29
2.9.5 Waste and value loss due to material management..30
2.9.6 Waste and value loss due to non-productive time….30
2.9.7 Waste and value loss due to safety issues………….30
2.10 New concept of waste in production activities……………31
2.11 Lean production model for waste in lean construction….32
2.12 Waste classification…………………………………………35
2.13 Key construction waste causes……………………………39
2.14 Waste and performance in construction……………….…39
2.15 Conclusion ……………………………………………….…39
3.0 Research methodology…………………………………………………….….41
3.1 Method of research……………………………………………….….41
3.2 Profile of respondents…………………………………………….….45
3.3 Hypotheses……………………………………………………………45
3.4 Structure of the questionnaire………………………………………46
3.5 Conclusion…………………………………………………………….47
4.0 Data analysis and interpretation………………………………………………48
4.1 Introduction……………………………………………………………48
4.2 Response………………………………………………………………48
4.3 General waste recognition……………………………………………49
4.4 Waste mitigation scenario……………………………………………52
4.5 Frequency of occurrence……………………………………………54
4.6 Sources and causes of waste……………………………………….56
4.7 Discussion of findings……………………………………………..…57
5.0 Conclusion and recommendations……………………………………………59
5.1 Introduction………………………………………………………….…59
5.2 Relating findings to research objectives……………………………59
5.3 Relating research findings to hypotheses………………………….61
5.4 Recommendations……………………………………………………62
6.0 References………………………………………………………………………66
7.0 Appendix…………………………………………………………………………70
Table of figures
1.1 Breakdown of the scopes of each phase of the research methodology……11
1.2 Gantt chart for approximate duration of research activities…………………14
2.1 Fundamental differences between manufacturing and construction……....17
3.1 Direct waste elements on site…………………………………………………..44
4.1 Response ………………………………………………………………...52
4.2 Classification of respondents …………………………………………………..52
4.3 General waste recognition………………………………………………………54
4.4 Waste mitigation…………………………………………………………………55
4.5 Frequency of occurrences………………………………………………………57
Table of Tables
2.1 Differences between manufacturing and construction……………..……………………….…
17
2.2 Direct waste on site ……….……………………………………………………...44
4.1 Key of waste type………………………………………………………………….52
4.2 Key of waste variable ……………………………………………………………..52
4.3 Matrix of general waste recognition …………………………………………….54
Dissertation Title
Applying Lean Construction Techniques to Identifying and Reducing Waste in
Grinaker-LTA Building Inland (GLTA)
1.1 Introduction
Grinaker-LTA Building Inland is a building construction company based in
South Africa and is part of the listed company Aveng Group. The company
has a long history dating back to the early 20th century and is currently one of
the “big five” construction companies in South Africa.(CIDB, 2004)
The construction business is a key sector in the world economy and more so
for developing countries like South Africa. The industry is probably one of the
longest surviving that has had a slow evolution mainly triggered by advances
in technology. Advances in technology have enabled buildings to be erected
faster and be more complicated in design. The globalization of the world
economy has seen a lot of movement of companies, capital and skills within
the industry. For individual companies this translates to more threats from the
operating environment. Government interventions especially on regulating the
green environment mean that it is not business as usual for most construction
companies. The current downturn in the world economy has resulted in fierce
competition for contracts. For example, the world’s largest destination for
construction work, Dubai, has seen a cut of up to 30% in the amount of
contracts available due to investors suspending projects.( EngineeringNews,
2009)
From its crude beginnings, the construction industry has seen an evolution
where building construction and management has become scientific. Whilst
trying to address endemic problems in the industry such as low productivity,
low client satisfaction, poor health and safety, scholars and practitioners have
developed scientific empirical ways of measuring success in projects. (Leng,
2004). Advances in Total Quality Management and the subsequent
development of the ISO 9000 series are all attempts to ensure that quality
and customer satisfaction are achieved.
However, companies are in business to make profits. According to the centre
for Experiential Education and Shingo (1989), the only way of increasing
profits in a competitive environment is to reduce costs. Most studies in the
construction industry have been centred on introducing new technologies and
speeding up the construction process without much regard for the companies’
bottom line. Recently there has been a shift to Lean construction, a new
paradigm that seeks to optimize the construction process; emulating the
successes in the lean manufacturing processes like the Toyota Production
System (Leng, 2004). The new paradigm is based on the concept, of
conversion and flow process similar to that of the manufacturing industries.
Opportunities for reducing costs are realised through the identification of
wastes and minimising them in parallel to value adding strategies such as
training and new technology. However, the concept of waste is grossly
misunderstood by a lot of construction personnel. It is the pursuit of
eliminating waste that will differentiate companies in the competitive
environment of the construction business. Companies like GLTA that have
over time perfected their systems and are accredited for quality assurance
systems and must move further and broaden the concept of waste so that
they optimize their competitiveness.
Organizations constantly change in response to their external, internal and
temporary environments (Senior, 2002 p.26). Construction has been a slow
evolving industry with the major changes happening due to harnessing new
technology that makes the construction process faster. However, it is time
that softer issues of management be adopted and be widely used to optimize
the conversion and process flow for more productivity, less waste and higher
profits.
1.2 Problem Statement
Grinaker-LTA is one of the “big five” construction companies in South Africa.
Over the years the company has developed cultures and systems that have
made it competitive and have capacity. GLTA is ISO 9001 accredited. This
accreditation helps with the “end” side of the construction process as it
ensures that certain processes are adhered to for quality purposes. However,
the company is still bedevilled by some chronic problems found in
construction such as low productivity and poor health and safety record and a
lot of rework of jobs. There is still need to optimize the construction process at
site level so that the “mean” end of production is efficient as well.
Lean Construction is a new paradigm that has roots in the manufacturing
processes such as the Toyota Production System. According to researchers
and scholars, Lean Construction philosophy is laid on the concept of
conversion and flow process. If a construction process is evaluated as a
conversion and flow process, waste identification opportunities are possible
thereby improving performance of the system. This should be done in parallel
to value adding strategies already in place for the company.
Having joined the group recently, the writer has identified some waste on site
and presumably the same observation may be extended to other similar
construction sites within the company. It is assumed that the concept of waste
is not fully understood and by utilizing techniques of Lean Construction and
education of key construction personnel, further competitiveness will be
induced into the company. There is need to bridge the gap between the
existing practices and the Lean Construction paradigm first. Parameters for
waste measurement, value, cycle variability need to be defined and
understood as well as the examination of the current personnel’s
understanding of waste.
The organization might need to adopt a fine tuning or incremental adjustment
strategy both of which are aimed at allowing the organization to operate more
efficiently and optimize the consistencies between strategy, structure, people
and processes (Senior, 2002). According to the Lean Construction Institute,
the principles lie in taking further the principles of Total Quality Management
for the organization to improve productivity through, Flow and Value
Management, that is, lean design, lean supply, lean assembly, work
structuring and production control. All this is done to reduce waste and finally
increase customer satisfaction
The Lean Construction Institute states that:
Cycle time = Processing + handling + Inspection + Waiting
The old paradigm concentrated on improving processing (Conversion) while
disregarding handling, inspection and waiting waste. Processing is value
adding (conversion), whilst handling, inspections and waiting are non-
essential and therefore regarded as waste that must be minimized.
It is proposed that Koskela’s (1992) Conversion and Flow Process Model be
used along with the principles of Lean Construction to evaluate the current
state of waste recognition and mitigation for GLTA as well as to recommend
the road map to compliance.
1.3 Purpose and importance of the study
1.3.1 Purpose
The study is intended to evaluate the current understanding of Lean
Construction within GLTA in reference to waste management. The idea is to
gauge how lean the organization is and map a road for compliance. The
concept of lean construction will be proposed as a solution to see waste
recognition and reduction as a group strategy to improve productivity and
profitability
1.3.2 Importance
Given the current global economic trends it is important for GLTA to position
itself in a very competitive position if successes of the past are to continue
being realised. The group must take a leading role among its peers in the
industry and move the South African construction industry forward in the new
construction management paradigm. According to the centre for Experiential
Education and Shingo (1989), the only way of increasing profits is a
competitive environment is to reduce costs. This fact is an assumed known;
however, it has been scientifically elusive to fathom. Lean Construction
principles are meant to assist in improving the conversion and process flow of
the building process. GLTA has a department of continuous improvement and
this study is meant to assist in proposing Lean Construction as an alternative
solution to the group’s endeavours. This study will set up the ground work for
future thorough studies and implementation of lean construction techniques in
GLTA
1.4 Review of existing Literature
Ballad and Howell (1998) defines construction as the design and assembly of
objects fixed in place. Koskela and Huovila (1997) proposed 3 ways of
conceiving a construction processes: conversion of inputs into outputs, flow of
information and materials and generating value for the customer. However,
Ballad and Howell argue that this view of the conversion process has
dominated thinking and practice for a long time. Moving towards Lean means
consideration of value and flow processes.
Abdelhamid (2004) of the Lean Construction Institutes summarizes the history
of thinking effectively. The first stage was construction-as-usual, dominated
by fragmentations of responsibility between, the customer, management and
the artisans on site. Ineffective communication and non-alignment of goals
resulted in a lot of waste and less customer satisfaction. The second stage
saw scholars and practitioners ushering in new improvement initiatives that
included, Value engineering, Design and construct, Partnering, Total Quality
Management, Health and Safety and many more. These new initiatives were
broadly centered on productivity improvement mainly through new
technology. However there was less elimination of waste resulting in less
customer satisfaction still.
The new thinking is Lean Construction that basically involves flow and value
management. This all entails lean design, lean supply, lean assembly, work
structuring and production control. This thinking also recognizes the seven
wastes that must be minimized as: correction, motion, overproduction,
conveyance, inventory, processing and waiting. According to scholars, this
thinking and practice eliminates waste and results in better customer
satisfaction and in turn more profit for the construction company.
A thorough review of literature shall be done in subsequent chapters that will
show the history of production management that culminated in the concept of
Lean Construction.
1.5 Research Objectives
The research is aimed at one organization but forms a basis for further
research in the subject to the construction industry in South Africa.
For the sake of this study, the major objectives are:
To examine the general perception and attitude towards and practice of
lean construction principles within GLTA.
Examine the extent of problems arising from waste identified in the current
scenario
Identify the sources of waste
Study the possible improvements aimed at eliminating waste
1.6 Research Methodology
Table 1.1: Breakdown of the scopes of each phase of the research
methodology
Formulate Problem
Statement
Identifying an area of study and research
of current literature so as to understand the
subject matter.
Finalizing the research topic
Research Design A quantitative research approach will be
adopted for this study
The survey will be conducted within two
construction sites of GLTA
A questionnaire shall be designed and
structured in such a way that the factors and
variables relevant to the study are captured
Data collection and
processing
Data will be collected by hand delivered
questionnaires as the population is
composed of colleagues
Data will be sorted according to level of
responsibility of the respondents within the
company
Data analysis Statistical analysis will be done through
the descriptive and inference statistics
The significance of the factors and
variables will be compared to the problem
statement
Conclusions and
recommendations
A comparison of the outcomes of the
data with the problem statement will be
done.
Constructive recommendations will be
drawn based on the objectives of the study
Research report Write up of the final draft to be submitted
1.6.1 Definition and scope of the research study
1.6.2 Definition
This study is aimed at applying the principles of Lean Construction to GLTA
Building Inland. An evaluation of the current extent of practice of the
principles and wastes identified shall be done and based on that,
recommendation on the way forward in the implementation shall be
suggested.
1.6.3 Scope
The study is limited to GLTA Building Inland construction sites in Gauteng
Province
Primary data will be collected from site personnel who are directly involved
in planning and executing building work.
1.6.4 Limitations of the research Study
There are certain limitations to this research as the writer wishes to highlight:
1.6.4.1 Research validity
GLTA has several business units based on province and speciality. This
study will be limited to GLTA Building Inland that is based in Gauteng
Province. The outcomes of the study may be biased towards building
construction projects and to a certain culture created over the years within the
Inland business unit. It is recommended that further extensive research be
carried out throughout the group to get a more representative view of the
performance of the group.
1.6.4.2 Research reliability
The subject of lean construction is relatively new in South Africa, thus there
may be very little attention at documenting parameters of variability on the
various projects undertaken. This might affect the understanding of questions
by respondents and hence the consistency of the results obtained.
1.7 Structure of the Dissertation
Chapter 1, Introduction:
This chapter covers the overall perspective of the research study such as
background to the study, problem statement, research aims, scope and
objectives, methodology and limitations of the study
Chapter 2, Problems in Construction and the trends in Improvement
Strategies:
This chapter will examine the problems faced in construction and the various
thinking and practices that have been developed over the years to try and
resolve the problems. The concept of Lean Construction will be introduced.
Definition of waste and models for waste minimization shall be discussed as
well.
Chapter 3, Research Methodology:
This chapter shall focus on the design of the questionnaire, formulation of the
hypothesis and how they are to be tested. A general overview of the statistical
analysis to be applied shall also be discussed
Chapter 4, Data Analysis and Interpretation:
The results from the questionnaires shall be interpreted with reference to the
hypothesis and the research objectives.
Chapter 5, Conclusions and Recommendations:
This chapter shall conclude the study based on the findings. The findings
shall be used to provide a strategic solution to the problems identified in
GLTA and to provide a roadmap for the formalisation on the practice in the
company
1.7Time lines:
Table 1.2: Gantt chart for approximate duration of research activities
Description Drn Week
Wks 2 2 1 Literature review 8 2 Questionnaire design 4
3Send out questionnaire 4
4 Data analysis 6
5Conclusions and recommendations 4
6 Drafting final report 4
1.8 Conclusion
It is not easy to differentiate strategies among construction companies as there are so
many similarities among them. However, company cultures and practices are
different. Profitability within companies emanates from internal efficiencies. It is
imperative that GLTA embark on a scientific evaluation of its activities to build
efficiencies that will give it an edge over their competition with the ultimate goal of
profitability and customer satisfaction. To this end, this study will attempt to look at
one aspect of operations where the company can improve itself and also to act as a
propellant for further in-depth studies to be carried out within the group.
2.0 Related Literature Review
2.1 Introduction
According to the Construction Industry Indices (CIDB, 2007) there was 26%
customer dissatisfaction, 33 quality problems that were not acceptable, 25%
defects that were not acceptable and safety remains a concern with the
construction industry that recorded the second highest fatalities in the
workplace after mining between the year 2006 and 2007. The CIDB quotes
the M4I as saying “Clients in construction want their projects delivered on
time, on budget, free from defects, efficiently, right the first time, safely and by
profitable companies. Regular clients expect continuous improvement from
their construction companies to achieve a year on year reductions in project
cost and reduction in project cost”. This indicates that customer satisfaction is
also achieved through the organization’s internal processes. According to
research carried out by Koskela (1993) on studies done in Sweden, it was
discovered that there is a lot of none value adding activities in construction
and associated costs as shown below:
Quality (non-conformance) 12%
external quality costs (during facility use) 4%
lack of constructability 6-10%
poor materials management 10%
excess consumption of materials on site 10%
time used for non-value adding activities on site 66%
lack of safety 6%
Problems in Construction
There are endemic problems in construction such as poor work quality, poor
safety practices, low productivity and others that are well known. Most of
these problems have been left unattended for a long time because of the
inherent belief that they cannot be solved. These problems are attributed to
the nature of the industry, such as one-of a kind, once off, in situ, temporary
multi-organization and over time have not been given attention and are simply
factored in on pricing projects. Conclusions from some scholars are that it is
the fragmented nature of the industry, lack of coordination and
communication, adversarial contractual relationships and lack of customer
focus that inhibit industry performance. Scientific study of the industry has
been difficult as appropriate models are difficult to draw. When compared with
manufacturing where activities are controlled and routine, construction has
got a lot of variables that make it difficult to streamline information flow and
waste management. This is exacerbated by use of temporary labour, moving
machinery and other factors that cannot be easily predicted and planned for.
However some of these can be overcome by applying new flow designs,
improving the existing and use of new technology (Alarcon, 1994). The new
thinking is that the solution lies in the organization, planning, allocation and
control of resources, processes and technologies for the achievement of
higher productivity
2.2 Comparison to Manufacturing
The Manufacturing Industry has been a source of reference for improvements
in construction, although some believe that both industries still learn from one
another (Howell et al, 1998) Efforts to transfer the successes of the
manufacturing industry to construction have been done, for example the use
of new technology and process adoption, industrialization, prefabrication and
modularization and computer integrated construction. According to Koskela
(2000), there has been no major improvement in construction due to this
adoption mainly due to the fundamental differences between the two
industries as indicated in the Table 2.1 below
Table. 2.1 Fundamental differences between manufacturing and construction.
Source: Leng (2004), The application of lean thinking to reduce waste in
construction flow process)
Start of manufacturing Start of construction
What Highly defined Evolving
How Highly defined
Ops plan is in great
detail based on many
trials
Primary sequence of
tasks is inflexible and
interdependency is
documented and
approved
Positions in sequence
determines skills
requirement
Partly defined but
details unexamined
Extensive planning
still remains by hard logic
Interdependencies
due to conflicting
measurements, shared
resources and
intermediate products only
partly understood
Skills vary in all areas
Assembly objectives Produces one of a finite
set of objects with clear
definition from the
beginning
Make one only with details
that are not clearly known
from the beginning
Improvement strategy Rapid learning from the
first units preparing for
production line
Rapid learning during both
planning and early sub
assembly cycles
In the late 1980’s there was a new trend in production that caught the
attention of academics and construction practitioners. The fundamentals of
this new development are that new industries are “lean”, using less of
everything and these changes have been due to application of a new
philosophy called Lean Production. Among the pioneers in the academic
circles to try and adopt this new philosophy are Koskela and Alarcon. Koskela
(1992) identified the dominance of the “conversion” thinking in construction
and argued for the replacement of it with the “conversion-flow” thinking.
Alarcon (1995) also identified this fact and argued that performance could be
improved by waste identification and reduction in parallel to the value adding
strategies. The challenge is identifying and measuring waste as an effective
tool to improve production systems as it points out areas that need attention.
Waste modelling and measurement assist with process management since
operational costs can be properly modelled and information used for
decentralised control
2.3 Lean Production in Manufacturing
Traditional production thinking after the industrial revolution never went
beyond the concept of production as a transformation process, thereby
ignoring the flow processes that are part of production and inhibited
improvements in the system
There was a paradigm shift in the 1950’s when Ohno, a former Toyota
executive set out to develop a new production system called the Toyota
Production System (TPS). The basic idea was to adopt strategies that are
based on downstream demand in the production chain. This maintained a
planned pace of production and avoided unnecessary inventories. According
to Conte and Gransberg (2001), the TPS goal is to achieve continuous
production by adopting monitoring measures for each process aiming to
reduce waste. Elimination of inventories and other waste through small lot
production, reduced set up times, semi-autonomous machines, co-operation
with suppliers and other techniques
The off-shoot from this system is termed Just-In-Time (JIT) and has
contributed to major improvements in productivity in manufacturing from the
1970’s (Koskela 2000). Simultaneously quality was attended to through
consultants like Deming, Juran and Feigenbaunm. This was a statistical
method of quality assurance that was refined by industrial engineers through
trial and error. Other philosophies emerged such as Total Quality
Management (TQM), Value Based Management and Concurrent Engineering
but where all based on the same principles viewed from different angles.
At the beginning of the 1990’s, a new production philosophy emerged known
by several names (Lean production, world class production, new production
system). It was mainly applied in manufacturing but has diffused to services,
administration and product development. The latest trend is for a leaner
production chain through all stages of production that must include the whole
value chain. Krafcik coined the name lean to emphasizes less of everything,
less people, less materials and lower cost. Womack and Jones (1996)
suggested that lean thinking provides production processes a way to specify
value, line up value adding processes in best sequence, conduct them
without interruption and more effectively.
2.4 The New Production system
All production systems consist of Conversion and Flow (waiting, moving,
inspection) processes. Conversion adds value while flow does not. Value is
realised through customer satisfaction and the money paid for the
goods/services. Profit is realized through streamlining flow processes and
making conversion more efficient. According to Koskela (1992), traditionally
the production system compounded conversion and flow as if it were all value
adding, resulting in complex, uncertain and confused flow processes,
expansion of non-value adding activities and reduction of value adding output.
Enton (1994) summarized the applicability of lean thinking in construction
process as:
1. Analysis and separation of conversion and flow processes
2. Conversion activities go through QC, QA and TQM
3. The flow activities should find ways of simplification, elimination
and automation in order to reduce them
2.5 Impact of new production system on construction
Since the 1990’s, the new production system has been applied in the US and
Europe recently on a regular basis where a lot of work is being done by
academics and practitioners to use it to improve the construction industry.
Koskela (1992) identifies the dominance of the conversion thinking in
construction and argues that this should be replaced by the Conversion-Flow
thinking that runs along the new production system. Howell (Civil Engineer)
and Ballard (Researcher), have put forward the concept of Lean Construction
by seeing potential for applying the general principles set by Koskela. The
Lean Construction Institute says that Lean Construction is a production
management based approach to project delivery by maximizing value and
reducing waste. Lean Construction has gained momentum since 1993 and
new curriculum especially at post graduate level is now being introduced to
students. A nationwide “Rethinking Construction” movement in the UK is
taking place led by a report from Sir John Egan in 1998. The essence of the
Egan report is to set targets for improvement on a year-to-year-basis of
productivity processes through waste reduction such as time, cost, rework
and accidents and increasing value in quality, finished products, etc.
2.6 Impact of the new production system in South Africa
Following the trend of manufacturing being the predecessor of many
production improvement strategies, Lean production is mainly applied in
South Africa’s manufacturing industry. There are many initiatives in tertiary
institutions to permeate the knowledge to industry and one such example is
the Lean Development Group base at Nelson Mandela Metropolitan
University (www.nmmu.ac.za). There is no clear evidence of a deliberate aim
to apply lean production methods in construction production. However, most
construction firms apply one or more of the predecessors of lean thinking
especially in quality assurance such as Value Engineering, TQM and QA. The
Government in its quest to provide affordable housing to the population, has
embarked on a quest to find technology and methodologies that provide fast
and cheaper erection methods for low cost housing. One such initiative is
through the Moladi modular houses that are created from low strength
concrete (www.moladi.com).
Given that lean production in construction is a relatively new concept and is
still in its infancy in Europe and the USA, it is going to take time for the new
thinking to filter in South Africa and be appreciated as the solution to
improving the current industry practices.
2.7 The Concept of production
Koskela did a historical analysis of the production concept and revealed that
there are 3 sub-concepts to production and that the whole concept could be
identified and separated into Transformation, Flow and Value generation
(TFV Model)
2.7.1 Transformation
This has been the dominant theory since the beginning of the 20th century
where production was viewed as transformation of inputs to outputs.
Production management is there fore the decomposition of transformation
into elementary tasks and transformations, acquiring the inputs to these tasks
with minimal costs and the carrying out as efficiently as possible of these
tasks. The core principle is “the decomposition” of sub- transformations into
smaller and more manageable tasks for individuals”
Production Process
Sub-process A Sub-process B
Products
MaterialsLabour
Figure 2.1. Production as a transformation process.
Source: An exploration towards a production system and its application to
construction, Koskela, Lauri (2000)
The total cost can be minimized through minimization of each sub-
transformation processes. The assumption is that sub-processes are
independent of each other and cost reductions can be achieved through cost
management of each sub-process. Furthermore, it is recommended that it is
advantageous to insulate the production process from the external
environment through physical or organizational buffering. The assumption is
that the transformation process is so important that it is necessary to insulate
it from the erratic external environment
Shortcomings of the transformation concept
Transformation concept is conventionally widely-accepted in terms of
production mainly due to its sufficient power to model reality, and excellent
power of various tools to analyze and control of production in an easy and
simple way. However it over simplifies processes and tends to undermine the
full potential to optimize the efficiency of production process.
The transformation concept has its shortcomings. By focusing on
conversions, the model abstracts away physical flows between conversions.
The flows have cost and time variables that must be taken into account in the
overall production process.
2.7.2 Flow Concept
Time is introduced 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. Time is consumed by two types of activities in the overall
production flow which are transformation activities and non-transformation
activities. Non-transformation activities are unnecessary and the less of them
is better and best if there are none of them.
The principles of eliminating the flow activities include reducing the share of
non-value-adding activities, reduce lead time and variability and providing
practical ways in implementation such as simplifying by minimizing the
number of steps, parts and linkages, increase flexibility and increase
transparency.
2.7.3 Value Generation Concept
The underlying concept is the satisfaction of the customer. This concept
covers external needs and the production system is structured in such a way
that customer needs are taken into account. Production management equates
to translating these needs accurately into a design solution, and then
producing products that conform to the specified design.
It focused on control of the transformation and flow, namely control for the
sake of the customer and it is important to highlight 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.
2.7.4 Just In Time (JIT)
JIT is mainly applied in Industrial Engineering as initiated at Toyota car
factories in the 1950’s. The principal idea in the approach was the reduction
or elimination of inventories. This, in turn, led to other techniques that were
forced responses to coping with fewer inventories such as lot size reduction,
layout reconfiguration, supplier cooperation, 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.
2.7.5 Total Quality Control (TQC)
TQC is a technique that is founded on the use statistical methods to control
quality through inspection. The technique was started in Japan and has
evolved from mere inspection of products to total quality control of the
organization through:
The focus has evolved from an inspection orientation (sampling
theory), through process control such as Fishbone Diagram, Control Chart,
Pareto Chart, Run Graphs, Histogram, Flow charts or Check sheets &
Correlation Diagram) to continuous process improvement through the new
seven tools, that is, Affinity Diagram, Interrelationship Diagraph, Tree
Diagram, Matrix Diagram, Prioritization Grid, Process Decision Programme
Chart and Activity Network Diagram), and presently to designing quality into
the product and process (Quality Function Deployment).
2.7.5 Total Productive Maintenance (TPM)
Total Productive Maintenance is a comprehensive program to maximize
equipment availability in which production operators are trained to perform
routine maintenance tasks on a regular basis, while technicians and
engineers handle more specialized 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).
2.7.6 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.
2.7.7 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 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.
2.7.8 Visual management
Visual management is an orientation towards visual control in production,
quality and workplace. 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. 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.
2.7.10 Value based strategy Management
Value based strategy management is a customer-oriented, in contrast to
Competitor oriented approach toward overall production process. It is a
continuous improvement to increase customer satisfaction by conceptualizing
and articulating value as the basis for competing.
Principles of lean production for production improvement
FLOW C OMPR ESSION
Reduce the share of non-val ue addi ngacti viti es
Reduce variability
Reduce the cycl e ti me
Simplify by mi ni mizing s teps
FLOW D YNAM IC AND FLEXIBILITY
Increase output value
Increase output flexi bility
Increase process transparencybenchmar king
FLOW STABILIT Y AND CONTROL
Focus control on the complete process
Build conti nuous i mpr ovement i nto sys tem
Bal ance fl ow i mprovement with conversionimpr ovement
Figure 2.2 Summary of principles of lean production:
Source: Leng (2004), The application of lean construction to reduce waste in
construction process flow
2.8 Flows in construction production
Ballard and Howell (1998), concluded that the production in construction is
assembly-type, where different materials flow to the end product. Koskela
(2000) suggested that there are three types of flow associated with
construction, namely material flow (transportation of components site for
particular installation), location flow (movement of trades on site) and
assembly flow (sequence of work)
There are at least seven resource flows that generate the construction task as
illustrated In Figure 2.3 below. Many of these resource flows are of high
variability, and thus the probability of a missing input is considerable.
For instance, it is not uncommon that detailed drawings are still lacking at the
project start date. 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. The degree of variability is higher in construction
production compared to manufacturing production.
Koskela (2000) says that ‘realization of tasks depends on flows, and progress
in turn is dependent on realization of tasks’, basically meaning that planning
and controlling production is very important and tasks and flows have to be
considered in parallel in production management.
TASK
Construction design
Materials
Workers
Equipment
Space
Connecting works
External conditions
Figure 2.3 Flows in Construction.
Source: Koskela (2000), The preconditions of a construction task
2.9 Construction Waste
2.9.1 Introduction
An inclusive definition of waste is all activities and processes that produce
cost directly or indirectly or do not add value. Waste is generally measured in
cost or/and opportunity cost. Some wastes are related to efficiency and are
difficult to measure because the optimal performance is not usually known.
The association of only physical material as waste in construction has over
the years caused a lot of other waste to go unquantified and hence neglected.
This is clearly due to the dominance of the conversion model thinking that
describes processes as conversion from one to another.
2.9.2 Waste and value loss in construction
Koskela (1992), 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. He summarized some of the findings
as follows:
2.9.3 Waste and value loss due to quality of works
Unacceptable quality of work and nonconformance costs can be very high
due to re-work. It is estimated that these cost are on average 10-20% of the
project cost. In various studies conducted in Europe and USA it was noted
that the causes of poor quality of work result from design (46%), construction
(22%) and material (15%). Deviation costs amount to an estimate of 12% as
studied in the USA mainly due to design related issues. Quality costs are also
incurred by the customer during facility use.
2.9.4 Waste and value loss due to constructability
Constructability is the capability of a design to be constructed. Good designs
should take into account the constraints and possibilities of the construction
process. Good constructability makes costs savings in time, materials and is
good for controlling variability. It is cost effective for a project if the production
process utilizes off-the-shelf materials.
2.9.5 Waste and value loss due to material management
According to Lend (2004), 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.
2.9.6 Waste and value loss due to non-productive time
Workers’ time is not usually utilized in activities that add value. 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. Leng (2004) indicates that 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) during 1990 and
1994 shows that the minimum value of productive work was 35% and the
maximum was 55%.
2.9.7 Waste and value loss due to safety issues
According to Levitte and Samelson(1988), in the USA, safety-related costs
are estimated to be 6 percent of total project costs.
2.10 New concept of waste in production activities
In the new production paradigm, waste is defined more broadly than its usual
limited scope as any inefficiency that results in the use of equipment,
materials, labour, or capital in larger quantities than those deemed necessary
in the production of a construction project. Waste includes both incidences of
material losses and the execution of unnecessary work, which generate
additional costs but do not add value to the product (Koskela 1992). Waste
may also 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. Pioneers of Lean production, Toyota, see waste as “Anything
that is different from the minimum quantity of equipment, material, parts and
labour time that is absolutely essential for production.”
The above definitions of waste clearly allude to the fact that waste must be
seen from an activity point of view and not from aggregate inputs such as
material, machinery and labour as the traditional thinking focuses on. Lean
thinking is essentially an extension of the traditional thinking that covers items
that hitherto have not been studied in detail and exposed as stand-alone
waste items. By delving deeper and into more detail on the basis of activities,
Lean Thinking digests construction production into smaller molecules that
help to understand the causes and losses due to waste. It also becomes
easier for practitioners to have specific targets for improving the production
system. There is opportunity to improve production in two ways using the
Lean Thinking approach. The first is to increase efficiency of value adding
activities and the second is to eliminate or reduced waste. From a business
perspective, this increases the bottom line of the organization, that is, more
profit is realized.
There is also a very big benefit to construction production that was not so
obvious using the traditional approach. Using lean thinking, the construction
project is viewed as one production system. This means that customer
satisfaction becomes the primary objective. Instead of concentrating on single
activities as points of focus, total project cost and duration become the single
most important goal. Coordination will be achieved through the central
schedule whilst smaller sections are managed by persons who are aware of
the project goals and work together for the achievement of that goal.
2.11 Lean Production Model for Waste in Lean Construction
The Lean production model in construction should be based on the
Conversion-Flow model that has an ultimate goal of reducing waste in any
production system. Production is a flow that creates value through conversion
processes and is a function of cost, time and value. In other words, lean
production seeks cycle time reduction, waste elimination, zero defects and
flexible output. The parameters that are variable in the model need to be
measurable and standards set for continuous evaluation of the efficiency and
performance.
Koskela (1992) proposed a conversion-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.
Moving waiting Process A inspection Moving
scrap
Figure 2.4. Koskela’s Flow Process Model (Koskela, 1992)
This model distinguishes between value-adding and non value-adding
activities. The model 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 and the rest are waste and reducing their
share in the process is the target for continuous improvement.
Serpell et al. (1995) have proposed an open and dynamic construction
process model as described in Figure 3.7 below. The model presents the
construction production process that is linked to its external environment.
Some variables in the external environment are controllable and some are
not.
Flow and Process management
Conversion process
productsExternal flows
Controllable area
Internal flows
Flow regulation
feedback
Operational methods
Non controllable area
Environment
Figure 2.5 Model of the construction process.
Source: Serpell (1995)
Flow and conversion management are responsible for making the decision
that define the performance of the system. Flows are the inputs to the system
that may 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 are usually uncontrollable, for example,
suppliers’ provision of resources and design information. Internal flows are
usually controllable, for example, materials from a warehouse. Conversion
activities transform the flows into finished and semi-finished products. The
methods used in this activities decided by the flows and conversion
management. Products are results of conversion activities.
2.12 Waste classification
Scholars and practitioners acknowledged that there are many non-value
adding activities during the design and construction process and the majority
of these wasteful activities consume time and effort without adding value for
the client. From the inception of a construction project, Construction
Managers have to deal with many factors that may negatively affect the
construction process, producing different types of waste
Formoso, et al. (1999), commented that there is an acceptable level of waste,
that 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, that is, Unavoidable waste (or natural waste), in which the investment
necessary to its reduction is higher than the economy produced, The
percentage of unavoidable waste in each process depends on the
organization and on the particular site, since it is related to the level of
technological development. The second is avoidable waste, where the cost of
waste is significantly higher than the cost to prevent it.
Waste can also be classified according to its origin, that is, the stage that the
main root cause is related to. Although waste is usually identified during the
production stage, it may also be originated by processes that precede
production, such as materials manufacturing, training of human resources,
design, materials supply, and planning.
The most classical waste classification according to lean production paradigm
is perhaps the classification done by Shigeo Shingo. He proposed the
following waste classification whereby waste was classified by its nature,
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
4. Waste due to the system itself
5. Waste due to stock
6. Waste due to operation
7. Waste due to defects
Formoso, et al. (1999) gave further clarity on waste classification based on
studies done on construction site in Brazil. His classification is meant to assist
managers to understand the different forms of waste, why they occur and how
they can be avoided or reduced.
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. A classic
example is the overproduction of mortar that cannot be used on time.
Substitution: is monetary waste caused by the substitution of a material by
a more expensive one that has 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.
Waiting time: related to the idle time caused by lack of synchronization and
levelling of material flows, and pace of work by different groups or
equipments. An example would be a gang waiting one operation to be
complete before they can start working.
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 consequences are: waste of
man hours, waste of energy, waste of space on site, and the possibility of
material waste during transportation.
Processing: related to the nature of the processing (conversion) activity,
which could only be avoided by changing the construction technology. For
instance, concrete is wasted if placed in confined spaces using a bucket.
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.
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.
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 , 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.
9. Others: waste of any nature different from the previous ones, such as
burglary, vandalism, inclement weather, accidents, etc.
Waste that is time based is difficult to model because there are no optimal
efficiencies to compare to. Instead of classifying the waste of productive time,
Serpell et. al (1995) broke down those wastes factors in relation of work
categories.
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
examples such as transporting, instruction, measuring and cleaning
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
2.13 Key construction waste causes
Understanding the causes of waste would help in reducing or eliminating
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. Some of the key areas that cause
waste are administration processes, use of resources and information
systems.
2.14 Waste and performance in construction
Modelling and evaluation of wastes and performance in construction projects
is a challenge. 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 such as waste, value, cycle time or variability.
Scholars have characterized performance in a broad definition as seven
criteria on which management should focus its efforts on as discussed and
that is namely effectiveness, efficiency, quality, productivity, quality of work
life, innovation and profitability.
2.14 Conclusion
There are endemic problems in the construction industry including waste that
have been attributed historically to the nature of the product, which is, once off,
in- situ and composed of many variables. There has been a drive to steer the
industry towards a manufacturing production kind of scenario where
management and production principles are systematic and scientific. To this end
a new system of thinking called Lean Construction has been put forward to
challenge the conventional thinking that regards construction as a conversion
only process but also to include the flow part of the process. There a lot of
opportunities to recognize waste using Lean Construction models whose aim is
to eventually eliminate or minimize waste. Using Lean Construction models is
both systematic and scientific. The use of the new thinking coupled with other
strategies within organizations is aimed at waste reduction and hence increased
efficiency. It is there fore possible to use the Lean construction models within
GLTA to test waste recognition and mitigation, sources of waste and to
compartmentalize the characteristics of waste.
3.0 Research Methodology
3.1 Method of research
The purpose of this academic research is to find out the degree of awareness
and recognition of waste on site using the Lean Construction process-flow
model as a yardstick. The study will also try to search for the attitude towards
waste by site construction personnel, that is, whether there are deliberate
steps taken of preventing and averting waste should it be recognized. Site
staff that includes foremen, site engineers and managers will be targeted for
this study.
The research is based on a quantitative and deductive approach that requires
the use of a structured questionnaire that seeks to elicit certain variables that
will be used for evaluation. Fortunately for this study that was limited to a
single business unit of Grinaker-LTA, responses could be obtained from the
whole targeted population. There would be no need for probability sampling in
this case (Saunders et al, 2007). Critical realism will be used to study the
current situation regarding practice and attitude so that meaning can be
extracted according to the model for evaluation. It is also hoped that given
that the company has a long history, there might be subjectivity that will
emanate from the acquired culture and that would subsequently point directly
to the root of some of the anticipated challenges.
This research was postulated around Lean Construction techniques that
recognize waste in construction through the process-flow models as
suggested by Koskela (1992) and Serpell et al. (1995). Waste is categorized
into three, that is, direct conversion waste, non-contributory time waste and
contributory time waste and each category has 9, 7 and 3 identified wastes
respectively as tabulated below in Table 3.1
Table 3.1. Direct waste elements on site
Source: Leng. “The application of lean construction to reduce waste in the
construction process flow
Direct conversion
waste
Non-contributory
time waste
Contributory
time waste
1 Over
allocation/unnecessary
equipment on site
Waiting for others to
complete work
before
commencement of
the next task
Time for
supervising
and inspection
of works
2 Over
allocation/unnecessary
materials on site
Waiting for
equipment to be
delivered to site
Time for
instruction and
communication
between
different tiers
of workers
3 Over
allocation/unnecessary
workers on site
Waiting for materials
to be delivered to
site
Time for
transporting
workers,
materials and
equipment
4 Unnecessary
procedures and
working protocol
Waiting for specialist
skills to arrive on site
5 Material loss/stolen
from site
Waiting for
clarification and
confirmation from
consultants or client
6 Material
deterioration/damage
during construction
periods
Time for repair or
rework of defective
work
7 Mishandling/error in Time for workers
construction
applications or
installations
resting on site and
other physiological
needs
8 Materials for rework or
repair of defective
work
9 Accidents on site
It is also imperative in this research to acknowledge some of the causes of
these waste on site so that a relationship between waste and cause is
established as a basis for thriving for continuous improvement. Five groups of
causal factors, that is, management & administration, people, execution,
material and information & communication factors have been recognized and
listed below.
1. Management and administration
Poor coordination among project participants
Poor planning and scheduling
Lack of control
Bureaucracy
2. People
Lack of trade skills
Inexperienced inspectors
Too few supervisors or foremen
Uncontrolled subcontracting practices
Poor labour distribution
Untimely supervision
3. Execution
Inappropriate construction methods
Outdated equipment
Equipment shortage
Ineffective equipment or poor choice of equipment
Poor site layout
Poor site documentation
4. materials
delay of material deliveries
poorly scheduled delivery of materials to site
poor quality material
misappropriation or misuse of material
poor storage of material
poor material handling on site
5. Information and communication
Defective or wrong information
Late information and decision making
Unclear information
3.2 Profile of respondents
This study is limited to site personnel. The respondents targeted include
foremen, site engineers and site based managers.
The foremen are the specific practitioners who are in direct contact with
labour, material and equipment and execute the construction. Site engineers
generally are the interface between the consultants and the construction
artisans. They interpret and explain the project to the foremen and artisans.
They are also involved in resource requisition and allocation. Site based
management will be involved in overall project execution, resource
management and coordination.
The profile of respondents may result in some research limitations of reliability
and validity, however care was taken to eliminate as much of the limitations
as possible (Saunders et al. 2007). The respondents work in the same
environment and fortunately for Grinaker-LTA, most of them have been with
the organization for a long time. The questionnaire will be structured in such a
way as to eliminate participant error, biases and observer errors. The study is
limited to two sites and may have limited validity, but due to the similarity of
operations within this particular business unit, the result will be a good
reflection of the real situation and be a good basis for future extensive studies
within the operating group. It is also assumed that there is a good chance of
generalizability of the result of the study.
3.3 Hypotheses
Descriptive analysis will be used to decipher the primary data once they are
collected. The descriptive analysis will be used to profile the respondents with
special emphasis being put on their work experience and exposure to the
Grinaker-LTA company culture. It is hoped that there is a correlation between
waste recognition and control with company culture that will emerge.
Analysis will be done separately for the three categories of waste so that
there is a better comparison of the conventional waste and new waste
categories under Lean Construction. The relationship between waste
recognition and deliberate attempt to control the waste will also be examined.
It is logical that recognition must lead to attempted control, but this may not
be so depending on company culture.
The hypotheses that will be tested in this study are:
Hypothesis 1: Direct conversion wastes are highly recognized and there is
an attempt to control them
Hypothesis 2: Non contributory time wastes are not easily recognized and
there is no attempt to control them
Hypothesis 3: Contributory time wastes are highly recognized but there is
no attempt to control them
3.4 Structure of the questionnaire
The questionnaire is divided into 4 sections. The first 2 sections of
questionnaire are intended to examine the general perception and
acceptance of Lean Construction philosophy based on the respondents’
waste recognition concepts. Respondents will asked to recognize 20 waste
elements and their personal experiences in controlling these waste elements
during construction processes. There are 2 options available for the
respondents and they will be required to answer whether the waste elements
listed is actually 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 the company by ranking them in terms of frequencies of
occurrences and rate the likelihood of particular waste sources and causes in
their construction practices where they work. For section 3, Respondents will
be able to identify how frequently the waste occurs using 5 categories: (1)
Never; (2) Very Rare; (3) Seldom; (4) Frequent; and (5) Very Frequent.
Respondents will be provided with five different scales from 1 (no significant
effect variable) to 5 as (high detrimental effect variable); In Section 4,
Respondents will be asked to determine the likelihood of particular waste
sources/ causes occurring using 4 categories: (1) Most unlikely; (2) Unlikely;
(3) Likely; (4) Most Likely and the respondents will be provided with five
different scales from 1 (no significant likelihood) to 5 (high likelihood).
3.5 Conclusion
Lean Construction models enable the categorization of waste and recognition
of the sources of waste. The conversion and flow model makes it possible to
track waste types along the construction process. The methodology applied in
this study is to first of all profile the respondents so that it may be possible to
correlate the findings to the profiles. Secondly, respondents will be asked to
recognize waste, say if it is mitigated on site and where they think the waste
emanates. Further more, three hypotheses have been put forward that will be
tested using descriptive analysis of the findings.
4.0 Data Analysis and Interpretation
4.1 Introduction
This chapter will give a presentation of the results from all returned
questionnaires as well as a discussion on the significance of the results. The
results will be tabulated showing the percentage rating of each variable.
Results from the tables will be drawn into graphs in order to give a visual view
of the results.
4.2 Response
A total of 42 questionnaires were sent out to personnel at Eastgate and
Samrand construction sites. There were 30 responses that were handed back
and used for this analysis. The response rate was 71% and the highest
number of responses came from Site Engineers as out of all the respondents
they represent 50%. Figure 4.1 below shows the classification of
respondents. It was hoped that Foremen would have had a higher response
so that the results of the study would not be biased towards the other groups.
Position held in GLTA
20%
20%50%
10%
Student
Foreman
Engineer
Manager
Figure 4.1. Response rate according to position within GLTA
Distribution of Experience in GLTA
30%
50%
10%
10%
0-2yr
2-5yr
5-10yr
10+yr
Figure 4.2. Respondent classification according to experience within
GLTA
Figure 4.2 above show the classification of respondents according to the
number of years that they have been in GLTA. 70% of the respondents have
been with the company for at least 2 years. This is a good enough time span
for the employees to have observed the practices within the company and
also form opinions about “how things are done around here”. Most importantly
there is 20% of respondents who have been within GLTA for more than 5
years.
4.3 General waste recognition
For the discussions on waste recognition, mitigation and frequency of
occurrence that are coming now a key of waste type and variables has been
done below that will identify waste as a colour code and variables as a
number.
Table 4.1 Key of waste type
Direct Conversation Waste Contributory Waste Non Contributory Waste
Table 4.2 Key of Variables
Variable Description
1Waiting for others to complete their work before proceeding with other work
2 Waiting for equipment to be delivered to site3 Waiting for materials to be delivered to site4 Waiting for specialist subcontractors to come to site
5Waiting for clarification and confirmation from the client and consultants
6 Time for rework/repair of defective work7 Materials for rework/repair of defective work8 Time for workers resting on site during working periods9 Over-allocation/unnecessary equipment on site
10 Over-allocation/unnecessary material on site11 Over-allocation/unnecessary workers on site12 Unnecessary protocols on site13 Unclear lines of communication14 Materials stolen from site during construction15 Material deterioration on site16 Errors in construction applications17 Accidents on site18 Time for supervising and inspection of work
19Time for instructions and communication among different trades on the same job
20 Time for transporting workers, equipment and materials
Table 4.3 Matrix of results for general waste recognition
Variable WasteNon Waste
% %1 80 202 90 103 100 04 80 205 100 06 100 07 90 108 80 209 100 0
10 90 1011 90 1012 90 1013 100 014 90 1015 100 016 100 017 100 018 30 7019 30 7020 20 80
Genaral Waste Recognition
0
20
40
60
80
100
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Variable
% R
eco
gn
itio
n
Waste
Non Waste
Figure 4.3 General waste recognition
There was a high rate of identification of direct conversion and non
contributory wastes. However there seemed to be an unawareness of
contributory waste. This may be attributed to the traditional thinking of waste
in construction. The Conversion-Flow Model recognizes contributory time as a
waste that must also be minimized. There was a tolerance towards waiting
and break times for workers. A lot of respondents identified this as non-waste.
The mean recognition of waste was 83% which indicates that personnel on
site are highly aware of waste.
4.4 Waste Mitigation Scenario
Table 4.4 Matrix of results for mitigation of waste
Variable Yes No % %
1 50 502 50 503 70 304 60 405 70 306 70 307 80 208 70 309 50 50
10 40 6011 40 60
12 60 4013 30 7014 70 3015 50 5016 50 5017 40 6018 60 4019 60 4020 50 50
Mitigation Scenario
0
10
20
30
40
50
60
70
80
90
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Variable
% M
itig
atio
n
Mitigation
No Mitigation
Figure 4.4 Waste mitigation scenario
The mean mitigation rate is 56% and non-mitigation is 44%. Contributory and non
contributory have a higher margin with mean mitigation rate of 56% and 65%
respectively. Direct conversion wastes have problems with a mean mitigation rate of
48%. The overall picture however is inconclusive because the results show that
although personnel can recognize waste, it does not necessarily mean that they
mitigate these wastes.
4.5 Frequency of Occurrence
Table 5.5 Matrix of frequencies of waste occurrences
Variable 1 2 3 4 5 % % % % %
1 0 0 20 60 202 0 10 40 30 203 10 0 40 30 204 0 20 40 30 105 0 10 30 40 206 0 20 10 30 307 0 10 40 20 308 20 10 40 10 209 0 20 40 30 10
10 10 20 30 30 1011 20 10 40 20 2012 10 30 30 20 1013 10 0 20 40 3014 0 10 20 50 2015 10 30 20 30 1016 10 10 40 20 2017 0 30 30 30 1018 0 0 30 30 4019 0 0 40 20 4020 0 0 50 10 40
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
never
very rare
seldom
frequently
very frequently
Figure 4.5 Frequency of occurrence of wastesThe mean frequencies are; never (6%), very rare (12%), seldom (32%), frequently
(29%) and very frequently (21%). The frequency of occurrence that is between
wastes occurring frequently and very frequently is 50%. This shows that half the time
when any operation is taking place on site there is wastage.
4.6 Sources and Causes of Waste
In the table below, the figures in red are the mean values of each selected rating options.
Table 4.6 Sources and causes of waste
` Description Most
unlikely unlikely likelyMost likely
% % % %
1
Management and Administration 0 30 55 15
Poor coordination among project participants 0 10 80 10
Poor planning and scheduling 0 40 20 40
Lack of control 0 30 60 10 Bureaucracy 0 40 60 02 People 4 20 50 26 Lack of trade skills 0 10 40 50 Inexperienced inspectors 20 10 30 40 Too few supervisors 0 40 50 10 Uncontrolled subcontracting practices 0 30 50 20 Poor labour distribution 0 10 80 103 Execution 4 40 42 14 Inappropriate construction methods 0 20 70 10 Outdated equipment 0 30 50 20 Lack of equipment 0 40 40 20 Poor site layout 10 60 20 10 Poor site documentation 10 50 30 104 Material 10 14 44 34
Poor schedule of delivery of material to site 10 20 40 30
Late delivery of materials to site 0 20 50 30 Misuse of materials 0 10 60 30 Poor storage of materials 20 10 50 30 Poor handling of materials 20 10 20 505 Information and Communication 0 13 23 63 Wrong information 0 30 30 40 Late information 0 0 20 80 Unclear information 0 10 20 70
The results in Table 4.6 above show that all the 5 variables are likely or most
likely sources of waste. In all cases, the mean of the variable being a cause of
waste is above 50%. Poor planning (40%), lack of trade skills (50%), poor
handling of materials (50%), late information (80%) and unclear information
(70%) stand out as the problem areas that most likely cause waste on site
4.6 Discussion of findings
The findings of this study in many respects concur with literature that has
been discussed in Chapter 2. The derivative equation from the conversion
flow model suggests that the cycle time of a process involves conversion,
handling, inspection and waiting. That is
Cycle time = processing + handling + inspection + waiting
On the aspect of waste recognition, it is clear that site staff identified
processing, handling and waiting wastes but failed in most instances to
recognize inspection as a waste. The equation above recognizes inspection
as a consumer of time that must be minimized in as much as it is necessary.
The other categories of waste were easily identified because they could be
easily turned into monetary value.
As surprising as it is to difficult to understand, recognition of waste does not
necessarily lead to its mitigation. It was easy to recognize direct conversion
waste but no proportional effort was spent in mitigation. From literature it was
acknowledged that one of the endemic problems in construction is waste that
has become acceptable over time that it is actually factored when tendering
for work. This thinking may be so deep-rooted that site staff does not see the
negative consequence of wastage in processing activities. Contributory and
non-contributory wastes were viewed as avoidable wastes because they do
not take a lot of money to rectify. This view is supported by Serpell’s
classification of waste as avoidable or unavoidable waste.
The findings also point to the fact that all sources of waste as suggested in
the Lean Construction theory are in fact causes of waste in GLTA. All five
sources had scores of higher than 50% likelihood of being a cause of waste
on site.
According to Shingo and the Institute of Lean Thinking, these findings imply
directly that GLTA is not lean and that it is losing profitability and the
competitive edge by not making its operations efficient.
5.0 Conclusions and Recommendations
5.1 Introduction
This chapter concludes the study by discussing the results in relation to the
objectives of the study and the hypotheses postulated. Recommendations will
also be suggested on improvements that can be made based on the problem
areas and positives found in the study.
5.2 Relating research findings to research objectives
5.2.1 Objective 1: To examine the general perception and attitude
towards and practice of lean construction principles within Grinaker-
LTA.
From the research results, it was discovered that there was a high incidence
of recognition of direct conversion and non-contributory waste and a dismally
low recognition of contributory waste. The underlying reasons for this may be
that personnel can easily quantify waste or loss due to conversion processes
and non contributory time into monetary value. For instance, it is easy to
quantify how much loss one makes by paying an employee for an hour for no
work done or throwing away material. Contributory waste is regarded as
acceptable because traditionally without the professional teams’ approval of
work, no further work may be carried out. What must be realised according to
the Lean thinking process is that although contributory waste may be
necessary, it is still a waste that must be minimized. If there is minimization,
then the cycle time is reduced which results in less waste. As surprising as it
is unfathomable, the tendency to mitigate the recognized waste is not as
great. There is need to study why personnel do not have an attitude that
wants to eliminate waste. My suspicions are that this problem may be deep
rooted in the GLTA culture or there is little encouragement and support to
achieve no waste on sites. In conclusion, it seems that there is some
appreciation of Lean Construction principles within the site personnel albeit
unscientific. GLTA is neither traditionalistic nor modernistic in approach and
there is need to formalize the principles of lean construction in order to
achieve less wastage and more profit.
5.2.2 Objective 2: Examine the extent of problems arising from waste
identified in the current scenario
The scenario that close to 90% of waste is identified on site and only 56% is
actively mitigated paints a grim picture of an organization that is trying to
move forward in terms of operational efficiency. The study shows that
personnel are able to see what is going wrong on site and for some reasons
they do not take action to mitigate the wrongs. The extent of the problems is
that on any activity that is happening on site, half the time there is wastage
taking place and nobody bothers to eliminate the waste or its causes.
5.2.3 Objective 3: Identify the sources of waste
In the study, there were 5 areas identified by lean thinking as possible
sources and causes of waste that were tested. It clearly came out that all the
5 sources, namely management and administration, people, execution,
material and communication and information are all sources and causes of
waste. Each of these areas had a mean score above 50% for the likelihood
that it was a source of waste. GLTA needs to do an introspection of the whole
organization to see where improvements can be made. This in no way means
that the company is not successful, but simply points to the fact that the
organization is not realizing its full potential. In conclusion, the study identified
the sources and causes of waste in GLTA.
5.2.4 Objective 4: Study the possible improvements aimed at eliminating
waste
Although no direct questions were paused suggesting areas of improvement,
the study shows all the areas that cause or are a source of waste. These are
the areas that need attention and should be worked on. In the next
discussions possible improvements will be suggested on how to eliminate
waste. The study there fore, was successful in identifying waste and its
sources. This information will be utilized in formulating interventions aimed at
reducing and eliminating waste
5.3 Relating research study to hypotheses
The hypotheses suggested in Chapter 4 will be re-written in view of the facts
gathered from the study as follows:
Hypothesis 1: Direct conversion wastes are highly recognized and there is
a significant attempt to control them.
Hypothesis 2: Non contributory time wastes are easily recognized and
there is no significant attempt to control them.
Hypothesis 3: Contributory time wastes are not easily recognized and
there is no significant attempt to control them.
The fact that only direct conversion wastes have a significant attempt at being
controlled shows a traditional mindset of waste control. Recognizing waste does not
prompt action to control the waste. There could be a lot of factor for this fact. It could
be that personnel are not empowered to take action, the cost of taking action may be
higher than letting waste occur or utter ignorance of the principles of waste control.
This defies logic; however it is a fact that was discovered in the research study.
However, without any deliberate scientific interventions, it will be impossible to
really measure the attitude of personnel on waste management. There fore further
studies need to be done in educating personnel about waste and waste control. This
will be the basis where GLTA can start to learn about itself and improving itself.
5.3 Recommendations
The process of implementing lean construction methods to identifying and
reducing waste involves a change of mindset and sometimes organizational
culture. The overall goal is to achieve construction process optimization and
efficiency in sub-activities by embracing the attitude of waste identification
and elimination. As such, it is a challenge to introduce lean thinking into an
organization. For GLTA, the challenges are similar but this section will look at
ways that the organization can take itself forward and start performing at
world class levels. The reality of the situation is that with globalization and
increased competition from foreign companies, only lean companies will
survive. The following are some of the fundamental recommendations that
GLTA can make on the road to Lean Construction:
Management commitment
Management must provide leadership for the new philosophy. They must
understand the philosophy of Lean Construction and be able to preach it to
their subordinates. There will always be resistance to change especially new
endeavours that may be met with a lot of scepticism from employees that
have been in the organization for along time. Management commitment will
be required for that change to occur. Management must take time to
communicate and filter the new ideology to employees. Road shows may be
conducted on sites and must include junior and senior staff.
Benchmarking
Successes in Lean Construction must be measurable. Initially the
organization needs to understand itself through a process of Value Stream
Mapping. Deliberate interventions must be identified in the system and goals
set for improvement. The focus should be on actionable and measurable
improvement rather than on developing abstract capabilities. Successes must
be quantified and celebrated as these short term successes create motivation
and reinforcement to further successes. Steadily GLTA will create its on
benchmarks for lean construction which may be compared to external
benchmarks for further improvement or maintaining industry leadership.
Employee Involvement
Employees are motivated when they are made to be part of the solution.
Hierarchies in the organization do not need to change, but whenever there is
an intervention needed, employees must be made part of the solution seeking
team. This may be done in focus groups that brainstorm solutions. Feedback
must be given back so that they appreciate their involvement. Such solutions
are likely to be accepted and implemented without too much resistance.
Employees must also be given the powers to make major decisions as long
as they fall within the company guidelines. Planning for the job must also
involve foremen and engineers on site so that they take ownership of the
plan, rather than have it forced down their throat.
Learning
Implementation requires a substantial amount of learning. Initial learning for
employees who are already in the company would involve teaching them the
principles and tools of lean construction and the rewards that come with the
new philosophy. On the job reinforcement will be required to make the
process of adaptation work. For new employees, there must be a process of
orientation that will reinforce the requirements of GLTA. This will ensure a
workforce that is cohesive. A learning organization is a winning organization.
After every project there must be a debriefing process that captures mistakes
and successes and these would be put in the company knowledge vault for
future use.
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Appendix
1. Questionnaire
INTRODUCTION
This questionnaire is part of a study to find the extent to which GLTA Building Inland sites have waste problems and create a road map to reducing the waste. The questionnaire is divided into 4 sectionsthat will need to be filled in as accurately as possible depending on your experiences, perception oropinion
I would you to thank you for taking part in this study and would like to assure you that your responseswill be treated with the utmost confidence
PROFILE
How many years have you been with the company
0-2 years 2-5 years 5-10 years over 10 years
What position do you hold on site
Student Foremen Engineer/QS Management
1 General Waste IdentificationIndicate in the following Table items that according to your opinion and understanding are "waste" or
"non-waste". Please indicate with X
item Description wastenon-waste
1 Waiting for others to complete their work before proceeding with other work
2 Waiting for equipment to be delivered to site
3 Waiting for materials to be delivered to site
4 Waiting for specialist subcontractors to come to site
5 Waiting for clarification and confirmation from the client and consultants
6 Over-allocation/unnecessary equipment on site
7 Over-allocation/unnecessary material on site
8 Over-allocation/unnecessary workers on site
9 unnecessary protocols on site
10 Unclear lines of communication
11 Materials stolen from site during construction
12 Material deterioration on site
13 Errors in construction applications
14 Time for rework/repair of defective work
15 Materials for rework/repair of defective work
16 Time for workers resting on site during working periods
17 Time for supervising and inspection of work
18 Time for instructions and communication among different trades on the same job
19 Time for transporting workers, equipment and materials
20 Accidents on site
2 Existing ScenarioAccording to your experience in the construction within Grinaker-LTA, are the following items properly
controlled or mitigated wherever they occur. Please indicate with X whether you agree or disagree
item Description Yes No
1 Waiting for others to complete their work before proceeding with other work
2 Waiting for equipment to be delivered to site
3 Waiting for materials to be delivered to site
4 Waiting for specialist subcontractors to come to site
5 Waiting for clarification and confirmation from the client and consultants
6 Over-allocation/unnecessary equipment on site
7 Over-allocation/unnecessary material on site
8 Over-allocation/unnecessary workers on site
9 Unnecessary protocols on site
10 Unclear lines of communication
11 Materials stolen from site during construction
12 Material deterioration on site
13 Errors in construction applications
14 Time for rework/repair of defective work
15 Materials for rework/repair of defective work
16 Time for workers resting on site during working periods
17 Time for supervising and inspection of work
18Time for instructions and communication between different trades on the same job
19 Time for transporting workers, equipment and materials
20 Accidents on site
3 Frequency of Occurrence
According to your experience in GLTA, what is the prevalence of occurrence of the following items. The response must be between never and vey
frequently. Please indicate with X in the appropriate box
item Description NeverVery rare
1 Waiting for others to complete their work before proceeding with other work
2 Waiting for equipment to be delivered to site
3 Waiting for materials to be delivered to site
4 Waiting for specialist subcontractors to come to site
5 Waiting for clarification and confirmation from the client and consultants
6 Over-allocation/unnecessary equipment on site
7 Over-allocation/unnecessary material on site
8 Over-allocation/unnecessary workers on site
9 Unnecessary protocols on site
10 Unclear lines of communication
11 Materials stolen from site during construction
12 Material deterioration on site
13 Errors in construction applications
14 Time for rework/repair of defective work
15 Materials for rework/repair of defective work
16 Time for workers resting on site during working periods
17 Time for supervising and inspection of work
18Time for instructions and communication among different trades on the same job
19 Time for transporting workers, equipment and materials
20 Accidents on site
4 Sources and Causes of Waste
In your opinion and experience in GLTA, rate the items shown in the following Table as the cuases or sources of waste on site. You may rate the items as most unlikely up to most likely. Indicate with X the appropriate rating
item Descriptionmost
unlikely unlikely
1 Management and Administration
Poor coordination among project participants
Poor planning and scheduling
Lack of control
Bureaucracy
2 People
Lack of trade skills
Inexperienced inspectors
Too few supervisors
Uncontrolled subcontracting practices
Poor labour distribution
3 Execution
Inappropriate construction methods
Outdated equipment
Lack of equipment
Poor site layout
Poor site documentation
most unlikely unlikely
4 Material
Poor schedule of delivery of materil to site
Late delivery of materials to site
Misuse of materials
Poor storage of materials
Poor handling of materials
5 Information and Communication
Wrong information
Late information
Unclear information