Lean Six Sigma

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MINIMIZING WASTAGE IN CONSTRUCTION

USING SIX SIGMA METHODOLOGY

A PROJECT BY

Monish U. Balsurkar , Akash R. Butole

Babasaheb Ambedkar Marathwada University, Jawaharlal Nehru Engineering college

Aurangabad, Maharashtra, 431003

Chapter 1. INTRODUCTION:-

1.1 Introduction to six sigma

Six Sigma is a philosophy based on setting attainable short-term goals while

striving for long-term objectives. Six sigma is a highly disciplined approach used to reduce the process variations to the extent that the level of defects are drastically reduced to less than 3.4 per million process, product or service opportunities (DPMO). Six Sigma, in many organizations, simply means a measure of quality that strives for near perfection. Six Sigma is a disciplined, data-driven approach and methodology for eliminating defects (driving towards six standard deviations between the mean and the nearest specification limit) in any process; from manufacturing to transactional and from product to service and also in construction processes. The Six Sigma method allows us to draw comparisons to other similar or dissimilar products, services, and processes. In this manner, we can see how far ahead or behind we are. Six Sigma helps us to establish our course and gauge our pace in the race for total customer satisfaction.

Six Sigma is a highly disciplined process that helps us focus on developing and

delivering near-perfect products and services. Why Sigma? The word is a statistical term that measures how far a given process deviates from perfection. The central idea behind Six Sigma is that if you can measure how many defects you have in a process, you can systematically figure out how to eliminate them and get as close to zero defects as possible. In construction field Six Sigma is used specially to prevent wastage during various construction processes by finding the root causes for wastages and rectifying the same.

The aim of this project to use Six Sigma methodology in construction field so as to

improve construction processes and minimize wastages occurring in various construction processes so as to increase profit while maintaining the quality standards in construction.

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1.2 SIX SIGMA PERPECTIVES:

1. Statistical approach. 2. Quality conscious approach combined with profit. 3. Customer satisfaction approach.

Process capability is defined as the probability of a product or service or process meeting customer requirements. The process capability index is defined as allowable process spread over actual process spread. Thus:

Cp = (USL LSL)/6

Where, USL and LSL are the process upper and lower specification limits. A three-

sigma process (normally distributed) gives a Cp of 1.0 with 66,807 defects per million

opportunities. In contrast, a six-sigma process will give a rate of only 3.4 p.p.m. outside the

limits. The higher the Sigma level, the less likely a process is to create defective parts.This

is a normal distribution curve which shows number of parts falling within and outside the

control limits (as shown in fig.1).

LSL USL

u 6 6 6 6 6

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1.3 HISTORY OF SIX SIGMA:-

The roots of Six Sigma as a measurement standard can be traced back to Carl

Friedrich Gauss (1777-1855) who introduced the concept of the normal curve. Six Sigma as

a measurement standard in product variation can be traced back to the 1920s when Walter

Shewhart showed that three sigma from the mean is the point where a process requires

correction. Many measurement standards (Cpk, Zero Defects, etc.) later came on the scene

but credit for coining the term Six Sigma goes to a Motorola engineer named Bill Smith.

About Bill Smith:

Bill Smith is a key person in inventing Six Sigma concept though many news media

ignore his contribution. Born in Brooklyn, New York in 1929, Bill Smith graduated from the

U.S. Naval Academy in 1952 and studied at the University of Minnesota School of Business.

In 1980s, after working for nearly 35 years in engineering and quality assurance, he joined

Motorola, serving as senior quality engineer for the Land Mobile Products Sector. He

passed away after a heart attack in early 90s and Bill Smith is recognized as "The father of

Six Sigma" for his great contribution to the quality's evolution journey.}

In the early and mid-1980s with Chairman Bob Galvin at the helm, Motorola

engineers decided that the traditional quality levels measuring defects in thousands of

opportunities didnt provide enough granularity. Instead, they wanted to measure the

defects per million opportunities. Motorola developed this new standard and created the

methodology and needed cultural change associated with it. Six Sigma helped Motorola

realize powerful bottom-line results in their organization in fact, they documented more

than $16 Billion in savings as a result of our Six Sigma efforts.

Since then, hundreds of companies around the world have adopted Six Sigma as a

way of doing business. This is a direct result of many of Americas leaders openly praising

the benefits of Six Sigma. Leaders such as Larry Bossidy of Allied Signal (now Honeywell),

and Jack Welch of General Electric Company.

GE saved $12 billion over five years and added $1 to its earnings per share.

Honeywell (Allied Signal) recorded more than $800 million in savings.

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1.4 MOTIVATION AND NEED OF THE PROJECT:-

The construction industry of India is an important indicator of the development as it

creates investment opportunities across various related sectors. The construction industry

has contributed an estimated 6708 billion to the national GDP in 2011-12 (a share of

around 9%). Civil or Construction is the oldest known engineering field. But still there is no

standard procedure followed while constructing buildings.

Unlike other engineering departments like mechanical, electrical, computer science,

etc where implementation by design is given high importance and a standard procedure is

followed during the work as given by the engineer, construction works or processes have no

standard procedure to follow and implementation according to the design given by the

engineer is merely followed practically on site.

The design of the building is always done precisely with the use of latest software

and techniques but the proper implementation of this design is where civil work fails to keep

the precision and hence problems like over use of materials and wastages of material are

faced by various construction companies. This leads to decrease in profits for the

constructing companies which the companies try to keep constant by increasing prices of

the units of the building which leads to customer dis-satisfaction and less sale of building

units which ultimately leads to less overall profits for the company or the builder or the

owner.

Hence, this project aims to solve the problems mentioned above by using Six Sigma methodology in construction field so as to improve construction processes and minimize wastages occurring in various construction processes so as to increase profit while maintaining the quality standards in construction.

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Chapter 2 Literature Overview 1: Minimizing waste in construction using Six sigma principles

Project by: Sunil V. Desale and Dr. Sharad V. Deodhar

A case study is carried out in Dhule district in Maharashtra. A Table shows list of prestigious

project and its location along with construction organizations name. So many Works are

going on out of these four organization where selected based on complete availability of

technical data has been taken into consideration who is going to construct residential

bungalow, flat system, and semi Govt.contractor work.

2: Implementing Six sigma in Concrete panel production

Project by: Yong-Woo Kim ,John Hutchison and Seungheon Han

Due to the lack of available information and many organizations reluctance to

disclose Lean Six Sigma Process Improvement Project(PIP) case study, we were able to

study only one case study. The case study is presented in this paper to investigate the Lean

Six Sigma methodology and the implementation in the construction industry. A brief

description of this case study project is given to provide the context. A description of

the analysis and key findings from this case study is also explained.

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3: Improving Precast Production Management

Project by :Luh-Maan Chang*, Chun-Hung Chao, Ya-Hui Lin

Professor, National Taiwan University

The goal of the Six Sigma project is to improve the manufacturing process of precast

column components and achieving savings. The scope is shown including the mold

assembly, the reinforcement cage and embedded assembly, concrete pouring and curing to

the finished product activities, but not includes the banding of the reinforcement cage and

storage of finished products, the above process operated by specific manufacturing crews.

4) Project: Study for Brick Masonary

Project by: Sunil V. Desale and Dr. Sharad V. Deodhar

A case study approach is used to compare the B.B Masonry work, constructed at

two similar, medium sized commercial construction projects located in at Walwadi area of

Dhule city. The objectives of this case study are to qualify the potential benefits. For a

concern site, Material related problems are identified and linked to the material

management practices. A Study for Brick Masonry is taken.

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Chapter 3. DMAIC methodology 3.1 SIX SIGMA METHODOLOGIES:-

Balanced Scorecard

Benchmarking

Business Process Management (BPM)

Design for Six Sigma (DFSS)

DMAIC

Harada Method

Kaizen

Lean

Metrics

Plan, Do, Check, Act

Project Management, etc.

From the following methodologies DMAIC methodology is used in this project for Six Sigma

implementation on an under-construction project or building for its waste management

which is explained below.

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3.2 DMAIC METHODOLOGY:-

DMAIC (an abbreviation for Define, Measure, Analyze, Improve and Control) refers

to a data-driven improvement cycle used for improving, optimizing and stabilizing business

and construction processes and designs. The DMAIC improvement cycle is the core tool

used to drive Six Sigma projects. However, DMAIC is not exclusive to Six Sigma and can be

used as the framework for other improvement applications.

DMAIC is an abbreviation of the five improvement steps it comprises: Define,

Measure, Analyze, Improve and Control. All of the DMAIC process steps are required and

always proceed in the given order.

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For a specific time, there were two sites under observation for the implementation of lean

methodology. These two sites are as follows:

Site: A (Lalitya Apartment)

Specifications :

Located in Osmanpura, behind Eknath mandir, Aurangabad

Area of site is 9600sq ft

RCC framed structure, external 6 internal 4 brickwork

G+4 storeyed building

Site: B (Nandanvan Apartment).

Specifications:

Located on Jalna road, opp. of airport, MIDC, Aurangabad.

Area of site is 10,000 Sq. ft

RCC framed structure, external 6 internal 4 brickwork

G+4 storeyed building

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Chapter 4 Lean Six Sigma System Development:

4.1 DEFINE:

The purpose of this step is to clearly articulate the business problem, goal, potential

resources, project scope and high-level project timeline. This information is typically

captured within project charter document. Write down what you currently know. Seek to

clarify facts, set objectives and form the project team. Define the following:

A problem

The customer(s)

The target process subject to DMAIC and other related business/construction processes

Project targets or goal

Project boundaries or scope

A project charter is often created and agreed upon during the Define step.

For site A:

Nature of activity : Construction

Dependency : Independent

Organization type : Privet limited.

Problem area: Material wastage.

Define problem: Wastage of materials during construction process.

Tools used: Flow chart, data collection, bar chart, root cause analysis, improvement

chart.

For site B:

Nature of activity: Construction.

Dependency: Independent.

Organization type: Privet limited.

Problem area: Material wastage.

Define problem: Wastage of materials during construction process.

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Tools used: Flow chart, data collection, bar chart, root cause analysis, improvement

chart.

4.2 MEASURE:

The purpose of this step is to objectively establish current baselines as the basis for

improvement. This is a data collection step, the purpose of which is to establish process

performance baselines. The performance metric baseline(s) from the Measure phase will be

compared to the performance metric at the conclusion of the project to determine objectively

whether significant improvement has been made. The team decides on what should be

measured and how to measure it. It is usual for teams to invest a lot of effort into assessing

the suitability of the proposed measurement systems. Good data is at the heart of the

DMAIC process:

Identify the gap between current and required performance.

Collect data to create a process performance capability baseline for the project metric,

that is, the process.

Assess the measurement system for adequate accuracy and precision.

Establish a high level process flow baseline. Additional detail can be filled in later.

For specific time, all data available for two sites was collected. For successful adopting

of lean methodology, it is most important job to find estimation and costing of project.

Monthly interval for selected 3 materials, viz., AAC blocks, cement, steel was made for

knowing their actual demand and total use. All data is collected and presented in a well-

mannered tabular form as shown below.

TOOLS FOR MEASUREMENT:-

Process Flowchart

Data Collection Plan/Example

Benchmarking

Measurement System Analysis/Gage R&R

Voice of the Customer Gathering

Process Sigma Calculation

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Problem definition: Wastage of AAC blocks during construction.

Site: A

Table 1

DESCRIPTION

December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

Total

ESTIMATE

575

1321

1948

648

1670

980

7142

TRANSPORTATION DAMAGE

3

136

46

4

23

12

224

USED

557

1284

1902

634

1639

963

6979

ON SITE DAMAGE

18

30

46

14

31

17

156

% WASTE

3.13%

2.3%

2.3%

2.16%

1.8%

1.73%

2.18%

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Problem definition: Wastage of AAC blocks during construction.

Site: B

Table 2

DESCRIPTION December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

Total

ESTIMATE

1072

900

600

750

380

450

4152

TRANSPORTATION DAMAGE

11

19

7

8

4

8

57

USED 1051

871

592

740

376

446

4076

ON SITE DAMAGE

21

29

8

10

4

4

76

% WASTE 1.95%

3.22%

1.33%

1.34%

1.05%

0.89%

1.83%

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Problem definition: Wastage of cement during construction.

Site: A

Table 3

DESCRIPTION

December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

Total

ESTIMATE

370 bags

340 bags

710 bags

240 bags

680 bags

180 bags

2520

USED

350 bags

335 bags

685 Bags

238 bags

676 bags

179 bags

2463

WASTED

3.5 bags

2 bags

5.5 bags

1.39 bags

3.33 bags

1 bag

16.72

% WASTE

1%

0.58%

0.77%

0.57%

0.49%

0.5%

0.66%

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Problem definition: Wastage of cement during construction.

Site: B

DESCRIPTION

December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

Total

ESTIMATE

200

520

650

1370

400

120

2970

USED

200

460

380

1040

360

120

2560

WASTED

Nominal

1.6

3

4.6

1.44

Nominal

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% WASTE

-

0.32%

0.48%

0.43%

0.36%

-

0.37%

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Table 4

Problem definition: Wastage of steel during construction.

Site: A

Table 5

DESCRIPTION

December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

Total

ESTIMATE

3050 kg

3092 kg

4585 kg

2065 kg

3563 kg

1500 kg

17855 kg

Wastage

5 kg

2.5kg

12kg

4kg

5kg

1kg

29.5 kg

% WASTE

0.16

0.08

0.28

0.19

0.15

0.06

0.17 %

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Problem definition: Wastage of steel during construction.

Site: B

Table 6

DESCRIPTION

December 2014

January 2015

February 2015

March 2015

April 2015

May 2015

Total

ESTIMATE

5394 kg

950 kg

6885 kg

1000 kg

7130 kg

4960 kg

26319 kg

Wastage

13 kg

4 kg

26 kg

3.2 kg

19.2 kg

8 kg

73.4 kg

% WASTE

0.24

0.42

0.38

0.32

0.27

0.16

0.27 %

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Chapter 5 Performance Analysis

5.1 Analyse:

The purpose of this step is to identify, validate and select root cause for elimination. A

large number of potential root causes (process inputs, X) of the project problem are

identified via root cause analysis (for example a fishbone diagram). The top 3-4 potential

root causes are selected using multi-voting or other consensus tool for further validation. A

data collection plan is created and data are collected to establish the relative contribution of

each root causes to the project metric, Y. This process is repeated until "valid" root causes

can be identified. Within Six Sigma, often complex analysis tools are used. However, it is

acceptable to use basic tools if these are appropriate. Of the "validated" root causes, all or

some can be

List and prioritize potential causes of the problem

Prioritize the root causes (key process inputs) to pursue in the Improve step

Identify how the process inputs (Xs) affect the process outputs (Ys). Data is analyzed to

understand the magnitude of contribution of each root cause, X, to the project metric, Y.

Statistical tests using p-values accompanied by Histograms, Pareto charts, and line

plots are often used to do this.

Detailed process maps can be created to help pin-point where in the process the root

causes reside, and what might be contributing to the occurrence. Analysing the time lapsed

for the construction and identification of the ways to eliminate gap between the current

performance of the system or process and the desired goal. Improving the top causes

identified in the Analyse phase, with the intent of either controlling or eliminating those

causes to achieve breakthrough performance. This step use creative ways to find new

ways to do things better, cheaper or faster.

TOOLS FOR ANALYSE:-

Histogram

Pareto Chart

Time Series/Run Chart

Scatter Plot

Regression Analysis

Cause and Effect/Fishbone Diagram

5 Whys

Process Map Review and Analysis

Statistical Analysis

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Hypothesis Testing (Continuous and Discrete)

Non-Normal Data Analysis

Qualitative analysis:

Asked for expert advice, on site investigation, investigate best practices through

benchmarking, fishbone analysis.

Graphical analysis:

Analyse historical data using box plots.

Pareto plots to identify the potential inputs

Risk analysis:

Failure mode effect analysis(FMEA)

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For site A problem analysis of AAC block wastage is as follows:

This whole root cause description is dependent on reason analysis. It includes following

reasoning:

1. AAC blocks transportation damage

WHY?

-Type of vehicle used is not suitable for proper transportation (vehicle)

- Blocks are originally transported from Nasik.(Distance)

(cannot be controlled or changed)

2. AAC blocks on site damage

WHY?

- Blocks are not properly loaded and placed.(unloading)

- Improper way of stacking of blocks & careless handling. (storage and handling)

- Less supervision on labours.

For site B problem analysis of AAC block wastage is as follows:

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Transportation

VehicleRoute

Distance

On site

Handling

Storage

SupervisionWastage ofAAC blocks

Damaged

Design change

Brickwork

Careless use

Lack of Skills

Labour

Site: B

This whole root cause description is dependent on reason analysis. It includes following

reasoning:

1. AAC blocks transportation damage

WHY?

-Type of vehicle used is not suitable for proper transportation (vehicle)

- Blocks are originally transported from Nasik.(Distance)

2. AAC blocks on site damage

WHY?

-Changes made to design while construction was in progress. (Brickwork)

-Blocks are not properly loaded and placed.

- Improper way of stacking of blocks & careless handling.

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For site A problem analysis of cement wastage is as follows:

Climate Over ordering

Wastage ofCEMENT

Improper storage

Lack of good supervision

Site: A

Loss during concreting

Labour tendency to use more concrete while concreting

CAUSE ANALYSIS

This whole root cause description is dependent on reason analysis. It includes following

reasoning:

Cement wastage on site

WHY?

- Due to sudden rainfall and improper storage of cement bags, resulted in watering effect on cement. (Climate change )

- Labour uses more cement while concreting. (Labour tendency )

- Ignoring measuring in design. (Over ordering )

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For site B problem analysis of cement wastage is as follows:

Unmeasured use

Wastage ofCEMENT

labour

Site: B

Tendency to use more concrete

On site

CAUSE ANALYSIS

Handling

Storage

Lack of skill

Cement wastage on site

WHY?

- Unavailability of proper shed for cement . (Storage, handling )

- Labour uses more cement while concreting. (Labour tendency )

- Ignoring measuring in design. (Over ordering )

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For site A problem analysis of steel wastage is as follows:

Ignorance in design

Over ordering

Wastage ofSTEEL

Lack of good supervision

Site: A

No availability of PRECISED record

CUTTING WASTE

CAUSE ANALYSIS

This whole root cause description is dependent on reason analysis. It includes following reasoning:

Steel wastage on site

WHY?

- Steel design of building was not properly checked. (Ignorance in design)

- Ignoring measuring in design. (Cutting waste)

- Ignoring steel design resulted in extra order. (Over ordering)

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For site B problem analysis of steel wastage is as follows:

Ignorance in design

Wastage ofSTEEL

Lack of good supervision

Site: B

Designing more than sufficient.

CUTTING WASTE

CAUSE ANALYSIS

This whole root cause description is dependent on reason analysis. It includes following

reasoning:

Steel wastage on site

WHY?

- Steel design of building was not properly checked. (Ignorance in design)

- Ignoring measuring in design. (Cutting waste)

- Ignoring steel design resulted in extra order. (Over ordering)

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5.2 IMPROVE:

The purpose of this step is to identify, test and implement a solution to the problem; in

part or in whole. Identify creative solutions to eliminate the key root causes in order to fix

and prevent process problems. Use brainstorming or techniques like Six Thinking

Hats and Random Word. Some projects can utilize complex analysis tools like DOE (Design

of Experiments), but try to focus on obvious solutions if these are apparent.

Create innovative solutions

Focus on the simplest and easiest solutions

Test solutions using Plan-Do-Check-Act (PDCA) cycle

Based on PDCA results, attempt to anticipate any avoidable risks associated with the

"improvement" using FMEA

Create a detailed implementation plan

Deploy improvements

Designing the factors to be improved and implemented such as Cement ,Bricks,

Formwork, Reinforcement and Labour. Measuring the losses and variation using the

methodology so as to rectify it further for minimum wastage.

An action plan is proposed to improve the current system of construction. Therefore, an

Expert Supervisor is appointed, to supervise and implement the action plan at the

construction site.However, practically it is impossible to rectify wastage @ 100%

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SITE A : Action Plan (Material AAC blocks )

Monthly action plan was made for improvement as follows.

Month- December 2014

Due to improper handling and stacking of blocks, 18 blocks out of 575 i.e., 3.13% were

damaged in this month.

Therefore, instructions were given to labour to handle blocks properly.

Month January 2015

In this month, out of 532 blocks, 126 blocks were broken in transportation.

Therefore, supervisor was advised that, such amount of broken blocks should not be

accepted and returned back to consigner. Also, these 126 broken blocks must be stacked

separately and labours were instructed to use these blocks first.

Month- February 2015

In this month out of 1948 blocks, 46 blocks were damaged.

Hence about 2.3% waste occurred.

Therefore, supervisor was suggested to guide labour about handling of AAC blocks.

Month- March 2015

In the month of March out of 648 bricks only 14 bricks were broken. This is a less amount of

wastage as compared to previous month as the percentage wasted is 2.16% .As the

estimate was less the delivery was made with other materials which damaged few blocks.

Month- April-May 2015

As per the measurement chart, only 48 blocks were broken but not totally damaged out of

2650 blocks, which is a very significant reduction in wastage as compared in previous

month. Here the lean methodology was applied throughout the construction activity and thus

only 1.8% of damage occurred.

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SITE A : Action Plan (Material Cement )

Month- December 2014

In this month, out of 370 estimated cement bags, 350 bags were used with wastage of 3.5

bags. Hence, about 1% wastage of cement occurred due to use of cement without

measuring by labour and without knowing sufficient amount needed.

Therefore, supervisor at the site was suggested to give proper knowledge to labour for use

of cement. Also labour were suggested to use only necessary amount of cement.

Month January 2015

In this month, out of 340 estimated cement bags, 335 bags were used with wastage of 2

cement bags. Hence about 0.58% wastage occurred. Though, labour was suggested to use

particular amount of cement, unfortunately 2 bags wasted.

Therefore, strict suggestions were given to labour about sufficient amount of use.

Month- February 2015

In this month the percentage wastage was increased from 0.58% to 0.77% due to the

delayed in work and some minor issues with the construction activities. To avoid these

problems the supervisor and site engineer was given a qualitative checklist and lean

procedure which can help to create a work structure.

Month- March 2015

In this month the wastage was reduced from 0.77% to 0.57%. An assessment was done to

check whether the procedure was followed by the supervisor and the checklist was

redesigned eliminating the errors.

Month- April-May 2015

In these months the percentage of waste was reduced to 0.5% which was marked as

optimum level of reduction as further reduction would lead to economic and time loss rather

which outcomes the gain. Hence, the supervisor was advised to operate under that system.

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SITE A : Action Plan (Material Steel )

Month- December 2014

In this month, out of 3050kg of estimated steel, total 2853 kg of steel was used with 5 kg of

wastage. About 0.16% waste.

Month January to February 2015

In this month, out of 3092 kg of steel estimated, 3080 kg of steel was used with 2.5 kg

wastage. About 0.08% waste.

REASONS-

Cutting waste occurred while using steel in construction which is unavoidable.

Month- March-June 2015

From the previous months it was observed that the loss of time required to manage the

cutting waste of steel was not worth the economic gain. Hence, a rather alternative was

chosen which included to perform the reuse of steel. This was done by using the remaining

steel in various construction activities.

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SITE B : Action Plan (Material AAC blocks )

Month- December 2014

Out of 1072 blocks 21 blocks were damaged during the construction process i.e 1.95% of

blocks were wasted.

Blocks were wasted due to bad adjustments in blocks as the wall sizes were not in standard

dimensions.

Hence, it was suggested to use good quality of cutting machine for less broken pieces.

Month- January 2015

Out of 900 blocks 29 blocks were damaged (i.e.3.22%) because, some portion was required

to deconstruct due to change in the design plan.

Hence the designer was advised to thorough the design plan and supervisor was advised to

check the design plan regularly. In addition to this , the broken block pieces were piled at

one single place and labours were instructed to use these blocks if suitable and not to cut

the fresh blocks.

Month- Feburary2015

As compared to analysis of previous month and its improvement, only 8 blocks were

damaged out of 600 blocks i.e. 1.33% wastage.

In this improvement phase, the labors were instructed to handle and store the bricks

properly.

Month- March 2015

The wastage percentage remained unchanged so a procedure and checklist was prepared

and the supervisor was advised to follow it to reduce more amount of wastage.

Month- April-May 2015

In these two months, due to the use of lean system given to the supervisor, a significant

results were observed as only 1% wastage occurred in the construction activity. Also

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attempt was made to use all the damaged and non-useful blocks for waterproofing. This

system was advised to keep operating in future work.

SITE B : Action Plan (Material Cement )

Month- December 2014:

In this month, out of 200 estimated cement bags. As per information given site engineer

approximately 200 bags were used with nominal waste.

Month- January 2015 :-

Here out of 520 cement bags 460 bags were used and half bag was wasted due to non-

measurement use of cement.

Hence, supervisor was suggested to instruct the labours to use cement by measuring it do

decrease the over use of cement.

Month-February 2015 :

In this month, out of 650 bags 3bags were wasted from which 2bags were wasted due to

unpredicted rainfall, because proper ground protection from water entering in the shelter

was not provided.

Month- March-June 2015

In these months, the prepared system and checklist proved a useful way to reduce the

wastage as the total wastage was observed to be only 0.37% .Hence this was marked as

the optimum wastage reduction. The engineer was advised to manage the inventory control

for further easy assessment of the work.

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5.3 Control :

Control:

The purpose of this step is to sustain the gains. Monitor the improvements to ensure

continued and sustainable success. Create a control plan. Update documents,

business process and training records as required.

A Control chart can be useful during the Control stage to assess the stability of the

improvements over time by serving as guide to continue monitoring the process and

provide a response plan for each of the measures being monitored in case the

process becomes unstable.

Control phase is about sustaining the changes made in the Improve phase to

guarantee lasting results. The best controls are those that require no

monitoring.Controls are required to ensure that the improvements are

maintained over time.

A check list is prepared which determines total improvement.

Choose type of construction -

Small scale Medium scale Large scale

Small scale projects

Define material and its specifications

Bought material should satisfy specific limits

Transportation of materials

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Distance between site and supplier should be minimum as possible. If possible, stable

vehicle should be preferred for transportation.

Contract

As far as possible, contract should be taken without material; materials which satisfy

specification should be provided with optimum cost.

If not possible, the quality of materials should be checked thoroughly according to its

specifications.

On site

Due to being a small scale project, if latest equipments are not available, then skilled labour

should be preferred so as to minimize waste due to delay mistakes and overuse.

On site usage of materials

1. BRICKS

Choosing type of bricks

Machine made AAC blocks/ bricks are more preferred than handmade red bricks.

Stacking of bricks

1. Stacking in pile formation

2. Providing appropriate shelter

3. Stacking near to working area

Prefer use of cutting machine for bricks than normal cutting.

37

As per the requirement, prefer use of broken bricks instead of fresh ones.

Reuse of broken bricks pieces :

Reuse of AAC blocks

Small broken pieces of AAC blocks should be used for PCC flooring.

Reuse of red bricks Small broken pieces of red bricks should be used for waterproofing

purposes.

2. CEMENT

Stacking of cement

1. Cement should be stacked on higher ground.

2. Appropriate arrangements must be made under cement bags to avoid contact with

water. For ex. Place cement bags over bamboos to prevent contact from water

beneath it.

Handling of cement

Place plastic sheet below cement bags to avoid wastage of cement while handling.

Avoiding overuse of cement

To maintain M15 grade mix design (1:2:4), it is advised that 6 liter tub must be used for

concrete proportion to avoid overuse of cement annually.

3. STEEL

Precise design estimation of steel requirement so as to order the steel accordingly.

38

Specify the order of steel bar length 32 feet or 30 feet only.

Reuse of steel cutting wastage

The steel wastage from cutting can be used for construction of lintels and compound walls.

It is recommended to use steel rapidly and order accordingly to avoid rusting of steel.

Medium scale projects

Define materials and their specifications.

Materials satisfying the specific limits should be bought. Most minimum costing brand with

satisfying specification should be used.

Transportation of materials

Truck for transporting materials is recommended. If not, possible, then tractor

with 2 axle is preferred.

If received materials like bricks are broken more than 15% of ordered quantity

then consignment should not be accepted and returned to consigner.

Contract

As far as possible, contract should be taken without material; materials which satisfy

specification should be provided with optimum cost.

If not possible, the quality of materials should be checked thoroughly according to its

specifications.

On site

Machines such as mixer, material lift, vibrators etc. should be used. Skilled labour to

avoid mistakes and delay.

39

On site usage of materials

1. BRICKS

Choosing type of bricks

Machine made AAC blocks / bricks are more preferable than handmade red

bricks.

Stacking of bricks

1. Stacking in pile formation

2. Providing appropriate shelter

3. Stacking near to working area

Handling of bricks

Circulation of bricks within the site should be carefully done and handled. If

possible, instrument should be used.

Reuse of broken bricks

Small broken pieces of AAC blocks should be used for PCC flooring and compound wall.

2. CEMENT

Stacking of cement bags

1. Cement should be stacked on higher ground.

2. Appropriate arrangements must be made under cement bags to avoid contact with

water. For ex. Place cement bags over bamboos to prevent contact from water

beneath it.

40

Handling of cement

Place plastic sheet below cement bags to avoid wastage of cement while handling.

Avoiding overuse of cement

To maintain M15 grade mix design (1:2:4), it is advised that 6 liter tub must be used for

concrete proportion to avoid overuse of cement annually.

Preparation of cement concrete shall be restricted to anticipated daily usage Release of cement to labour shall be controlled by the site in-charge on daily consumption basis.

3.STEEL

Specify the order of steel bars of length 40 feet and 32 feet only. Rest is same as small

scale construction.

Usage of steel shall be planned and executed by site in-charge to minimize wastage. As and when smaller length pieces of steel are available to meet the requirement, the same shall be used rather than cutting from long pieces. This requires effective control and monitoring by site in-charge.

Instructions to Contractor:

1. Provision of waste reduction training to on-site staff is also considered important in raising environmental awareness and helping site staff generating a better working procedure to reduce generation of materials wastage. 2. Use suitable, safe and secure storage For trades or materials where just in time

deliveries cannot be set up, suitable, safe and secure storage should be provided so that

damage during storage and moves is avoided.

3. Consider mechanical systems and machinery for moving materials This is particular useful for trades where materials are delivered in large quantities ( brickwork, block work). 4. By using mechanical handling of materials damage and loss during materials movement on site is minimised. 5. Consider off site construction Off site construction of elements is becoming a popular method to improve efficiency and quality. Offsite construction minimises the amount of work required on Site and in particular reduces wastage.

41

6. Programme and monitor construction activities This can be achieved by creating procedure which allows monitoring of performance and control of the construction process. Project management activities should also include regular reviews of the materials management process. Planning work helps in fast competition of project. 7. Use packaging in an efficient way Contractors and sub-contractors should investigate ways of packaging. Where possible, take back schemes for packaging unused materials.

42

Qualitative Checklist

Focus on: Producing an accurate estimate of the materials required for the project as this is the first step in avoiding unnecessary waste. Think about: Ways to ensure accurate estimates includes obtaining robust and reliable Information and using this information to produce accurate measures

How was the material quantity calculated?

CAD take-off Measure from printed drawings Cost plan / BQ quantity Site measurement Other (please specify)

Remarks

Focus on: The waste allowance can be split between design waste (i.e. off cuts) and construction process waste. By doing this, more accurate estimates can be made, resulting in tighter material ordering and more focused mitigating actions. Think about: Using accurate material estimates, what are the factors that generate waste and how they relate to design and/or the construction process

How was the allowance for construction process waste developed?

Based on historical data Personal experience Other (Please identify)

Remarks

Are there opportunities to reduce this wastage through the construction process? If so, what are they?

Yes....................... No........................

Remarks

43

Focus on: Identifying the largest contributors to waste specific to this project and in identifying ways to reduce this waste with minimal effort. Think about: How opportunities to reduce waste can be achieved

To what extent do the following factors influence the waste allowance and why

1 - Material delivery

Remarks

2- On site storage

3- Co-ordination & sequencing

4- Complexity of design

5- Rework

6- Design changes

7 - Others (please list) ...................................

Focus on: How to minimise the quantity of materials which are unused. Think about: How to reuse or recycle materials that are left over after work is completed.

What will be done with unused materials?

Returned to supplier Taken away by sub-contractor Given away Recycled

Remarks

What will be done with damaged materials?

Recycled Sent to landfill Other

Remarks

44

Focus on: How work is planned to avoid damage and rework. Think about: Who takes responsibility for reducing waste.

Is work programmed in a way that avoids damage and rework?

Responsibility Remarks

Does the programme include project reviews that require waste performance assessments?

Are procedures in place to record the causes of waste on site and prompt effective actions?

Is training in place to educate people on how to reduce waste?

45

Various planned flow chart were provided for both sites for all materials.

For both sites flow chart for reducing AAC blocks wastage is as follows-

TRANSPORTATION OF MATERIAL

UNLOADING MATERIAL

LARGE AMOUNT OF BROKEN

BLOCKS

YES

NO

Supervised handling

Proper cutting (use of machine)

Reuse of cut block

Stacking of blocks at particular

place

RETURN TO THE CONSIGNER

46

For both sites flow chart for reducing cement wastage is as

follows-

ACCURATE DESIGN CHECK

PROPER DEMAND OF CEMENT

SUPERVISED PROCEDURE

DAILY OBSERVATION

SUFFICENT USE WITHOUT HARMING QUALITY

47

For both sites flow chart for reducing steel wastage is as

follows-

DESIGN BY USING MODERN SOFTWARE

PROPER DEMAND OF STEEL

REGULAR RECORD OF STEEL USE

DAILY OBSERVATION

ATTEMPT TO DECREASE CUTTING WASTE

48

Chapter no. 6 Evaluation

6.1 Comparison of work structure before and after the start of the project

From the above data compilation, the wastage of the materials were compared with the current wastage and the wastage before starting the project. It was found that a major

units of materials wastage was minimized and the lean methodology also proved a

continuum improvement in the ways of material management.

Following data shows us the improvements before starting the project.

BEFORE AFTER

Broken bricks were discarded Stacking of broken bricks

49

Manual cutting of bricks Use of machine for cutting

Improper stacking of cement bags Provision of storage for cement bags

50

Improper stacking of bricks Proper way to pile and

stack bricks

Mix left unattended led to wastage Use of machine for mixing

51

Unused damaged bricks left unstacked Reuse of damaged bricks

The above images shows the implementation of Improvement Phase in Lean

methodology.

6.2 Graphical representation of monthly reduction in wastage

Bar chart showing the reduction of Bricks wastage

0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

3.50%

AAC Blocks Site A AAC Blocks Site B

December

January

Febuary

March

April

May

52

Bar chart showing the reduction of Cement wastage

6.3 Benefit of the project:

According to the measurement charts and implementation of the solutions, we can

observe the difference of material use in each month. This project has proposed a way to

use the optimum amount of materials and a common framework for almost every

construction activity.

As this project is a Cost-Saving project, it is obvious that it will not be able to trace a hard

benefit. But due to wastage minimization, the original cost of the construction can be

reduced thus increasing the percentage profit. This economic gain is called as Soft benefit.

Hence, in this project an attempt has been made to gain a soft profit.

6.3.1 Bricks

In case of the bricks, the total percentage wastage on site was 3.13% but using the lean

methodology it was reduced to 1.73%, i.e. the current wastage is 45% less than it was

before starting the project. The amount of AAC blocks which were damaged included in the

wastage were used for waterproofing. This makes the total utilization of the blocks, in other

words the amount of blocks which was estimated for the waterproofing was saved and this

is a soft financial benefit which will ultimately sum up along the other materials boosting the

economic gain.

0%

0%

0%

0%

0%

1%

1%

1%

1%

1%

1%

Cement Site A Cement Site B

December

January

February

March

April

May

53

6.3.2 Cement

In case of cement, the wastage of cement only occurs due to carelessness and

improper storage of the cement. But the lean methodology has attempted to reduce its

defects and mistakes and the measurement charts show the wastage reduction percentage.

The soft benefit of the cement is hardly makes any difference in the overall economic gain

but it sure makes an impression on the way of the work structure and how it should have

been. Hence, the project focuses on the management of the use of cement and its storage,

because it may not differ much in the profit but if implemented it can sure prevent any

uncertain losses.

6.3.3 Steel

The major amount of loss in steel was occurred due to the cutting of steel. As the

dimensions of the construction may differ respectively it is impossible to manufacture exact

dimension of individual steel requirement. As a result, in this project an attempt has been

made to reuse the steel instead of reducing the wastage technically. In this case, the steel

of appropriate dimensions were used for other construction activities. This helped to

manage the estimate of the steel thus saving the cost of extra steel required for those

activities.

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Chapter no. 7 Conclusion

The use of Lean six sigma methodology led to the minimization of the wastage of

materials but in addition to that it provided a work breakdown structure which provided as a

common framework for other exercises of the entire project. The complex project had many

activities which was impossible to be managed individually so the qualitative checklist

prepared proved an effective method to manage every aspect of the wastage management.

The proposed method enabled quality assessment of the design and construction

process, which also served as quality assurance method due to the possibility to avoid

potential defects. The use of lean methodology reduced the percentage of wastage in each

parameter thus increasing the percentage profit. Also the materials were salvaged and

reused which is beneficial as environmental point of view. The finished quality was

assessed by the site engineer and effective results were obtained which satisfied the

customer as well as the owner of the project. This method made an excellent use of project

management softwares, project planning, communication and manager role.

It validated that Lean Six Sigma approach can be effectively applied to the

construction industry, not only to reduce the wastage but also to improve the quality and

economic gain.

Hence, the Six Sigma approach may provide to the construction industry for the

pursuit of high level of quality and minimize the wastage beneficial in terms of finance as

well as environment.

7.1 Scope for future work

The aim of this project is the assessment of each and every exercise and construction activity of the project. Hence, this is a continuous process and it must be

evaluated periodically. The framework given in the Control phase can prove useful in the

assessment of the each aspects of the activities. As this project was only intended for

limited materials that are Bricks, Cement and Steel, but the project manager can perform

this work structure to manage every material used for the construction and ultimately reduce

its wastage and improve the quality of the project.

This work structure can continue until the completion of the project. The manager

can keep records before the use of this method and after the use of the method to compare

the statistics. At the end of the project, the sum of benefited cost will add in the profit

percentage and will show the overall economic gain

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Chapter 8 References

1. IJETT - Implementation Barriers for Six Sigma in Construction

http://www.ijettjournal.org/archive/ijett-v4i2p218

2. Minimising waste in construction by using lean six sigma by Sunil V. Desale, Dr Sharad

V.Deodhar

http://www.iaeme.com/MasterAdmin/UploadFolder/MINIMISING%20WASTE%20IN%20CONSTRUC

TION%20BY%20USING%20LEAN%20SIX%20SIGMA%20PRINCIPLE%5CMINIMISING%20WAST

E%20IN%20CONSTRUCTION%20BY%20USING%20LEAN%20SIX%20SIGMA%20PRINCIPLE.pd

f

3. Minimising wastage in construction using Lean six sigmahttp://

www.academia.edu/4752273/

MINIMISING_WASTE_IN_CONSTRUCTION_BY_USING_LEAN_SIX_SIGMA_PRINCIPLES

4 Six Sigma-Based Approach to Improve Performance in Construction Operations journal by Seung Heon Han, M.ASCE; Myung Jin Chae, Ph.D., P.E.; Keon Soon Im, P.E.; and Ho

Dong Ryu

https://notendur.hi.is/aho4/Lesk%C3%BArs%20hj%C3%A1%20Helga/Six%20Sigma-

Based%20Approach%20to%20Improve%20Performance%20in%20Construction%20Operat

ions.pdf

5 Six sigma in lean construction systems: Opportunities and challenges Tariq S. Abdulhamid http://leanconstruction.dk/media/16779/Six-

Sigma%20in%20Lean%20Construction%20Systems_Opportunities%20and%20Challenges.

pdf

6 International Journal of Emerging Technology and Advanced Engineering, Department of Civil Engineering,SSVPS Deore College of Engineering,Dhule ,India

http://www.ijetae.com/files/Volume3Issue5/IJETAE_0513_88.pdf

1.3 HISTORY OF SIX SIGMA:-The roots of Six Sigma as a measurement standard can be traced back to Carl Friedrich Gauss (1777-1855) who introduced the concept of the normal curve. Six Sigma as a measurement standard in product variation can be traced back to the 1920s when Wal...About Bill Smith:Bill Smith is a key person in inventing Six Sigma concept though many news media ignore his contribution. Born in Brooklyn, New York in 1929, Bill Smith graduated from the U.S. Naval Academy in 1952 and studied at the University of Minnesota School of...In the early and mid-1980s with Chairman Bob Galvin at the helm, Motorola engineers decided that the traditional quality levels measuring defects in thousands of opportunities didnt provide enough granularity. Instead, they wanted to measure the ...Since then, hundreds of companies around the world have adopted Six Sigma as a way of doing business. This is a direct result of many of Americas leaders openly praising the benefits of Six Sigma. Leaders such as Larry Bossidy of Allied Signal (now H...GE saved $12 billion over five years and added $1 to its earnings per share. Honeywell (Allied Signal) recorded more than $800 million in savings.1.4 MOTIVATION AND NEED OF THE PROJECT:-1. IJETT - Implementation Barriers for Six Sigma in Construction