lecture 8- project quality management

7/25/2019 Lecture 8- Project Quality Management

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Construction QualityConstruction QualityManagementManagement

Dr Anisur Rahman

G09 1.19

[email protected]

mailto:[email protected]

mailto:[email protected]



QualityQuality

The totality of features and characteristics ofa product or a service that bears on its ability

to satisfy given needs.Satisfaction to customer’s need – meeting or

exceeding customer expectation.

Quality not only satisfies the features butalso should satisfy the cost and on timedelivery.

Quality is a moving target.



Costs of QualityCosts of Quality Prevention costs: Money required to prevent defects

– spent in establishing methods & procedures

– spent in training

– spent in planning quality

Spent before the product is actually built

Appraisal costs: Money required to control defects

– testing, inspection and examination costs

Money spent after the product is built

Failure costs: cost of failure due to poor quality

– esign changes! vendor re"ects! re#or$! scrap and materialrenovations! #arranty etc%



Quality CostsQuality Costs



Quality in Proect ManagementQuality in Proect Management

A!ility to manage a "roect and meet userre#uirements

$ Conformance to standards $ %n time and to !udget

&or #uality to !e achie'ed( all "artici"ants

in'ol'ed in a "rocess must !e committed

)*%+9000 standards used to hel" managersde'elo" QM*s



Quality Management ,'olutionQuality Management ,'olution



Quality ControlQuality ControlThe major objectives of quality control can be

defined as follows

To ensure that the completed wor! meets thespecification.

To improve the reliability of products or wor!produced

To reduce client’s compliant.

To increase client’s confidence.

To reduce production costs.



Tools for Quality "ontrolTools for Quality "ontrol

The problem solving Tools

o #rainstorming$

o %areto &iagramo 'unchart$

o "ause and (ffect &iagram )nd So *n

Statistical Quality "ontrol

o Statistical process control

o )cceptance sampling



%areto &iagram%areto &iagram

*ne form of bar chart$ first developed by +ilfredo%areto ,-/s0 that provides information on therelative importance of problems.

%areto principle1 A relatively small proportion ofitems accounts for a large percentage of variableslinked to those items.

2istorically$ /3 of the problems are due to the

4/3 of the factors. 2elps select the most crucial problem5s and helps

in choosing the areas$ where quality improvementactions should be concentrated



,-am"le of Pareto Analysis+ Different ty"es of defects

found in Precast Concreate "roducts used for high rise

!uilding "eriod

efect types umber of occurrences

&imensional deviation 6-

"hip off -72oneycomb and %inholes

8rong alignment 6

"rac!s 96

8rong details 6

Strand slippage 9



Different ty"es of defects found in *"eedometer duringDifferent ty"es of defects found in *"eedometer during

one month "eriodone month "eriod

&raw the #ar diagram showing the different types of defects

as classes in the hori:ontal axis in the same order as in the

table with the most frequent defect shown on the left.

;umber of defects are read on the left scale and percentages

on the right scale.

The line graph that moves up from left to right shows thecumulative number or cumulative percentage up to and

including any given number.



Pareto AnalysisPareto AnalysisNumber

of

occurrences

Cummulative

%Defect

Cum%Def

Dimensionaldeviation 61 61 45 45

Cracks 36 97 27 72

Chip of 15 112 11 83

Honeycom and!inholes 8 12" 6 89

#ron$ali$nment 6 126 4 93

#ron$ details 6 132 4 98

%trand slippa$e 3 135 2 1""



Pareto Analysis of *"eedometer DefectsPareto Analysis of *"eedometer Defects

The %areto diagram shows that two type of defects –

&imensional deviation and "rac!s problems account for

almost <73 of the defects.

) significant reduction of any of these two defects or both will

cause a substantial decrease in the overall defect rate.

*n the other hand$ a complete removal of one or more of the

rest of the defects would not ma!e a major dent in the overallrate. This does not imply that these defects should not be

wor!ed on. =t should be wor!ed on$ whenever possible with

little efforts.



Run Chart or Time Series PlotRun Chart or Time Series Plot

>raph for time ordered data. This chart is useful in examining the behaviour of quality

variables over time. =n a 'un chart the hori:ontal axis represents the time$

whereas the vertical axis represents the individualobservations of numeric variable of interest.

'oad wor! delays due to ?achine brea!down

Week &elay hours

- 7

4 99 4

@ 7

7 @

6 <



Cause and ,ffect &ish !one/ DiagramCause and ,ffect &ish !one/ Diagram

The Tree diagram originally developed by Aaoru =shi!awain -B79 to identify problem areas where data can becollected and analysed.

=t displays the problem$ all contributing factors and theirrelationship.

The problem is called the effect and the factors that affectit are called the causes.

=t is helpful in eliminating problems by tac!ling their causesand also useful in understanding the effects byunderstanding several factors of the process.

;ormally used in #rainstorming session where possiblesolutions are being sought.



Cause and ,ffect &ish !one/ Diagram Cause and ,ffect &ish !one/ Diagram o too to

ConstructConstruct// The problem is firstly agreed and defined precisely.

) team of people familiar with the process suggest the

different possible causes through brainstormingsession5s.

The effect box and the central line are then drawn.

The causes would be grouped together and theirinterrelations would be shown.



Effect

Manpower

Machine

Material

Method

Cause and ,ffect Diagram &ormat forCause and ,ffect Diagram &ormat for

Construction 2Production "rocess/Construction 2Production "rocess/



Effect

People

Plant & Eqpt.

Policies

Procedure

Cause and ,ffect Diagram &ormat for ser'ice orCause and ,ffect Diagram &ormat for ser'ice or

administrati'e "rocess/administrati'e "rocess/



Cause and ,ffect &ish !one/ Diagram ,-am"le/Cause and ,ffect &ish !one/ Diagram ,-am"le/

%roduction of %recast "oncreteCour project is to build a high rise building. Dor this

purpose you are using different precast concreteproducts which you can either produce in your projectsite or procure from outside supplier. *ne of the majorproblem with the precast product is &imensional defectsthat would affect the joint element. )nalyse the probablecauses of such defect using cause and effect diagram

so that you can ta!e proper action to eliminate suchproblem.



Cause and ,ffect diagram of DimensionalCause and ,ffect diagram of Dimensional

de'iation in "recast concrete "roductde'iation in "recast concrete "roduct



Cause and ,ffect diagram of Dimensional

de'iation



Rigidity

,-"erience ContentMould "re" 3raining

4noledge3olerance

Personality

3ime PlacementDimensional

Deiation

!or"er!or" method process

MeasurementRaw materials

Demoulding

"roces


de'iation



Rigidity


4noledge3olerance

Personality


Deiation


MeasurementRaw materials

Demoulding

"roces

*u""lier

%n

%utsource


de'iation



Rigidity


4noledge3olerance

Personality


Deiation


MeasurementMaterials

Demoulding

"roces

*u""lier

%n

%utsource

Method

Place

%utside

)n+Com"


de'iation



Scattered Dia#ramScattered Dia#ram

Esed for graphing the relationship between two

variables ,quality variables0.

This diagram shows a fairly tight relationship

between two characteristics.



3ensile *trength and the ardness of Alloy3ensile *trength and the ardness of Alloy



,-am"le of *cattered Diagram,-am"le of *cattered Diagram



ardness+ 3ensile *trength Diagramardness+ 3ensile *trength Diagram

The diagram shows a linear relationship between

the hardness and tensile strength.

Test of tensile strength is expensive$ whereas

hardness can be measured through non1

destructive test which is relatively cheaper.

So$ one can easily estimate tensile strength at

considerable savings.



*tatistical Quality Control*tatistical Quality Control

SQ" is the application of statistical techniques to measure Fevaluate the quality of a wor!$ product$ or process.

Two basic categories of SQ" Statistical %rocess "ontrol ,S%"0 –

"ontrol "harts 1 used to chec! if a process is performingas desired and to prevent quality problems in process.

)cceptance Sampling

Esed to determine whether a product lot is acceptable

based on inspection of random sample ,s0.



Statistical Process ControlStatistical Process Control

Esed to evaluate and control the output of process

to determine its acceptability – monitors quality

characteristic

?onitoring is maintained by using control charts

S%" helps us

– To detect unusual behaviour in the process

– To determine whether process outcomes are

affected by special events and

– To decide whether a process is stable over time.



Common Causes of $ariationCommon Causes of $ariation

"auses that are natural ,inherent0 to the process and

are always present in some degree ,73 of problems

in the system0

"an only be removed through system improvement =t is the aggregate result of many relatively small

factors$ such as

– (nvironment1 temperature or humidity

– *perator1 mentality or capability of the operator – 'aw material1 quality of material from different

supplier

– (quipment – age, model, capacity.



*"ecial2Assigna!le Causes of 5ariation*"ecial2Assigna!le Causes of 5ariation

+ariation that is due to one or very few factors

The main sources can usually be identified F

eliminated

%rocess with special variations leads to out of control andcan results in large variations

Examples - defective materials, output of a

machine that is set up incorrectly or output of an

inexperienced/untrained operator, tool wear G

These variations can be detected and acted for correction

They are controllable



The Control ProcessThe Control Process

(ffective control is achieved by the following&efine in sufficient detail what is to be

controlled =nspect the portion of the goods or services"ompare the results to the predetermined

standard

(valuate deviations from the standardTa!e corrective action when necessary

Dollow up to ensure that problems havebeen corrected



Data Cate#oriesData Cate#ories

Quality characteristics

+ariables+ariables are quality characteristics that are

numeric in nature and can be measured.(xamples 8eight$ length$ time or any othermeasurable characteristics.

)ttributes )ttributes are quality characteristics thatcan not be measured numerically.

)ttributes concentrates on defects or non1conformity. (xample a computer set can

be either good or faulty.



Control ChartControl Chart

%C% '

np '(

)C% '*



+ut of control process, -one for out of

control patterns

)C%

%C%

C%

-+E /

-+E /

-+E 0

-+E 0

-+E C

-+E C



%ut of Control Pattern%ut of Control Pattern

)ny point falls outside the control limits.

Two out of three consecutive points in :one ) and on

the same side of the centre line.

Dour out of five consecutive points in :one # and on

the same side of the centre line.

(ight consecutive points on one side of the "H.

6 consecutive points increasing or decreasingI

-@ consecutive points that alternate up and down.

-7 consecutive points within :one "



Control Charts for Attri!utesControl Charts for Attri!utes 'hen the process output is individual items, relatively

simple and inexpensive%

– p charts: control charts for proportion or fraction

defectives% (sed for fixed or variable sample si)e*+

– np chart: control charts for number defectives used for

fixed sample si)e%

inspected number Total

defectivesof number Total p =

( ) i

n p p pUCL 216 −+= ( ) in p p p LCL 216 −−=

( ) p pn pnUCL −+= 16

( ) p pn pn LCL −−= 16

inspected number Total

defectivesnumber Total n pnCL ×==



"ontrol charts for number of defectives in an item

– c charts – area of opportunity for defects to occur stays same$ eg no. of

defects in monitors

"entre line

– u charts 1 area of opportunities vary – eg. ;o. of spelling mista!es in

documents.

Control Charts for Attri!utesControl Charts for Attri!utes

inspected Itemof number Total

Itemsall indefectsof number Total c =

ccUCL 6+= cc LCL 6−=

inspected areaTotal

observed defectsof number Total u = i

a

uuUCL 6+=

ia

uu LCL 6−=



Control Charts for 5aria!lesControl Charts for 5aria!les

+ariables are controlled by monitoring both

their average level and their spread.

#ecause a shift in average level or anincrease in spread or combination of both

may result in output that does not satisfy its

requirement.

"ontrol charts for variables come in pair – *ne for controlling )verage level and

– *ne for controlling the Spread



3he Pair Charts3he Pair Charts

J1#ar "harts and ' "harts

J 1 bar for average level and ' charts for

spread.

These are the most widely used variable

control charts.

*ther popular pair1charts are?edian chart for average level and

Standard deviation charts for spread.



Quality AssuranceQuality Assurance

Quality control defect detection and currection

Quality assurance defect prevention

3here are no standard methods for im"lementing #uality control techni#ues(

hence it is unlikely that there is a consistency of quality between the companiesclaiming to use quality control

Quality assurance is created to o'ercome this situation !y esta!lishinginternationally acce"ted #uality standards such as )*% 9000 family.



Quality AssuranceQuality Assurance

Quality assurance is a set of activities which documents down processes to be performed and how they are accomplished , howeach process can be completed correctly by self-checking.

The policy of recording the process underta!en$ together with thechec!ing and recording of procedures$ assures the client that thecompany is aiming to achieve an acceptable standard of quality .

Quality assurance shall at least serve two major purposes

Satisfying the clientK and

>etting it right in the first instance.



)*% 9000)*% 9000

Quality assurance "ur"oses can !eQuality assurance "ur"oses can !e

achie'ed !y esta!lishing internationallyachie'ed !y esta!lishing internationally

acce"ted #uality standards such as )*%acce"ted #uality standards such as )*%

9000 family9000 family



1S+ *(((1S+ *(((

=S* B/// is a family of standards for quality management systems.

=S* B/// is maintained by the =nternational *rgani:ation forStandardi:ation and )dministered by accreditation and certification

bodies. Some of the requirements in =S* B//- ,which is one of the standards

in the =S* B/// family0 would include

– a set of procedures that cover all !ey processes in the businessK

– monitoring processes to ensure they are effectiveK

– !eeping adequate recordsK – chec!ing output for defects$ with appropriate corrective action

where necessaryK

– regularly reviewing individual processes and the quality systemitself for effectivenessK and

– facilitating continual improvement

http://en.wikipedia.org/wiki/Standardisation

http://en.wikipedia.org/wiki/Standardisation



)*% 9000 &amily)*% 9000 &amily

=S* B/// family includes the following standards

=S* B///4//7=S* B///4//7$ Quality management systems 1 Dundamentals$ Quality management systems 1 Dundamentalsand vocabularyand vocabulary. "overs the basics of what quality managementsystems are and also contains the core language of the =S*B/// series of standards.

=S* B//-4/--=S* B//-4/-- Quality management systems 1 'equirementsQuality management systems 1 'equirements

– =t is intended for use in any organi:ation which designs$develops$ manufactures$ installs and5or services any productor provides any form of service.

– =t provides a number of requirements

=S* B//@4//B=S* B//@4//B Quality management systems 1 >uidelines forQuality management systems 1 >uidelines forperformance improvements.performance improvements. >uidelines for performanceimprovements. "overs continual improvement. This gives youadvice on what you could do to enhance a mature system.



)*% 9000 3eam)*% 9000 3eam

Senior management staff

Quality manager ,QS0

&epartment headsTechnical staff

>eneral staff

Enion =n general$ to get a member of staff at all

levels of the organisation involved



Critical Success 2actorsCritical Success 2actors

"ommitment of top management

Haunching ceremony$ hanging banners onpremises

Staff must be made aware of desire to see! =S*B/// accreditation 1?anagement must explainimportance of =S* B/// accreditation

)ll staff attend training – appreciation course$quality policy and procedure manual

%rovide bonus incentives

%reparation of manual requires participation fromall identifying areas of improvement

;ot an Linstant’ transformation



7enefits of )*% 90007enefits of )*% 9000

(nhance organisational image with internationally recognised

standards

'eduction in number of customer complaints

Satisfy customers and current mar!et environment =ncrease quality awareness$ motivation$ co1operation$

wor!manship and consciousness

Docuses training and professional development

Sets a baseline for continuous improvement

=mprove productivity and efficiency

'educe mista!es and rewor! ,right first time0



3otal Quality Management3otal Quality Management

LTQ? is a management tool$ philosophy and aset of principles which guides every memberof organisation who involved in the

continuous improvement process to meetcustomer satisfaction.

TQ? is the integration of all functions andprocesses within an organisation in order to

achieve continuous improvement of thequality of goods and services.

The goal is customer satisfaction’



3otal Quality Management Princi"les3otal Quality Management Princi"les

"ommitment to quality

TQ? must be company wide.

TQ? must be initiated by top management whomust demonstrate that they are serious aboutquality.

?iddle management must grasp the principlesof TQ? and explain them to the people forwhom they are responsible$ while doing so theymust also communicate their commitment toquality.



3he Cultural *hift Re#uired for 3QM3he Cultural *hift Re#uired for 3QM

From -o

?eeting specification "ontinuous improvement

"omplete on time Satisfy customersDocus on final product Docus on process

Short1term view Hong1term view

=nspection1based quality %revention1based

%eople as cost burdens %eople as assets?inimum cost suppliers Quality suppliers

"ompartmentalisedorganisation

Top1down management

=ntegration

(mployee participation



Main ,lements of 3QMMain ,lements of 3QM



Quality ChainQuality Chain

&'ality increase Decreased cost (ed'ced delays

)ncreasedprod'ctivity

)ncreasedmarket share

*ore +os



345ar345ar

charts and R chartscharts and R charts -his charts are applicable to process #here each sample

consists of sub group%

.xample:

– A/* produces plastic chord #ith nominal tensilestrength of 01 pounds% -o determine the stability of the

process a 23 samples, each consisting of four pieces of

chords, ta$en at hourly intervals as sho#n in the next

slide% 4n statistical process control terminology, each of

these sample of four pieces of chord is called subgroup% evelop an 5 bar chart and 6 chart from the

data given and comment on the process%



8+!ar charts and R charts8+!ar charts and R charts



Deelopment of 345ar chartsDeelopment of 345ar charts

)re developed based on the sample si:e ,si:e of sub group0.

Subgroups of si:e nM@ or nM7 are very often used.

The centre line for J1bar chart is set at the overall

average.

"omputation of control limits requires a factor which

depends on the subgroup si:e.

The control limits are

X

9 A

A X LCL

A X UCL

9

9

−=

+=



Ta5le '.Ta5le '.

Control Chart 2actorsControl Chart 2actors



De'elo"ment of R chartsDe'elo"ment of R charts

The computation of centre line and control limits for ' chart is

based on the data presented in the table.

The same data are used for the ' chart and the J1bar chart. The centre line is the average of range of the subgroup.

The computation of control limits requires two factors$ &9 and &@

that depend on the number of sub group. These +alues

for common sub group si:es are included in the table -.

The control limits are

! LCL

!UCL

6

:

=

=



Re#uirements of )*% 9000Re#uirements of )*% 9000

Management res"onsi!ility

Quality system

Contract re'ie

Design control Document control

Purchasing

Purchaser+su""lied "roduct

Product identification andtracea!ility

Process control

)ns"ection and testing

)ns"ection( measuring and testinge#ui"ment

)ns"ection and test status

Control of non+conforming "roducts Correcti'e action

andling( storage( "ac;aging anddeli'ery

Quality records

)nternal #uality records 3raining

*er'icing

*tatistical techni#ues

lecture 8- project quality management

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