text book~productivity and work study techniques in constr

7/30/2019 Text Book~Productivity and Work Study Techniques in Constr

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______________________________________________________________________By : Ajay Kumar Singhal

AKS/TRG-NR/PRO/Rev-2 Productivity and Work Study Techniques in Construction Page 1 of 22Dated 08-Dec-2010

Productivityand

Work Study Techniquesin Construction

Prepared by

Ajay Kumar SinghalMobile # 98101 53530

All rights reserved. No part of this document may be reproduced or transmitted in any form or by anymeans, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of

Writer.


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What Clients Want ?

Timely Delivery,

Better Quality,

Minimum Cost,

Safe Operation.

What Shareholders Want ?

Value Addition,

Real Growth.

What Business Wants ?

Efficiency,

Economy.

What is Productivity ?

A simple way of looking at productivity in a business organization is to think of it in terms

of the productivity model below.

Essentially, productivity is a ratio to measure how well an organization (or individual,

industry, country) converts input resources (man, materials, machines etc.) into goods

and services.

Productivity means the ability to produce.

It is ratio between output and input.

Output

InputProductivity =

Productivity is a measure of the output produced by a unit of input.


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The Productivity Conceptual Model below, takes the form of a 'productivity tree'. The

Fertilizers and Minerals denote the Inputs to the system, the Trunk the ConversionProcess and the Leaves and Fruits the systems Outputs.

The successful management of this process, is ultimately the key to survival of any

organization. It should be the concern of and a development goal for all organizational

members, irrespective of their position.

Inputs

Outputs

Fertilizers & Minerals

Roots & Trunk

Leaves & Fruits

ConversionProcess

Productivity Conceptual Model


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Basic INPUTS are :

Materials : Quality and quantity of input materials.

Tools : To undertake the work efficiently.

Equipments : To ensure faster & qualitative production.

Processes : processes adopted, the technology employed and the systems

used.

Manpower : Correct skill levels, age.

Basic OUTPUTS are :

Goods

Services

Process Approach

There are three terms often confused : Procedure, Process, and Work

Instruction. These are defined for you with examples.

Process : Any activity, or set of activities, that uses resources to transform inputs

to outputs can be considered as a process.

Processes must have defined (but not necessarily measurable) objectives(s),

input(s), output(s), activities, and resources. You should be able to ask these

when defining a process :

o Activities

What are the basic jobs carried out in your department ?

Can you explain to me your operations here ?


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o Inputs / Resources

What information do you need to start your work ?

Where does it come from ?

o Outputs

Who receives the result of your work ?

How do you know if youve done your job correctly ? (meet

objectives)

Procedure : A procedure outlines how to perform a process, such as

Purchasing.

o Who performs what action.

o What sequence they perform the steps in the task.

o The criteria (standard) they must meet.

It may be documented or not. Procedures will describe how you operate and

control your business and meet the ISO 9001 requirements.

Work Instructions : A work instruction describes how to perform a task, which is

a more detailed portion of the procedure such as Completing a Purchase Order

or Ordering supplies..

Many businesses include work instructions to aid in training, to reduce

mistakes, a point of reference for jobs, etc.

ISO 9001 has a process approach.


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Process Approach : The systematic identification and management of the

processes / activities employed and the interactions between such processes /

activities.

Process Approach

A process approach emphasizes the importance of :

1) Understanding and meeting requirements.

2) Determining if the processes add value.

3) Obtaining results of process performance and effectiveness.

4) Using objective measurement for continual improvement of the processes.


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Example : Purchasing Process

o Over a period of time, one can say that productivity has increased.

o How?

o Due to combination ofimproved technology, better planning, greater skills etc.

o Note that, increased production does not mean increased productivity.

Higher productivity means that more is produced with the same input.

Alternatively, same amount is produced by deploying less input.

Hence for better Productivity, it is essential that we look for ways and means to :

reduce input,

cut down wastage,

elevate quality and

safety standards.

Let us examine the primary inputs :

Manpower : Animate object with intelligence, emotions, aspirations..

Materials : Inanimate objects handled and re-handled by man...

Equipments / Tools : Apparatus created and used by man...

Processes : Made and adopted by man.


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Let us examine what is output :

Output is the product of a process or conversion of Inputs through a Process.

Quality of Output depends on :

Quality of Inputs,

Quality of Process,

Quality ofMan handing both input & process.

Hence

quality,

efficiency,

productivity.

all them boil down to motivation and handling MAN.

Since MAN is involved in all the aspects

Through Monitoring System and through Training, he gets . AWARENESS

Awareness gives him . MOTIVATION


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Motivation increases his . EFFICIENCY

and Efficiency increases his . PRODUCTION

So .

For more OUTPUT i.e. for

Increased Volume of Goods

Improved Services

Following INPUTS are also required

Knowledge : People with experience and expertise in the appropriate areas of

the business.

Skill : Trained and developed for the purpose.

Attitudes : Ability to adapt, cooperate, change, resourcefulness and

motivation.

Systems : Procedures to ensure organization can undertake conversionprocess efficiently.

Management : Skill, ability, leadership, right caliber and competence to efficiently

operate and maintain the system.

Hence


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Productivity Conceptual Model

Inputs

Outputs

Materials

Tools

Equipments

Systems

Management

Processes

Manpower

Knowledge

Skill

Attitudes

Increased Volume Improved Services

ConversionProcess

Quality & quantity ofinput materials

Procedures to ensureorganization canundertake conversionprocess efficiently

To undertake the workefficiently

Skill, ability,leadership, rightcaliber andcompetence toefficiently operate andmaintain the system

To ensure faster &qualitative production

Processes adopted,the technologyemployed and thesystems used

Correct skill levels, age

People withexperience andexpertise in theappropriate areas ofthe business

Trained and developedfor the purpose

Ability to adapt,cooperate, change,resourcefulness andmotivation

Able to reach wider

market

Better delivery, better

quality & better benefitsto Customer

Reduced Costs

Lower unit cost, moreprofit or more sales


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Productivity In Construction

Workers productivity =Work quantity executed

Workers engaged

Machines productivity =Work quantity executed

Machines engaged

Materials productivity =Work quantity executed

Materials consumed

Total productivity =Goods or Services Produced

All inputs used to produce them

Workers Productivity

EXAMPLE

A task involving 160 Sqm of fixing timber formwork for the roof slab of a singlestorey

building completed in 4 days, by a workers team, consisting of 8 skilled and 16

unskilled workers, then calculate the workers productivity :

Productivity of team = Formwork quantity / Completion period

= 160 Sqm / 4 days

= 40 Sqm per day by 8 SKL + 16 USL

or = 5 Sqm per day by 1 SKL + 2 USL


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Staff Productivity

EXAMPLE


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Equipments Productivity

EXAMPLE

Equipment actual hourly output = Actual load per cycle cycles per hour.

If a front-end loader on a given job moves a load of 1.5 M of loose soil in one cycle,

consisting of loadingliftingtravelingunloadingreturn tripready for loading, and each

cycle time is 1.2 minutes, then :

Actual output per working hour

= Load per cycle cycles per hour

= 1.5 M 60 minutes/1.2 minutes

= 75 M per hour.


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The Factors Affecting Productivity

The computation of production efficiency factors depends upon numerous variables,

which affect productivity under actual job conditions at the project site. These variables

vary from project to project and with place and time. Some of the typical factors

affecting the production efficiency are given below.

Of Machines and Manpower :

1) Work complexity :

A simple, familiar work is easier to execute than unfamiliar, complex work.

2) Repetition of work :

While the first time execution of an unfamiliar work needs extra effort and results in

low output, the skill acquired in the process, when utilized over a period of time to

execute similar works, improves the productivity rate, especially when the crew of

workers is the same.

3) Quality control :

Sensitive projects, like the construction of a nuclear reactor calls for stringent quality

control demands frequent inspections which involve elaborate documentation and

are time consuming. They increase the nonproductive time of workers.

4) Equipmentintensive tasks :

The construction tasks that can be performed wholly or partly with equipment includeexcavating, handling, transporting, filling, compaction, grading, hoisting, fabricating,

pre-casting, erecting, plastering, finishing, paving, trenching, cable laying, pipe

laying, and so on.

The construction equipment executes works speedily. The equipmentintensive

tasks are less susceptible to productivity changes than the labourintensive ones.


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5) Supervision :

A supervisor manages his assigned technical work as well as the workers under

him. The accomplishment of tasks economically and on schedule mostly depends

upon the competence of the supervisor, which in turn, affects the workers'

productivity. An efficient and effective supervisor can get a higher productivity from

workers.

6) Climatic and weather conditions :

Generally, under average weather conditions, with temperature varying from 40 ~ 70

degrees Fahrenheit and relative humidity of 60%, workers continue working at the

same productivity level. But, extreme weather situations and seasonal changes, like

extreme hot or cold climate, high humidity and strong winds and rains affect both

productivity as well as the work performance.

7) Labour availability :

Labour productivity also depends upon the employment opportunities available in

the market. If jobs are in plenty and labour is scarce, labour productivity tends to

become less. During a slump in the construction market, labour is easily available

while there is a dearth of jobs. In such situations, employers can afford to beselective, as hiring and firing of workers become easy. In a scarce job situation, the

overall productivity improves, since the employers can then select suitable labour.

There is also a tendency among labour to move to highvalue, largesized projects,

since they offer them longer service, better job opportunities and more stability.

8) Role of management :Project management has a key role to play in planning and controlling productivity. It

is responsible for specifying the weekly target of work to be accomplished by the

workers as well as how the work is to be executed and using which resource.

Productivity is bound to suffer if the management fails to fulfill its role and obligations

effectively and fails to conduct prework preparation.


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9) Working methods :

Working methods of operation causing wasted movements, time and efforts.

10) Careless workmanship :

Careless workmanship causing scrap or rework.

11) Safety standards :

Insufficient safety measures and failing to observe safety standards.

Of Machines :

Common Correction factor

(1) Soil Factor, Multiply

Easy Dig Medium Dig Hard Dig

(loam, sand, gravel) (common earth) (Stiff, slay, soft rock)

1.00 0.85 0.67

(2) Swell Factor for in-place volume conversion, divide

Common earth Sand and gravel Clay (dry)

1.2 1.1 1.3

(3) Working Efficiency, Multiply

60 Min. 55 Min. 50 Min 45 Min. 40 Min

1.00 0.92 0.83 0.75 0.67

(4) Swing Factor (for Excavator)

Angle of swing (Degrees) 45 60 75 90 120 150 180

Factor 1.25 1.15 1.05 1.0 0.90 0.80 0.70

(5) Load Factor (for Excavator)

Side Casting 1.0 Loading in Vehicles 0.8


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How to Improve the Productivity ?

Productivity Importance

Changes in the industrial and business environment.

- Economically

- Practically

The only way a business or enterprise can grow and increase its profitability is by

increasing its productivity.

Productivity improvement refers to the increase in output per work-hour or time

expended.

Effective utilization and maximum productivity is an important source of

cost reduction.


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How To Do It ?

Understand the work,

Understand the environment,

Plan your work to the minutest details,

Identify the Risk and plan accordingly,

Find the pitfalls and pain areas,

Make contingency plans,

Arrange the resources,

Care for them,

Get trained and train your people,

Transfer of Technology : up-grade yourself according to time,

Be vigilant and Keep records,

Ensure safe operation and qualitative production.

Review, analyze and Recast plans,

Always look for improvement,

Some more techniques :

- By replacing unskilled labour by machines, wherever feasible, in jobs like

loading, unloading, shifting, barcutting, etc.

- By using appropriate and efficient tools as equipment.

- By continuously improving the methods of production.

- Through improved working conditions and incentives.

- By implementing the job-oriented financial incentive schemes.

- By training workers to overcome the initial learning period.


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Fundamental of METHOD STUDY :

Designing

Creating

Selecting

Manufacturing methods

Processes

Tools

Equipments

Skills

Manufacture a productthat have been

developed by theProduct engineering

section

the best to

2) WORK MEASUREMENT

Various techniques may be used separately or in combination depending on the

nature of the work. The Work Study Engineer must assess which technique or

combination of techniques should be used in a given situation.

Time Study Definition

The application of techniques designed to establish the time for a qualified worker to

carry out a specified job at a defined level of performance.

Direct Measurement (Time and Motion Study)

Time Study is a technique for recording the times and rates of working for the

elements of a specified job carried out under specified conditions, and for analyzing

the data so as to obtain the time necessary for carrying out the job at a defined level

of performance.

A Time and Motion Study would be used to reduce the number of motions in

performing a task in order to increase the productivity. Each operation is studied

minutely and analyzed in order to eliminate unnecessary motions and thus reduce

production time and raise output.


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AKS/TRG NR/PRO/Rev 2 Productivity and Work Study Techniques in Construction Page 22 of 22

Flow Process Chart

A flowchart is a common type of diagram that

represents a process showing the steps as boxes of

various kinds, and their order by connecting these with

arrows.

Flowcharts are used in analyzing, designing,

documenting or managing a process or program in

various fields.

String Diagram

The placement of equipment in work areas is often

done randomly and sequentially, rather than with

any sense of what positioning will make the work

easier.

The result is that subsequent work requires much

more moving about than is necessary.

The String Diagram is a simple tool for analyzing and designing work spaces

such that movement can be minimized. The basic diagram simply consists of a

map of the work area, with the actual movements drawn on top.

Multiple Activity Chart

A chart on which the activities of more than

subject (item, worker, machine or equipment)

are each recorded on a common time scale to

show their interrelationship.

To contact, e-mail at : [email protected]

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