Work measurement, time study, calculation of standard time

1. 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.
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2. Various techniques of work measurement are:
1. Time study
A work measurement technique for recording the times and rates of working
for the elements of specified job.
2. Synthesis
A work measurement technique for building up the time for a job or parts of
the job at a defined level of performance by totaling element times obtained
previously from time study.
3. Work sampling
A technique in which a large number of observations are made over a period
of time of one group of machines, processes or workers.
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3. 4. Predetermined motion time study
A work measurement technique whereby times established for basic human
motions are used to build up the time for a job at the defined level of
performance.
5. Analytical estimating
A work measurement technique, being a development of estimating,
whereby the time required to carry out elements of a job at a defined level of
performance is estimated partly from knowledge and practical experience of
the elements concerned and partly from synthetic data.
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4. Time Study Steps
• Bottleneck operations, Repetitive jobs,
• Jobs using a greater deal of manual labour, Jobs with longer cycle time,
• Sections/ department frequently working overtime
Select
• Correctness of the method employed.
• The selection of the operator, Working conditions
• Working positions
Obtain & Record
• Break the job in to elements convenient for timingDefine
• Measure duration for each element,
• a) Cumulative t timing
• b) Fly back timing
Measure
• Convert observed time into normal time (Basic time)Extend
• Relaxation and personal allowancesDetermine
• Standard time for the operation for defined job or operationCompute 29-10-2017 08:27R.A. Pasale 4

5. Element
Element is a distinct part of a specified job selected for convenience
of observation, measurement and analysis.
Work cycle
Work cycle is a complete sequence of elements necessary a specified
activity or job to yield one unit of production.
Types of elements
1. A repetitive element
It is an element which occurs in every work cycle of the job.
e.g. picking a part for assembly
2. An occasional element
Is one that does nor occur in every work cycle of the job or which may
occur at regular intervals. e.g. tool changing after sometime
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6. 3. A constant element
It is an element for which basic time remains constant whenever it is
performed. e.g. switch on machine
4. A variable element
It is an element for which the basic time varies in relation to some basic
characteristics of the product, equipment or process.
e.g. dimensions, weight, quality
5. A manual element
It is an element performed by a worker.
6. A machine element
It is an element automatically performed by a power driven machine.
e.g. Power press
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7. 7. Governing element
It is an element occupying a longer time than that of any other element
which is being performed concurrently .
e.g. Gauge dimensions while turning diameter.
8. A foreign element
It is one that is observed during study but do not form part of the given
activity of the cycle. e.g. Dropping work on the floor, operator talking to his
colleague.
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How many cycles to be timed?
Time required to complete one element of an operation in different
time cycles never remains same, it varies cycle to cycle.
The reasons for such variations may be:
1. Variation in material quality,
2. Variation in tools and equipments,
3. Variation in location of tools and material from cycle to cycle,
4. Inherent variation in equipment
5. Variation in performance of an operation,
6. Working conditions,
7. Errors in measurement of stop watch.
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Large number of samples should be taken to achieve accuracy.
From statistics, for 95 % confidence level and +/- 5% accuracy,
number of cycles required are:-
Where,
N’ = Required number of time cycles or observations for 95% confidence level
and 5% accuracy,
X = Each stop watch reading,
ΣX = Summation of individual reading,
ΣX2 = Summation of square of each reading
N= Number of stop watch reading
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Duration of each Element:
There are two principle methods of timing with the stop watch;
a) Cumulative timing
b) Fly back timing
Extend Observed time into Normal time
The observed time is converted into basic or normal time by
multiplying it by rating factor.
Performance Rating
It is the process of adjusting the actual pace of working of an operator
comparing it with the mental picture of pace of an operator working at normal
speed.
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Factors Affecting Performance Rating
• External Factors
• Internal Factors
Methods of Performance rating
1. Speed Rating
2. Westing House system
Westing house method.jpg
3. Synthetic rating
R=P/A
P- PMT for element
A- Actual time
4. Objective rating
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Time study equipments
1. Time Study board
2. Stop watch
a) Cumulative stop watch, b) Fly back stop watch
3. Time study forms
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Selection of Worker for Time Study
A Qualified Worker as Defined by ILO
A qualified worker is one who is accepted as having the necessary
physical attributes, who possesses the required intelligence and education, and
who has acquired necessary skill and knowledge to carry out the work in hand
to satisfactory standards of safety quantity and quality.
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Allowances
The allowances are categorized as
1. Relaxation allowance
2. Interference allowance
3. Contingency allowance
4. Policy allowance
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1. Relaxation allowance
 To allow the worker to recover from fatigue.
 To recover from the physiological and psychological effects of carrying out
specified work,
 Relaxation allowances are of two types: Fixed allowances and Variable
allowances
 Personal needs allowance: Drinking water, smoking, washing hands, to
attend nature calls etc.
 Personal allowance for men is 5% and for women 7%.
 Basic fatigue allowance: To compensate energy level. A common fatigue
allowance is 4% of basic time.
 Variable allowance is considered when worker working under poor working
environment. This allowance is vary organisation to organisation.
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2. Interference allowance
To compensate the operator for the unavoidable loss of production
due to simultaneous stoppage of two or more machine being operated by him.
Interference allowance varies in proportion to number of machines
assigned to the operator.
3. Contingency allowance
this allowance provides for small unavoidable delays as well as for
occasional minor, extra work.
e.g. Tool breakage, Power failure for small duration, getting tools and
other material from store
Contingency allowance should not exceed 5%.
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4. Policy Allowance
A policy allowance is an increment, other than bonus increment,
applied to a standard time to provide a satisfactory level of earnings for a
specified level of performance under exceptional circumstances.
Computation of Standard Time
Standard time is the time allowed to an operator to carry out the
specified task under specified conditions and defined level of performance.
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