l - 16 work measurement

7/30/2019 L - 16 Work Measurement

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Work Study & WorkMeasurement


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WORK STUDY

Objectives of work & method study :

1.To analyze the present method of doing the job inorder to develop a new and better method.

2.To measure the work content of the job by measuring

the time required to do the job by a qualified worker

and hence to establish a standard time.

3.To increase the productivity by ensuring the best

possible use of human, machine and materials

resources and to achieve best quality product at

minimum possible cost.


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Work study

4.To reduce excessive material handling or movement

and thereby reduce the fatigue to workmen.

5.To improve utilization of resources

6.To eliminate wasteful and inefficient motions

7.To standardize work methods or processes, working

conditions, machinery, equipment and tools.


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WORK STUDY

BENEFITS OF WORK & METHOD STUDY

1.Work simplification

2.Improved working method3.Improved workplace layout

4.Improved equipment design

5.Better working condition

6.Better material handling

7.Improved work flow

8.Less fatigue to workmen


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WORK STUDYBENEFITS OF WORK & METHOD STUDY

9.Optimum utilization of resources

10.Higher safety to workmen

11.Shorter production cycle time

12.Higher job satisfaction for workmen

13.Reduced wastages

14.Reduced manufacturing cost and higher productivity


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Work Measurement

Work Measurement helps to determine how

long it should take to do a job


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Standard Time

Standard Time - The length of time a qualified worker

takes to complete a specific job, using appropriate

processes and tools and allowing time for personal

fatigue, and unavoidable delays

Standard time is used in:

Costing the labor component of products

Tracking employee performance

Scheduling & planning required resources


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Normal Time


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Other Time Factors Used in

Calculating Standard Time


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Computation of Standard Time

OT PRF PA RA CA SA POA

NT

ST

AT


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OT=Observed time

PRF=Performance rating factor

PA=Process allowance

RA=Relaxation allowance

CA=Contingency allowance

SA=Special allowance

POA=Policy allowanceST=Standard time

AT=Allowed time


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Normal Time = Observed Time x Rating Factor

= Observed Time x (Observed Rating Standard Rating)

Relaxation allowance Allowance given to overcome the fatigue

due to physical exertion, working condition, and personal needs such

as for drinking water, for going to wash room, for attending telephone

calls etc.

Contingency allowance This allowance is given for infrequent

activities such as obtaining special materials from store, sharpening of

tools, getting a special tool from store etc.

Process allowance Allowance given to the worker to

compensate him forenforced idleness due to nature of a process or

operation such as working on Automatic Machine during which worker

is forced to be idle.


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Special allowance :

(i) Inference allowance is given to a worker when he/she is looking

after2 / 3 machines. One machine may be idle when the workerworks on another machine for a short period and allowance has to be

given to the worker for this loss of production.

(ii)Periodic activity allowance - for activities carried out periodically

during a work cycle e.g. setting up a tool on the machine.

Standard Time = Normal Time + All relevant allowances


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Setting Standard Times

Step 1: Choose the specific job to be studied

Step 2: Tell the worker whose job you will be studying

Step 3: Break the job into easily recognizable units

Step 4:Estimate the sample size based on level of accuracy and

confidence level

Step 5: Time each element, record data & rate the workers

performance

Step 6: Compute the normal time

Step 7: Compute the standard time


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Doing a Time Study Need to determine how many observations are required

Involves determining the level of accuracy required and confidence

level desired

n : number of observations of an element that are needed

Z : the number of normal standard deviations needed for desired

confidence

S : the standard deviation of the sample

a : desired accuracy or precision

x-bar : the mean of the sample observations

2

x

s

a

z

n


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Pats Pizza Place: Pat hires an analyst to determine a standard time to preparea large pepperoni and cheese pizza. He takes 10 observations of the 7elements and calculates the mean time and the standard deviation perelement. He must then calculate the # of observations to be within 5% of the

true mean 95% of the time.

The analyst must calculate the observations for each element to determine how

many additional observations must be taken. The maximum number of 25 (in this

case) for element #7 means that an additional 15 observations must be made and

then the observed times are revised.

nsobservatio25

0.24

0.03

0.05

1.96

x

s

a

zn

22

7

1

2

3

4

5

6

7

8

9

10

A B C D E

Example 11.3 Pat's Pizza Place

Standard Deviation Mean Observed Revised Observed

Work Element (minutes) Time (minutes) Time (minutes) # Observations

1. Get ball of dough 0.010 0.12 0.15 11

2. Flatten dough 0.030 0.25 0.25 23

3. Spin and toss dough 0.040 0.50 0.60 10

4. Place dough on counter 0.005 0.12 0.15 3

5. Pour sauce on formed dough 0.035 0.30 0.30 21

6. Place grated cheese on top 0.025 0.25 0.28 16

7. Place pepperoni on sauce 0.030 0.24 0.28 25


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Work Measurement Problem 1

For a certain element of work, the Normal Time is

established to be 20 seconds. If for three observations, a

time study observer records rating of 100,125 and 80

respectively, on a 100-normal scale, what are the

observed timings?


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Work Measurement


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Problem 2

An 8-hours work measurement study in a plant

reveals the following :Units produced = 320 Nos.

Idle Time=15%.

Performance Rating=120%

Allowance=12% of Normal Time

Determine the Standard Time per unit produced.


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Work Measurement


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Problem 3

Compute the production cost per piece from following data :

(i)Direct materials cost per piece = Rs.2.00

(ii)Wage rate Rs.2000.00 per month pertaining to 25 working

days and 8 hours per day.

(iii)Overheads expressed as a percentage of Direct Labour

Cost 200%

(iv)The time for manufacture of 4 pieces of the item wasobserved during time study. The manufacture of the item

consists of 4 elements

A, B, C, and D. The data collected during the time study are as

under. Time observed (in minutes) during the various cycles are

as below :


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Work Measurement

The personal, fatigue and delay allowance may be taken as 25%

Element Cycle-1 Cycle-2 Cycle-3 Cycle-4 Element

Rating on

Scale

0-100

A 1.2 1.3 1.3 1.4 85

B 0.7 0.6 0.65 0.75 120

C 1.4 1.3 1.3 1.2 90

D 0.5 0.5 0.6 0.4 70


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Elements Average Observed

Time

NT=(OT x Observed

Rating) Standard

Rating

A (1.2+1.3+1.3+1.4)/4=1.3 (1.3x85)/100=1.105

B (0.7+0.6+0.65+0.75)/4=0.675 (0.675x120)/100=0.81

C (1.4+1.3+1.3+1.2)/4=1.3 (1.3x90)/100=1.17

D (0.5+0.5+0.6+0.4)/4=0.5 (0.5x70)/100=0.35Normal Time for the Job = 3.435


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Work Measurement

Standard Time for the Job = Normal Time + Allowances

= 3.435 + 3.435 x 0.25 = 3.435+0.858

= 4.3 minutes

As this time is the time taken for producing 4 pieces,

so, Standard Time per piece = 4.3 4 = 1.075 minutes =1.075/60 hr

=0.0179 hr

Calculation for the costLabor Rate per hour = (2000) (25x8) = Rs.10

Direct Labor Cost = (Standard Time per piece in hour) x

(Labor Rate per hour)

= 0.0179 x 10 = Re.0.18


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Work Measurement

Overhead cost = 200% of Direct Labor Cost

= 2 x 0.18 = 0.36

Total production cost per piece = Direct labor cost +

Materials cost + Overhead cost

=0.18 + 0.36 + 2.0

=Rs.2.54


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THANK YOU

l - 16 work measurement

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