Work Sampling1

8/14/2019 Work Sampling1

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Work Sampling

- MEGHANT NICHANTIndustrial Engineer - IE


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A technique that discovers the proportions

of total time that various activitiescontribute to the job by taking a relativelylarge # of observations at randomintervals

Used to determine: production standards,machine and personnel utilization, and joballowances. Typically faster and cheaperthan other techniques


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Probability based on the binomial distribution

(p + q)n = 1

Mean = np, Variance = npq

As n becomes large, the binomial distribution

approaches the normal distribution

This proportion has distribution of Mean =p,

Variance =pq/n

Theory


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There are many sources of tabulated data for

determining the # of samples required at

various confidence levels and accuracys.

Formula for calculation purposes simplifies

to: n = Z2(1-P)(P)/(L2)

Theory


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A work sampling study requires 95-percent

confidence with five-percent accuracy. How

many observations are required if the machinedown time is eight percent?

n = (1.960)2*(1-0.08)*0.08/(0.05)2

n = 225,76 observations

Example of Sample Size

Calculation


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Sample Size Table

L 0.01 0.05 0.1

N 5644 225.76 56.44

Z=1.96 accuracy at 95% confidence interval,


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Randomized Time of Observation

1st day

1 2 3 4 5

1 30 170 230 20 30

2 150 220 250 170 80

3 160 280 270 260 2404 190 350 280 270 260

5 220 360 290 300 290

6 230 390 350 330 310

7 360 430 480 410 390

8 480 500 530 420 4609 570 560 580 540 480

Data are taken from Random Table(Methods Standards and

Work Design(by Benjamin Niebel and A. Freivalds))


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2nd day

1 2 3 4 5

1 70 60 100 20 50

2 90 100 120 40 70

3 130 160 230 60 90

4 180 350 310 250 2105 200 370 320 320 250

6 220 380 340 330 270

7 240 440 390 340 280

8 290 460 520 370 350

9 570 530 520 380 470


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3rd day

1 2 3 4 5

1 150 20 40 50 50

2 220 30 50 80 90

3 230 60 100 90 220

4 280 100 150 170 280

5 360 130 160 240 310

6 390 210 200 250 340

7 410 300 220 450 360

8 420 330 240 470 440

9 520 560 320 480 450


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4th day 1 2 3 4 5

1 80 40 30 70 50

2 90 90 50 150 60

3 160 90 90 270 90

4 220 130 130 270 1105 330 180 180 280 120

6 440 210 260 300 150

7 460 290 410 310 220

8 540 380 430 380 440

9 560 520 580 490 470


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5th day

1 2 3 4 5

7 20 150 60 80 60

5 40 210 140 100 170

1 100 270 180 130 210

2 280 370 210 130 220

9 280 410 230 150 230

8 310 460 420 230 410

3 340 470 450 340 430

4 360 540 500 430 500

6 470 570 530 570 540


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1st days Work Sampling Summary Sheet

idle

Cla

ssrooms

Flo

or

Ga

rden

WC Labs

Sta

irs

Offices

Posting

Total

Worker1 5 1 2 1 9

Worker2 6 1 1 1 9

Worker3 5 3 1 9

Worker4 7 1 1 9

Worker5 4 1 4 9


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WORKERS DAILY NUTRITION

W3 CONSUMED AV. APPR. CALORIES

CUBE SUGAR 10*2 12*20

NON-ALCOHOLIC DRINKS 2glass/week 41

SNACKS 1 pad 150BREAKFAST .75bread,cheese,olives,jam,sometimes egg 650

LUNCH french fries,rice,soup,salad, 880

sometimes chicken,1 bread

(2 dishes of which is cooked)

DINNER 1 bread,omlette or menemen 750

Total 2126

W4 CONSUMED AV. APPR. CALORIES

CUBE SUGAR 9*2 18*12

NON-ALCOHOLIC DRINKS 1glass/week 20

SNACKS 1pad,1 dessert/week 180

BREAKFAST 1 bread,cheese,olives, jam,sometimes egg 775

LUNCH french fries,rice,soup,salad, 880

sometimes chicken,1 bread

(2 dishes of which is cooked)

DINNER soup,salad,0.5 bread 530

Total 2601

W5(postman) CONSUMED AV. APPR. CALORIES

CUBE SUGAR - -

NON-ALCOHOLIC DRINKS - -

SNACKS - -

BREAKFAST He doesn't have breakfast for years -

LUNCH he eats from cafeteria 850

DINNER chicken,fish,beans,rice 350

(small amounts) Total 1200


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WORKERS' ENERGY CONSUMPTION

(KCAL/MINUTE)

W3 (Heart beat:76)

Floor Cleaning Gardening At rest W.T: 9H 45 M

3.219 2.536 1.485

3.125 2.894 1.176

2.987 2.569 1.205

3.456 2.753 0.857

3.265 2.412 1.025Mean 3.2104 2.6328 1.1496

St. Dev. 0.17362 0.1903069 0.23313

W4 (Heart Beat:72)

Floor Cleaning Gardening At rest W.T: 9H 45 M

3.012 2.154 0.658

2.609 2.423 0.517

3.751 2.036 0.576

2.501 1.956 0.682

2.982 2.125 0.542

Mean 2.971 2.1388 0.595St. Dev. 0.490445 0.1769003 0.072097

W5 postman(Heart Beat:85) W.T: 9H

Posting Lab Res. At rest

5.156 4.856 2.502

5.002 4.256 2.402

4.98 4.987 2.308

5.236 5.123 2.568

5.128 5.236 2.654

Mean 5.1004 4.8916 2.4868

St. Dev. 0.107726 0.3829207 0.13596

WORKERS' OTHER PHYSICAL ACTIVITIES

W3

15 minutes walking for bus stop to go to work 23.5

1-1.5 hours walking for spare times 141

W4

20 minutes walking for bus stop to go to work 26

W530 minutes pysical exercise before sleeping 46

1 hour working for extra time 92

WORKER 3 DAILY CALORY CONSUMPTION


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9H 45M= 585 MINUTES MINUTES CAL.CONS TOTAL CAL.

%56 IDLE 327.6 1.1496 376.6

%33 FLOOR CLEANING 193.05 3.2104 619.8

%11 GARDENING 64.35 2.6328 169.42

1H 45M other activities 105 164.5

12.5 H at home 750 1.1496 862.2

TOTAL 2192.52


9H 45M= 585 MINUTES MINUTES CAL.CONS TOTAL CAL.

%78 IDLE 456.3 0.595 271.5

%11 FLOOR CLEANING 64.35 2.971 191.183%11 GARDENING 64.35 2.1388 137.63

20 M other activities 20 26

13H 55M at home 835 0.595 496.825

TOTAL 1123.14


9H = 540 MINUTES MINUTES CAL.CONS TOTAL CAL.

%44 IDLE 237.6 2.4868 590.863

%45 POSTING 243 5.1004 1239

11% LAB RES. 59.4 4.8916 290.56

30 M exercise 30 46

1 H extra working 60 92

13.5 H at home 810 2.4868 2014.308

TOTAL 4272.73


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PRE-RESULTS

CALORY GAIN CALORI CONSUMPTION

W3 2126 2193

W4 2601 1123

W5 1200 4273


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QUESTIONS AND ANSWERSQUESTIONS AND ANSWERS

CHRISTINE AICKINCHRISTINE AICKIN

ÈRGONOMIC ASSESSMENT (Manual Handling)ÈRGONOMIC ASSESSMENT (Manual Handling)

OF CLEANING WORKÒF CLEANING WORK`


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Cleaners sustain a high frequency of back, shoulder, neck, arm and

hand injuries. This was verified through a review of Workers'

Compensation statistics, consultation with cleaners and a review of

the literature. What are the factors that build the risk for cleaners

and cleaning in ergonomic means?

Postures required by tasks

Duration and frequency of tasks

Weights handled

Equipment design

Work organization issues

QUESTION 1


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Which suggestions can be made for improvement in the design ofcleaning work, workplace and equipment?

Equipment design and equipment selection Review of equipment prior to purchase, usage of prototypes

Job Design and Work Organisation

Care should be taken that cardiovascular requirements ofcleaning work do not exceed the considered safety level of theworkforce.

Cleaners should be involved in reviewing and planning the waywork is done using their knowledge of cleaning methods,cleaning alms, productivity requirements and health and safetyeffects

Job rotation or job sharing should be practiced where jobswhich have been identified as difficult and are performed forover half an hour

Team work should be performed for heavy works

QUESTION 2


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Education and Trainig

Cleaners should be trained in required job skills as well as team building,

problem solving, occupational health and safety Maintenance and replacement for powered and non-powered

equipment

Improvement of the interface between schools and cleaners

Condition of garbage bins

Condition of classrooms Relationship between cleaners, students and management

Long Term Improvements

Design of the work place (school)

NOTE: Questions & answers are prepared according to Christine AickPaper that has the topic Ergonomic Assessment (Manual Handling)Of Cleaning Work`


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