UNIVERSITY OF TORONTO

FACULTY OF APPLIED SCIENCE AND ENGINEERING

FINAL EXAMINATION, December 15, 2018

DURATION: 2 and % hours

Third Year - Mechanical and Industrial Engineering

M1E343H1 F

Calculator Type: 2

Exam Type: B

Examiner - P. White

TOTAL MARKS = 110

Write answers in exam booklets only.

Return exam with booklet.

Write answers only in ink.

1. Ms. Cerberus wants higher productivity from her office staff at Hades Foundry Inc.; she's sick of seeing them

slumped at their desks and has asked you, her favorite Industrial Engineer, to whip them into shape. She has taken

pictures of these slackers and wants you to investigate what can be done to buck them up. For each picture, identify

the problems, the cause of the problems, the possible negative health outcomes and some fixes.

Present your findings in your exam book in a table like the one below. (15 marks)

Employee The problem Cause of the

problem

Negative health

outcome

A fix

Persephone Pomegranate

'4 ,. • .4,:

I)

Al, V

2 1 Page

Hermes Tinhat

Vera Tiresias

I

3 1 P d g e

Discuss office chair armrest design with respect to the ultimate test for fit for the individual user. Consider: armrest height, armrest length and position, and inside distance between armrests. (15 marks)

Discuss the effects of shiftwork with respect to: a) workers' circadian rhythms; b) gastrointestinal disorders and cancer; c) family and social life; d) worker performance and safety. Be sure to use the four as headings in your response. (20 marks)

Jared Kushner and Ivanka Trump have flown their private jet to a secluded field not far from Wichita Kansas. The Koch brothers have left a fabulous campaign contribution there for them to load into their plane. The packages of small, used US bank notes weigh 2 kg each and they expect that it will take them a minimum of 8 hours to load the plane. They have organized themselves so that one of them is outside and carries a bundle to the plane and up the stairs where he hands it to the other who then carries it into the plane and stacks it neatly. Because it's money, they are working at a steady rate. They are switching the tasks every hour and have plenty of champagne to drink. Unfortunately, it is summer in Kansas and the weather is not on their side: DB =300 C, WB = 290 C GT = 360 C. Luckily, the cabin of the plane is air conditioned and the interior readings are DB =20° C, WB = 180 C GT = 200 C.

Jared is wearing a stylish black Alexander Amosu suit and waistcoat. Ivanka is wearing a Stuart Hughes Diamond Edition pantsuit, silk blouse and sport tights. They also claim to be wearing underwear. This is the first time they have been outside Trump Tower for years. After half an hour they notice moisture on their foreheads and begin to worry that they might succumb to heat stress. They immediately email you, their personal Industrial Engineer, and demand to know: a) Are they at risk?; b) What can they do to protect themselves from heat-induced illness? (20 marks)

For Heat Exhaustion, provide: the causes, the symptoms, the treatment, and means of prevention. Be sure to organize your answers under these headings. (10 marks)

Explain why the NRR for ear plugs and earmuffs varies between laboratory and field tests. The difference is larger for plugs compared to muffs; why? (5 marks)

In what units is whole-body vibration measured? In what units is hand-arm vibration measured? (5 marks)

What are the general features of sound-proofing enclosures, e.g., an enclosure for industrial compressors? (5 marks)

What is the mechanism that leads to hearing loss after prolonged exposure to loud noise? (5 marks)

What are the reasons why a company should work hard to return an injured employee to work as soon as possible? (10 marks)

4I:

Table 2. Clothing Adjustment Factors

Clothing Worn CAF

WO.K clothes (long sleeves and pants). Examples Standard cotton shirt/pants 0

Coveralls (v/only underwear underneath) Examples: Cotton or light polyester material 0

Double-layer woven clothing 3

SMS Polypropylene Coveralls 0.5

Pcyoletln coveralls Examples: Micro-porous Fabric (e.g. Tyvek) 1

Limited-use vapor-barrier coveralls. Examples. Encapsulating suits, whole-body chemical protective suites, firefighter turn-out gear. 11

Table 3. Metabolic Work Rates

Work Category Metabolic Rate (Watts)

Rest 115

Light 180

Moderate 300

Heavy 415

Very Heavy 520

Examples

Sitting

Sitting, standing, light arm/hand work and occasional walking

Normal walking, moderate lifting

Heavy material handling, walking at a last pace

Pick and shovel work

Tdb = the dry-bulb temperature

Inwb = the natural wet-bulb temperature

Tg = the globe temperature

WBGT Outdoors

WBGT0 t = 0.7Tnwb + 0.2Tg '4- O.11db

WBGT Indoors

WBGT 0.7Tnw, +

Average WBGT

WBGT8vg = (WBGT1)(t't) + (WBGT2)(t2) 4. . . + (WBGTn)(tn)

(t1) r- (t2) + . . . + (ta)

where tn = time in minutes

5J Page

Table 4. Threshold Limit Values

% Work Workload

Light Moderate Heavy* Very Heavy

75t0 100% (Continuous) 310°C 280°C N/A N/A

50 to 75% 310°C 290°C 275°C N/A

25 to 50% 32.0°C 30.0°C 29.0°C 28.0°C

0to25% 32.5°C 31.5°C 30.5°C 30.0°C

*C-ftepa values are not provided for Heavy/Very Heavy work for continuous and 25% rest because of the extreme physical strain. Detailed job hazard analyses and physiological monitoring should be used for these cases rather than these screening criteria.

See Table 3. Metabolic Work Rates, for work category

Source: ACGIH 2017 TLVs and BEls TABLE 2

Table 5. Action Limits

% Work Workload

Light Moderate Heavy* Very Heavy

75 to 100% (Continuous) 28.0°C 25.0°C N/A N/A

50 to 75% 28.5°C 26.0°C 24.0°C N/A

25 to 50% 29.5°C 27 0°C 25.5°C 24.5°C

0 to 25% 30.0°C 29.0°C 28.0°C 27.0°C

*Criteria values are not provided for Heavy/Very Heavy work for continuous and 25% rest because of the extreme physical strain. Detailed job hazard analyses and physiological monitoring should be used for these cases rather than these screening criteria.