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.