My Class

1

IE 553 Engineering of Human Work Dr. Andris
Freivalds Class 35
2
2) Wet-Bulb Globe Temperature
WBGTout 0.7 WB 0.1 DB 0.2 GT
3
HSI

• Radiation - heat gain/loss, absolute temperature
• R (kcal/hr) 4.375 (TW - TSk)
• TW (TG 460)4 1.03108V0.5(TG -
  TDB)0.25460
• Convection - heat gain/loss, air movement
  (ft/min)
• C (kcal/hr) 0.189 V0.6 (TDB - TSk)
• Evaporation - heat loss (only), evaporation of
  water (1 l 580 kcal)
• Emax (kcal/hr) 2.575V0.6 (PSk - PA)
• Psk 42 mm Hg at 37C

4
HSI

• S M R C Cd - E - W
• If S 0, then Ereq M R C
• HSI Ereq/Emax
• S (kcal) BW (kg) 0.83 ?TC
• S (kcal) (Ereq - Emax) x Time

5
(No Transcript)
6
Final

• Final Exam
• Monday (12/18) 230-420 PM
• 307 Hammond
• Closed book/notes
• Bring 3x5 formula card
• Similar to HW and Labs
• Extra office hours Mon 1000-1150 AM
• Material covered mostly since midterm, emphasis
  on work physiology not biomechanics

7

• Sample Final Exam Question
• You have been hired as a consultant/ergonomist
  by the Bureau of Mines (research agency for
  mining, now consolidated under NIOSH) in order to
  evaluate the working conditions of bratticemen.
  Building brattices or stoppings for 8 hours is
  one of the more difficult jobs in coal mining.
  Typically, a bratticeman builds the wall from
  cinder blocks weighing 35 lbs each at a rate of 6
  blocks/min. The wall is typically 3 blocks high
  and 15 blocks wide. NOTE that each row height is
  12 inches to give a 36 inch wall. Assume an
  average coal miner is a male, 5 foot 9 inch tall
  and weighing 180 lbs. Because of water sprayed at
  the cutting coal face to keep down the coal dust,
  the relative humidity is 100 and globe
  temperaturedry bulb temperature 80F.

8

• a) Evaluate the work based on metabolic
  energy expenditure, lifting criteria, and heat
  stress criteria. For each of the three criteria,
  calculate whether the conditions are acceptable.
• b) If they are not acceptable, calculate how
  much rest would be needed to make that an
  acceptable job and how much work they can safely
  perform (i.e either number of lifts/min or number
  of brattices/day) given that rest. If they are
  acceptable, calculate how many more brattices the
  bratticeman could complete in a day.
• c) What would you recommend to improve this job
  for all three aspects? Support your answers
  ergonomically.

9
Review Questions for Final

• 1) What factors affect the flow of blood through
  the circulatory system?
• 2) Describe the peripheral vasculature.
• 3) What extrinsic factors affect peripheral
  circulation?
• 4) What intrinsic factors affect peripheral
  circulation?
• 5) Describe how peripheral circulation change
  during exercise?
• 6) How are respiration, ventilation, metabolism
  related?
• 7) What factors affect the amount of oxygen
  delivered to the periphery?
• 8) How is oxygen consumption related to work
  intensity?

10

• 9) What factors affect O2 carrying capacity of
  blood?
• 10) Why is aerobic metabolism so important for
  sustained work?
• 11) What limits the amount of sustained work?
• 12) Why are frequent short breaks more effective
  than long breaks?
• 13) What is the primary method of O2 transport?
  Of CO2 transport?
• 14) What are the various components of lung
  volume?
• 15) What happens to the circulatory system during
  static contractions?
• 16) What is the recommended 8-hr physical work
  capacity (RPWC)? How was it determined?

11

• 17) What factors change the RPWC?
• 18) How is aerobic capacity found?
• 19) How does aerobic capacity vary between
  individuals?
• 20) How can a job energy requirement be found?
  What are the pros and cons of each approach?
• 21) What symptoms may result from excessive heat?
• 22) What methods are used to estimate the
  environmental heat load? What are the pros and
  cons of each approach?
• 23) What physiological changes occur during heat
  acclimation?