1 / 19

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #14

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #14. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #14. Manual Materials Handling Limits (Ch. 8). 60% low back pain → overexertion LBP & lost time → > ⅔ out Overexertion → ¼ occupational injuries

lerato
Download Presentation

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #14

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #14 IE 553

  2. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #14 IE 553

  3. Manual Materials Handling Limits (Ch. 8) • 60% low back pain → overexertion • LBP & lost time → > ⅔ out • Overexertion → ¼ occupational injuries • ⅔ overexertion due to lifting • NIOSH (1981, rev 1991) lifting guidelines • Epidemiology of injuries • Biomechanical loading • Physiological loading • Psychophysical concepts IE 553

  4. Conflicting Guidelines Karwowski (1983) Jung & Freivalds (1991) IE 553

  5. Recommended Weight Limit (RWL) • RWL based on an optimum weight • With adjustments for task variables • Resulting in stress limits of: • Fcomp = 3,400 N • Emax = 4.7 kcal/min • Strength requirement achieved by: • 75% of women • 99% of men • 90% mixed population IE 553

  6. RWL Limitations • Smooth lifting, no jerks • Objects of moderate width • Hand separation < 75 cm • Unrestricted lifting posture • Good coupling (hands and feet) • Reasonable temperatures IE 553

  7. RWL = LCxHMxVMxDMxAMxFMxCM • LC = 51 lbs • HM = 10/H (10≤H≤25) • VM = 1 – 0.0075|V – 30| (0≤V≤70) • DM = 0.82 + 1.8/D (10≤D≤70) • AM = 1 – 0.0032A (0≤A≤135) • FM = from table • CM = from table IE 553

  8. H, V, D coordinates IE 553

  9. Frequency Multiplier IE 553

  10. Work Duration Three categories: • Work ≤ 1 hour, rest = 1.2 x work • 1 < Work ≤ 2 hours, rest = 0.3 x work • 2 < Work ≤ 8 hours IE 553

  11. Coupling Multiplier IE 553

  12. APPLICATION • Lifting Index (LI) = Load/RWL • Measure of relative stress • Compare jobs • Always two RWL calculations • 1) origin and 2) destination • Smallest RWL counts • Note: 0 ≤ M ≤ 1 IE 553

  13. Ex. Lifting Box into Car RWLor = 51(10/H)(1-.0075|V-30|)(.82+1.8/D)(1-.0032A)FMxCM RWLdest = 51(10/H)(1-.0075|V-30|)(.82+1.8/D)(1-.0032A)FMxCM IE 553

  14. Effect of Multipliers - 1 IE 553

  15. Effect of Multipliers - 2 IE 553

  16. Effect of Multipliers - 3 Frequency Multiplier IE 553

  17. Multi-Task Lifting • Multi-task lifting ↑ LI over single-task • ↑ LI from worst case, as marginal effect • Calculate Composite LI (CLI) from: • Single task RWL (STRWL) • Frequency independent RWL (FIRWL), FM=1 • Single task LI (STLI) • Frequency independent LI (FILI) • CLI = STLI1 + FILI2x(1/FM1,2 – 1/FM1) IE 553

  18. Ex. Multi-Task Lifting IE 553 CLI = 1.6 + 1.0x(1/.88–1/.94) + 0.67x(1/.7–1/.88) = 1.9

  19. Frequency Multiplier IE 553

More Related