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Allowances

Allowances. Practice Problems. Example 1. Suppose you have a fine assembly task Standing Requires approximately 300 kCal / hr (based on HR measurement) NT = 90 cmin. Additional Considerations include Illumination – 25 fc in work area Noise – fairly continuous 91 dBA in work area

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Allowances

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  1. Allowances Practice Problems

  2. Example 1 • Suppose you have a fine assembly task • Standing • Requires approximately 300 kCal / hr (based on HR measurement) • NT = 90 cmin. • Additional Considerations include • Illumination – 25 fc in work area • Noise – fairly continuous 91 dBA in work area • Heat – First hot day of the year, WBGT = 80 °F • No significant mental strain, monotony, or repetitiveness. • What is the Standard Time?

  3. Example 1 (cont’d) • ST = NT (1+ allowances) • 2 ways to find allowances • Quick & Dirty way • Table 11-2 (ILO Recommendations) • More thorough way • Calculate individual relaxation allowances, RA, for each variable and special allowance factor.

  4. ILO Recommendations Table 11-2, Niebel & Frievalds p. 437

  5. Example 1 (cont’d) • More thorough method • Use Table 11-11, p. 453. • Some factors can be found directly from the table • Constant • Posture • Visual Strain • Others must be calculated.

  6. Example 1 (cont’d) • Personal needs = 5% (always constant) • Basic Fatigue = 4% (always constant • Posture – standing = 2% • Why isn’t there an option for seated? • Visual Strain – Fine assembly = 2% • Mental Stress, Monotony, Repetitiveness = 0%.

  7. Example 1 (cont’d) • Illumination • Looks like a chart lookup, but what are IES subcategories? • Refer to Ch. 6, p. 237, Table 6-2. • Our illumination = 25 fc, or CAT D. • What should our illumination category be? • Do you see “fine assembly” listed? • Should be between “medium” & “extra-fine” assembly. • Should be CAT F, but we are 2 categories below. • From Table 11-11, illumination allowance = 3%

  8. Example 1 (cont’d) • Atmospheric Conditions (HEAT) • Workload, W = 300 kcal/hr • WBGT = 80 °F • How do you determine WBGT? • RA = e (-41.5 + 0.0161W + 0.497WBGT) • = e (-41.5 + 0.0161x300 + 0.497x80) • = e (3.09) = 22% • Can also lookup RAL from Fig 6-11, p. 253. • RAL for 300 kcal/hr & WBGT = 80 °F is 48 min/hr • 12 min rest / 48 min work = 25% allowance.

  9. Example 1 – (cont’d) • Noise • SPL = 91 dBA • What is SPL • Need to calculate dose for 8 hour day. • If 90 dBA is 8 hour-100% dose, what about 91dBA? • Must find time for 100% dose T = 8 / 2 [(L-90)/5] • T = 8 / 2 [(91-90)/5]. • T = 6.96 hours is a 100% dose for 91 dBA. • D = 8/6.96 = 1.15. • RA = 100 x (D – 1) • = 100 x (1.15-1) • RA = 15%

  10. Example 1 (cont’d) • Find Standard Time • ST = NT x (1 + Σ allowances) • ST = 90 cmin x (1+0.05+0.04+0.02+0.03+ 0.02+0.22+0.15) • ST = 90 cmin x (1 + 0.16 + 0.22 + 0.15) • HEAT NOISE • ST = 90 x (1.53) • ST = 137.7 cmin

  11. Example 1 - Redesign • As a process engineer, what would be the first things you would want to do to bring the standard time closer to the NT? • The heat allowance is the largest? • It can be reduced to eliminate extra heat fatigue. • How? • The noise allowance is the next largest • What would you do about that one?

  12. Measurement • How do you measure… • Illumination? • Heat? • Noise? • For the next 3 labs, you will practice measuring these three environmental factors • This week, we will begin with noise. • You will write one report that considers the impact of these three factors on work performance • based on the data you will collect • AND, based on some homework problems you will receive in lab.

  13. Homework • Work the following problems • Ch. 11 – Prob #1, 2, 3, 5 & 7. • Due one week from today. • This is in addition to the homework you will receive in lab today!! • But, there’s no report due next week. 

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