PA 9 - u of waterloo PDF

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Student Name: Tianshu Wang

20817396

BME162 Participation Activity #8 Answer Template NIOSH Lifting Equation: Poets Problem A student working at POETS must lift and stack cases of beverages. Each case currently holds 24 beverages and weighs 13 kg. The student works for no more than 2 hours. The handles on the cases are fair. The student must hold the cases at 30 cm from the body (measured from the midpoint between the ankles). The vertical distance at the start of the lift is 78 cm. The vertical distance of the student’s hands from the floor at the destination is 165 cm. The student rotates 45 degrees during the lift. The student is expected to move 100 cases during the work shift. a) Use the NIOSH Lifting Equation to calculate whether or not this is a safe lift for the student. b) If you were to redesign this lifting task, pick one feature that would be the easiest to change? PART A: RWL  LC HM VM DM AM FM CM LI Weight of tote RWL Calculate load constant (LC): Hint: See Table 13.1. LC = 23kg (constant)

Calculate Horizontal Multiplier (HM): HM=25/H H is horizontal distance between hands lifting load and midpoint between ankles (cm) Horizontal distance between hands lifting load and midpoint between ankles is 30cm HM = 25/30 = 0.833333

Calculate Vertical Multiplier (VM): Hint: Consider the beginning and the end of the lift! VM=1-0.003|V-75| V is the vertical distance of the hands from the floor (cm) The vertical distance of the hands from the floor is: 165 cm VMstart = 1-0.003 |78-75| = 0.991 VMend = 1-0.003 |165 - 75| = 0.73

Student Name: Tianshu Wang

20817396

Calculate the Distance Multiplier (DM): DM=0.82 + 4.5/D D is the vertical travel distance between the origin and the destination of the lift (cm) The vertical travel distance between the origin and the destination of the lift: 78cm DM = 0.82 + 4.5/(165-78) = 0.871724137

Calculate the Asymmetry Multiplier (AM): AM = 1-0.0032A A is the angle of torso twisting involved in the lift (in degrees) A is 45 degrees AM = 1 – 0.0032(45) = 0.856

Calculate the Frequency Multiplier (FM): Hint: See Table 13.2, Round up Less than 2 hours 100 lifts within 2 hours: 100/120 min = 0.83333 FM = 0.88

Calculate the Coupling Multiplier (CM): Hint: See Table 13.3 Coupling is fair CM = 1

Calculate the overall RWL: Hint: Consider the beginning and the end of the lift! RWL  LC HM VM DM AM FM CM RWLstart = 23 * 0.833 * 0.991 * 0.87 * 0.856 * 0.833 * 1 = 11.7783515 = 11.78 RWLend = 23 * 0.833 * 0.73 * 0.87 * 0.856 * 0.833 * 1 = 8.679755042 = 8.68

Student Name: Tianshu Wang

20817396

Calculate Lift Index (LI): Hint: Consider the beginning and the end of the lift! LI Weight of tote RWL LIstart= 13 kg / 11.78 = 1.1037 LIend= 13kg / 8.68 = 1.4977

Interpret Lift Index (LI): (This is the answer to part A) LI ≤ 1.0: Lift is safe LI > 1.0: Will pose an increased risk to some workers LI > 3.0: Will pose a high risk of low-back pain and injury to most workers Answer to part A: the lift will pose an increased risk to some workers, so the student should use proper methods to lift and be very cautious.

PART B: For this lifting task, what would be the easiest element to change? Instead of using the fair condition handles, use slings and hooks to move loads without handles. This would be the easiest element to change because it does not require a lot of resources and reduce effort and risk.

Student Name: Tianshu Wang

20817396

Table 13.1. NIOSH Lifting Equation Components and Related Equations (Liu et al., p. 433)

Component Load Constant (LC) Horizontal Multiplier (HM) Vertical Multiplier (VM) Distance Multiplier (DM) Asymmetric Multiplier (AM) Frequency Multiplier (FM) Coupling Multiplier (CM)

Metric System 23 kg 25/H 1 - 0.003|V-75| 0.82 + 4.5/D 1 - 0.0032A See Table 2 See Table 3

US System 51 lb 10/H 1 - 0.0075|V-30| 0.82 + 1.8/D 1 - 0.0032A See Table 2 See Table 3

Table 13.2. Frequency Multiplier (FM) Values (75 cm = 30 in) (Liu et al., p. 433)

Frequency (lifts/min) 0.2 0.5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 >15

≤ 1 hr V < 75 cm V ≥ 75 cm 1.00 0.97 0.94 0.91 0.88 0.84 0.80 0.75 0.70 0.60 0.52 0.45 0.41 0.37 0 0 0 0

1.00 0.97 0.94 0.91 0.88 0.84 0.80 0.75 0.70 0.60 0.52 0.45 0.41 0.37 0.34 0.31 0.28 0

Work Duration ≤ 2 hr V < 75 cm V ≥ 75 cm 0.95 0.92 0.88 0.84 0.79 0.72 0.60 0.50 0.42 0.35 0.30 0.26 0 0 0 0 0 0

V < 75 cm

0.95 0.92 0.88 0.84 0.79 0.72 0.60 0.50 0.42 0.35 0.30 0.26 0.23 0.21 0 0 0 0

Table 13.3. Coupling Multiplier (CM) Values (75 cm = 30 in) (Liu et al., p. 434)

Coupling Good Fair Poor

Coupling Multipliers (CM) V < 75 cm 1.00 0.95 0.90

V ≥ 75 cm 1.00 1.00 0.90

0.85 0.81 0.75 0.65 0.55 0.45 0.35 0.27 0.22 0.18 0 0 0 0 0 0 0 0

≤ 8 hr V ≥ 75 cm 0.85 0.81 0.75 0.65 0.55 0.45 0.35 0.27 0.22 0.18 0.15 0.13 0 0 0 0 0 0...