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13 March, 21:40

A worker is asked to move 30 boxes from a desk onto a shelf within 3 minutes (assume there is enough space and no other lifting work within 8 hours). The shelf height is 55 inches, and the desk height is 30 inches. The initial horizontal distance from the box to the body is 7 inches. Assume that all the boxes are in the same size (8 inches edge, cube), each weigh 20 lb., and have well designed handles. Is there any lifting risk according NIOSH lifting guide

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  1. 14 March, 01:17
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    LI = Lifting Index = 0.71

    No lifting risk is involved

    Explanation:

    NIOSH Lifting Index

    LI = Load Weight / Recommended Weight Limit

    LI = L / RWL ... Eq (A)

    NIOSH Recommended Weight Limit equation is following,

    RWL = LC * HM * VM * DM * AM * FM * CM ... Eq (B)

    Where,

    LC = Load constant

    HM = Horizontal multiplier

    VM = Vertical multiplier

    DM = Distance multiplier

    AM = Asymmetric multiplier

    FM = Frequency multiplier

    CM = Coupling multiplier

    Given data

    V = 30 + (8/2) = 34 in

    H = 7 in

    D = 55 - 30 = 25 in

    A = 0

    F = 10 boxes/min

    C = 1 = Good coupling

    According to NIOSH lifting guide

    LC = 51 lb

    HM = 10/H

    VM = 1 - {0.0075 * (v-30) }

    DM = 0.82 + (1.8/D)

    AM = 1 - (0.0032*A)

    FM = 0.45 (Table 5 from NIOSH lifting guide)

    CM = 1 (Table 7 from NIOSH lifting guide)

    Solution:

    RWL = 51 * (10/7) * [1-{0.0075 (34-30) }] * (0.82 + 1.8/25) * (1-0.0032*0) * 0.45 * 1

    RWL = 51 * (10/7) * 0.97 * 0.892 * 1 * 0.45 * 1

    RWL = 28.37 lb

    Using equation A

    LI = L / RWL

    LI = 20 / 28.37

    LI = 0.71

    According to NIOSH lifting guide LI < = 1

    So No lifting risk is involved
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