The revised NIOSH lifting equation can be used to calculate the recommended weight limit for workers performing two-handed manual lifting.
recommended weight limit in kilograms =
= (load constant in kilograms) * (horizontal multiplier) * (vertical multiplier) * (distance multiplier) * (asymmetric multiplier) * (frequency multiplier) * (coupling multiplier)
|
Component |
Metric |
US Conventional Units |
|---|---|---|
|
load constant |
23 kg |
51 lbs |
|
horizontal multiplier |
25 / H |
10 / H |
|
vertical multiplier |
1 - (0.003 * (V - 75)) |
1 - (0.0075 * (V-30)) |
|
distance multiplier |
0.82 + (4.5 / D) |
0.82 + (1.8 / D) |
|
asymmetric multiplier |
1 - (0.0032 * A) |
1 - (0.0032 * A) |
where:
• each parameter is measured at the site of origin and at the destination
• distances are in centimeters or inches
• H = horizontal location of hands from midpoint between the ankles, measure in cm or in
• V = vertical location of the hands from the floor, measured in cm or in
• D = vertical travel distance between the origin and the destination of the lift, measured in cm or inches
• A = angle of asymmetry; angular displacement of the load from the sagittal plane, measured in degrees
Frequency Multiplier
Work Duration <= 1 hour
|
average lifting frequency rate in lifts per minute |
vertical location of hands from floor < 75 cm (30 in) |
vertical location of hands from floor >= 75 cm (30 in) |
|---|---|---|
|
0.2 |
1.00 |
1.00 |
|
0.5 |
0.97 |
0.97 |
|
1 |
0.94 |
0.94 |
|
2 |
0.91 |
0.91 |
|
3 |
0.88 |
0.88 |
|
4 |
0.84 |
0.84 |
|
5 |
0.80 |
0.80 |
|
6 |
0.75 |
0.75 |
|
7 |
0.70 |
0.70 |
|
8 |
0.60 |
0.60 |
|
9 |
0.52 |
0.52 |
|
10 |
0.45 |
0.45 |
|
11 |
0.41 |
0.41 |
|
12 |
0.37 |
0.37 |
|
13 |
0.00 |
0.34 |
|
14 |
0.00 |
0.31 |
|
15 |
0.00 |
0.28 |
|
> 15 |
0.00 |
0.00 |
where:
• work duration assumes appropriate allowances for recovery
Work Duration > 1 and <= 2 hours
|
average lifting frequency rate in lifts per minute |
vertical location of hands from floor < 75 cm (30 in) |
vertical location of hands from floor >= 75 cm (30 in) |
|---|---|---|
|
0.2 |
0.95 |
0.95 |
|
0.5 |
0.92 |
0.92 |
|
1 |
0.88 |
0.88 |
|
2 |
0.84 |
0.84 |
|
3 |
0.79 |
0.79 |
|
4 |
0.72 |
0.72 |
|
5 |
0.60 |
0.60 |
|
6 |
0.50 |
0.50 |
|
7 |
0.42 |
0.42 |
|
8 |
0.35 |
0.35 |
|
9 |
0.30 |
0.30 |
|
10 |
0.26 |
0.26 |
|
11 |
0.00 |
0.23 |
|
12 |
0.00 |
0.21 |
|
13 |
0.00 |
0.00 |
|
14 |
0.00 |
0.00 |
|
15 |
0.00 |
0.00 |
|
> 15 |
0.00 |
0.00 |
Work Duration > 2 and <= 8 hours
|
average lifting frequency rate in lifts per minute |
vertical location of hands from floor < 75 cm (30 in) |
vertical location of hands from floor >= 75 cm (30 in) |
|---|---|---|
|
0.2 |
0.85 |
0.85 |
|
0.5 |
0.81 |
0.81 |
|
1 |
0.75 |
0.75 |
|
2 |
0.65 |
0.65 |
|
3 |
0.55 |
0.55 |
|
4 |
0.45 |
0.45 |
|
5 |
0.35 |
0.35 |
|
6 |
0.27 |
0.27 |
|
7 |
0.22 |
0.22 |
|
8 |
0.18 |
0.18 |
|
9 |
0.00 |
0.15 |
|
10 |
0.00 |
0.13 |
|
11 |
0.00 |
0.00 |
|
12 |
0.00 |
0.00 |
|
13 |
0.00 |
0.00 |
|
14 |
0.00 |
0.00 |
|
15 |
0.00 |
0.00 |
|
> 15 |
0.00 |
0.00 |
Coupling Multiplier
|
Couplings |
vertical location of hands from floor < 75 cm (30 in) |
vertical location of hands from floor >= 75 cm (30 in) |
|---|---|---|
|
good |
1.00 |
1.00 |
|
fair |
0.95 |
1.00 |
|
poor |
0.90 |
0.90 |
Purpose: To calculate the NIOSH recommended weight limit for occupational lifting. This can be used to help reduce the incidence of low back pain in workers.
Specialty: Sports Medicine & Rehabilitation, Surgery, orthopedic, Neurology
Objective: disability and performance
ICD-10: X50,
