Civil Engineering Reference
In-Depth Information
1.0
0.9
0.8
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0.1
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(cm)
30
(in.)
0
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Horizontal location
FIGURE 11.26 Horizontal factor, (HF) varies between the body interference limit and the limit of functional reach.
(Adapted from National Institute for Occupational Safety and Health (NIOSH), Work practices guide for manual
lifting, Department of Health and Human Services (DHHS), NIOSH, Cincinnati, OH, No. 81-122, 1981. With
permission.)
associated with these figures, the HF, which is associated with the external moment has the most dramatic
effect on acceptable lifting conditions. VF and DF are associated with the back muscle's length-strength
relationship. FF attempts to account for the cumulative effects of repetitive lifting.
The second benchmark associated with this guide is the maximum permissible limit or MPL. The MPL
represents the point at which significant risk, defined in part, as a significant risk of vertebral endplate
microfracture (Figure 11.10). The MPL is associated with a compressive load on the spine of 6400 N,
which corresponds to a point at which 50% of the people would be expected to suffer a vertebral endplate
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(cm)
20
60
100
140
180
0
20
40
60
80
(in.)
Vertical location
FIGURE 11.27 Vertical factor, (VF) varies both ways from knuckle height. (Adapted from National Institute for
Occupational Safety and Health (NIOSH), Work practices guide for material lifting, Department of Health and
Human Services (DHHS), NIOSH, Cincinnati, OH, 81-122, 1981. With permission.)
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