Civil Engineering Reference
In-Depth Information
FIGURE 11.33 The lumbar motion monitor (LMM).
has been shown to have a high degree of predictability (odds ratio
10.7) compared to previous
attempts to assess work-related LBD risk. The advantage of this assessment is that the evaluation pro-
vides information about risk that would take years to derive from historical accounts of incidence rates.
The model has also been validated in a prospective study (Marras et al., 2000a, b). Chapter 49 further
explains the logic and validity of this tool.
¼
11.4.7 TLVs
Threshold Limit Values or TLVs have been recently introduced for controlling biomechanical risk to
the back in the workplace. These limits have been introduced through the American Conference of
Governmental Industrial Hygienists (ACGIH) and provide lifting weight limits as a function of lift
origin “zones” and repetitions associated with occupational tasks. The lift origin zones are defined
by the lift height off the ground and lift distance from the spine associated with the lift origin.
Twelve zones are defined that related to lifts within
of asymmetry from the sagittal plane.
These zones are represented in three figures with each figure corresponding to different lift frequency
and time exposures. Within each zone limits are specified based upon the best information available
from several sources, which include: (1) EMG-assisted biomechanical models, (2) the 1993 revised
lifting equation, and (3) the historical risk data associated with the LMM database. This tool is
further described in Chapter 50.
+
30
8
Search WWH ::
Custom Search