Civil Engineering Reference
In-Depth Information
34.4.1.4 OSU
BWC Lifting Guidelines
The Ohio State University (OSU) and the Ohio Bureau of Workers' Compensation (BWC) also devel-
oped lifting guidelines that are easy for the practitioner to use. An important feature of these guidelines
is the incorporation of data for individuals currently experiencing low back pain. The data for the guide-
lines are based on research presented by Marras et al. (2001), which showed that the trunk loading of
individuals with a low back disorder (LBD) is higher than for asymptomatic individuals under the
same lifting conditions. The increased loading can be attributed to trunk muscle coactivation in individ-
uals with low back pain.
The inputs to the lifting guide are: health status of worker (healthy or LBD), category of asymmetry
angle (less than 30
/
), horizontal reach distance (less than
12 in. or between 12 and 24 in.), and vertical lift origin (floor, knee, waist, or shoulder). The output of the
model indicates the level of risk (low, medium, or high), which is given in weight ranges for the particular
lifting conditions.
The OSU
8
, between 30
8
and 60
8
, and between 60
8
and 90
8
BWC Lifting Guideline charts are presented in Figure 34.1, Figure 34.2, and Figure 34.3;
instructions for using the charts are as follows:
/
1. Determine the angle of asymmetry associated with a specific lifting task. Then, choose the chart
that corresponds. There are three separate charts:
+
30
8
(Figure 34.1), between 30 and 60
8
(Figure 34.3).
2. Choose a column indicating whether the individual has an LBD or is healthy.
3. Determine the maximum horizontal reach distance from spine (measured from spine to hands)
using the guide at the top of the columns. The guide is broken down into distances of 12 and 24 in.
4. Choose the vertical lift origin for the specific task from the right side of the chart. Vertical lift
origin is the level from which lifts will be made. This can be from the floor, from the knees,
from the waist or shoulder level. Also, choose the weight of the lift in pounds.
5. Determine if your specified lifting conditions fall within the green zone (low risk), yellow zone
(moderate risk), or red zone (high risk).
6. To minimize the risk of injury, change any lifting criteria in the high or moderate risk zone so that
the lifting task is in a green area of the chart.
(Figure 34.2), and between 60 and 90
8
The guidelines apply to two-handed, low-frequency lifts performed in unrestricted postures with good
coupling. Ergonomics practitioners can use the results of the guidelines in a similar manner to the
Horizontal reach distance from spine
12 in.
24 in.
Healthy
LBD
Healthy
LBD
10
15
20
25
10
15
20
25
10
15
20
25
10
15
20
25
Maximum
safe load
35 pounds
Shoulder
Maximum
safe load
70 pounds
Maximum
safe load
35 pounds
Waist
Maximum
safe load
40 pounds
Knee
Floor
Low risk
High risk
Medium risk
FIGURE 34.1 Guidelines for lifts involving trunk twisting angle of asymmetry between 0 and 30
8
(The angle
between the front of the body, when facing forward, and the load being lifted).
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