b 7.8.1
The bending factor shall be calculated where any steel wire rope sling or grommet is bent round a
shackle, trunnion, padear or crane hook, resulting in a reduction of strength. The bending factor shall
be calculated as follows (based on IMCA M 179, Ref. [7]):
Bending factor
b
= 1 / {1 - 0.5 /
(D/d)} where:
d = the sling or cable laid rope diameter
D = the minimum diameter over which the sling body, sling eye, or grommet is
bent.
7.8.2
For wire rope slings and grommets, this results in the bending factors detailed in the Table 7-1.
Table 7-1 Bending Factors D/d <1.0 1.0 1.5 2.0 3.0 4.0 5.0 6.0 7.0 Factor
See Section
7.8.5
2.00
1.69
1.55
1.41
1.33
1.29
1.26
1.23
7.8.3
The bending factors at each end of a sling or grommet may differ, and the more severe value should
be taken.
7.8.4
For fibre rope slings, the bending factor may normally be taken as 1.0, provided the bending diameter
is not less than the minimum specified by the manufacturer and subject to the specific
recommendations of the sling manufacturer.
7.8.5
Under no circumstances should the sling or grommet body contact any surface where the diameter is
less than 1.0d to maintain the sling / grommet in a good condition under load. Bending of a sling eye
around a surface with a smaller diameter than the sling is permissible but this is not recommended as
the applied bending factor on the sling eye will be greater than 2.0 and thus the eye capacity will be
less than the capacity of the main body of the sling. Note, in order to maintain the sling eye in a good
condition, it is normally recommended that the sling eye is not bent around a diameter less than two
times the sling diameter.
7.8.6
Bending in way of splices shall be avoided unless recommended by the supplier as several suppliers
of braided fibre rope grommets recommend placing the splice on the hook or shackle to ensure an
even load distribution.
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