A major portion of any wire rope inspection
is the detection of broken wires. The number
and type of broken wires are an indication
of the rope's general condition and a benchmark
for its replacement.
Frequent inspections and written records
help determine the rate at which wires are
breaking. Replace the rope when the values
given in the table below are reached.
Valley wire breaks -- where the wire fractures
between strands or a broken wire protrudes
between strands -- are treated differently
than those that occur on the outer surface
of the rope. When there is more than one valley
break, replace the rope.
Broken wire removal criteria cited in many
standards and specifications, like those listed
below, apply to wire ropes operating on steel
sheaves and drums. For wire ropes operating
on sheaves and drums made with material other
than steel, please contact the sheave, drum
or equipment manufacturer or a qualified person
for proper broken wire removal criteria.
| |
# OF BROKEN WIRES
IN RUNNING ROPES |
# OF BROKEN WIRES IN
STANDING ROPES |
| Standard |
Equipment |
In one rope lay |
In one strand |
At end connection |
In one rope lay |
At end connection |
|
ASME/B30.2 |
Overhead & gantry cranes |
12** |
4 |
N/S |
Not
Specified |
| ASME/B30.4 |
Portal,
tower, & pillar cranes |
6** |
3 |
2 |
3 |
2 |
| ASME/B30.5 |
Mobile & locomotive
cranes |
Running ropes |
6** |
3 |
2 |
3 |
2 |
|
Rotation-resistant
ropes |
2 randomly distributed
broken wires in 6 rope dia.or 4 randomly
distributed broken wires in 30 rope
dia. ** |
| ASME/B30.6 |
Derricks |
6** |
3 |
2 |
3 |
2 |
|
ASME/B30.7 |
Base-mount drum hoists |
6** |
3 |
2 |
3 |
2 |
| ASME/B30.8 |
Floating
cranes and derricks |
6** |
3 |
2 |
3 |
2 |
|
ASME/B30.16 |
Overhead hoists |
12** |
4 |
N/S |
Not
Specified |
| ANSI/A10.4 |
Personnel
hoists |
6** |
3 |
2 |
2** |
2 |
|
ANSI/A10.5 |
Material hoists |
6** |
Not
Specified |
Not
Specified |
**Also
remove for 1 valley break.
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