Guide to Examination
The continued safe operation of lifting equipment, lifting
accessories (e.g. slings) and other systems employing wire
rope depends to a large extent on the operation of well
programmed periodic rope examinations and the
assessment by the competent person of the fitness of the
rope for further service.
Examination and discard of ropes by the competent person
should be in accordance with the instructions given in the
original equipment manufacturer’s handbook. In addition,
account should be taken of any local or application specific
regulations.
The competent person should also be familiar, as
appropriate, with the latest versions of related ASME B30,
International, European or National standards.
Particular attention must be paid to those sections of rope
which experience has shown to be liable to deterioration.
Excessive wear, broken wires, distortions and corrosion
are the more common visible signs of deterioration (see
below).
Note: This publication has been prepared as an aid for rope
examination and should not be regarded as a substitute for the
competent person.
Wear is a normal feature of rope service and the use of the
correct rope construction ensures that it remains a
secondary aspect of deterioration. LUBRICATION may
help to reduce wear.
Broken wires are a normal feature of rope service towards
the end of the rope’s life, resulting from bending fatigue
and wear. The local break up of wires may indicate some
mechanical fault in the equipment. Correct lubrication
in service will increase fatigue performance.
Distortions are usually as a result of mechanical damage,
and if severe, can considerably affect rope strength.
Visible rusting indicates a lack of suitable lubrication,
resulting in corrosion. Pitting of external wire surfaces
becomes evident in some circumstances. Broken wires
ultimately result.
Internal corrosion occurs in some environments when
lubrication is inadequate or of an unsuitable type.
Reduction in rope diameter will frequently guide the
observer to this condition. Confirmation can only be made
by opening the rope with clamps or the correct use of spike
and needle to facilitate internal inspection.
Note: Non-destructive testing (NDT) using electromagnetic
means may also be used to detect broken wires and/or loss in
metallic area. This method complements the visual examination
but does not replace it.
Pictures courtesy of S.M.R.E. Crown Copyright 1966
Some of the More Common Types of Wire
Fractures Can Include:
Multi-layers of the rope on the drum can result in severe
distortion in the underlying layers.
Bad spooling(due to excessive fleet angles or slack
winding) can result in mechanical damage, shown as severe
crushing, and may cause shock loading during operation.
Small diameter sheaves can result in permanent set of the
rope, and will certainly lead to early wire breaks.
Oversize grooves offer insufficient support to the rope
leading to increased localized pressure, flattening of the
rope and premature wire fractures. Grooves are deemed to
be oversize when the groove diameter exceeds the nominal
rope diameter by more than 15%.
Undersize grooves in sheaves will crush and deform the
rope, often leading to two clear patterns of wear and
associated wire breaks.
Excessive angle of fleet can result in severe wear of the
rope due to scrubbing against adjacent laps on the drum.
Rope deterioration at the Termination may be exhibited in
the form of broken wires. An excessive angle of fleet can
also induce rotation causing torsional imbalance.
This page reprinted with permission from Bridon American