ISO 4309:2017 wire rope inspection and discard criteria
What ISO 4309:2017 says about wire rope: scope, how often to inspect, what to
inspect and when a rope must come off. Written in our own words with the clause number for each point.
Send us a photo of a completed sheet and we send back a free analysis, usually the same day. Every standard.
Scope
Sets out general principles for looking after, inspecting and deciding when to retire steel wire ropes on cranes and hoists. 1
Besides storage, handling, installation and maintenance guidance, it gives retirement criteria for running ropes that spool in several layers on a drum, where the crossover points wear out faster than any other part of the rope. 1
It also gives updated retirement criteria for decrease in diameter and for corrosion, plus a method for judging several kinds of damage acting together at one spot on the rope. 1
Crane types covered: cable and portal cable cranes; cantilever cranes of pillar-jib, wall-mounted or walking type; deck cranes; derrick and guy derrick cranes; derricks with rigid bracing; floating cranes; mobile cranes; overhead travelling cranes; portal or semi-portal bridge cranes; portal or semi-portal cranes; railway cranes; tower cranes; and offshore cranes on fixed or floating platforms. 1 a) to m)
Covers rope on cranes, winches and hoists doing hook, grab, magnet, ladle, excavator or stacking work, whether driven by hand, electric or hydraulic power, and also rope on hoists and hoist blocks. 1
Exclusion: no retirement criteria are given for rope spooling in a single layer on the drum while running only on synthetic sheaves or metal sheaves with synthetic liners, because large numbers of internal breaks can occur before any outside sign appears. That combination is not recommended. 1, NOTE
The general principles for care, inspection and discard apply when the crane maker's operator manual and the rope maker or supplier give no specific instructions of their own. 4.1, 5.1, 6.1
Inspection frequency
Daily visual inspection. Every day, look over at least the length of rope expected to work that day for general wear or mechanical damage, including where the rope is attached to the crane. Also confirm the rope sits properly on the drum and sheaves and has not jumped out of position. 5.2
Daily visual inspection - who. The crane driver or operator can be given the daily check, provided they are adequately trained and judged competent to do it. 5.2
Daily visual inspection - follow-up. Any noticeable change in the rope's condition must be reported, and a competent person must then examine the rope to the periodic inspection standard. 5.2
After re-rigging or relocation. Whenever the rigging is changed, for example when the crane is moved to a new site and rigged again, the rope must get the daily-type visual inspection. 5.2
Periodic inspection - who and purpose. Periodic inspections must be done by a competent person. The findings decide whether the rope can stay in service and by when it must next be inspected, or whether it must come off at once or within a set time. 5.3.1
Periodic inspection - how often. No fixed interval is given. The competent person sets it, considering at least: local legal requirements, crane type and operating environment, mechanism classification group, earlier inspection results, experience with similar cranes, how long the rope has been working, how often it is used, and the crane maker's recommendations. 5.3.2
Periodic inspection - shortening the interval. The competent person may call for inspections more often than the law requires, and may shorten the interval if the rope's condition changes, after an incident, or when operating conditions change. 5.3.2, NOTE 1
Periodic inspection - late in rope life. Ropes tend to break wires faster toward the end of their life than when new, which is relevant when setting inspection intervals. 5.3.2, NOTE 2
Periodic inspection - tracking break rate. Where bending fatigue is the main cause of wear, carefully count and record broken wires at each periodic inspection so the rate of increase is known; that trend can then be used to set the next inspection date. Annex F, F.1 a)
Periodic inspection - record. After every periodic inspection the competent person must issue a rope inspection record and state the longest time allowed before the next periodic inspection. Keeping a running record over the life of the rope is preferred. Sample record forms are in Annex E. 5.3.5
Periodic inspection - extra working length. If only the working length was inspected on a long rope and a longer working length is later expected before the next inspection, the extra length should be inspected before it is put to use. 5.3.3
After an incident. If something has happened that may have damaged the rope or its end fitting, inspect them to the periodic inspection standard before work restarts, or as the competent person requires. 5.4
Crane out of service (idle). If the crane has sat idle for over three months, give the rope a full periodic inspection before restarting work. 5.5
Magnetic rope test (MRT). MRT is optional and can help periodic inspection locate sections that may be deteriorating. It should be used where defects might be missed by eye, and must always be done together with a visual inspection. 5.6
MRT baseline on new rope. If MRT will be part of periodic inspection, take a first baseline scan as early as possible in the rope's life, ideally before installation or soon after, to compare against later. 4.2, 5.6
MRT recommended for rotation-resistant rope. MRT is recommended for rotation-resistant ropes, especially those with three or more layers of strands, since extensive internal breaks can occur with no outside breaks and opening the rope with clamps does not work well. Annex F, F.1 a)
New rope - on receipt / before installation. Before fitting, and preferably when it arrives, check the rope and its certificate match what was ordered. Its minimum breaking force must not be below the crane maker's figure. 4.4
New rope - diameter on installation. Measure the new rope's diameter on a straight length with no load on it and record the value. 4.4
New rope - after storage. If a rope has been stored long enough for corrosion to be possible, a visual inspection and an MRT before use can be worthwhile. 4.4
New rope - pre-service damage. Any damage the rope may have picked up before it was run in and put into service must be judged and written down by a competent person. 5.3.1
New rope - running in. Before full duty, confirm all hoist limit and indicating devices work, then run the crane for a number of cycles at reduced speed and load (as low as 10 % of WLL) so the rope can bed in. 4.6
Rope change record. Each time a rope is replaced, a record of the change must be kept on file. 4.2
Ropes in storage. Stored ropes must be checked from time to time for deterioration such as surface rust and, if a competent person thinks it necessary, dressed with a compatible preservative or lubricant. 4.3
Corrosive environment / no dressing. Where upkeep is lacking, the crane works in a corrosive setting, or rope dressing cannot be applied, rope life will be shorter and the time between inspections must be cut accordingly. 4.7
Drums and sheaves. Besides following the crane manual, drums and sheaves must be checked periodically to make sure they turn freely in their bearings. 4.8
Change in deterioration rate. If the rope starts deteriorating noticeably faster, the cause must be investigated and fixed where possible; in extreme cases the competent person can shorten the time to the next periodic inspection. 6.1
Inspection criteria
Daily check content. Watch the day's working section for general wear or mechanical damage, include the attachment points, and confirm the rope is correctly seated on the drum and over the sheaves. 5.2
What a periodic inspection involves. A periodic inspection is a thorough visual examination plus measurement of the rope and, where practical, an assessment of its internal condition. It can include an MRT done by someone competent in that equipment. 3.7
Rating severity. For each type of damage, the competent person rates how far it has progressed toward its discard limit, either as a percentage in steps (for example 20, 40, 60, 80, 100 %) or in words (slight, medium, high, very high, discard). 5.3.1
How each damage type is assessed. The standard lists common damage types and how each is judged: broken wires by counting, decrease in diameter by measuring, metal loss and corrosion visually or by MRT, and strand fracture, mechanical damage and heat damage visually. Waviness is judged visually and by measurement. 5.3.1, Table 1
Length to inspect. Inspect each rope over its whole length. For a long rope the competent person may limit the inspection to the working length and no fewer than five wraps on the drum. 5.3.3
Critical areas - ends and anchorage. Take particular care at the drum anchorage and at and near every rope end fitting. 5.3.3 a), b)
Critical areas - sheaves and blocks. Take particular care over any length passing through sheaves, through a load indicator with sheaves, through the hook block, over a compensating sheave, and, on cranes doing repetitive work, any length that sits on a sheave while loaded. 5.3.3 c) to g)
Critical areas - drum, spooling, abrasion, heat. Take particular care over lengths passing through a spooling device, lengths that spool on the drum (especially crossover zones with multi-layer spooling), lengths rubbed by outside features such as hatch coamings, and any part exposed to heat. 5.3.3 h) to k)
Key areas - single-layer spooling. On a single-layer drum, look hardest at: rope spooling on the drum at the lift point and where fleet angle interference is worst; rope entering block sheaves at the lift point; and rope in contact with compensating sheaves, especially where it enters. Annex A (normative), Figure A.1
Key areas - multi-layer spooling. On a multi-layer drum, look hardest at: crossover zones and the worst fleet-angle interference; rope entering the head sheave at the lift point; rope entering bottom block sheaves at the lift point; and the attachment point to the crane. Annex A (normative), Figure A.2
Crossover zones. On multi-layer drums, broken wires and deformation at crossover zones are expected to be the main damage, and these zones should be the focus of periodic inspection. Annex F, F.1 b)
Termination - rope entry point. Inspect the rope near each end fitting, especially where it enters the fitting, since vibration, dynamic loads and corrosion make this spot prone to wire breaks. A spike can be used to probe for loose wires that suggest a hidden break inside the fitting. 5.3.4
Termination - fitting condition. Check the end fitting itself for too much distortion or wear. 5.3.4
Ferrules. Check ferrules on eyes or loops visually for cracks and for any sign the rope is slipping in the ferrule. 5.3.4
Wedge sockets and detachable fittings. On detachable fittings such as symmetrical wedge sockets, look for broken wires where the rope enters and confirm the fitting is assembled correctly. 5.3.4
Eye splices. Eye splices must be checked to confirm the serving covers only the tapered part, so the rest of the splice can be seen and checked for broken wires. 5.3.4
Diameter - how a measurement is taken. A measured diameter is the average of two readings taken at right angles to each other, each across the full circle that encloses the rope. 3.2
Diameter - baseline. The baseline (reference) diameter is measured on a length of rope that does not bend over sheaves or drum, right after the new rope has been run in. Later decrease in diameter is judged against this figure, not the catalogue size. 3.3
Diameter - calculating the decrease. The decrease in diameter is worked out as (reference diameter minus measured diameter) divided by nominal diameter, times 100, giving a percentage of nominal size to compare with the discard table. 6.4.2, Formula (1)
Diameter - not at crossover zones. The uniform diameter-loss limits apply only to rope on single-layer drums or steel sheaves; they are not used at crossover zones or other lengths deformed by multi-layer spooling. 6.4.1; Annex G, NOTE 2
Diameter - uneven wear. A decrease in diameter can be uniform along the rope or local. If wear is uneven, find the cause and correct it where possible. Wear is usually heaviest where rope contacts sheave and drum grooves while the load speeds up or slows down. Annex F, F.2
Diameter - internal causes. Diameter can also drop from hidden causes: internal wear and wire indentation, friction between strands under bending, a failing fibre core or broken steel core, or broken inner strands in rotation-resistant rope. MRT can help. Annex F, F.2
Counting breaks - rope category. To use the broken-wire tables, find the rope's category number (RCN) from the cross-section examples in Annex H. If the construction is not shown, count all wires in the outer strand layer except filler wires to get the number of load-bearing wires (and, for rotation-resistant rope, also note the number of outer strands). 6.2.2; Annex H
Counting breaks - two inspection lengths. Broken wires are counted over two rope lengths, 6 times and 30 times the nominal diameter, and each count is compared with the table. 6.2.2
Counting breaks - one wire, two ends. A broken wire shows two ends but counts as one broken wire. Table 3, footnote b
Counting breaks - non-service breaks. Isolated wires broken during manufacture, shipping, storage or installation are not normally counted, since they are not in-service fatigue, but they should be recorded to help later inspections and the competent person must allow for them. 6.2.3
Counting breaks - removed wires. A protruding broken wire can be removed by bending it back and forth until it snaps off. If this is done, record where it was, and it still counts as a broken wire when judging discard. 4.7
Protruding non-service breaks. If non-service broken wires stick out and could cause local damage if left, they must be removed. 6.2.3
Finding valley breaks. Breaks hidden in the valleys between strands can often be exposed by flexing the rope, particularly on smaller ropes, by moving it out of its normal position and bending it with no load on it. 6.2.3, Figure 8; Annex F, F.1 d)
Single valley break. Even one valley break can point to internal deterioration, so that length of rope needs a closer look. Annex F, F.1 d)
Where breaks occur by rope type. On single-layer and parallel-closed ropes over steel sheaves, breaks usually appear at random on the strand crowns, often with outside wear. On rotation-resistant ropes most breaks may be internal and hard to see, which is why fewer visible breaks are allowed. Annex F, F.1 a)
Opening the rope. If the competent person decides to open the rope to check the inside, this should be done with great care to avoid damaging it (see Annex D). MRT is another source of information. 5.3.3
Internal examination with clamps - method. Where an internal check is needed and MRT is not possible, it should be done with no tension in the rope: clamp it at two points with jaws that grip without distorting it, and turn them against the lay so the outer strands lift off the core. Near an end fitting one clamp is enough. Not all ropes can be opened this way. Annex D, D.1, D.2.1, D.2.2
Internal examination with clamps - what to look for. Inside the rope, check the amount of corrosion, wire indentation from pressure or wear, broken wires in outer strands and core, and the state of internal lubrication. Dress the opened section and close the rope fully before returning to work. Annex D, D.2.1
Corrosion - clean before judging. Before rating corrosion, wipe or brush the section clean so rust from foreign particles on the surface is not mistaken for corrosion of the wires. Avoid solvents. 6.6
Corrosion - photo guide. Annex I gives photographs showing stages of outside corrosion as a visual guide to rating it. Annex I, Figures I.1 to I.4
Corrosion - internal is hard to see. Internal corrosion is harder to find than outside corrosion but they often occur together. If suspected, a competent person should examine the inside, though this can be very difficult; MRT can help. Annex F, F.3
Waviness - how to measure. Waviness is checked by laying a straight edge along the rope and measuring the gap between it and the underside of the rope helix. 6.7.2, Figure 9
Loss of elasticity - signs. A rope can lose elasticity, often from its environment, which is hard to detect. Signs include reduced diameter, stretched length, strands or wires packed tight with no gaps, fine brown powder in the valleys, and a stiff feel with more decrease in diameter than wear alone explains. Annex F, F.4 h)
Heat damage - signs. Heat damage can show as heat colours on the wires, such as a bluish tint, or a clear loss of grease. 6.7.10; Annex F, F.4 g)
MRT - information needed. For MRT break (local fault) readings the tester needs either the diameters and numbers of all wires, or the largest wire diameter and the metallic cross-section. For metal-area loss readings the metallic cross-section is needed. The rope maker or supplier should provide this. 6.3
MRT - limitations. MRT works only on ferromagnetic steel rope, may miss breaks whose gap is smaller than the instrument can detect, and is hard to use where access is restricted, such as near end fittings or equalizer sheaves. 5.6, NOTE
Sheave and drum grooves. Before fitting a new rope, check sheave and drum grooves fit the rope size, have no irregularities such as corrugations, and have enough wall left. Sheave grooves should be 5 % to 10 % larger than nominal rope diameter, and ideally at least 1 % above the new rope's actual diameter. 4.4
Stiff or jammed sheaves. Sheaves or rollers that are stiff or seized wear badly and unevenly and badly abrade the rope; compensating sheaves that do not work can load the reeving unevenly. 4.8, NOTE
Discard criteria
Order of precedence. The individual discard criteria apply unless the crane maker's manual or the rope maker or supplier gives other instructions. 6.1
Combined effect required. Damage often comes from several causes at the same spot, so the competent person must judge their combined effect, not just each one alone. 6.1
Combined effect - Annex G method (concept). One suggested method: record each type of damage at a location (broken wires, decrease in diameter, corrosion and so on), rate each as a percentage of its own discard limit or in words, then add the ratings where they occur at the same spot, or judge the overall severity in words. When the total reaches the discard level, the rope is retired. The outcome also guides whether to keep running, inspect more often, prepare for replacement or discard. Annex G (informative), G.1, Table G.1Limit set by the standard's table: check your rope in the calculator
Combined effect - MRT versus visual break count. If MRT finds more broken wires than the visual count, use the MRT figure in the combined assessment. Annex G, G.1
Combined effect - spread versus concentrated. The method assumes gradual deterioration. Damage split fairly evenly across two or three types is seen as less serious than the same total from a single type. Other methods based on the competent person's experience are equally acceptable. Annex G, NOTE 1, NOTE 3
Faster deterioration. If deterioration speeds up noticeably, the cause must be investigated and corrected where possible. In extreme cases the competent person can retire the rope, shorten the next inspection interval, or tighten the discard limits, such as allowing fewer visible broken wires. 6.1
Short damaged section on a long rope. If damage is confined to a short length of a long rope, the competent person may remove just that section instead of the whole rope, provided the rest is serviceable. 6.1
Broken wires - random breaks. Randomly spread breaks on rope running over steel sheaves and on a single-layer drum, or at crossover zones on a multi-layer drum, are judged against the broken-wire tables: one table for rotation-resistant ropes and another for single-layer and parallel-closed types. 6.2.1, Table 2 (row 1), Tables 3 and 4Limit set by the standard's table: check your rope in the calculator
Broken wires - single-layer and parallel-closed ropes. The allowable number of visible broken outer wires, counted over 6d and 30d, depends on the rope category (number of load-bearing outer wires), ordinary versus Lang lay, whether the section runs over steel sheaves or a single-layer drum versus a multi-layer drum, and the mechanism classification. Seale-strand constructions with few wires per strand are rated more strictly, and higher counts may apply for mechanisms known to be in the heavier classification groups. 6.2.4, Table 3Limit set by the standard's table: check your rope in the calculator
Broken wires - rotation-resistant ropes. The allowable number of visible broken outer wires, counted over 6d and 30d, depends on the rope category (number of outer strands and load-bearing outer wires) and whether the section runs over steel sheaves or a single-layer drum versus a multi-layer drum. Fewer visible breaks are allowed than for single-layer ropes because many breaks may be hidden inside. 6.2.5, Table 4; Annex F, F.1 a)Limit set by the standard's table: check your rope in the calculator
Broken wires - localized groups. Where breaks are grouped in one strand or two neighbouring strands on rope that does not spool on the drum, the rope may need to be retired even if the count is below the table limit over 6d. For breaks concentrated in one strand or repeating each lay, the competent person sets a limit lower than the tables. 6.2.1, Table 2 (row 2); Annex F, F.1 c)Limit set by the standard's table: check your rope in the calculator
Broken wires - valley breaks. A small number of valley breaks within one lay length signals discard, as set in Table 2. Annex F explains that two or more valley breaks in one lay length suggest the core is no longer fully supporting the outer strands. 6.2.1, Table 2 (row 3); Annex F, F.1 d)Limit set by the standard's table: check your rope in the calculator
Broken wires - at a termination. A small number of broken wires at an end fitting signals discard, as set in Table 2. If the rope is sound elsewhere, it may be shortened and the fitting remade, provided enough wraps remain on the drum at the crane's extreme operating position. 6.2.1, Table 2 (row 4); 4.7Limit set by the standard's table: check your rope in the calculator
MRT - broken wires (local fault). When MRT is used, a discard limit is set for loss of metallic area from broken wires over 6d and over 30d, for all constructions. If the MRT breaks can be confirmed visually as outer breaks, the visual broken-wire tables may be used instead. 6.3; Annex C, C.1, Table C.1Limit set by the standard's table: check your rope in the calculator
Uniform decrease in diameter. For rope on a single-layer drum or steel sheaves, the table sets the allowable uniform decrease in diameter from the reference diameter, as a percentage of nominal size, with separate limits for fibre-core single-layer rope, steel-core single-layer or parallel-closed rope, and rotation-resistant rope, plus intermediate severity steps. It does not apply at crossover zones. 6.4.1, Table 5Limit set by the standard's table: check your rope in the calculator
Local decrease in diameter. A clear local drop in diameter, for example from a failed core or rope centre or a sunken strand, means the rope must be retired. 6.4.3
Strand fracture. A completely broken strand means the rope must be retired immediately. 6.5
External corrosion. The table rates outside corrosion by condition, from light surface rust that wipes off, through wires rough to the touch, up to heavy pitting with slack wires, which is a discard condition. In-between conditions are rated for their contribution to the combined effect. 6.6, Table 6; Annex ILimit set by the standard's table: check your rope in the calculator
External corrosion - galvanized wire. Zinc-coated wires can feel rough when oxidized without being as serious as bare wires in the same state, so the inspector may give them a lower contribution to the combined effect. 6.6, Table 6, footnote cLimit set by the standard's table: check your rope in the calculator
Internal corrosion. The table treats clear visible internal corrosion, such as corrosion debris oozing from the valleys between outer strands, as a discard condition, unless the competent person finds internal examination practical. If there is any doubt about how serious it is, the rope should be retired. 6.6, Table 6, footnote eLimit set by the standard's table: check your rope in the calculator
Fretting corrosion. Fretting shows as a dry reddish powder from wires rubbing together without lubricant. It should be investigated further, and if there is doubt about its severity the rope should be retired. 6.6, Table 6Limit set by the standard's table: check your rope in the calculator
Dangerous condition. Any rope judged to be in a dangerous condition must be retired immediately. 6.7.1
Waviness - straight rope. On a straight length that never passes over a sheave or onto the drum, retire the rope if the gap under a straight edge to the rope helix reaches one third of nominal diameter or more. 6.7.2 a)
Waviness - running rope. On a length that passes over a sheave or spools onto the drum, retire the rope if that gap reaches one tenth of nominal diameter or more. 6.7.2 b)
Basket (birdcage) deformation. A basket or lantern deformation means immediate retirement, or removal of the affected section if the rest of the rope is serviceable. 6.7.3
Core or strand protrusion. Core or strand protrusion or distortion means immediate retirement, or removal of the affected section if the rest of the rope is serviceable. 6.7.4
Protruding wire loops. Wires standing out in loops, usually in groups on the side away from the sheave groove, mean immediate retirement. One core king wire poking out between the outer strands is not automatically grounds for retirement if it can be taken out or causes no interference with other rope elements. 6.7.5
Local increase in diameter. If diameter grows in service by 5 % or more on a steel-core rope, or 10 % or more on a fibre-core rope, find out why and consider retiring the rope. Swelling may come from a wet fibre core or trapped corrosion debris. 6.7.6; Annex F, F.4 e)
Flattening - over sheaves. Flattened lengths that run over a sheave tend to deteriorate fast and break wires; depending on how flat, retirement may be considered. 6.7.7
Flattening - static rigging. Flattened lengths in fixed rigging can corrode faster, especially if strands open and let water in. If kept in service they must be inspected more often; otherwise consider retiring the rope. 6.7.7
Kink or tightened loop. A kink or a loop pulled tight means immediate retirement. 6.7.8
Severe bend. A severe bend in a length that runs over a sheave means immediate retirement. A fold on the underside of the bend should be treated as severe whether or not that length runs over a sheave. 6.7.9
Minor bend. If a bend is not judged severe and the rope stays in service, it must be inspected more often; otherwise consider retiring it. 6.7.9
Heat damage. A rope not meant for high-temperature work that has been exposed to extreme heat, shown by heat colours on the wires or a clear loss of grease, must be retired immediately. 6.7.10
Electric arcing. If two or more wires are locally damaged by electric arcing, for example from a badly grounded welding lead, the rope must be retired. 6.7.10
Loss of elasticity. A rope can lose so much elasticity, usually because of its working environment, that it is no longer fit for use (informative annex). Annex F (informative), F.4 h)
Twin-rope hoists. On twin-rope hoisting systems both ropes often have to be replaced even when only one has reached discard, because a new rope differs in size and stretch from the old one and changes how rope pays off the drum. 5.4, NOTE
Terms used
Nominal diameter (d). The size the rope is sold and designated by. 3.1
Measured (actual) diameter (dm). The average of two diameter readings taken at right angles, each across the circle enclosing the rope. 3.2
Reference diameter (dref). The measured diameter of a non-bending length of rope taken just after the new rope is run in; it is the baseline for judging a uniform decrease in diameter. 3.3
Crossover zone. The part of the rope where one wrap crosses another on the drum, or where the rope climbs to the next layer at the drum flange. 3.4
Wrap. One turn of rope around a drum. 3.5
Reel. A flanged spool that rope is wound on for shipping or storage. 3.6
Periodic inspection. A detailed visual inspection with measurement and, where practical, a check of internal condition, which may include MRT. 3.7
Competent person. Someone with enough knowledge and experience of crane and hoist ropes to judge rope condition, decide if it can stay in service and set the longest interval between inspections. MRT must be done by someone competent in that discipline. 3.8
Valley wire break. A wire break at the contact point or valley between two outer strands; outer wire breaks anywhere between one valley and the next, including breaks in the strand core, may also be treated as valley breaks. 3.9, Figure 1
Crown wire break. Not formally defined; Annex F places crown breaks on the outer surfaces of the outer strands, typical of single-layer ropes over steel sheaves and often linked to outside wear. Annex F, F.1 a); Figure B.2
Severity rating. How far deterioration has progressed toward discard, as a percentage, for one type of damage or several combined. 3.10
Magnetic rope test (MRT). Non-destructive testing that measures magnetic flux leakage from a magnetized rope. 3.11
Base trace. The MRT signal recorded the first time a rope is tested, used as the baseline for later comparisons. 3.13
Local fault (LF). A short discontinuity in the rope such as a broken wire, welded wire, corrosion pit or nicking between strands. 3.14
Loss of metallic area (LMA). The change in steel cross-section as a percentage of the new rope's nominal metallic area, usually from corrosion, wear, abrasion or broken wires. 3.15
Rope category number (RCN). A category assigned to a rope construction (examples in Annex H) that selects the correct row of the broken-wire tables. 6.2.2; Annex H
Load-bearing wires / filler wires. For break counting, filler wires are not treated as load-bearing and are left out of the outer-wire total. Tables 3 and 4, footnote a
Deformation. Any visible change of the rope away from its proper shape, usually causing uneven, often local, stress. 6.7.1
Waviness. A deformation where the rope's centre line forms a helix, loaded or unloaded; it may not cut strength but causes abnormal stress, odd wear and early breaks. Annex F, F.4 a)
Basket / lantern deformation (birdcage). Deformation caused by a length difference between the core and the outer strands, for example from large fleet angles or sheave grooves that are too tight. Annex F, F.4 b)
Kink or tightened loop. Deformation from a loop pulled tight without letting the rope rotate, upsetting lay length; in severe cases little strength remains. 6.7.8, NOTE
Bend. An angular deformation of the rope caused by outside influences. 6.7.9, NOTE
Fretting corrosion. Internal rust formed when dry wires and strands rub and shed fine steel particles that oxidize into a dry red powder. 6.6, Table 6
This page summarises ISO 4309:2017 in our own words for general information. It is not
a copy of the standard, does not reproduce its tables and does not replace it. Clause numbers refer to
ISO 4309:2017, fifth edition (2017-11). The full standard is available from ISO. The rope or crane manufacturer's criteria take
precedence where they are stricter, and inspection and discard decisions remain those of your competent
or qualified person.
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All specifications must be verified before purchase and before installation. Rope specifications can change between machines of the same model and between model years. Confirm against your machine's logbook, reeving and the manufacturer's documentation before ordering. Inspection and discard decisions remain those of your competent person.