API RP 2D (7th edition) offshore crane wire rope inspection and removal criteria
What API RP 2D 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.
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Scope
Covers safe operation and maintenance of pedestal-mounted revolving cranes used offshore: on fixed or floating platforms, offshore support vessels, jackups, semi-submersibles and other mobile offshore drilling units. It is meant to be used alongside API 2C and API 2D-2. 1.1
It also addresses planning of lifts, plus pre-use checks and testing for temporary cranes erected offshore. 1.1
Typical uses include offshore oil exploration and production cranes mounted on fixed (bottom-supported) or floating platform structures, or on vessels used in drilling and production. 1.2 a)
Typical uses include shipboard cranes on surface vessels moving cargo and containers while in a harbour or sheltered water. 1.2 b)
Typical uses include crane vessels (ship-shaped, semi-submersible, barge or self-elevating) doing heavy or unusual lifts for construction, pipe lay, renewables, salvage and subsea work, in harbour or offshore. 1.2 c)
Exclusion: davits, launch frames and similar gear used only to launch lifeboats or liferafts are outside this standard. 1.3
Lifting devices outside the standard are expected to be run, inspected and maintained as their manufacturer recommends. 1.4
The inspection requirements apply to every crane, temporary installations included, and are stated as minimums. The owner sets the actual inspection scope using manufacturer and other relevant input. 5.1.3.1
Section 6 covers inspection, maintenance and replacement of wire rope and slings. In this standard 'rope' means wire rope unless stated otherwise. 6 (title); 3.1.60
Exclusion: Section 6 does not apply to the rigging (chains, shackles and the like) of anti-two-block equipment. That rigging must instead be covered by the periodic inspection program. 6.1.2
Wire rope is treated as a structural crane component that must be replaced periodically, since wear, abuse and other deterioration reduce its strength. Selection, inspection and maintenance follow Annex F. 6.2.1
Inspection frequency
Usage categories (basis for intervals). In-service cranes are placed in one of three usage (duty cycle) categories, assigned by the user crane by crane, based on actual hours in use. The category decides which inspections are needed. See Annex B. 5.1.2.1
Infrequent usage cranes. Cranes used 10 hours a month or less (averaged over a quarter) must be inspected before use and once a year. 5.1.2.2
Idle crane (infrequent usage). If an infrequent usage crane stands idle for three months or longer, it needs a monthly inspection plus a full function operation check. 5.1.2.2
Moderate usage cranes. Cranes used more than 10 but under 50 hours a month (averaged over a quarter) need pre-use, quarterly and annual inspections. 5.1.2.3
Heavy usage cranes. Cranes used 50 hours or more a month (averaged over a quarter) must have all four inspections: pre-use, monthly, quarterly and yearly. Hours need not be tracked for this category unless the owner says so. 5.1.2.4
Usage review. For infrequent and moderate cranes, the owner should periodically review actual usage to confirm the inspection intervals are still right. 5.1.2.2; 5.1.2.3
Default category. To class a crane as infrequent or moderate use, the owner must keep usage records separate from the pre-use log. An owner who does not record usage should treat the crane as heavy usage. B.2.1.1
Measuring usage. Usage can be tracked with a log of actual use or with devices such as drum counters or hour meters. Engine run time may be used but will overstate crane use. Tracking and documenting each crane's duty cycle should be the owner's responsibility. B.2.1.2
Change of usage category. When a crane moves up from infrequent usage to a higher category, a quarterly inspection should be done. The annual inspection should still be no more than twelve months after the previous one. B.3.1
Initial inspection. Required for new cranes entering service, cranes permanently relocated, and temporary cranes. Done by a qualified inspector and always includes a load test per 4.7 and Annex D. 5.1.3.2
Pre-use inspection. Done and documented before the first use of the crane each day, before or during each operator change, and again during long operations when the operator judges it necessary. Applies to every usage category. Done by a qualified crane operator; a qualified inspector may also do it. 5.1.3.3
Monthly inspection. Once a month, required only for heavy usage cranes. Either a qualified operator or a qualified inspector may do it. 5.1.3.4
Quarterly inspection. Once every three months for moderate and heavy usage cranes. Must be done by a qualified inspector. 5.1.3.5
Annual inspection. Every 12 months on all cranes regardless of usage category, by a qualified inspector. 5.1.3.6.1
Out of service over 12 months. A crane idle and out of service beyond 12 months should carry an OUT-OF-SERVICE sign on the main controls, and must get an annual inspection before returning to service. 5.1.3.6.2
Temporary cranes. Temporary cranes are inspected per B.3.5 and must be load tested per Annex D after every rig-up or relocation. 5.1.3.6.3
Summary matrix. Figure 3 is a matrix showing, for each usage category, which inspections are required and whether a qualified inspector or qualified operator does them. It summarises 5.1.2 and 5.1.3 (matrix not reproduced). 5.1.3.6.5; Figure 3
Wire rope at pre-use and monthly. A qualified crane operator should visually check the wire rope at each pre-use and monthly inspection. 6.2.2.2
Wire rope at quarterly and annual. Qualified inspectors should carry out the further rope inspection in F.2 at quarterly and annual inspections, as the pre-use and monthly findings warrant. 6.2.2.2
Quarterly, annual and rope change checks. At quarterly and annual inspections, and whenever ropes are changed, the areas that affect rope performance and life should be checked and corrected as needed (see F.2 and F.3). 6.2.2.4
Pre-use rope check content. The pre-use inspection includes a visual look at the wire rope for obvious deterioration, damage or wrong reeving, and special attention to rope condition, spooling and lubrication. B.3.2 h); 5.1.2.1
Quarterly rope check content. The quarterly inspection includes everything in the pre-use and monthly inspections, plus inspection of the wire rope per 6.1 and inspection of sheaves. B.3.4 g); B.3.4 c)
Annual inspection content. The annual inspection includes all pre-use, monthly and quarterly items plus other critical components and checks of weight indicator accuracy where applicable. B.3.5.1
After broken wires are found. Once broken wires start to show, inspect more often, because more breaks can be expected soon. F.4.2
New rope installation. Install and break in new rope as the manufacturer recommends. Take and record baseline dimensional measurements at installation and use them in later inspections. F.6.9; 6.2.1
Loose rope on drum. If rope is found loose on the drum, re-spool it under tension soon and inspect it visually while doing so. At every inspection other than pre-use, re-spool under tension where needed and practical. F.9 c)
Owner's rope policy. The crane owner must write and follow a policy covering how wire rope and slings are inspected, lubricated, maintained and replaced, including rejection criteria and a replacement schedule based on crane type, facility, usage, maintenance history and manufacturers' advice. 6.1.1
Who decides on replacement. The qualified crane operator or inspector deciding whether a rope needs replacing must know the rope inspection and maintenance requirements set by the manufacturer, the owner, or both. 6.1.1
Qualified inspector. A qualified crane inspector completes the classroom training set out in API 2D-2 and requalifies at least every four years, and may then carry out every inspection type (initial, pre-use, monthly, quarterly, annual). 8.3.2
Records: pre-use log. Keep a log of pre-use inspections, as set out in clauses A.1.3 and 4.1.5.16. 5.2.1
Records: inspection reports. Written reports of initial, monthly, quarterly and yearly inspections, dated and initialled, plus repair and modification records, should be kept on hand for four years, naming the person who inspected. 5.2.2
Records: wire rope. Rope inspection records must be kept to set the replacement interval, should stay available until that rope is replaced, and must list every rope deficiency found (per Annex F). 6.2.3.2
Records: rope life history. The owner's policy should document work done on each rope over its life, such as who did it, when, measurements taken, and the lubricant type, amount and application method. 6.1.2
Records: rope certificate. The rope manufacturer must supply a break test certificate for every wire rope, with testing per API 9A. 6.2.6
Pendant lines. Each pendant leg must be proof loaded by its maker to recognised industry standards, and the proof test certificate given to the owner. Each pendant should be tagged with maker, working load, certificate number, length, diameter and proof test date. 6.2.7.1-6.2.7.3
Inspection criteria
Diameter reduction. Check for rope diameter that has dropped below nominal or below the baseline measurements, caused by outer wire wear, lost core support, or corrosion inside or outside the rope. F.2 a)
Core failure in rotation-resistant rope. Core failure in rotation-resistant rope is hard to see. Check for it by measuring diameter (it shrinks as the core fails) and by measuring lay length (it grows when the core fails). F.2 a)
Diameter measurement example. A photo figure (captioned 'Measurement - Diameter') shows the same rotation-resistant rope measured under load with the core intact and with the core broken, illustrating the reduction in diameter that core failure causes. Figure on page 67 (number not visible; F.2 a) cites Figure F.3)
How to measure diameter. Figure F.6 shows the right and wrong way to caliper a rope: measure the full outer (circumscribed) diameter across opposite strands, not across the flats between strands. Figure F.6; F.4.2 g)
Broken wires. Count broken outer wires and note how closely they are grouped. Look especially for valley breaks, where wires break at the points where strands touch each other. F.2 b)
Wear. Look for worn outer wires. F.2 c)
End connections. Look for corroded or broken wires at terminations, and for end fittings that are corroded, cracked, bent, worn or wrongly fitted. F.2 d)
Mechanical damage. Look for kinks, crushing, cuts or strands coming apart. F.2 e)
Drum spooling. Look for poor spooling on the hoist drum: crushed strands, core poking out, abrasion, large gaps between strands, loose or uneven wraps, and high stranding. F.2 f)
Critical area: equalizer sheaves and saddles. Rope in contact with some crane parts wears and breaks wires faster and must be checked with care, including where it sits on equalizer sheaves, saddles (fixed guides) or other sheaves. F.2 g)
Critical area: terminations. Check sockets and other end fittings on running ropes as well as on pendants and other standing ropes. F.2 g)
Critical area: repeated sheave travel. Check rope lengths that keep running over sheaves in the hoist systems, especially where boom angle and block position change often over short distances. F.2 g)
Critical area: drum crossover and flange. Check the rope where it crosses over and where it meets the flanges on the hoist drums. F.2 g)
Inspection tools. Tools should include a steel tape, groove gauges for checking worn sheaves (used per API 9B), good calipers or micrometers accurate to 0.001 in. (0.025 mm) or better, and chalk. 6.2.2.3
Baseline measurements. Record the rope's dimensions when it is installed, keep them in the crane file, and compare against them at later inspections. 6.2.1
Rotation-resistant rope. Rotation-resistant rope has special properties and needs extra precautions; it is also more prone to kinks and twist damage when unreeled or uncoiled. 6.2.1; 6.2.4.3
Sheaves: groove. Use a groove gauge to check sheave grooves for wear and for corrugation (rope imprint in the groove). F.3 a)
Sheaves: flanges and hub. Check sheaves for broken or chipped flanges and cracked hubs. F.3 b), c)
Sheaves: rotation and bearings. Check that sheaves turn freely without drag, and check bearing wear with the bearing type in mind. F.3 d), e)
Sheaves: rope path. Check the sheave rope path for chips, cracks or other deterioration. F.3 f)
Sheaves at quarterly inspection. At quarterly inspections, sheaves should be checked for wear, cracks, rope path alignment and bearing condition. B.3.4 c)
Drum wraps. At least five full wraps should stay on the drum in every operating condition, taking the hoist maker's advice into account, especially for breakaway anchor-type hoists. 4.2.3.7
Lubrication. Keep rope well lubricated against corrosion and friction, with field lubricant compatible with the maker's original lubricant. Never use used oil. Accepted methods are pouring at a sheave while catching excess, swabbing a stationary rope, brushing or spraying, and pressure lubrication. 6.2.4.10; F.8
Wire rope clips. Clips must be drop-forged steel, single or double saddle; malleable cast iron clips are not allowed. The U-bolt must sit on the dead end with the live rope in the saddle, clips must be torqued evenly and re-torqued after the first load. Nuts should also be re-torqued periodically in service. Clip number, spacing and torque come from the clip maker. 6.2.4.8
Wedge sockets. Check socket and wedge are the right size for the rope (the wedge fits one size only), eye and pin are round and unworn, a pin keeper is fitted, there are no burrs, the live end is on the straight side, and the wedge is seated by gradual loading without shock. F.7 a)-e)
Wedge socket dead end. Figure F.8 shows the accepted ways to secure the dead end of a wedge socket and a table of minimum dead-end tail lengths that differs for standard 6 to 8 strand rope on boom suspensions and rotation-resistant rope on main and auxiliary hoists (values not reproduced). Figure F.8 (Dead end tail lengths table)
Terminations: who. Wedge socket fitting or other terminating of rope should be carried out or overseen by a qualified operator or a qualified inspector. 6.2.4.7
Reeving and spooling at installation. Run rope from reel top to drum top (or reel bottom to drum bottom) to avoid reverse bends and twist, keep back tension on the reel, spool the first layer with special care, and reeve for the actual crane configuration. F.6.1-F.6.4
Swivels. On multi-part hoists with rotation-resistant rope, no dead-end swivel is allowed unless both crane and rope makers recommend it. On single-part systems, fit a swivel at the dead end per the crane and/or rope maker. F.6.7; F.6.8
Operation affecting rope life. Avoid slack rope on the drum: keep slight tension in the boom hoist when at rest, and slow the drum before braking when moving an empty block or ball. F.9 a), b)
Removal (discard) criteria
Basis and limited use. The rejection criteria assume the rope is worked at maximum load. If any condition is found the rope should be replaced, but limited use may continue until replacement. That decision rests with a qualified operator or a qualified inspector. F.4.1
Broken wires: boom hoist running rope. Boom hoist running rope: reject at six broken wires scattered within one lay length, or three broken wires in a single strand within one lay length. F.4.2 a)
Broken wires: rotation-resistant hoist rope. Rotation-resistant running rope on main or auxiliary hoists: reject at four scattered broken wires within 30 rope diameters, or two broken wires in a single strand within six rope diameters. F.4.2 b)
Broken wires: standing rope. Standing ropes such as boom pendants: reject at 3 broken wires in a single lay length, or 2 broken wires at the termination. F.4.2 c)
Valley breaks. A single valley break may signal internal damage, so inspect that length closely. Retire the rope if any valley break (one or more) is present within a lay length. Valley breaks are worse than surface breaks. F.4.2 d); F.4.2
Distortion. Reject rope whose construction is distorted by kinks, crushing or similar damage. F.4.2 e)
Heat damage. Reject rope showing heat damage from any source, for example engine exhaust, flare towers, a seized sheave, rubbing on crane structure, badly grounded welding leads or lightning. F.4.2 f)
Diameter reduction: method. Diameter reduction is judged against the baseline: compare the non-working area (away from sheaves) with the smallest reading from three working areas (where rope regularly runs over a sheave). Reject when the loss exceeds the limit for the rope size. F.4.2 g)
Diameter reduction: up to 3/4 in.. Ropes up to and including 3/4 in. (19.1 mm): reject if the reduction is more than 1.2 mm (3/64 in., i.e. 0.047 in.). F.4.2 g)
Diameter reduction: 7/8 to 1 1/8 in.. Ropes 7/8 in. to 1 1/8 in. (22.2 to 28.6 mm): reject if the reduction is more than 1.6 mm (1/16 in., i.e. 0.062 in.). F.4.2 g)
Diameter reduction: 1 1/4 to 1 1/2 in.. Ropes 1 1/4 in. to 1 1/2 in. (31.8 to 38.1 mm): reject if the reduction is more than 3/32 in. F.4.2 g)
Diameter reduction: over 1 1/2 in.. Ropes larger than 1 1/2 in.: reject if diameter loss from the baseline measurement is more than 5 %. F.4.2 g)
Lay length increase. Reject when a rope lay is seen to have lengthened. Along with a reduction in diameter this can mean core failure, which happens more readily in rotation-resistant rope. F.4.2 h)
Pitting corrosion. Corrosion that pits the surface of individual wires means the rope must be replaced. F.4.2 i)
Remove and tag unfit rope. Rope unfit for cranes, slings or other load-carrying use must be taken out of service and marked as unfit. 6.2.3.3
Use of inspection findings. Rope conditions found at inspection should decide whether the rope stays in service or is retired. Rejection criteria are in F.4. 6.2.3.1; 6.2.3.4
Unsafe condition. If an inspection reveals an unsafe condition, the crane must be removed from service, or its use limited, until the hazard is eliminated. 5.3.3.1
Replacement: boom hoist rope. Replace boom hoist rope with rope matching the original in diameter, length, construction, grade and minimum breaking load (galvanized or bright), or as the crane maker or other qualified source advises. Do not use rotation-resistant rope for boom hoists. F.4.3 a)
Replacement: pendants and standing ropes. Replace pendants and standing ropes with rope matching the original diameter, length, construction, grade and minimum breaking load, or as the crane or rope maker advises. End fittings should match the original or follow the crane maker or other qualified source. F.4.3 b)
Replacement: load hoist rope. Replace load hoist rope with rope matching the original diameter, length, construction, grade and minimum breaking load, or as the crane maker or other qualified source advises. F.4.3 c)
Replacement: different rope type. If the new rope differs in type or grade from the original, all load charts should be reviewed and revised as needed by the original crane maker, an API 2C-licensed maker, an authorised surveyor, or a qualified engineer with crane rope experience, as the owner decides. F.4.3 d)
Terms used
Rope. In this standard, rope means wire rope unless stated otherwise. 3.1.60
Rotation-resistant rope. Wire rope with an inner layer of strands laid one way and an outer layer laid the opposite way, which counters torque and reduces the rope's tendency to spin. 3.1.61
Reeving. A rope system in which the rope passes around drums and sheaves. 3.1.57
Lay length (rope lay). The distance along the rope axis in which one strand makes a full turn around the core. Annex F text before Figure F.2 (sub-clause number not shown); Figure F.2
Valley break. A wire break at the points where strands contact each other; treated as more serious than surface breaks. F.2 b); F.4.2
Working / non-working area. A working area is where the rope regularly passes over a sheave; a non-working area is a section away from the sheaves, used as the comparison point for diameter reduction. F.4.2 g)
Running vs standing rope. The rejection criteria treat boom hoist and main/auxiliary hoist ropes as running ropes, and boom pendants as an example of standing ropes. F.4.2 a)-c)
Usage categories. Infrequent: 10 hours a month or less. Moderate: over 10 and under 50 hours a month. Heavy: 50 hours a month or more. All averaged over a quarter. 5.1.2.2-5.1.2.4
Qualified crane inspector. A person designated by the employer who has the experience and classroom training in crane and hoist maintenance and structural aspects set out in API 2D-2; authorised surveyors may inspect if they meet API 2D-2. 8.3.2
This page summarises API RP 2D 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
API RP 2D, 7th edition (2014) with Addendum 1 (October 2020). The full standard is available from API. 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.