guidance on the management of life cycle maintenance wire ropes

AB The International Marine Contractors Association

Guidance on the Management of Life Cycle Maintenance of Non-Man-Riding Wire Ropes Excluding Crane Ropes

www.imca-int.com

IMCA SEL 012 December 2004

AB

The International Marine Contractors Association (IMCA) is the international trade association representing offshore, marine and underwater engineering companies. IMCA promotes improvements in quality, health, safety, environmental and technical standards through the publication of information notes, codes of practice and by other appropriate means. Members are self-regulating through the adoption of IMCA guidelines as appropriate. They commit to act as responsible members by following relevant guidelines and being willing to be audited against compliance with them by their clients. There are two core committees that relate to all members:

Safety, Environment & Legislation Training, Certification & Personnel Competence

The Association is organised through four distinct divisions, each covering a specific area of members’ interests: Diving, Marine, Offshore Survey, Remote Systems & ROV. There are also four regional sections which facilitate work on issues affecting members in their local geographic area – Americas Deepwater, Asia-Pacific, Europe & Africa and Middle East & India.

IMCA SEL 012 This guidance was developed by a cross-industry workgroup with input from various relevant IMCA committees.

www.imca-int.com/sel

The information contained herein is given for guidance only and endeavours to reflect best industry practice. For the avoidance of doubt no legal liability shall attach to any guidance and/or recommendation and/or statement herein contained.

Guidance on the Management of Life Cycle Maintenance of Non-Man-Riding Wire Ropes

Excluding Crane Ropes

IMCA SEL 012 – December 2004

Contents

1 Definitions .............................................................................................................. 1

2 Introduction ........................................................................................................... 1

3 Purpose ................................................................................................................... 2

4 Scope....................................................................................................................... 2

5 Causes of Wire Rope Deterioration.................................................................... 3 5.1 Fatigue ................................................................................................................................................................. 3 5.2 Corrosion ........................................................................................................................................................... 4 5.3 Abrasion ............................................................................................................................................................. 4 5.4 Crushing............................................................................................................................................................... 5 5.5 Rotation ............................................................................................................................................................... 5 5.6 Cabling.................................................................................................................................................................. 5 5.7 Unlaying................................................................................................................................................................ 5 5.8 Vibration .............................................................................................................................................................. 5 5.9 Elongation............................................................................................................................................................ 5 5.10 Other Deformations and Damage ................................................................................................................. 6

6 Inspection and Testing .......................................................................................... 8 6.1 Overview............................................................................................................................................................. 8 6.2 Records................................................................................................................................................................ 8 6.3 Inspection ............................................................................................................................................................ 8 6.4 Damaged ropes .................................................................................................................................................. 8 6.5 Types of Non-Destructive Testing ................................................................................................................ 9 6.6 Inspection Relating to Storage and Transport of Wire Ropes................................................................. 9

7 Storage.................................................................................................................. 10

8 Transport.............................................................................................................. 11 8.1 General .............................................................................................................................................................. 11 8.2 Deployment to Work Site............................................................................................................................. 11

9 Maintenance ......................................................................................................... 13 9.1 Overview........................................................................................................................................................... 13 9.2 Lubrication ........................................................................................................................................................ 14 9.3 Maintenance Timetable................................................................................................................................... 14

10 Discard Criteria ................................................................................................... 15

11 Documentation/Records..................................................................................... 16

12 Notes..................................................................................................................... 17 12.1 Critical Ropes ................................................................................................................................................... 17 12.2 Discard Criteria ............................................................................................................................................... 17 12.3 Safety .................................................................................................................................................................. 17 12.4 Machinery .......................................................................................................................................................... 17 12.5 Lubricating Wire ropes .................................................................................................................................. 17 12.6 Cutting Wire Ropes........................................................................................................................................ 17 12.7 IMCA Safety Cards .......................................................................................................................................... 18 12.8 Memoranda for ordering wire ropes........................................................................................................... 18

13 Appendices ........................................................................................................... 20 13.1 Example Wire Rope Utilisation Matrix ....................................................................................................... 20

1 Definitions

A&R Abandonment and recovery

API American Petroleum Institute

BS British Standard

DNV Det Norske Veritas

IMCA International Marine Contractors Association

ISO International Organization for Standardization

IWRC Internal wire rope core

NDT Non-destructive testing

PMS Planned maintenance system

PPE Personal protective equipment

RHOL Right hand ordinary lay

ROV Remotely operated vehicle

SWL Safe working load

2 Introduction

This publication is focused on the inspection, testing, storage, transport, maintenance and general care of wire ropes other than those used on cranes and/or designated for man-riding equipment. These latter two groups of ropes are already covered by other industry guidance. IMCA publishes guidance in respect of crane wire ropes used in diving and ROV operations, such as that included in, for example, IMCA D 018, D 024, R 003 and R 004 Rev. 2. The wire ropes referred to in this guidance are typically those reeled on winches and used for moorings, towing and A&R wires and also lifting slings.

A workgroup formed from IMCA’s Marine Division Management Committee, Safety Environment & Legislation Core Committee and Training Certification & Personnel Competence Core Committee produced this guidance with the assistance from the industry including Bridon International, Pfeifer Drako Ltd, Casar and Kiswire Europe BV.

Wire ropes are used throughout the offshore industry in many ways, thus this guidance is generic. Each wire rope must be considered individually, depending on its specific operational requirements. The following text is not taken from legislation and is not mandatory. It is taken from company procedures and wire rope manufacturers’ guidance and compiled to form a useful reference to current best practice in the offshore industry. It is thus merely guidance on best practice intended to assist users in assessing or formulating their policies on the inspection, testing, storage, transport, maintenance and general care of wire ropes as designated above. A list of some relevant current standards at the time of publication follows below.

IMCA documentation is constantly subject to review and the secretariat would be interested in feedback from members regarding any improvements to the document, which can be e-mailed to [email protected]

Relevant standards and guidance at time of publication:

ISO 4309 Wire Rope for Lifting Appliances – Code of Practice for Examination and Discard

ISO 3578 Steel Wire Ropes – Standard designation.

ISO 2532 Steel Wire Ropes – vocabulary.

ISO 8792 Wire rope slings - safety criteria and inspection procedures for use

ISO 19901 – 7 Station keeping systems for offshore structures – in draft at time of publication

API RP 2I American Petroleum Institute Recommended Practice for in service inspection of Mooring hardware for Floating Drilling Units (2nd Edition 1996)

API RP 9B American Petroleum Institute Recommended Practice for Application, Care and Use of Wire rope for Oilfield Services

API 9A American Petroleum Institute Specification for wire rope [to become API 9A-ISO 10 425]

IMCA SEL 012 1

mailto:[email protected]

BS 6570 British Standard Code of Practice for the Selection, care and maintenance of Steel Wire Ropes

BS 302 Wire Ropes for Cranes, Excavators and General Engineering purposes.

BS 462 Specification for Wire Ropes Grips

BS 461 Bordeaux Grips

BS 463 Sockets for Wire Ropes

BS 464 Thimbles for Wire Ropes

EN 13414-1 Steel Wire Rope Slings Safety Part 1: Slings for general lifting services. 2003.

EN 13414-2 Steel Wire Rope Slings Safety Part 2: Specification for information for use and maintenance to be provided by the manufacturer. 2003.

EN 13414-3 Steel Wire Rope Slings Safety Part 3: Grommets and cable laid slings

BS 5281 Ferrule secured eye termination for wire ropes

DNV 1994 Rules for Certification of Lifting Appliances.

IMCA D 018 Code of Practice on the Initial and Periodic Examination, Testing and Certification of Diving Plant and Equipment.

This list is not expected to be all inclusive and there may be additional local legislation, guidance, standards and also client requirements to consider, depending on flag state of the vessels involved, other jurisdictional issues and the location of the operation.

3 Purpose

The purpose of this guidance is to provide an overview of best practice in the care of wire rope, as described in the introduction to this document, which would be useful around the world. Although the guidance is focused on a relatively small area of wire rope usage, a number of points relate to the care of wire rope generally.

4 Scope

To provide a comprehensive guide, suggest an overview and detail requirements for the inspection, testing, storage, transport, maintenance and general care of wire ropes other than those used on cranes and/or designated for man-riding equipment; that is, wires reeled on winches for use, for example, in A&R, mooring and towing and in lifting slings. The guidance does not apply to taut wire ropes used in navigational positioning systems or to slings below 60mm diameter; some relevant guidance on such slings can be found in EN 13414–3.

IMCA SEL 012 2

5 Causes of Wire Rope Deterioration

The main causes of deterioration of a rope in service are fatigue, corrosion, abrasion and mechanical damage. One or more of the effects of these causes may be present, depending on the service that the rope is put to; and all must be taken into consideration when selecting a wire rope for a particular application. Incorrect reeling of a wire rope onto a drum can also cause serious damage (see under 8.2 for deployment of wire rope to a drum), as can badly aligned or inappropriate sheaves.

5.1 Fatigue

Fatigue in a wire rope is normally caused by repeated bending of ropes under tensile loading, for example when ropes operate over sheaves and rollers and around drums. Shock loading is likely to affect the rope at these points. If a wire rope moves through sheaves at high speeds it is likely to wear correspondingly quicker.

Imag

e co

urte

sy o

f Bri

don

Inte

rnat

iona

l

Wire construction that resists bending fatigue will have a large number of small wires, for example 6/36 as opposed to 6/19.

Given correctly operating and properly rigged equipment in good condition, the main factors affecting fatigue are, therefore:

♦

♦

♦

♦

♦

the load on the rope;

the number of operating cycles.

the ratio of sheave and drum diameters to rope diameters;

fleet angles;

rope flexibility;

The difficulty of recording the operating cycles of a wire rope is usually exacerbated by the type of use. Ideally all wire ropes should be monitored for working loads and number of operating cycles, with the information recorded in the maintenance history of the wire rope, but that might be very difficult to achieve in all cases, as for example with some mooring wires.

In the case of heavy subsea utilisation, wires are normally cut back, or subject to cut out sections and/or de-rating/change of use, to eliminate the section most subjected to fatigue. Cutting techniques need to be safe and appropriate for the particular wire rope and relevant manufacturer’s information should be available. The cut back sample can then be subjected to test, by destructive testing and close examination. If the results of the test are acceptable, the wire could be re-terminated and tested in accordance with applicable standards. The procedures used in destructive testing should be rigorously checked, to help prevent variations in results. This should include the following stages:

Assessment of the rope test house to ensure that they have a certified and suitable test bed with suitably experienced engineers;

Proper preparation of the sample at the work site;

Appropriate packaging and transportation (see 6.6);

Proper preparation at the test house for the destruction test.

Companies’ discard criteria for ropes used in different applications and the requirements of local regulations will establish when a wire rope would be discarded after a prescribed time.

Manufacturers’ guidance should be sought as to the expected life of their products, but such guidance needs to relate to the actual usage of the wire rope. See 12.8 regarding points to consider when ordering a new wire rope, which will help manufacturers to estimate wire rope life expectancy.

IMCA SEL 012 3

5.2 Corrosion

Corrosion, often in combination with fatigue, is a main cause of wire rope deterioration and failure in service. Even in very dry conditions there is always some corrosion of unprotected steel wires.

In some respects, requirements for corrosion resistance and fatigue are opposed. For the former, a small number of large wires are an advantage, whereas for the latter a large number of small wires are to be preferred.

Choice of construction, for example in the number of strands and/or their lay is, therefore, nearly always a compromise.

To inhibit the onset of corrosion, ropes need to be properly lubricated in manufacture and afterwards as necessary and given frequent applications of suitable dressings during their working life. In the marine environment there is always a risk of severe corrosion and galvanised wire ropes are often used. Clearly, subsea and tow wires are highly prone to corrosion. There is a serious risk of internal corrosion in wire ropes of compact construction, where lubrication may not be penetrating to the centre, especially when such ropes are used sub sea. Careful monitoring and suitable discard policies help to avoid the possibility of failure.

Imag

e co

urte

sy o

f Bri

don

Inte

rnat

iona

l

5.3 Abrasion

Abrasion occurs primarily in the outer wires. Ropes pulled across or through abrasives like sand or stone will clearly wear more quickly. Ropes with fewer, but larger outer wires give a longer working life under abrasive conditions than those with many smaller outer wires.

Images courtesy of Bridon International

Ropes with long exposed lay lengths of outer wires are also an advantage under abrasive conditions.

Severe wear in Langs lay, caused by abrasion

It is of note that over 50% of the strength of a rope may be in the outer wires.

The requirements for abrasion resistance in a wire rope are almost opposite to those for fatigue resistance. For six-strand equal laid ropes, as the number of outer wires increases, the resistance to abrasion decreases.

5.4 Martensite

A useful description of martensite is given by the Wire Rope Corporation of America: ‘Martensite is a hard, non-ductile phase of steel formed when the outside wire surface is heated above its critical temperature, followed by rapid cooling by the adjacent ‘cold’ metal within the wire and the rope structure. As the affected area continues to bend, it will crack very easily, quickly spreading through the wire rope and eventually leading to complete rope breaks.’

Imag

e co

urte

sy o

f Bri

don

Inte

rnat

iona

l

It can develop in circumstances such as:

when a rope reverses direction over a sheave that is still spinning in the opposite direction (heavy lubrication in the throat of the sheave might assist); or

if a rope continually slaps against a solid stationary surface; or

when a rope runs through an undersized sheave; or

if a rope is continually pulled through the heap of stone/gravel in front of a drag bucket, such as in a self discharging gravel dredger. or when pulling equipment along the sea bed.

IMCA SEL 012 4

5.5 Crushing

Where crushing is expected to be a main cause of deterioration, equal lay ropes with relatively few wires and having steel cores are to be preferred. Equal lay means that all the wires have the same length of lay, such that the wires do not cross over each other but lay in between the wires of the next interior layer. This avoids layers of wire being crushed across each other. Ropes that resist crushing are those with compacted equal lay construction, with solid steel cores, or triangular strand ropes having steel cores.

Inappropriate sheave sizes and condition can cause crushing.

Two parallel paths of broken wires, indicative of bending through an undersize groove in the sheave

Drum groove type and condition can affect how a rope turns on to a drum and can result in crushing damage, for example as the rope turns onto the next layer.

If correct back tension is not achieved when coiling a rope onto a drum, (see 8.2), severe crushing

A rope that ‘cuts in’ to a lower layer on a drum due to bad spooling can jam and if the drum continues

5.6 Rotation

Rotation is a factor which can affect the efficient operation of a rope and in some circumstances can

5.7 Cabling

Can occur when ropes with high rotation characteristics are used between blocks that are free to

5.8 Unlaying

Can occur if ropes of different types and lay are joined in series. Unlaying could lead to catastrophic

5.9 Vibration

Vibration can cause deterioration. Wire fractures can occur which might not be visible from outside

5.10 Elongation

Elongation occurs for a number of reasons:

g in) – occurs on new rope;

♦

♦

♦ ge - recoverable;

♦

Image courtesy of Bridon International

damage can be caused to underlying layers when the rope comes under heavy load.

to rotate the shock loading can severely damage or even break the rope and can cause significant problems with the load itself.

cause premature deterioration. All ropes are liable to some degree of rotation in service, but experience has shown that some ropes are not suitable where one end is free to rotate. Liaison with the manufacturer to ensure the correct selection of rope helps to avoid this (see 12.8).

rotate. Care needs to be taken in block and swivel connections as incorrect application can lead to premature failure. Their use needs to be taken into consideration when establishing discard criteria.

failure.

the rope. Also vibration of a wire against another object over a period of time can cause damage, therefore in-service inspection should take this into account, as it may be necessary to adjust discard criteria.

♦ settlement of its components (beddin

elastic stretch due to tension in the rope - recoverable;

inter-wire wear;

temperature chan

rope rotation;

IMCA SEL 012 5

♦

♦ sed change of lay length can indicate deformation of a wire due to overload.

5.11 Other Deformations and Damage

ondition whereby the outer part of the rope is stretched out

♦ mproperly sized sheaves, or

♦ rope cannot rotate around its axis to release torque.

♦ wires on the inside

♦ y bad drum spooling or by being dragged over a sharp

splice slippage;

overload – locali

♦ ‘Bird caging’ of the wire, is the cwhen the inner parts are not, causing a deformation known as bird caging. This can be caused by excessive rotation, shock loading, incorrect use of a swivel (see sketches below), inappropriate sheaves or heavy loading on a new rope before its strands have settled into position. Other stress or damage can have a significant affect on a wire rope’s strength. Shock loading and torsional imbalance can cause characteristic loops in the wires. Other damage could include core popping, weld splatters and exposure to strong heat; funnel eexample. Paint splashes or spills on wire can prevent lubrication.

Distortion due to high pressure against a sheave or against i

xhaust o

Image courtesy of Bridon International

r chemical fumes for

grooves on a drum.

Kinks caused when a

Flattening caused when a rope is bent severely over a sharp edge when theof the bend are forced out of position.

Misplaced outer wires can be caused bedge.

Imag

es c

ourt

esy

of B

rido

n In

tern

atio

nal

Severed by wear Plastic wear Severed by tension Sheared end

Mechanical damage due to rope movement over sharp edge projection

Narrow path of wear, resulting in fatigue fractures, caused by working in

Severe wear, associated with high tread pressure

whilst under load

a grossly oversized groove or over-small support rollers

Severe corrosion Internal corrosion whilst external surface shows little evidence of deterioration

Typical wire fractures as a result of bend fatigue

IMCA SEL 012 6

Wire fractures at the strand, or core

ct from ‘crown’ features

Break-up of IWRC, resulting from high Looped wires as a result of torsional interface, as distin stress application imbalance and/or shock loading

Substantial wear and severe interTypical example of localised wear deformati

and on

centre resulting from build-up of turn (‘core popping’)

nal corrosion

rotation.

Protrusion of rope

The twistsrope length.

sprea

d along the available

Sketch to show an example of the possible result of using a swive

the first sheave.

The swivel releases the twists outside of the sheave system. The twists that remain in the g the available r ift can increase the twists remaining inside the system.

l with a rope that is not resistant to

The rope twists as it takes the load and the twists are brought over the first sheave in the system.

Part of the rope is run back out over

system spread alonope length. Each l

Imag

es c

ourt

esy

of B

rido

n In

tern

atio

nal

IMCA SEL 012 7

6 Inspection and Testing

6.1 Overview

Inspections can be carried out at the beginning of each work period and at intermediate periods identified in the vessel’s planned maintenance system (PMS). The definition of when a work period starts depends upon a company’s own assessment of its particular operational activities. Inspections would include, but not necessarily be limited to:

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

statutory requirements;

type of appliance and/or design of the system;

operational environmental conditions;

method and frequency of operation;

manufacturer’s recommendations;

results of previous inspections and examinations;

experience with previous ropes on the appliance or system;

analysis of usage history.

6.2 Records

Adequate records of inspections, tests, lubrication and usage are helpful additions to the formal certification and a useful guide to the quality of the rope.

6.3 Inspection, Examination and Testing

Inspection, examination and testing could include, but not necessarily be limited to:

external visual inspection of the complete rope length against a set of discard criteria;

investigation as to the causes of broken wires or other visual damage (e.g. as in 5.11);

system load and/or overload testing as appropriate ensuring that a suitable calibrated load cell is used;

cut-back and re-termination;

NDT;

destruction testing;

The frequency of inspection, examination and testing should comply with local legislation and company policy.

The length, diameter of and access to a wire rope in the system in which it is rigged will need to be considered in respect of the time and facilities required for inspection.

Each particular work site is different. An A&R winch drum could be laden with 600 or perhaps 3,600 metres of wire rope; if there is a large amount of rope on a reel, is there a convenient place that is large enough to run it to in order to allow inspection?

On some occasions it may be possible to lower some of the rope into water; is the depth sufficient, is it a practical area to do that? Would the weight of the rope be manageable?

Equipment required might for example include use of a diesel powered, deck mounted spooler or another vessel such as a work boat with suitable equipment on board.

A vessel could have a complex system for ropes to be reeved through, which might mean that proper inspection requires access to difficult or restrictive areas.

IMCA SEL 012 8

High importance should be given to considering what it means in practice to actually inspect and maintain the wire rope in use at each work site in terms of time and equipment required, which in turn relies on the accessibility of the rope and the work areas available. It can prove beneficial to keep a record of the methods used for rope inspection, if only to assist new personnel in understanding what is required and assist in the development of appropriate practices at work sites.

6.4 Damaged Ropes

Inspection should be increased after the first broken wires or other damage is noticed, or when subjected to overload or other harm suspected. Company policy should set out the procedures for the competent person (see 12.8) inspecting a damaged wire rope, if there is any doubt about its safe operation. For example, the rope should not be used until it has undergone further examination and tests and has been declared fit for further service.

An inspection is usually carried out immediately after any incident involving the use of a wire rope in which there could have been damage to a rope, or a vessel, or an installation.

6.5 Types of Non-Destructive Testing

With smaller wire ropes it is possible, with the use of specialist tools, to open up the strands to inspect the interior strands and core. As it is not always practical or possible to open up a wire rope, such examination is sometimes complemented or substituted by using electro-magnetic or other non destructive testing equipment, to detect broken wires and loss of cross sectional area. Equipment is available which can scan wire ropes at the same speed as a pressure lubricator operates, thus it might, in some situations, be convenient to carry out both tasks during one spooling operation.

With sheathed ropes inspection can be very much more difficult, apart from visual inspection of the sheath. Ropes that are sheathed in this way could be heavy mooring ropes and there might be difficulty in obtaining NDT equipment suitable for inspection.

An initial NDT signature print out may be requested at time of purchase for later comparison to aid with a discard decision.

6.6 Inspection Relating to Storage and Transport of Wire Ropes

Company procedures can set out a system whereby the information obtained by the inspection process is protected throughout a rope’s quarantine in storage. Points to consider include, but are not necessarily limited to the following:

♦

♦

♦

♦

♦

making records of inspection on storage, which also cover the rope’s history of usage at that time;

recording whatever subsequent inspections that are practical and necessary during storage, or prior to redeployment;

establishing a method of securing a document trail to the rope, so that documentation such as certificates, proof tests, damage reports, information as to the rope’s use and areas of wear (for example which end had been immersed at depth, or loaded repeatedly over sheaves) would be easily available. This would ease personnel’s assessment of which ropes were suitable for deployment in various situations; and ease that deployment on board a vessel;

establishing a method of identifying a wire rope by correlating it with its documentation, such as by use of a fibre identifying tape laid into the rope during manufacture; a metal tag, on the rope or in its termination socket, or by painting a colour coding on the rope;

the method of marking the wire rope could also indicate if one end has been subject to wear/immersion etc., as described above.

IMCA SEL 012 9

7 Storage

Ideal storage requires the following:

clean, dry, well ventilated, covered areas;

away from high temperatures or any effects of chemical fumes, steam or other corrosives;

if open storage is inevitable, a waterproof covering should be arranged, using a breathable fabric to avoid condensation problems;

if stored on a reel for a long period, it is beneficial to rotate the reel periodically to prevent lubricant seeping out of the rope, especially in warm environments;

the wire rope should be stored clear of the ground or deck, on a timber grating that allows air to pass beneath;

manufacturers should supply details of suitable protective dressings that are available for storage purposes, that would be compatible with the lubricant used;

periodic inspections should be made.

usage on a first come first out basis.

IMCA SEL 012 10

8 Transport

8.1 General

♦

♦

♦

♦

♦

♦

♦

♦

♦

Ideally in the same conditions as those recommended for storage.

Care is needed to compensate for the expected environmental changes en route and to prevent physical damage to the rope.

8.2 Deployment to Work Site

On deployment to a vessel or other work site, the documentation accompanying the rope, as specified in 6.6, will provide helpful information as to the expected quality of the rope and whether it is correctly certified and appropriate for the required task;

If the rope is to be taken from the storage reel and stowed on its working drum, correct working procedures are necessary to ensure that the rope is not damaged in the process;

For example, if moving a reel of wire rope with a fork lift, avoid contact with the rope by using a shaft through the axis of the reel, or use a wide textile webbing sling, or if the fork is longer than the width of the reel, lifting it on the reel’s flanges; or if a rope is being unwound onto a deck ensure that the deck is clean so that the rope does not pick up grit;

Examine the working drum for wear and damage; if it is a grooved drum, the groove size and condition can be checked as being appropriate for the rope size and suitable for use. Ideally, the groove contour will support about one third of the rope’s circumference;

All sheaves and rollers that the rope will utilise should also be inspected to ensure good condition, correct operation of moving parts such as swivels and ease of rotation of sheaves and rollers;

Depending on the size and weight of rope, different methods will be used to rig or load the rope into its system. A suitably competent person (see 12. 8) would supervise the operation in accordance with company procedures. Safety is paramount with all wire rope operations (see 12.3). For example, rope ends released from storage reels can move suddenly and violently. Wire ropes secured to reels or shackled to equipment can have twists and retained torque in them which are not apparent until the rope is released;

If the rope needs to be reeved through a system whereby it is necessary to pull the rope through with the use of another rope, some of the points that need to be kept in mind include: Sometimes the only practical way might be to use the old rope to pull the new rope on.

This has a number of disadvantages however. The old rope will probably induce torsional twist into the new rope and if this happens, the new rope will need to be flagged or marked so that any turn inadvertently induced is taken out before it is secured to the drum;

The connection between the two ropes must be safe. It must be able to withstand turning through the sheaves and bending around any rollers or negotiating any other directional changes, and sufficiently shaped to pass through all the throats and other possible choke points in the system. Butt welding the ends of the wire ropes is unlikely to be adequate, although it might be sufficient as part of a connection where a very simple installation is possible;

The messenger rope should not be allowed to rotate. Rotation resistant rope or three strand fibre ropes may be appropriate;

When using conventional wire ropes ensure that they have the same direction of lay as the new rope;

Wire rope socks or ‘Chinese fingers’ can be used to connect the two ropes. The socks need to be securely attached to the rope by a serving or a clip. If used on a Langs lay rope, care needs to be taken that the Chinese finger does not unwind like a nut from a bolt – wrapping that part of the rope with tape could help avoid that. The two socks can be connected by a length of rope of adequate strength. This should avoid turns being induced in the new wire rope. A swivel connection is not advisable because it can cause a new rope to unwind as it is reeved;

IMCA SEL 012 11

Wire rope ends may have pad eyes or chain links welded on, or there might be a similar fitting already on the rope end. If there is such a fitting and it is known to be safe, then suitable strength fibre ropes, or thin wire ropes, or wire rope strands could be used to connect the two. The twists that are induced in these ropes or strands during the operation will indicate the intensity of torque in the old rope.

♦

♦

♦

♦

The reel from which the rope is pulled should rotate (under control - see next bullet point) to avoid kinking and subsequent severe damage to the rope, jeopardising its operational use;

When wire ropes are being loaded onto their working drum, back tension should be applied to maintain uniform reeling onto the drum. Manufacturer’s guidelines will usually indicate how much back tension should be applied. The required tension is often given as a percentage of the minimum breaking force of the rope, for example Bridon suggest a general guide for installation tension of between 2% and 10% of the minimum breaking force of the rope whereas another supplier suggests 1% to 2%. Although a wide range of tensions might be advised, a practical application is to roll the rope on as tight as possible over and above the manufacturer’s minimum;

The method of achieving the required back tension must relate to the application and the system concerned. For instance with a small, easily managed wire rope such as could be manhandled around the deck, it could be possible to apply tension to a secured reel with a simple lever used as a brake against the emptying reel flanges (not against the rope as this could deform the rope beyond repair) a risk application should be made, the safest solution being a piece of equipment made and risk assessed for the job; but with heavy ropes or those being reeved into a system, more sophisticated methods of applying the back tension are required utilising appropriate equipment, for example a diesel powered, deck mounted spooler;

Imag

es c

ourt

esy

of B

rido

n In

tern

atio

nal The rope should travel from top of reel to top of

drum, or from under reel to under drum to avoid reverse bending and putting a twist in the rope. Correct reeling of a wire rope onto a drum is important. Loose or unevenly wound wire will be subject to crushing and distortion. The correct direction of coiling (from left or right side depending on the lay of the rope and whether under or over the barrel) will assist the rope to wind on evenly. Manufacturer’s guidelines will usually give advice on the fleet angles required;

♦

♦

♦

♦

The rope should be loaded onto the drum in even layers. Its condition can be constantly checked as it is loaded, which is of especial importance if it is a previously used rope. Lubrication and non destructive testing might be possible at this time;

Extra care needs to taken in the handling of heavy sheathed ropes, due to difficulties of gripping the sheathing when the rope might be slipping inside it;

After the rope is installed, it is advisable to run through its cycle under light loads several times, to help component parts to settle in and adjust themselves to the actual operating conditions before subjecting the system to any overload tests prior to actual operation; this will help to avoid damage to the rope which might otherwise occur on its first heavy test loading. If ‘light’ loading is difficult to define, manufacturers may be able to advise as a percentage of s.w.l.;

During the first few operational weeks after installation, inspection is advisable on each day of operations.

IMCA SEL 012 12

9 Maintenance

9.1 Overview

Good practice would require that the maintenance of the wire rope is specific to the particular operation, its use, its environment and the type of rope involved. The manufacturer should provide a rope that is lubricated properly for its expected use. Unless otherwise indicated by the manufacturer, a good maintenance regime would ensure that the wire rope is cleaned, lubricated and covered with an appropriate service dressing, particularly on those lengths which pass through and around sheaves and/or are used subsea. It would be essential to check that any cleaning fluid, lubrication and service dressing are compatible with the original lubricant used by the wire rope manufacturer. Manufacturers would also be able to advise whether pressure lubrication is suitable for a specific wire, or if not what method of lubrication and lubricant is recommended. Pressure lubrication needs to be carried out with care by operators trained in using the equipment (see also 12.5).

Lubrication is be more effective on a clean rope, and cleaning will usually help remove corrosion; but cleaning wire ropes effectively is sometimes difficult, not just because of the arduous nature of the task, but because there are possibilities of damaging the rope or its lubricant.

Maintenance can also include removing broken wire ends. It is essential to note the condition of the rope in the vicinity of a wire break, as more than one break within a short distance could indicate a more serious problem. As a wire rope ages, broken wires can start to appear, usually as a result of constant fatigue. These can be broken off to prevent them damaging the rest of the rope and indeed to prevent injury to handlers. It is usually best to bend them from side to side with pliers (not cutting through the wire) until they break off within the lay of the strands of the rope. Appropriate PPE should be used. When wires are broken off in this way, a record should be kept of their location on the rope. In this way, if wires continue to break in the same area it will indicate a potential danger in the rope’s use. Investigation can then be made as to the causes of broken wires.

Rope attachment points are particularly prone to deterioration. Provided there is spare rope within the system, and the remainder of the rope is sound, it may be possible to cut back the affected end of the rope and re-terminate. In some applications it may be viable to reverse the rope end for end, but this will depend on its particular operational use and company procedures. Both methods could shift the areas of wear to unworn parts of the rope and possibly increase the service life of the rope.

This guidance does not deal with maintenance of sheaves, swivels, rollers and other components of the rope system, but clearly their maintenance will affect the rope’s safety and service life (see also 12.4).

If wire ropes are removed from drums for maintenance purposes it is important to rewind them correctly (see 8.2 above).

Maintenance is also affected to an extent by the practical and physical aspects of handling the wire rope, access to the wire rope and the system into which it is rigged. Other relevant factors include but are not limited to the following:

Periodical cleaning of wire ropes can be very helpful to combat corrosion, make lubrication more beneficial and to assist when examining a rope. The effects of using steam or high pressure water jet should be considered in relation to what such cleaning might do to the lubricant in the rope. Wire brush equipment and air blast systems can perhaps be used and it is necessary for each operator to decide what is properly appropriate.

The length and diameter will affect the time required to carry out the maintenance, as will availability of access to all parts of the wire rope from suitable working areas.

The environmental conditions that the wire rope is working in will also be a consideration when deciding the frequency of maintenance operations.

The operating cycle and frequency of use.

Which areas of the wire rope will remain exposed to the elements when the rope is not in use.

Which parts of the rope may be subject to wear from the system that it is reeved through or even from gradual impact damage because of motion of the vessel.

IMCA SEL 012 13

It would be useful if all of these factors could be considered at the design stage of a vessel, or at the planning stage of a new project.

9.2 Lubrication

Good lubrication extends the life of the wire rope. The manufacturer should provide a rope that is lubricated properly for its expected use. This is only likely to last for a limited time in practice, depending entirely on the use and environment that the rope is subjected to and exists in. Maintenance should ensure continued lubrication as required and when pressure lubrication is not practicable other methods should be used, such as spreading or brushing penetrating lubricant in accordance with manufacturer’s recommendations. Correct PPE should be used (see 12.5). Lubrication may not always be achieving the optimum result and it can be difficult to ascertain whether it is. Examination of cut back sections will assist in this. A regular, timely or planned discard policy should help ensure that a system does not fail, and a practical balance needs to be achieved.

9.3 Maintenance Timetable

Wire rope maintenance is usually carried out periodically under a vessel’s planned maintenance system (PMS), taking into account the usage of the rope and the environment that it is working in. While this guidance is not directly concerned with the PMS, it is unlikely that a wire rope system would be subject to appropriate inspection, maintenance and tests unless an adequate PMS existed. An example of a possible utilisation matrix is given at Appendix 1.

The different ways in which identical wires are used in the industry has resulted in guidance from manufacturers being only generic. It would be prudent for the relevant competent person (see 12.8) in a company to identify and carefully assess the particular usage, revert to the manufacturer and check how that usage will affect the manufacturer’s recommendations and the wire rope’s anticipated working life.

IMCA SEL 012 14

10 Discard Criteria

Companies establish their own criteria for the discard of ropes. Examination of differing operational environments and types of rope use can highlight the results of different stresses and wear placed on ropes. Life expectancy of a rope can vary significantly dependant on its use so that each user needs to apply specific discard criteria.

Suggested criteria for discard are destruct/NDT test failures, but visual inspection would take priority over incremental service life. The condition of the rope when discard is thought necessary is as presently described in ISO 4309, 1990. The following examination results are examples which could lead to discard:

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

nature and number of broken wires;

broken wires at the termination;

localised grouping of wire breaks;

rate of increase of wire breaks;

fracture of strands;

reduction of rope diameter, resulting from core or external deterioration;

decrease in elasticity;

external and internal wear;

external and internal corrosion;

deformation;

damage due to heat or electric arcing;

rate of increase of permanent elongation;

decision based on usage history/loadings;

reduction in tensile strength;

exceeding defined life cycles (see 12.2);

After a prescribed number of years service (see 12.2);

Unusual features - for example rope giving out red dust; local reduction in diameter.

How much of the above list can be dealt with by the personnel on site and how much by contracted specialist laboratory services is to a large extent dependent on each company’s personnel and facilities.

Removing old wire ropes from drums can be dangerous. They can move violently and suddenly as they unwind from a reel and also when they are disconnected. Personnel removing old wire ropes from systems must also be alert to the possibility of broken wires which have potential to cause injury.

IMCA SEL 012 15

11 Documentation/Records

It is important for each wire rope to have its own identification and a method of linking the rope to its documentation (see 6.6). It would be helpful if a data sheet with all periodic maintenance, examination and test results recorded could be accessed by personnel as required.

Wire rope records should be entered in whatever form of PMS is in place and the records kept up to date.

Critical (see 12.1) wire ropes usage history can be recorded in the PMS.

Certificates of original examinations, inspections, load test certificates and destruct tests can be retained in the equipment file.

Copies of in-date certificates could accompany the wire rope in its movements to and from work sites and be available when requested. Copies of various documents could be electronic or on paper.

IMCA SEL 012 16

12 Notes

12.1 Critical Ropes

Companies can identify which ropes are considered critical, that is which require the most attention in terms of inspection and maintenance.

12.2 Discard Criteria

Discard criteria might be based on the number of cycles that a wire rope performs, or a period of time, or because of some particular tangible factor detected on inspection, or at re-termination; such as the point at which a wire’s protective galvanised coating starts to show signs of wear, or where other signs of wear are considered critical.

12.3 Safety

Working with wire rope is fraught with safety issues. Primarily there is always a risk of a wire failing in service. But there is a wide range of injuries that can result from working with wire ropes, ranging from cuts by broken strands, to death from, for example, breaking or violently moving ropes, being caught in bights, or by being dragged into reels. This guidance does not specifically deal with safety issues, other than those limited to wire rope lubrication listed at 12.5 and those relating to cutting ropes at 12.6, but companies need to adhere to stringent, effective safety procedures when dealing with wire rope maintenance and such procedures should be paramount when creating wire rope maintenance policies. Most work with large wire ropes requires task plans and risk assessments that should be produced well in advance of the work.

12.4 Machinery

This guidance does not cover aspects of the maintenance of winch machinery, control systems or any other mechanical equipment or plant. These could have a significant place in respect of the maintenance of wire ropes, but would be likely to be covered by a company’s PMS.

12.5 Lubricating Wire ropes

Precautions for personnel involved in lubricating wire ropes include but are not limited to:

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

Various ingredients used in rope lubricants are categorised as hazardous, although in normal usage reasonable care should be sufficient to prevent harm. Where persistent and/or repetitive skin contact is unavoidable, personnel should maintain high standards of hygiene to avoid skin disorders.

Appropriate PPE should be worn when handling rope lubricants and dressings, such as oil-resistant gloves/oil repellent barrier creams and protective clothing.

Refer to manufacturer’s safety data for the rope lubricant in use.

Obtain First Aid for any injury, however slight.

Wash thoroughly after work and before meals or toilet breaks.

Do not use solvents to remove oil from skin (e.g. paraffin) or use dirty rags when cleaning up.

Do not wear oil soaked clothing.

Do not put oily rags, tools etc. into pockets.

12.6 Cutting Wire Ropes

When cutting wire ropes, precautions that need to be taken include but are not limited to:

Note manufacturer’s instructions, particularly with regard to serving.

Prior to cutting, secure servings should be applied each side of the cut location.

IMCA SEL 012 17

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

The number of servings depends on the type of rope. If the rope is for example rotation resistant or low rotation type, or non-preformed, multi–layer or parallel closed type, at least two servings either side of the cut will be necessary. Refer to manufacturer’s instructions.

Position and/or secure the rope to cater for sudden movement by the two parts of the rope when cut, allowing for a suitable straight length of rope each side of the cut.

Cutting up to 8mm rope can be done with hand cutters, after which mechanical or hydraulic cutters are necessary. High speed abrasive disc cutters are often used. Flame cutting is not recommended unless the wire rope is being discarded. Use appropriate PPE. Be aware of danger from sparks, disc break-up and fumes.

If cutting lubricated rope, heat from the cutting method may create toxic fumes from the lubricant and/or toxic fumes or dust from material in the rope itself. Heated lubricant can also emanate from a rope and cause burns.

Ensure adequate ventilation, avoid build-up of fumes.

After cutting, the ends of the rope may need to be welded or brazed to secure the wires and strands. Refer to manufacturer’s instructions relating to the particular type of rope.

12.7 IMCA Safety Cards

IMCA pocket safety cards are useful reminders of safe working practices. Relevant cards produced at the time of publication are:

Manual handling safety guide (no. 1)

Preventing slips and trips (no. 2)

Toolbox talks (no. 3)

Lifting operations safety guide (no. 4)

Lifting equipment safety guide (no. 5)

Working at height (no. 6)

12.8 Memoranda for Ordering Wire Ropes

Manufacturers will usually provide guidance as to the expected life of their products, but such guidance needs to relate to the actual usage of the wire rope. Wire rope construction has become very sophisticated and there needs to be complete understanding between manufacturers and end users in respect to what is required from a wire rope.

Those involved with a project during the design phase, such as for example the engineers and project managers, need to assess wire rope requirements at an early stage in order to ensure compatibility of the rope for the purposes of the project.

Thus when a ‘competent person’ is referred to in this guidance it may not always be possible for it to be one person. The range of experience and knowledge required for some wire rope projects can be very wide. There is a need for both manufacturer and end-user to fully understand both the requirements and the compatibility of the ropes available. Companies can encourage manufacturers to provide the appropriate rope by early involvement, perhaps involving site visits.

The competent person in a company (see above) can advise the manufacturer of the expected environment and usage of a rope and they should work together to produce a purchase specification, with particular focus on:

description of the rope’s purpose;

the relevant classification society ;

the anticipated loads;

length, diameter and safe working load;

whether rotating or rotation resistant rope needed;

wire construction;

IMCA SEL 012 18

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

♦

fittings for the rope terminations;

the amount of sheaves and rollers that a wire rope will be rigged to pass through and over;

whether any swivel connections are needed (or should be avoided) and where;

the size and arrangement of sheave blocks and winch drums;

whether winch drums are grooved and the condition and size of the grooves;

heave compensation requirements;

the number of load cycles expected;

whether sub-sea use envisaged if so, depth, pressure, water penetration;

lubrication requirements;

environmental factors of anticipated operational area(s);

factors of safety required;

handling, transport and storage; wire ropes can delivered in a coil on a pallet, or up to 750 kg. on a simple one-use timber cross reel; up to 1500kg. on a stabilised re-usable timber cross reel; over 1500kg. on a wooden or steel reel which can also be lagged for rope protection; additional plastic or jute wrapping can be provided for sea transport or storage in a difficult environment; check with the provider for the appropriate method;

pre-tension requirements;

back tension needed when spooling on to winch drum;

winch drum and rigging – size, type and strength requirements;

documentation needed, for example: maintenance and handling instructions, actual break load certification of full rope (not just of the strands) serving instructions lubrication instructions what type of drum the rope is to be delivered on test certificates specification sheets for all items provided by the vendor (wire, sockets, drum, rigging for

drum) certificates for all items provided by the vendor(wire, sockets, drum, rigging for drum);

possibly some basic calculation of anticipated wear.

The manufacturer is likely to need this information before a reasonable estimate of life span can be given. The list is not necessarily exhaustive, but all these points need to be included at the design stage of a new vessel or at the planning stage of a new project.

IMCA SEL 012 19

13 Appendices

13.1 Example Wire Rope Utilisation Matrix

This appendix shows a typical matrix from a company manual as used to list maintenance, certification and discard criteria for various wire ropes in use. Each company may need to demonstrate its procedures by its own means; this matrix is only an example of what might be done.

IMCA SEL 012 20

Appendix 1

Example Wire Rope Utilisation Matrix

The information given in the columns of this example matrix is merely for guidance as to how a matrix might be completed and is not meant to indicate that a particular wire rope is to be used for the applications indicated.

IMCA SEL 012 21

IMC Appendix 1 – Example Wire Rope Utilisation Matrix A

SEL 012

22

Utilisation/Plant Wire Type Subsea Application Standards Maintenance (see company procedures)

Certification Procedure Discard Criteria

VLS Abandonment & Recovery Winch Wires

Rotation resistant Yes Non Man-Riding Utility

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744 DNV 1994

(Insert code to company procedure)

(Insert standard requirements for inspection periods))

As per annual examination and test results, every (enter number) years or meeting any of the criteria detailed in company procedures.

Pulling Winch Wires Umbilical Winches

Galvanised RHOL Rotation resistant

Yes NonMan-Riding Utility

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744


Non Man-Riding Tugger

Rotation resistant Yes Non Man-Riding Utility

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744 IMCA D018


Heave Compensation Systems Wires (Stumpy & Plough)

RHOL Rotation resistant

No NonMan-Riding Dynamic Load

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744


Tensioner Wires RHOL Rotation Resistant

No NonMan-Riding Dynamic Load

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744


IMC

A SEL 012

23

Utilisation/Plant Wire Type Subsea Application Standards Maintenance (see company procedures)

Certification Procedure Discard Criteria

Subsea Winch Wires

Rotation resistant galvanised

Yes NonMan-Riding Utility

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744


Guide Line Wires Rotation resistant galvanised

Yes NonMan-Riding Dynamic Load

ISO 4309 BS-6570, BS-302 BS-3578, BS-5744


Lifting/Rigging Wires RHOL Rotation resistant

No NonMan-Riding Utility

BS-1290 BS-6166 BS-6210


Towing wires To be advised by manufacturer


Mooring wires To be advised by manufacturer

API RP 21 As per annual examination and test results, every (enter number) years or meeting any of the criteria detailed in company procedures.

Lifting slings To be advised by manufacturer

BS 6210DIN EN 13414 BS 1290 1SO 8792


guidance on the management of life cycle maintenance wire ropes

Documents