Aspiring Enterprises

EQUIPMENT INSPECTION

Harness inspection and retirement

Harness retirement chart

Rope inspection and retirement

Karabiner inspection and retirement

Health and safety

Under the Health and Safety in Employment Act, employers are required to identify workplace hazards, and take reasonable steps to eliminate, isolate or reduce them. In the context of outdoor education, the organisation also has a "duty of care" extending to anyone who undertakes a course under its auspices.

This document is primarily concerned with the safety of equipment used for abseiling, climbing, and high ropes activities, and no doubt has some application to equipment used by rescue teams, as well as those working at height.


Product standards

During the last decade the European Committee for Standardisation (CEN) has produced a series of standards for climbing equipment. World-wide there is little else available in climbing equipment standards, although the UIAA (International Federation of Alpine Clubs) has long had standards for some items, such as ropes and karabiners, upon which the CEN standards are closely based.

Among other things these standards specify minimum strengths for products. In the case of harnesses a minimum strength of 15 kN (approximately 1500 kg) is required. Karabiners, slings, and quick-draws have a minimum strength of 22 kN (approximately 2200 kg).


Inspection procedures

Aside from legal obligations, most organisations wish to project a professional image, as far as possible using equipment which looks to be in good order. It is normal procedure to set up regular inspections to ensure that the equipment has not deteriorated excessively.

The CEN standard requirements and the manufacturer's rating are of course only applicable to the equipment when it is new. Having a higher level of strength when new provides insurance against degradation of the equipment by whatever process. The purpose of regular inspection and retirement procedures is to ensure that the integrity of the item is retained, and that the strength does not fall below a safe limit, say 10 or 12 kN.

The frequency of the inspection will depend on the organisation, and could be anything from daily to yearly. A register should be kept so that the inspections can be recorded, and retirement decisions noted. Numbering of each item will normally be necessary to keep track of purchase date and usage.

 
Retirement criteria

Some organisations keep records of the number of hours or days that they use particular items, or the number of abseils, etc. This is useful for making assessments of the ultra-violet light exposure an item has undergone (see below), or if there are procedures established which use that information. However, it is simplistic to assume, for example, that a harness is good for say 200 abseils, and then must be retired. What happens to it during those abseils is the important thing, and the end result could vary enormously. Much depends on the type of harness as well as the environment of use. In most cases it is better to examine the item and assess its condition.

Harness inspection and retirement

This section is concerned primarily with harnesses, but also applies to other equipment made from webbing, such as slings, quickdraws, lanyards, and strops. Generally harnesses are made from polyester webbing, though nylon is sometimes used. Slings, strops, and quickdraws are invariably made of nylon.

Webbing equipment may be retired for various reasons, which could include:

  • Age
  • Ultra-violet degradation
  • Damage by abrasion
  • Worn attachment protection
  • Corrosion of metallic components
  • Stitching damage
  • Cuts
  • Chemical damage
  • Glazed (melted) areas
  • General appearance, including dirtiness

Information sources

Most of this article is based on the author's prejudices, vague impressions, occasional tests, hearsay, and half-remembered second-hand reports from decades ago. Reliable data is hard to come by. However, the intention is to refine this article in time by incorporating the results of test programmes and overseas reports. Any additional information would be appreciated.


Ageing

To be able to use age as a retirement criterion, obviously the age has to be accurately known. Therefore record the date of purchase of all webbing equipment with the inspection records.

Retiring webbing equipment due to its age is based on the belief that polyamide (nylon) deteriorates spontaneously over time. This was true in the 1960s when nylon was new technology, but advances in processing nylon have resulted in a much more stable fibre.

As a single criterion, it is difficult to justify mandatory retirement of webbing in less than ten years. If the equipment has been kept in a dark cupboard and not used, 15 years is probably not an unreasonable time. However, in most cases UV degradation or obvious damage will force the decision before ten years is reached.

Dynamic climbing ropes should be considered differently from webbing items, as they may suffer a loss of elongation through ageing. The lower stretch may render them unsafe even if the laboratory strength is still adequate.


Ultra-violet degradation

Nylon and polyester yarns are subject to slow deterioration by the chemical effect of ultra-violet rays. The rate of deterioration varies with the type of yarn, with colour and type of dyestuffs, and the weave of the material. Normally fading of the dye is present if the webbing has had severe ultra-violet exposure.

Preliminary tests show that, though highly variable, polyester webbings lose about 10-20 % strength after the equivalent of one year in sunlight in Wellington (approximately 2000 hours), while nylon loses about 20-30 %. With these losses the materials are still more than adequately strong, but caution suggests a greater amount of exposure may be unwise.

If webbing equipment is routinely used in sunlight for several hours a day, it may be necessary to assess the likely damage resulting from this. For example, four afternoons' use per week on a sunny cliff may amount to over 3000 hours' exposure after about five years, and retirement may be wise at this time. However, if the location used is a shady gorge, then ultra-violet exposure is not an issue.


Abrasion damage

Judging by the limited testing done so far, general overall abrasion damage - wear and tear - has a greater effect on webbing strength than a single instance of acute damage, such as a significant cut on the edge of the webbing. However, if such a cut is at a critical point, such as where the webbing passes through a buckle, the situation is more serious.

Abrasion damage is particularly hard to assess, as it is difficult to quantify the amount of damage that the item has sustained. The recommended approach is to select suitably worn items of each type of equipment and define them as examples for comparison, so that an item under inspection would be rejected if it appears to be more worn than the defined example. While the decision is still arbitrary, this enables the people carrying out inspections to make judgements which are reasonably consistent from year to year and from person to person. For each type of equipment there could be two type examples: a very worn one which is the basis of comparison for retirement on this criterion alone, and one less worn, so that if an inspected harness falls between the two examples, it might be retired on other criteria.


Attachment protection

Most harnesses have some means of protecting the attachment point from wear caused by the constant rubbing of descender karabiners, etc. Usually this is a small piece of fabric or webbing. When it becomes worn through, subsequent wear takes place on the structural webbing underneath, which is weakened as a result, and can become a failure point if the wear continues.

In the case of the Adventure harness, a small square of PVC material offers initial protection. Under this is a piece of black webbing which protects the main structural webbing. Below this again is a thicker piece of blue webbing. While the PVC commonly wears through after a year or two, the webbing underneath will sustain much more wear and is unlikely to ever be worn right through. Other harnesses, though, rely solely on the PVC or other material, and should be watched carefully in this regard.


Metallic corrosion

Harness buckles are usually made from steel, or occasionally from aluminium or stainless steel. Steel buckles are protected from corrosion by electroplating, usually by zinc, though there are other possibilities, including cadmium and nickel. On the more expensive harnesses the buckles often have an additional "powder coating" applied by a spray-painting process, usually in a black colour.

Zinc plating discolours fairly rapidly, and is poor in a corrosive environment, such as sea cliffs. It should generally stand up to 10 years of ordinary use, but occasionally breaks down earlier and allows corrosion to start. If a buckle has severe rust the harness probably should be retired.


Stitching damage

Webbing equipment is always stitched together, so it seems obvious that if the stitching is damaged, the item will be weakened. However, this depends whether the weakened join is normally the weakest part of the harness. If the webbing (for example) breaks at a lower load than that particular join, then the article may not be weakened at all. This of course can be difficult to assess.

Aside from safety in the sense of strength, there is also the possibility of the item disintegrating and becoming non-functional or difficult to use.

In the case of webbing slings, the stitching may be the weakest point (although this can depend on the test method), and it's obvious that damaged stitching could produce a failure, as nothing else is holding the sling together. With harnesses an assessment is much more difficult. Classic harnesses have no critical load-bearing stitching. Adventure harnesses have never failed at stitching during testing, and all the structural stitching (four areas) is protected by not being exposed on the outside of the webbing - you can only see it on the inside. Most recreational Aspiring harnesses share this feature.

Generally stitching is robust, but if structural stitching does become significantly abraded, it is obviously a case for instant retirement, unless it can be repaired. Often this is difficult to do.


Other damage

This category is to include damage to the webbing which should not ordinarily happen; however it often does. The three possibilities are cuts, chemical damage, and melting. Each one can seriously weaken the webbing. The seriousness depends on the position; for example a burn on the very end of a buckle tail strap is of absolutely no consequence, whereas a small cut on the edge of the webbing just where the buckle usually fastens could lead to the webbing tearing there in the worst case scenario, such as severe leader fall.

Cuts are quite common, and are generally caused by a sharp edge of rock, or some other sharp object, passing across the webbing while it is being used, especially if under tension.

Melting is sometimes said to be caused by abseil devices becoming too hot and glazing the webbing. It is probably more often caused by a rope passing across the webbing during a fast abseil. If minor, it will have relatively little effect on the strength of a harness, however if there is significant damage the harness must obviously be retired.

Chemical damage is rare, as nylon and polyester are immune to most common chemicals, including detergents, lubricants, paints, solvents, and fuels. Spilling petrol on a harness will have absolutely no effect on it. However, nylon is attacked by acids of moderate strength, and polyester by alkalis, so sources of these, such as lead acid batteries and alkaline cleaners, must be identified, and care must be taken to isolate them from webbing equipment. Bear in mind that a harness made from polyester webbing may be sewn with nylon thread.


General appearance

An organisation will be judged by its equipment, so if the webbing equipment looks rough, this alone may be a suitable reason for retirement. No-one is happy putting on a harness which has the auxiliary straps frayed and tatty, even though the safety of the item may not be in doubt. A related issue is cleanness. It is good practice to wash webbing equipment occasionally, perhaps to coincide with a six-monthly or annual inspection. Use a mild soap

Retirement chart

The retirement chart below shows eight separate criteria on which a harness might be retired. Each criterion has three categories, which might loosely be termed good, satisfactory, and bad. An organisation could set up a colour coding system, in which column one is green, column two is orange or yellow, and column three is red.

It is intended that the chart be used as follows: If under any single criterion the item falls into the third column, it should be retired. If three or more assessments fall into the second column, the item be retired also. For example, a seven year old harness with a rusty buckle and wear starting in the attachment area is probably not worth retaining.

 

RETIREMENT CHART

  GREEN ORANGE RED
Age: 0-6 years 7-10 years over 10 years
UV history: up to 1500 hrs 1500-3000 hrs over 3000 hrs
Abrasion damage: minor wear moderate wear severe wear
Other damage: none minor major
Corrosion: minor moderate severe
Stitching damage: none minor severe
Attachment area: O.K. wearing worn
Appearance: used worn tatty

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Rope inspection and retirement

Climbing ropes and static ropes are extremely strong and are capable of holding a large number of short falls without major damage. On the other hand, each fall does cause some slight deterioration, and the number of falls that can be taken is finite.

Nylon rope has the following limitations:

  • The melting point is relatively low
  • It is relatively easily cut under tension
  • It is attacked by acids
  • It may lose its elongation over time

The last form of degradation shows no sign. However, if a rope has suffered an excessive number of falls, it shows blackening and severe furring of the sheath.
Use

Ropes used for climbing, caving, abseiling, rescue, or height safety must never be used for anything other than the intended purpose. The rope should not be repeatedly loaded on any one section, as it stretches at each fall and needs time to "relax" before it is loaded again. After a climbing fall the rope should be untied and the other end used for the next attempt. Fixed top-ropes should be turned around every week or so, and any accumulation of surplus sheath at the belay end should be cut off and the end re-melted.

Care

Ropes should be dried at room temperature if they become wet, and stored in a cool, dry place away from direct sunlight.

Standing on ropes must be avoided, as well as contact with sharp edges and snags, as they are relatively soft and can be easily damaged.
Maintenance

Ropes should be kept as clean as possible, so that dirt particles do not work their way into the interior of the rope. They can be washed, either by hand, or by using a tubular rope washer, or in a front-loading washing machine on a gentle cycle (the agitator in a top-loading machine is tough on ropes). Use only mild natural soaps and definitely not a bleach-based detergent. Dry-treatment ropes should be washed in water only.

Inspection

At the required inspection interval the rope should examined by passing it through the hands metre by metre and checking for the following:

  • severe blackening caused by a large number of falls on one section of the rope;
  • glazing of the sheath caused by the fibres being melted;
  • severe furring of the rope, caused by excessive falls or running the rope across rock edges under tension;
  • powdering of the fibres, caused by chemical attack;
  • excessive sheath slippage, leading to the sheath bunching at the end (due to the sheath of the rope being too loose on the core);
  • soft spots, caused by changes to the internal structure of the core, probably arising from a severe fall;
  • cutting of sheath fibres due to sharp edges, stone-fall, crampon points, or burrs on metal equipment;
  • any sign of the core showing through (rope cores are always white), caused by disruption of the sheath of a loose-sheathed rope, usually in conjunction with fibre damage as above.

Retirement

Retirement of the rope should be considered if any of the problems above are found. If damage is restricted to one area, the rope can be cut into two pieces. A "dynamic" climbing rope should be retired if the rope is more than five years old. Even unused ropes use part of their elasticity with time, which makes old ropes unsuitable for lead climbing.

In some cases ropes may be retired from lead climbing but reserved for top-roping or abseiling, if it is certain that the usage can be controlled.

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Karabiner inspection and retirement

Use of different types

Non-locking karabiners are used for primarily for climbing protection. They are not used on anchor systems, except where they are connected to a single anchor which forms a component of an anchor system, and the karabiner as well as the anchor are thereby backed up by other equipment. They are not used in belay systems or in abseiling.

Occasionally snap-links are used on cowstails (particularly in caving), but this use is only safe if there are always two cowstails connected to the anchors. Otherwise a twist-lock karabiner should be used on one cowstail.

Snap-links are also used for carrying gear, and occasionally for other uses such as on re-direction anchors in caving.

Bent-gate snap-links are designed to be easy to clip the rope to. Therefore they are used as the lower karabiner on a quickdraw, and as the karabiner on other protection (camming devices, etc). Care must be taken not to twist quickdraws, as bent-gates are as easy to unclip as they are to clip.

Plain-gate snap-links (straight-gates) are used on slings, protection, and at the top end of a quickdraw. Plain-gates may be used, with care, on anchors, if they are doubled and have the gates opposed.

If quickdraws are used on bolt hangers, the same karabiner should always be at the rope end, because burrs which develop from contact with the hanger could damage the rope.

Generally locking karabiners are used for belaying, abseiling, and anchor attachments. Screw-locks or triple-locks are used for belaying and abseiling. Twist-locks must not be used for abseiling with a figure-8 descender as they can be twisted out of the attachment eye. However they are excellent for cowstails, as they are fast to operate and are secure in this role.

Care

Karabiners must not be dropped, as they can develop fine cracks on impact. If they become wet, they should be dried before storage. Any identification markings should be confined to the gate: the body of the karabiner must not be altered.

Keep karabiners away from heat and wash salt water off to avoid corrosion. If they become dirty, wash them in warm water (30-40 degrees).
Maintenance

Very little maintenance is required for karabiners. It may be desirable to lubricate the pin and spring sparingly with a silicone-based spray lubricant occasionally. Any excess must be wiped off, as it will attract dirt, which will finish up on the ropes.

Inspection

During regular, scheduled inspections the following should be checked:

  • The gate mechanism should operate freely
  • The gate should close straight so that it cleanly engages the latch pin
  • The body of the karabiner should be free of cracks, marks and deep scratches
  • There should be no corrosion evident
  • The inside top corners of plain-gate karabiners should be checked carefully, as they may develop burrs by contact with bolt hangers
  • Locking mechanisms should operate freely
  • The sleeves of screw-lock karabiners should remain in the closed position without any free movement
  • The tangs on the end of the gate should be examined very closely for fine cracks. Some types of karabiner are prone to cracks there which can seriously weaken the karabiner

Retirement

The life of karabiners can be indefinite if they are treated well, are not damaged, and their moving parts continue to function properly. However, the possibility of invisible corrosion around the pins should be considered.

If any of the defects listed above are found, the karabiner should be retired, unless the defect can be fixed by cleaning or lubrication. Burrs on the inside corner caused by bolt hangers must be removed by filing to avoid damaging ropes. However, the amount of material removed must not exceed 10%, or the karabiner will be significantly weakened and must be retired.

Triple-lock karabiners are prone to failure of the gate mechanisms, and must not be used if they do not close and lock properly.

Any retired karabiners should be destroyed or distinctively marked.

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