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 or other materials are sometimes used. 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
Ageing
The actual lifespan of the textile equipment cannot be predicted precisely, as it is influenced by many
factors (environment of use, weather factors, storage conditions, frequency and intensity of use, etc.) but it is possible to estimate its maximum life span, which is constituted by an initial period of optimum storage and by a period of operational life. Refer to the manufacturer’s instructions to find out the operational life of your equipment. The general rule of thumb is that any soft goods should be retired after 10 years from the date of manufacture (unless stated otherwise) even with little use and optimal storage. The life span can be limited even to just one use, where it is involved in an exceptional event (hard falls or swinging falls, extreme temperatures, contact with harmful chemical agents or sharp edges, wet conditions, etc.). In case of doubts on the functioning and good condition of any equipment, do not use it and immediately contact your safety manager or the manufacturer. Webbing does deteriorate over long periods of time, so harnesses cannot be used indefinitely. If the age and/or history of your equipment is unknown, it should be removed from service.
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, and the weave of the material. Normally fading of the dye is present if the webbing has had severe ultra-violet exposure. 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 may not be not as much of 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 descenders, carabiners, slings, 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.
Metal attachment points are susceptible to corrosion, oxidization, and normal wear. Wear underneath the webbing on these attachment points can be hard to see and should be checked regularly.Â
Metallic corrosion
Harness buckles are usually made from steel, or occasionally from aluminum 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 typically stitched together, so it seems obvious that if the stitching is damaged, the item will be weakened. 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. Any notable damage to stitching should be treated as serious and constitute retirement. Stitching is susceptible to abrasion like other webbing areas but it can also be damaged by connections being loaded in unintended ways. If stitching is being pulled apart, it is also considered serious. Not all stitching is structural however, so if in doubt, contact the manufacturer.
Other damage
This category is to include damage to the webbing which should not ordinarily happen; however it often does. Three common 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 little 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. 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 or accidental contact with hot tools or industrial environments. If minor, it will have relatively little effect on the strength of a harness, however if there is significant damage the harness must be retired. 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 organization 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. Regular cleaning and maintenance will also prolong the life of the equipment.
Manufacturers may have specific criteria and documents available to assess their equipment. It is a good idea to familiarize yourself with the available information specific to your gear.