Proper care, maintenance, and inspection of climbing ropes to reduce degradation and help determine when to retire them

Abstract

The topic of care and maintenance, including inspection and testing, of climbing and safety ropes is very important to climbers and workmen who wish to avoid unsafe and possibly life-threatening situations. For this reason, the following paper examines how climbing and safety ropes degrade in various environments, and to a limited extent how they can be maintained, inspected and tested to avoid unwanted mishaps, injuries, and deaths. The main focus of this paper is the dynamic kernmantle rope used for climbing. Dynamic ropes are specially engineered and manufactured to elongate as much as 30% under loading so the kinetic energy of the climber can be slowly absorbed by the rope and thus reduce the impact at the bottom of the fall. Because these and most other ropes are used mainly outside, the primary forms of degradation/corrosion examined are abrasion, erosion, heat- and UV-aging, and accidental or inadvertent cutting. These ropes are not constantly exposed to corrosive environments as they are used while climbing then conveyed home by various means and typically stored indoors by the owner. Hence to prevent, detect, and monitor serious and suspect aging damage to ropes, storage locations, coiling techniques, and currently available testing and inspection techniques are presented. Some common inspection and testing techniques as well as at least one novel technique are presented and discussed. Currently climbers inspect for damage and defects using both tactile and visual methods by simply pulling the rope, meter by meter, through one's hand while scanning the length visually as it passes. Damage and defects are evaluated by climber experience and guesswork and noted by memory or recorded if desired. However, a major problem results because of the unique and valuable design and construction feature of these kernmantle ropes — the major load carrying core strand members are both hidden from view and protected from UV and mechanical damage by a powerful external sheath of continuous webbing. Clearly damage can occur to both the sheath and the core but finding the weakest link in the hidden core provides the major challenge. Hence this paper also examines the need for more certainty in non-destructive testing, inspection instruments, and methods of detecting, locating, and defining damages. These inspection methods will also evaluate risk degree and monitor/track defects and damage in such ropes. Two narrow ultimate goals are to find the rope's “weakest link” and to know, predict, or determine when to retire such ropes in order not to go below a certain factor of safety in use. Recognizing that much valuable work has been done to try to attain this goal and that this goal remains substantially unattained, this paper also proposes a proof testing program to evaluate the efficacy of the classic and novel testing and inspection methods. Using the proposed testing program, the ropes could be examined for internal flaws and characterized by remaining life-span with a certain factor of safety, and thus they could be used longer, more effectively, and more safely than currently possible. Some of the technical inspection and maintenance techniques suggested and discussed will relate to classical and modified methods of measuring the most informative mechanical, dimensional, physical, and viscoelastic properties along the length of these ropes.